Cargo.lock

@@ -817,14 +817,13 @@ dependencies = [
 
 [[package]]
 name = "image"
-version = "0.25.6"
+version = "0.25.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "db35664ce6b9810857a38a906215e75a9c879f0696556a39f59c62829710251a"
+checksum = "99314c8a2152b8ddb211f924cdae532d8c5e4c8bb54728e12fff1b0cd5963a10"
 dependencies = [
  "bytemuck",
  "byteorder-lite",
  "num-traits",
- "png",
 ]
 
 [[package]]
@@ -1345,14 +1344,12 @@ dependencies = [
  "haku",
  "haku2",
  "handlebars",
- "image",
  "indexmap",
  "jotdown",
  "mime_guess",
  "rand",
  "rand_chacha",
  "rayon",
- "rkgk-image-ops",
  "rusqlite",
  "serde",
  "serde_json",

Cargo.toml

@@ -6,7 +6,6 @@ members = ["crates/*"]
 haku.path = "crates/haku"
 haku2.path = "crates/haku2"
 log = "0.4.22"
-rkgk-image-ops.path = "crates/rkgk-image-ops"
 tiny-skia = { version = "0.11.4", default-features = false }
 
 [profile.dev.package.rkgk-image-ops]

crates/haku2/build.rs

@@ -6,8 +6,6 @@ use std::{
 };
 
 fn main() -> Result<(), Box<dyn Error>> {
-    println!("cargo::rerun-if-changed=build.zig");
-    println!("cargo::rerun-if-changed=build.zig.zon");
     println!("cargo::rerun-if-changed=src");
 
     let out_dir = env::var("OUT_DIR").unwrap();
@@ -60,5 +58,8 @@ fn main() -> Result<(), Box<dyn Error>> {
         panic!("zig failed to build");
     }
 
+    println!("cargo::rustc-link-search={out_dir}/zig-out/lib");
+    println!("cargo::rustc-link-lib=haku2");
+
     Ok(())
 }

crates/haku2/build.zig

@@ -12,6 +12,13 @@ pub fn build(b: *std.Build) void {
         .optimize = optimize,
         .pic = true,
     });
+    const lib = b.addStaticLibrary(.{
+        .name = "haku2",
+        .root_module = mod,
+    });
+    lib.pie = true;
+    lib.bundle_compiler_rt = true;
+    b.installArtifact(lib);
 
     const mod_wasm = b.createModule(.{
         .root_source_file = b.path("src/haku2.zig"),

crates/haku2/src/lib.rs

@@ -1,3 +1,575 @@
-/// WebAssembly code for haku2.
+use std::{
-/// haku2 is purely a client-side library, and does not have Rust bindings.
+    alloc::{self, Layout},
+    error::Error,
+    fmt::{self, Display},
+    marker::{PhantomData, PhantomPinned},
+    ptr::{self, NonNull},
+    slice,
+};
+
+use log::trace;
+
 pub static WASM: &[u8] = include_bytes!(concat!(env!("OUT_DIR"), "/zig-out/bin/haku2.wasm"));
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn __haku2_alloc(size: usize, align: usize) -> *mut u8 {
+    if let Ok(layout) = Layout::from_size_align(size, align) {
+        alloc::alloc(layout)
+    } else {
+        ptr::null_mut()
+    }
+}
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn __haku2_realloc(
+    ptr: *mut u8,
+    size: usize,
+    align: usize,
+    new_size: usize,
+) -> *mut u8 {
+    if let Ok(layout) = Layout::from_size_align(size, align) {
+        alloc::realloc(ptr, layout, new_size)
+    } else {
+        ptr::null_mut()
+    }
+}
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn __haku2_dealloc(ptr: *mut u8, size: usize, align: usize) {
+    match Layout::from_size_align(size, align) {
+        Ok(layout) => alloc::dealloc(ptr, layout),
+        Err(_) => {
+            log::error!("__haku2_dealloc: invalid layout size={size} align={align} ptr={ptr:?}")
+        }
+    }
+}
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn __haku2_log_err(
+    scope: *const u8,
+    scope_len: usize,
+    msg: *const u8,
+    len: usize,
+) {
+    let scope = String::from_utf8_lossy(slice::from_raw_parts(scope, scope_len));
+    let msg = String::from_utf8_lossy(slice::from_raw_parts(msg, len));
+    log::error!("{scope}: {msg}");
+}
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn __haku2_log_warn(
+    scope: *const u8,
+    scope_len: usize,
+    msg: *const u8,
+    len: usize,
+) {
+    let scope = String::from_utf8_lossy(slice::from_raw_parts(scope, scope_len));
+    let msg = String::from_utf8_lossy(slice::from_raw_parts(msg, len));
+    log::warn!("{scope}: {msg}");
+}
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn __haku2_log_info(
+    scope: *const u8,
+    scope_len: usize,
+    msg: *const u8,
+    len: usize,
+) {
+    let scope = String::from_utf8_lossy(slice::from_raw_parts(scope, scope_len));
+    let msg = String::from_utf8_lossy(slice::from_raw_parts(msg, len));
+    log::info!("{scope}: {msg}");
+}
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn __haku2_log_debug(
+    scope: *const u8,
+    scope_len: usize,
+    msg: *const u8,
+    len: usize,
+) {
+    let scope = String::from_utf8_lossy(slice::from_raw_parts(scope, scope_len));
+    let msg = String::from_utf8_lossy(slice::from_raw_parts(msg, len));
+    log::debug!("{scope}: {msg}");
+}
+
+#[repr(C)]
+struct ScratchC {
+    _data: (),
+    _marker: PhantomData<(*mut u8, PhantomPinned)>,
+}
+
+#[repr(C)]
+struct LimitsC {
+    _data: (),
+    _marker: PhantomData<(*mut u8, PhantomPinned)>,
+}
+
+#[repr(C)]
+struct DefsC {
+    _data: (),
+    _marker: PhantomData<(*mut u8, PhantomPinned)>,
+}
+
+#[repr(C)]
+struct VmC {
+    _data: (),
+    _marker: PhantomData<(*mut u8, PhantomPinned)>,
+}
+
+extern "C" {
+    fn haku2_scratch_new(max: usize) -> *mut ScratchC;
+    fn haku2_scratch_destroy(scratch: *mut ScratchC);
+    fn haku2_scratch_reset(scratch: *mut ScratchC);
+
+    fn haku2_limits_new() -> *mut LimitsC;
+    fn haku2_limits_destroy(limits: *mut LimitsC);
+    fn haku2_limits_set_stack_capacity(limits: *mut LimitsC, new: usize);
+    fn haku2_limits_set_call_stack_capacity(limits: *mut LimitsC, new: usize);
+
+    fn haku2_defs_parse(
+        defs_string: *const u8,
+        defs_len: usize,
+        tags_string: *const u8,
+        tags_len: usize,
+    ) -> *mut DefsC;
+    fn haku2_defs_destroy(defs: *mut DefsC);
+
+    fn haku2_vm_new() -> *mut VmC;
+    fn haku2_vm_destroy(vm: *mut VmC);
+    fn haku2_vm_reset(
+        vm: *mut VmC,
+        s: *mut ScratchC,
+        defs: *const DefsC,
+        limits: *const LimitsC,
+        fuel: u32,
+    );
+    fn haku2_vm_run_main(
+        vm: *mut VmC,
+        scratch: *mut ScratchC,
+        code: *const u8,
+        code_len: usize,
+        local_count: u8,
+    ) -> bool;
+    fn haku2_vm_has_cont(vm: *const VmC) -> bool;
+    fn haku2_vm_is_dotter(vm: *const VmC) -> bool;
+    fn haku2_vm_run_dotter(
+        vm: *mut VmC,
+        scratch: *mut ScratchC,
+        from_x: f32,
+        from_y: f32,
+        to_x: f32,
+        to_y: f32,
+        num: f32,
+    ) -> bool;
+    fn haku2_vm_exception_len(vm: *const VmC) -> usize;
+    fn haku2_vm_exception_render(vm: *const VmC, buffer: *mut u8);
+
+    // improper_ctypes is emitted for `*mut CanvasC`, which is an opaque {} on the Zig side and
+    // therefore FFI-safe.
+    #[expect(improper_ctypes)]
+    fn haku2_render(vm: *mut VmC, canvas: *mut CanvasC, max_depth: usize) -> bool;
+}
+
+#[derive(Debug)]
+pub struct Scratch {
+    raw: NonNull<ScratchC>,
+}
+
+impl Scratch {
+    pub fn new(max: usize) -> Scratch {
+        // SAFETY: haku2_scratch_new does not have any safety invariants.
+        let raw = NonNull::new(unsafe { haku2_scratch_new(max) }).expect("out of memory");
+        trace!("Scratch::new -> {raw:?}");
+        Scratch { raw }
+    }
+
+    pub fn reset(&mut self) {
+        trace!("Scratch::reset({:?})", self.raw);
+        // SAFETY: The pointer passed is non-null.
+        unsafe {
+            haku2_scratch_reset(self.raw.as_ptr());
+        }
+    }
+}
+
+impl Drop for Scratch {
+    fn drop(&mut self) {
+        trace!("Scratch::drop({:?})", self.raw);
+        // SAFETY: The pointer passed is non-null.
+        unsafe {
+            haku2_scratch_destroy(self.raw.as_ptr());
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct LimitsSpec {
+    pub stack_capacity: usize,
+    pub call_stack_capacity: usize,
+}
+
+#[derive(Debug)]
+pub struct Limits {
+    raw: NonNull<LimitsC>,
+}
+
+// SAFETY: Limits's backing storage is only modified on creation.
+// Changing the limits requires creating a new instance.
+unsafe impl Send for Limits {}
+unsafe impl Sync for Limits {}
+
+impl Limits {
+    pub fn new(spec: LimitsSpec) -> Self {
+        // SAFETY: haku2_limits_new has no safety invariants.
+        let limits = NonNull::new(unsafe { haku2_limits_new() }).expect("out of memory");
+
+        // SAFETY: The following functions are called on a valid pointer.
+        unsafe {
+            haku2_limits_set_stack_capacity(limits.as_ptr(), spec.stack_capacity);
+            haku2_limits_set_call_stack_capacity(limits.as_ptr(), spec.call_stack_capacity);
+        }
+
+        Self { raw: limits }
+    }
+}
+
+impl Drop for Limits {
+    fn drop(&mut self) {
+        // SAFETY: The pointer passed is non-null.
+        unsafe {
+            haku2_limits_destroy(self.raw.as_ptr());
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct Defs {
+    raw: NonNull<DefsC>,
+}
+
+// SAFETY: Defs' backing storage is not modified after creation.
+unsafe impl Send for Defs {}
+unsafe impl Sync for Defs {}
+
+impl Defs {
+    pub fn parse(defs: &str, tags: &str) -> Self {
+        Self {
+            raw: NonNull::new(unsafe {
+                haku2_defs_parse(defs.as_ptr(), defs.len(), tags.as_ptr(), tags.len())
+            })
+            .expect("out of memory"),
+        }
+    }
+}
+
+impl Drop for Defs {
+    fn drop(&mut self) {
+        // SAFETY: The pointer passed is non-null.
+        unsafe {
+            haku2_defs_destroy(self.raw.as_ptr());
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct Code {
+    defs: Defs,
+    main_chunk: Vec<u8>,
+    main_local_count: u8,
+}
+
+impl Code {
+    /// Creates a new instance of `Code` from a valid vector of bytes.
+    ///
+    /// # Safety
+    ///
+    /// This does not perform any validation, and there is no way to perform such
+    /// validation before constructing this. The bytecode must simply be valid, which is the case
+    /// for bytecode emitted directly by the compiler.
+    ///
+    /// Untrusted bytecode should never ever be loaded under any circumstances.
+    pub unsafe fn new(defs: Defs, main_chunk: Vec<u8>, main_local_count: u8) -> Self {
+        Self {
+            defs,
+            main_chunk,
+            main_local_count,
+        }
+    }
+}
+
+/// A VM that is ready to run and loaded with valid bytecode.
+#[derive(Debug)]
+pub struct Vm {
+    scratch: Scratch,
+    code: Code,
+    limits: Limits,
+    inner: VmInner,
+}
+
+#[derive(Debug)]
+pub enum Cont<'vm> {
+    None,
+    Dotter(ContDotter<'vm>),
+}
+
+#[derive(Debug)]
+pub struct ContDotter<'vm> {
+    vm: &'vm mut Vm,
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct Dotter {
+    pub from: (f32, f32),
+    pub to: (f32, f32),
+    pub num: f32,
+}
+
+impl Vm {
+    pub fn new(scratch: Scratch, code: Code, limits: Limits) -> Self {
+        // SAFETY: haku2_vm_new cannot fail.
+        // Do note that this returns an uninitialized VM, which must be reset before use.
+        let raw = NonNull::new(unsafe { haku2_vm_new() }).expect("out of memory");
+        trace!("Vm::new({scratch:?}, {code:?}, {limits:?}) -> {raw:?}");
+        Self {
+            // SAFETY:
+            // - Ownership of scratch is passed to the VM, so the VM cannot outlive the scratch space.
+            //   - The VM never gives you any references back, so this is safe to do.
+            // - The other arguments are only borrowed immutably for construction.
+            inner: VmInner { raw },
+            scratch,
+            code,
+            limits,
+        }
+    }
+
+    /// Begin running code. This makes the VM enter a "trampoline" state: after this call, you may
+    /// proceed to call `cont` as many times as it returns a value other than [`Cont::None`].
+    ///
+    /// Calling `begin` again during this process will work correctly, and result in another
+    /// continuation being stack on top of the old one---at the expense of a stack slot.
+    pub fn begin(&mut self, fuel: u32) -> Result<(), Exception> {
+        trace!("Vm::begin({self:?}, {fuel})");
+        self.scratch.reset();
+        let ok = unsafe {
+            haku2_vm_reset(
+                self.inner.raw.as_ptr(),
+                self.scratch.raw.as_ptr(),
+                self.code.defs.raw.as_ptr(),
+                self.limits.raw.as_ptr(),
+                fuel,
+            );
+            haku2_vm_run_main(
+                self.inner.raw.as_ptr(),
+                self.scratch.raw.as_ptr(),
+                self.code.main_chunk.as_ptr(),
+                self.code.main_chunk.len(),
+                self.code.main_local_count,
+            )
+        };
+        if ok {
+            Ok(())
+        } else {
+            Err(self.exception().expect("missing exception after !ok"))
+        }
+    }
+
+    /// Returns whether `cont()` can be called to run the next continuation.
+    pub fn has_cont(&self) -> bool {
+        unsafe { haku2_vm_has_cont(self.inner.raw.as_ptr()) }
+    }
+
+    fn is_dotter(&self) -> bool {
+        // SAFETY: The pointer is valid.
+        unsafe { haku2_vm_is_dotter(self.inner.raw.as_ptr()) }
+    }
+
+    /// Returns how the VM should continue executing after the previous execution.
+    pub fn cont(&mut self) -> Cont<'_> {
+        match () {
+            _ if self.is_dotter() => Cont::Dotter(ContDotter { vm: self }),
+            _ => Cont::None,
+        }
+    }
+
+    /// Renders the current scribble on top of the stack.
+    /// If the value on top is not a scribble, throws an exception.
+    ///
+    /// The rendering is performed by calling into the [`Canvas`] trait.
+    pub fn render(&mut self, canvas: &mut dyn Canvas, max_depth: usize) -> Result<(), Exception> {
+        let mut wrapped = CanvasC { inner: canvas };
+        let ok = unsafe { haku2_render(self.inner.raw.as_ptr(), &mut wrapped, max_depth) };
+        if ok {
+            Ok(())
+        } else {
+            Err(self.exception().expect("missing exception after !ok"))
+        }
+    }
+
+    /// Render the current exception out to a string.
+    /// Returns `None` if there's no exception.
+    pub fn exception(&self) -> Option<Exception> {
+        // SAFETY: The pointer passed to this function is valid.
+        let len = unsafe { haku2_vm_exception_len(self.inner.raw.as_ptr()) };
+        if len == 0 {
+            return None;
+        }
+
+        let mut buffer = vec![0; len];
+        // SAFETY: The length of the buffer is as indicated by haku2_vm_exception_len.
+        unsafe {
+            haku2_vm_exception_render(self.inner.raw.as_ptr(), buffer.as_mut_ptr());
+        }
+        Some(Exception {
+            message: String::from_utf8_lossy(&buffer).into_owned(),
+        })
+    }
+
+    /// Take the `Scratch` out of the VM for reuse in another one.
+    /// The scratch memory will be reset (no bytes will be consumed.)
+    pub fn into_scratch(self) -> Scratch {
+        trace!("Vm::into_scratch({self:?})");
+        let Vm {
+            mut scratch,
+            code: _,
+            inner: _,
+            limits: _,
+        } = self;
+        scratch.reset();
+        scratch
+    }
+}
+
+impl ContDotter<'_> {
+    pub fn run(self, dotter: &Dotter) -> Result<(), Exception> {
+        trace!("ContDotter::run({self:?}, {dotter:?})");
+
+        let Dotter {
+            from: (from_x, from_y),
+            to: (to_x, to_y),
+            num,
+        } = *dotter;
+
+        let ok = unsafe {
+            haku2_vm_run_dotter(
+                self.vm.inner.raw.as_ptr(),
+                self.vm.scratch.raw.as_ptr(),
+                from_x,
+                from_y,
+                to_x,
+                to_y,
+                num,
+            )
+        };
+        if ok {
+            Ok(())
+        } else {
+            Err(self.vm.exception().expect("missing exception after !ok"))
+        }
+    }
+}
+
+#[derive(Debug)]
+struct VmInner {
+    raw: NonNull<VmC>,
+}
+
+impl Drop for VmInner {
+    fn drop(&mut self) {
+        trace!("VmInner::drop({:?})", self.raw);
+        // SAFETY: The pointer passed is non-null.
+        unsafe {
+            haku2_vm_destroy(self.raw.as_ptr());
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct Exception {
+    message: String,
+}
+
+impl Display for Exception {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.message)
+    }
+}
+
+impl Error for Exception {}
+
+/// Marker for the VM to indicate that the rendering did not go down correctly.
+/// If this is encountered, it throws an exception and aborts rendering.
+#[derive(Debug)]
+pub struct RenderError;
+
+pub trait Canvas {
+    fn begin(&mut self) -> Result<(), RenderError>;
+    fn line(&mut self, x1: f32, y1: f32, x2: f32, y2: f32) -> Result<(), RenderError>;
+    fn rectangle(&mut self, x: f32, y: f32, width: f32, height: f32) -> Result<(), RenderError>;
+    fn circle(&mut self, x: f32, y: f32, r: f32) -> Result<(), RenderError>;
+    fn fill(&mut self, r: u8, g: u8, b: u8, a: u8) -> Result<(), RenderError>;
+    fn stroke(&mut self, r: u8, g: u8, b: u8, a: u8, thickness: f32) -> Result<(), RenderError>;
+}
+
+// SAFETY NOTE: I'm not sure the ownership model for this is quite correct.
+// Given how the &mut's ownership flows through the Zig side of the code, it _should_ be fine,
+// but I'm not an unsafe code expert to say this is the case for sure.
+
+#[repr(C)]
+struct CanvasC<'a> {
+    inner: &'a mut dyn Canvas,
+}
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn __haku2_canvas_begin(c: *mut CanvasC) -> bool {
+    let c = &mut *c;
+    c.inner.begin().is_ok()
+}
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn __haku2_canvas_line(
+    c: *mut CanvasC,
+    x1: f32,
+    y1: f32,
+    x2: f32,
+    y2: f32,
+) -> bool {
+    let c = &mut *c;
+    c.inner.line(x1, y1, x2, y2).is_ok()
+}
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn __haku2_canvas_rectangle(
+    c: *mut CanvasC,
+    x: f32,
+    y: f32,
+    width: f32,
+    height: f32,
+) -> bool {
+    let c = &mut *c;
+    c.inner.rectangle(x, y, width, height).is_ok()
+}
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn __haku2_canvas_circle(c: *mut CanvasC, x: f32, y: f32, r: f32) -> bool {
+    let c = &mut *c;
+    c.inner.circle(x, y, r).is_ok()
+}
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn __haku2_canvas_fill(c: *mut CanvasC, r: u8, g: u8, b: u8, a: u8) -> bool {
+    let c = &mut *c;
+    c.inner.fill(r, g, b, a).is_ok()
+}
+
+#[unsafe(no_mangle)]
+unsafe extern "C" fn __haku2_canvas_stroke(
+    c: *mut CanvasC,
+    r: u8,
+    g: u8,
+    b: u8,
+    a: u8,
+    thickness: f32,
+) -> bool {
+    let c = &mut *c;
+    c.inner.stroke(r, g, b, a, thickness).is_ok()
+}

crates/rkgk-image-ops/src/lib.rs

@@ -1,36 +1,14 @@
-#[derive(Debug, Clone, Copy)]
+pub fn add(left: u64, right: u64) -> u64 {
-pub struct Image<'a> {
+    left + right
-    pub width: u32,
-    pub height: u32,
-    pub data: &'a [u8],
 }
 
-#[derive(Debug)]
+#[cfg(test)]
-pub struct ImageMut<'a> {
+mod tests {
-    pub width: u32,
+    use super::*;
-    pub height: u32,
-    pub data: &'a mut [u8],
-}
 
-impl ImageMut<'_> {
+    #[test]
-    pub fn composite_alpha(&mut self, src: &Image<'_>) {
+    fn it_works() {
-        assert_eq!(self.width, src.width);
+        let result = add(2, 2);
-        assert_eq!(self.height, src.height);
+        assert_eq!(result, 4);
-
-        fn fixp_mul(a: u8, b: u8) -> u8 {
-            ((a as u16 * b as u16 + 255) >> 8) as u8
-        }
-
-        fn alpha_blend(dst: u8, src: u8, alpha: u8) -> u8 {
-            fixp_mul(src, alpha) + fixp_mul(dst, 255 - alpha)
-        }
-
-        for (dst_rgba, src_rgba) in self.data.chunks_exact_mut(4).zip(src.data.chunks_exact(4)) {
-            let src_alpha = src_rgba[3];
-            dst_rgba[0] = alpha_blend(dst_rgba[0], src_rgba[0], src_alpha);
-            dst_rgba[1] = alpha_blend(dst_rgba[1], src_rgba[1], src_alpha);
-            dst_rgba[2] = alpha_blend(dst_rgba[2], src_rgba[2], src_alpha);
-            dst_rgba[3] = alpha_blend(dst_rgba[3], src_rgba[3], src_alpha);
-        }
     }
 }

crates/rkgk/Cargo.toml

@@ -18,13 +18,11 @@ haku.workspace = true
 haku2.workspace = true
 handlebars = "6.0.0"
 indexmap = { version = "2.4.0", features = ["serde"] }
-image = { version = "0.25.6", default-features = false, features = ["png"] }
 jotdown = "0.5.0"
 mime_guess = "2.0.5"
 rand = "0.8.5"
 rand_chacha = "0.3.1"
 rayon = "1.10.0"
-rkgk-image-ops.workspace = true
 rusqlite = { version = "0.32.1", features = ["bundled"] }
 serde = { version = "1.0.206", features = ["derive"] }
 serde_json = "1.0.124"

crates/rkgk/src/api/wall.rs

@@ -1,6 +1,5 @@
 use std::{
     collections::{HashSet, VecDeque},
-    io::Cursor,
     sync::Arc,
 };
 
@@ -13,14 +12,10 @@ use axum::{
 };
 use base64::Engine;
 use eyre::{bail, Context, OptionExt};
-use image::{DynamicImage, ImageFormat, ImageReader};
-use rayon::iter::{IntoParallelRefIterator, ParallelIterator as _};
-use rkgk_image_ops::{Image, ImageMut};
 use schema::{
     ChunkInfo, Error, LoginRequest, LoginResponse, Notify, Online, Request, Version, WallInfo,
 };
 use serde::{Deserialize, Serialize};
-use tiny_skia::{IntSize, Pixmap};
 use tokio::{
     select,
     sync::{mpsc, oneshot},
@@ -28,14 +23,13 @@ use tokio::{
 use tracing::{error, info, info_span, instrument};
 
 use crate::{
+    haku::{Haku, Limits},
     login::{self, database::LoginStatus},
+    schema::Vec2,
     wall::{
-        self,
+        self, auto_save::AutoSave, chunk_images::ChunkImages, chunk_iterator::ChunkIterator,
-        auto_save::AutoSave,
+        database::ChunkDataPair, render::ChunkCanvas, ChunkPosition, Interaction, JoinError,
-        chunk_images::{ChunkImages, LoadedChunks},
+        SessionHandle, UserInit, Wall, WallId,
-        chunk_iterator::ChunkIterator,
-        database::ChunkDataPair,
-        ChunkPosition, JoinError, SessionHandle, UserInit, Wall, WallId,
     },
 };
 
@@ -173,7 +167,6 @@ async fn fallible_websocket(api: Arc<Api>, ws: &mut WebSocket) -> eyre::Result<(
         wall_info: WallInfo {
             chunk_size: open_wall.wall.settings().chunk_size,
             paint_area: open_wall.wall.settings().paint_area,
-            max_edit_size: open_wall.wall.settings().max_edit_size,
             online: users_online,
             haku_limits: api.config.haku.clone(),
         },
@@ -202,6 +195,8 @@ async fn fallible_websocket(api: Arc<Api>, ws: &mut WebSocket) -> eyre::Result<(
         open_wall.chunk_images,
         open_wall.auto_save,
         session_handle,
+        api.config.haku.clone(),
+        login_request.init.brush,
     )
     .await?
     .event_loop(ws)
@@ -224,16 +219,9 @@ struct SessionLoop {
     pending_images: VecDeque<ChunkDataPair>,
 }
 
-struct EditWithData {
-    chunk: ChunkPosition,
-    data_type: String,
-    data: Vec<u8>,
-}
-
 enum RenderCommand {
-    Edit {
+    Interact {
-        chunks: LoadedChunks,
+        interactions: Vec<Interaction>,
-        edits: Vec<EditWithData>,
         done: oneshot::Sender<()>,
     },
 }
@@ -245,12 +233,26 @@ impl SessionLoop {
         chunk_images: Arc<ChunkImages>,
         auto_save: Arc<AutoSave>,
         handle: SessionHandle,
+        limits: Limits,
+        brush: String,
     ) -> eyre::Result<Self> {
         // Limit how many commands may come in _pretty darn hard_ because these can be really
         // CPU-intensive.
         // If this ends up dropping commands - it's your fault for trying to DoS my server!
         let (render_commands_tx, render_commands_rx) = mpsc::channel(1);
 
+        let thread_ready = {
+            let (done_tx, done_rx) = oneshot::channel();
+            render_commands_tx
+                .send(RenderCommand::Interact {
+                    interactions: vec![Interaction::SetBrush { brush }],
+                    done: done_tx,
+                })
+                .await
+                .unwrap();
+            done_rx
+        };
+
         // We spawn our own thread so as not to clog the tokio blocking thread pool with our
         // rendering shenanigans.
         std::thread::Builder::new()
@@ -261,11 +263,13 @@ impl SessionLoop {
                     let _span =
                         info_span!("render_thread", ?wall_id, session_id = ?handle.session_id)
                             .entered();
-                    render_thread(wall, render_commands_rx)
+                    Self::render_thread(wall, limits, render_commands_rx)
                 }
             })
             .context("could not spawn render thread")?;
 
+        thread_ready.await?;
+
         Ok(Self {
             wall_id,
             wall,
@@ -306,49 +310,51 @@ impl SessionLoop {
             }
 
             Request::Wall { wall_event } => {
-                match wall_event {
+                match &wall_event {
+                    // This match only concerns itself with drawing-related events to offload
+                    // all the evaluation and drawing work to this session's drawing thread.
                     wall::EventKind::Join { .. }
                     | wall::EventKind::Leave
-                    | wall::EventKind::Cursor { .. }
+                    | wall::EventKind::Cursor { .. } => (),
-                    | wall::EventKind::Interact { .. } => {
-                        self.wall.event(wall::Event {
-                            session_id: self.handle.session_id,
-                            kind: wall_event,
-                        });
-                    }
 
-                    wall::EventKind::Edit { edits } => {
+                    wall::EventKind::Interact { interactions } => {
-                        let chunk_data = recv_expect(ws).await?.into_data();
+                        let (done_tx, done_rx) = oneshot::channel();
-
-                        let mut edits_with_data = Vec::with_capacity(edits.len());
-                        for edit in edits {
-                            if let Some(data) = chunk_data
-                                .get(edit.data_offset..edit.data_offset + edit.data_length)
-                            {
-                                edits_with_data.push(EditWithData {
-                                    chunk: edit.chunk,
-                                    data_type: edit.data_type,
-                                    data: data.to_owned(),
-                                });
-                            }
-                        }
 
                         let chunks_to_modify: Vec<_> =
-                            edits_with_data.iter().map(|edit| edit.chunk).collect();
+                            chunks_to_modify(self.wall.settings(), interactions)
+                                .into_iter()
+                                .collect();
                         match self.chunk_images.load(chunks_to_modify.clone()).await {
-                            Ok(chunks) => {
+                            Ok(_) => {
-                                let (done_tx, done_rx) = oneshot::channel();
+                                if interactions
-                                // Wait during contention.
+                                    .iter()
-                                // We don't want to drop any edits, as that would result in
+                                    .any(|i| matches!(i, Interaction::SetBrush { .. }))
-                                // graphical glitches and desyncs.
+                                {
+                                    // SetBrush is an important event, so we wait for the render thread
+                                    // to unload.
                                     _ = self
                                         .render_commands_tx
-                                    .send(RenderCommand::Edit {
+                                        .send(RenderCommand::Interact {
-                                        chunks,
+                                            interactions: interactions.clone(),
-                                        edits: edits_with_data,
                                             done: done_tx,
                                         })
                                         .await;
+                                } else {
+                                    // If there is no SetBrush, there's no need to wait, so we fire events
+                                    // blindly. If the thread's not okay with that... well, whatever.
+                                    // That's your issue for making a really slow brush.
+                                    let send_result =
+                                        self.render_commands_tx.try_send(RenderCommand::Interact {
+                                            interactions: interactions.clone(),
+                                            done: done_tx,
+                                        });
+                                    if send_result.is_err() {
+                                        info!(
+                                            ?interactions,
+                                            "render thread is overloaded, dropping interaction request"
+                                        );
+                                    }
+                                }
 
                                 let auto_save = Arc::clone(&self.auto_save);
                                 tokio::spawn(async move {
@@ -360,6 +366,11 @@ impl SessionLoop {
                         }
                     }
                 }
+
+                self.wall.event(wall::Event {
+                    session_id: self.handle.session_id,
+                    kind: wall_event,
+                });
             }
 
             Request::Viewport {
@@ -435,82 +446,132 @@ impl SessionLoop {
 
         Ok(())
     }
-}
 
-fn render_thread(wall: Arc<Wall>, mut commands: mpsc::Receiver<RenderCommand>) {
+    fn render_thread(wall: Arc<Wall>, limits: Limits, mut commands: mpsc::Receiver<RenderCommand>) {
+        let mut haku = Haku::new(limits);
+        let mut brush_ok = false;
+        let mut current_render_area = RenderArea::default();
+
         while let Some(command) = commands.blocking_recv() {
-        let RenderCommand::Edit {
+            let RenderCommand::Interact { interactions, done } = command;
-            chunks,
-            edits,
-            done,
-        } = command;
 
-        let positions: Vec<_> = edits.iter().map(|edit| edit.chunk).collect();
+            let mut queue = VecDeque::from(interactions);
-
+            while let Some(interaction) = queue.pop_front() {
-        let chunk_size = wall.settings().chunk_size;
+                if let Some(render_area) = render_area(wall.settings(), &interaction) {
-        let chunk_int_size = IntSize::from_wh(chunk_size, chunk_size).unwrap();
+                    current_render_area = render_area;
-        info!("decoding edits");
-        let decoded = edits
-            .par_iter()
-            .flat_map(|edit| match &edit.data_type[..] {
-                "image/png" => {
-                    let mut reader = ImageReader::new(Cursor::new(&edit.data));
-                    reader.set_format(ImageFormat::Png);
-                    reader.limits({
-                        let mut limits = image::Limits::no_limits();
-                        limits.max_image_width = Some(chunk_size);
-                        limits.max_image_height = Some(chunk_size);
-                        limits
-                    });
-
-                    reader
-                        .decode()
-                        .context("image decoding failed")
-                        .and_then(|image| {
-                            if image.width() != chunk_size || image.height() != chunk_size {
-                                bail!(
-                                    "{:?} image size {}x{} does not match chunk size {}",
-                                    edit.chunk,
-                                    image.width(),
-                                    image.height(),
-                                    chunk_size
-                                );
-                            }
-                            Ok(image)
-                        })
-                        .map(DynamicImage::into_rgba8)
-                        .inspect_err(|err| info!(?edit.chunk, ?err, "error while decoding"))
-                        .ok()
-                        .and_then(|image| Pixmap::from_vec(image.into_raw(), chunk_int_size))
                 }
 
-                _ => {
+                match interaction {
-                    info!(edit.data_type, "unknown data type");
+                    Interaction::SetBrush { brush } => {
-                    None
+                        brush_ok = haku.set_brush(&brush).is_ok();
-                }
-            })
-            .collect::<Vec<Pixmap>>();
-        info!("edits decoded");
-
-        let mut chunks_locked = Vec::new();
-        for position in &positions {
-            chunks_locked.push(chunks.chunks[position].blocking_lock());
                     }
 
-        for (mut dst_chunk, src_pixmap) in chunks_locked.into_iter().zip(decoded) {
+                    Interaction::Dotter { from, to, num } => {
-            let mut dst = ImageMut {
+                        if brush_ok {
-                width: chunk_size,
+                            jumpstart_trampoline(&mut haku);
-                height: chunk_size,
+                            match haku.cont() {
-                data: dst_chunk.pixmap.data_mut(),
+                                haku2::Cont::Dotter(dotter) => match dotter.run(&haku2::Dotter {
-            };
+                                    from: (from.x, from.y),
-            let src = Image {
+                                    to: (to.x, to.y),
-                width: chunk_size,
+                                    num,
-                height: chunk_size,
+                                }) {
-                data: src_pixmap.data(),
+                                    Ok(_) => (),
-            };
+                                    Err(err) => error!("exception while running dotter: {err}"),
-            dst.composite_alpha(&src);
+                                },
+                                other => error!("received Dotter interaction when a {other:?} continuation was next")
+                            }
+                        }
+                    }
+
+                    Interaction::Scribble => {
+                        match haku.cont() {
+                            haku2::Cont::None => {
+                                draw_to_chunks(&wall, current_render_area, &mut haku);
+                            }
+                            _ => error!("tried to draw a scribble with an active continuation"),
+                        }
+
+                        current_render_area = RenderArea::default();
+                    }
+                }
             }
 
             _ = done.send(());
         }
     }
+}
+
+#[derive(Debug, Clone, Copy, Default)]
+struct RenderArea {
+    top_left: Vec2,
+    bottom_right: Vec2,
+}
+
+fn render_area(wall_settings: &wall::Settings, interaction: &Interaction) -> Option<RenderArea> {
+    match interaction {
+        Interaction::Dotter { from, to, .. } => {
+            let half_paint_area = wall_settings.paint_area as f32 / 2.0;
+            Some(RenderArea {
+                top_left: Vec2::new(from.x - half_paint_area, from.y - half_paint_area),
+                bottom_right: Vec2::new(to.x + half_paint_area, to.y + half_paint_area),
+            })
+        }
+        Interaction::SetBrush { .. } | Interaction::Scribble => None,
+    }
+}
+
+fn chunks_to_modify(
+    wall_settings: &wall::Settings,
+    interactions: &[Interaction],
+) -> HashSet<ChunkPosition> {
+    let mut chunks = HashSet::new();
+
+    for interaction in interactions {
+        // NOTE: This is mostly a tentative overestimation, and can result in more chunks being
+        // marked as needing autosave than will be touched in reality.
+        // It's better to play safe in this case than lose data.
+        if let Some(render_area) = render_area(wall_settings, interaction) {
+            let top_left_chunk = wall_settings.chunk_at(render_area.top_left);
+            let bottom_right_chunk = wall_settings.chunk_at_ceil(render_area.bottom_right);
+            for chunk_y in top_left_chunk.y..bottom_right_chunk.y {
+                for chunk_x in top_left_chunk.x..bottom_right_chunk.x {
+                    chunks.insert(ChunkPosition::new(chunk_x, chunk_y));
+                }
+            }
+        }
+    }
+
+    chunks
+}
+
+fn jumpstart_trampoline(haku: &mut Haku) {
+    if !haku.has_cont() {
+        if let Err(e) = haku.eval_brush() {
+            error!("eval_brush2 exception: {e:?}");
+        }
+    }
+}
+
+#[instrument(skip(wall, vm))]
+fn draw_to_chunks(wall: &Wall, render_area: RenderArea, vm: &mut Haku) {
+    let settings = wall.settings();
+
+    let chunk_size = settings.chunk_size as f32;
+
+    let top_left_chunk = settings.chunk_at(render_area.top_left);
+    let bottom_right_chunk = settings.chunk_at_ceil(render_area.bottom_right);
+
+    for chunk_y in top_left_chunk.y..bottom_right_chunk.y {
+        for chunk_x in top_left_chunk.x..bottom_right_chunk.x {
+            let x = f32::floor(-chunk_x as f32 * chunk_size);
+            let y = f32::floor(-chunk_y as f32 * chunk_size);
+            let chunk_ref = wall.get_or_create_chunk(ChunkPosition::new(chunk_x, chunk_y));
+            let mut chunk = chunk_ref.blocking_lock();
+            chunk.touch();
+            let mut canvas = ChunkCanvas::new(&mut chunk).translated(x, y);
+            if let Err(e) = vm.render(&mut canvas, 256) {
+                info!(chunk_x, chunk_y, "drawing failed: {e}");
+            }
+        }
+    }
+}

crates/rkgk/src/api/wall/schema.rs

@@ -42,7 +42,6 @@ pub struct Online {
 pub struct WallInfo {
     pub chunk_size: u32,
     pub paint_area: u32,
-    pub max_edit_size: usize,
     pub haku_limits: crate::haku::Limits,
     pub online: Vec<Online>,
 }

crates/rkgk/src/haku.rs

@@ -1,6 +1,20 @@
 //! High-level wrapper for Haku.
 
+// TODO: This should be used as the basis for haku-wasm as well as haku tests in the future to
+// avoid duplicating code.
+
+use eyre::{bail, Context, OptionExt};
+use haku::{
+    ast::Ast,
+    bytecode::{Chunk, Defs, DefsImage, DefsLimits},
+    compiler::{Compiler, Source},
+    lexer::{lex, Lexer},
+    parser::{self, Parser, ParserLimits},
+    source::SourceCode,
+    token::Lexis,
+};
 use serde::{Deserialize, Serialize};
+use tracing::{info, instrument, Level};
 
 #[derive(Debug, Clone, Deserialize, Serialize)]
 // NOTE: For serialization, this struct does _not_ have serde(rename_all = "camelCase") on it,
@@ -22,3 +36,123 @@ pub struct Limits {
     pub memory: usize,
     pub render_max_depth: usize,
 }
+
+pub struct Haku {
+    limits: Limits,
+
+    defs: Defs,
+    defs_image: DefsImage,
+
+    vm: Option<haku2::Vm>,
+}
+
+impl Haku {
+    pub fn new(limits: Limits) -> Self {
+        let defs = Defs::new(&DefsLimits {
+            max_defs: limits.max_defs,
+            max_tags: limits.max_tags,
+        });
+
+        let defs_image = defs.image();
+
+        Self {
+            limits,
+            defs,
+            defs_image,
+            vm: None,
+        }
+    }
+
+    fn reset(&mut self) {
+        self.defs.restore_image(&self.defs_image);
+    }
+
+    #[instrument(skip(self, code), err)]
+    pub fn set_brush(&mut self, code: &str) -> eyre::Result<()> {
+        info!(?code);
+
+        self.reset();
+
+        let code = SourceCode::limited_len(code, self.limits.max_source_code_len)
+            .ok_or_eyre("source code is too long")?;
+
+        let mut lexer = Lexer::new(Lexis::new(self.limits.max_tokens), code);
+        lex(&mut lexer)?;
+
+        let mut parser = Parser::new(
+            &lexer.lexis,
+            &ParserLimits {
+                max_events: self.limits.max_parser_events,
+            },
+        );
+        parser::toplevel(&mut parser);
+        let mut ast = Ast::new(self.limits.ast_capacity);
+        let (root, parser_diagnostics) = parser.into_ast(&mut ast)?;
+
+        let src = Source { code, ast: &ast };
+
+        let mut chunk = Chunk::new(self.limits.chunk_capacity)
+            .expect("chunk capacity must be representable as a 16-bit number");
+        let mut compiler = Compiler::new(&mut self.defs, &mut chunk);
+        haku::compiler::compile_expr(&mut compiler, &src, root)
+            .context("failed to compile the chunk")?;
+        let closure_spec = compiler.closure_spec();
+
+        if !lexer.diagnostics.is_empty()
+            || !parser_diagnostics.is_empty()
+            || !compiler.diagnostics.is_empty()
+        {
+            info!(?lexer.diagnostics, ?parser_diagnostics, ?compiler.diagnostics, "diagnostics were emitted");
+            bail!("diagnostics were emitted");
+        }
+
+        let scratch = self
+            .vm
+            .take()
+            .map(|vm| vm.into_scratch())
+            .unwrap_or_else(|| haku2::Scratch::new(self.limits.memory));
+        let defs = haku2::Defs::parse(&self.defs.serialize_defs(), &self.defs.serialize_tags());
+        // SAFETY: The code is fresh out of the compiler oven, so it is guaranteed to be valid.
+        // Well, more or less. There may lurk bugs.
+        let code = unsafe { haku2::Code::new(defs, chunk.bytecode, closure_spec.local_count) };
+        let limits = haku2::Limits::new(haku2::LimitsSpec {
+            stack_capacity: self.limits.stack_capacity,
+            call_stack_capacity: self.limits.call_stack_capacity,
+        });
+        self.vm = Some(haku2::Vm::new(scratch, code, limits));
+
+        info!("brush set successfully");
+
+        Ok(())
+    }
+
+    #[instrument(skip(self), err(level = Level::INFO))]
+    pub fn eval_brush(&mut self) -> eyre::Result<()> {
+        let vm = self
+            .vm
+            .as_mut()
+            .ok_or_eyre("brush is not compiled and ready to be used")?;
+        vm.begin(self.limits.fuel as u32)
+            .context("an exception occurred during begin()")?;
+        Ok(())
+    }
+
+    #[instrument(skip(self, canvas, max_depth), err(level = Level::INFO))]
+    pub fn render(&mut self, canvas: &mut dyn haku2::Canvas, max_depth: usize) -> eyre::Result<()> {
+        let vm = self
+            .vm
+            .as_mut()
+            .ok_or_eyre("VM is not ready for rendering")?;
+        vm.render(canvas, max_depth)
+            .context("exception while rendering")?;
+        Ok(())
+    }
+
+    pub fn has_cont(&mut self) -> bool {
+        self.vm.as_mut().expect("VM is not started").has_cont()
+    }
+
+    pub fn cont(&mut self) -> haku2::Cont<'_> {
+        self.vm.as_mut().expect("VM is not started").cont()
+    }
+}

crates/rkgk/src/wall.rs

@@ -23,6 +23,7 @@ pub mod broker;
 pub mod chunk_images;
 pub mod chunk_iterator;
 pub mod database;
+pub mod render;
 
 pub use broker::Broker;
 pub use database::Database;
@@ -134,7 +135,6 @@ pub struct Settings {
     pub max_sessions: usize,
     pub paint_area: u32,
     pub chunk_size: u32,
-    pub max_edit_size: usize,
 }
 
 impl Settings {
@@ -208,7 +208,6 @@ pub enum EventKind {
 
     Cursor { position: Vec2 },
     Interact { interactions: Vec<Interaction> },
-    Edit { edits: Vec<Edit> },
 }
 
 #[derive(Debug, Clone, Deserialize, Serialize)]
@@ -223,15 +222,6 @@ pub enum Interaction {
     Scribble,
 }
 
-#[derive(Debug, Clone, Deserialize, Serialize)]
-#[serde(tag = "kind", rename_all = "camelCase")]
-pub struct Edit {
-    pub chunk: ChunkPosition,
-    pub data_type: String, // media type of `data`
-    pub data_offset: usize,
-    pub data_length: usize,
-}
-
 #[derive(Debug, Clone, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct Online {
@@ -264,16 +254,11 @@ impl Wall {
         self.chunks.get(&at).map(|chunk| Arc::clone(&chunk))
     }
 
-    pub fn get_or_create_chunk(&self, at: ChunkPosition) -> (Arc<Mutex<Chunk>>, bool) {
+    pub fn get_or_create_chunk(&self, at: ChunkPosition) -> Arc<Mutex<Chunk>> {
-        let entry = self.chunks.entry(at);
+        Arc::clone(&self.chunks.entry(at).or_insert_with(|| {
-        let created = matches!(&entry, dashmap::Entry::Vacant(_));
-        (
-            Arc::clone(&entry.or_insert_with(|| {
             info!(?at, "chunk created");
             Arc::new(Mutex::new(Chunk::new(self.settings.chunk_size)))
-            })),
+        }))
-            created,
-        )
     }
 
     pub fn join(self: &Arc<Self>, session: Session) -> Result<SessionHandle, JoinError> {
@@ -306,9 +291,9 @@ impl Wall {
     pub fn event(&self, event: Event) {
         if let Some(mut session) = self.sessions.get_mut(&event.session_id) {
             match &event.kind {
-                // Events that get broadcasted through the wall such that all clients get them.
+                // Join and Leave are events that only get broadcasted through the wall such that
-                // No need to react in any way.
+                // all users get them. We don't need to react to them in any way.
-                EventKind::Join { .. } | EventKind::Leave | EventKind::Interact { .. } => (),
+                EventKind::Join { .. } | EventKind::Leave => (),
 
                 EventKind::Cursor { position } => {
                     session.cursor = Some(*position);
@@ -316,7 +301,7 @@ impl Wall {
 
                 // Drawing events are handled by the owner session's thread to make drawing as
                 // parallel as possible.
-                EventKind::Edit { .. } => {}
+                EventKind::Interact { .. } => {}
             }
         }
 

crates/rkgk/src/wall/auto_save.rs

@@ -1,4 +1,8 @@
-use std::{collections::HashSet, sync::Arc, time::Duration};
+use std::{
+    collections::{HashMap, HashSet},
+    sync::Arc,
+    time::{Duration, Instant},
+};
 
 use serde::{Deserialize, Serialize};
 use tokio::{

crates/rkgk/src/wall/chunk_images.rs

@@ -1,13 +1,13 @@
-use std::{collections::HashMap, sync::Arc, time::Instant};
+use std::{sync::Arc, time::Instant};
 
 use dashmap::DashSet;
 use eyre::Context;
 use rayon::iter::{IntoParallelIterator, IntoParallelRefIterator, ParallelIterator};
 use tiny_skia::{IntSize, Pixmap};
-use tokio::sync::{mpsc, oneshot, Mutex};
+use tokio::sync::{mpsc, oneshot};
 use tracing::{error, info, instrument};
 
-use super::{database::ChunkDataPair, Chunk, ChunkPosition, Database, Wall};
+use super::{database::ChunkDataPair, ChunkPosition, Database, Wall};
 
 /// Chunk image encoding, caching, and storage service.
 pub struct ChunkImages {
@@ -28,13 +28,6 @@ pub struct NewlyEncoded {
     pub last_mod: Instant,
 }
 
-/// Chunks loaded from a load operation.
-/// Returned from loads to keep reference counts above 1, such that the chunks are not garbage
-/// collected while they're loaded and being operated on.
-pub struct LoadedChunks {
-    pub chunks: HashMap<ChunkPosition, Arc<Mutex<Chunk>>>,
-}
-
 enum Command {
     Encode {
         chunks: Vec<ChunkPosition>,
@@ -43,7 +36,7 @@ enum Command {
 
     Load {
         chunks: Vec<ChunkPosition>,
-        reply: oneshot::Sender<eyre::Result<LoadedChunks>>,
+        reply: oneshot::Sender<eyre::Result<()>>,
     },
 }
 
@@ -75,7 +68,7 @@ impl ChunkImages {
         rx.await.ok().unwrap_or_default()
     }
 
-    pub async fn load(&self, chunks: Vec<ChunkPosition>) -> eyre::Result<LoadedChunks> {
+    pub async fn load(&self, chunks: Vec<ChunkPosition>) -> eyre::Result<()> {
         let (tx, rx) = oneshot::channel();
         self.commands_tx
             .send(Command::Load { chunks, reply: tx })
@@ -163,29 +156,20 @@ impl ChunkImageLoop {
         _ = reply.send(EncodeResult { data: all, new });
     }
 
-    async fn load_inner(self: Arc<Self>, chunks: Vec<ChunkPosition>) -> eyre::Result<LoadedChunks> {
+    async fn load_inner(self: Arc<Self>, mut chunks: Vec<ChunkPosition>) -> eyre::Result<()> {
-        // Reference all the chunks that we need, such that they're not garbage collected
+        // Skip already loaded chunks.
-        // during loading.
+        chunks.retain(|&position| !self.wall.has_chunk(position));
-        let mut chunk_refs = HashMap::new();
+        if chunks.is_empty() {
-        let mut positions_to_load = vec![];
+            return Ok(());
-        for &position in &chunks {
-            let (chunk, created) = self.wall.get_or_create_chunk(position);
-            chunk_refs.insert(position, chunk);
-
-            if created {
-                positions_to_load.push(position);
-            }
         }
 
-        if positions_to_load.is_empty() {
+        info!(?chunks, "to load");
-            return Ok(LoadedChunks { chunks: chunk_refs });
-        }
 
-        info!(?positions_to_load, "to load");
+        let chunks = self.db.read_chunks(chunks.clone()).await?;
 
-        let to_load = self.db.read_chunks(positions_to_load.clone()).await?;
+        let chunks2 = chunks.clone();
         let decoded = tokio::task::spawn_blocking(move || {
-            to_load
+            chunks2
                 .par_iter()
                 .flat_map(|ChunkDataPair { position, data }| {
                     webp::Decoder::new(data)
@@ -209,25 +193,30 @@ impl ChunkImageLoop {
         .await
         .context("failed to decode chunks from the database")?;
 
-        let mut chunk_locks = Vec::with_capacity(decoded.len());
+        // I don't know yet if locking all the chunks is a good idea at this point.
-        for (position, _) in &decoded {
+        // I can imagine contended chunks having some trouble loading.
-            let chunk_ref = &chunk_refs[position];
+        let chunk_arcs: Vec<_> = decoded
-            chunk_locks.push(chunk_ref.lock().await);
+            .iter()
+            .map(|(position, _)| self.wall.get_or_create_chunk(*position))
+            .collect();
+        let mut chunk_refs = Vec::with_capacity(chunk_arcs.len());
+        for arc in &chunk_arcs {
+            chunk_refs.push(arc.lock().await);
         }
 
-        info!(num = ?chunk_locks.len(), "replacing chunks' pixmaps");
+        info!(num = ?chunk_refs.len(), "replacing chunks' pixmaps");
-        for ((_, pixmap), mut chunk) in decoded.into_iter().zip(chunk_locks) {
+        for ((_, pixmap), mut chunk) in decoded.into_iter().zip(chunk_refs) {
             chunk.pixmap = pixmap;
         }
 
-        Ok(LoadedChunks { chunks: chunk_refs })
+        Ok(())
     }
 
     #[instrument(skip(self, reply))]
     async fn load(
         self: Arc<Self>,
         chunks: Vec<ChunkPosition>,
-        reply: oneshot::Sender<eyre::Result<LoadedChunks>>,
+        reply: oneshot::Sender<eyre::Result<()>>,
     ) {
         _ = reply.send(self.load_inner(chunks).await);
     }

crates/rkgk/src/wall/database.rs

@@ -1,4 +1,4 @@
-use std::{convert::identity, path::PathBuf, sync::Arc};
+use std::{convert::identity, path::PathBuf, sync::Arc, time::Instant};
 
 use eyre::Context;
 use rusqlite::Connection;
@@ -88,8 +88,6 @@ pub fn start(settings: Settings) -> eyre::Result<Database> {
 
     info!("initial setup");
 
-    let version: u32 = db.pragma_query_value(None, "user_version", |x| x.get(0))?;
-
     db.execute_batch(
         r#"
             PRAGMA application_id = 0x726B6757; -- rkgW
@@ -174,31 +172,10 @@ pub fn start(settings: Settings) -> eyre::Result<Database> {
         ),
     )?;
 
-    // Migrations
-
-    if version < 1 {
-        info!("migrate v1: add max_edit_size");
-        db.execute_batch(
-            r#"
-                PRAGMA user_version = 1;
-                ALTER TABLE t_wall_settings ADD COLUMN max_edit_size INTEGER;
-            "#,
-        )?;
-        db.execute(
-            r#"
-                UPDATE OR IGNORE t_wall_settings
-                SET max_edit_size = ?;
-            "#,
-            (settings.default_wall_settings.max_edit_size,),
-        )?;
-    }
-
-    // Set up access thread
-
     let wall_settings = db.query_row(
         r#"
             SELECT
-            max_chunks, max_sessions, paint_area, chunk_size, max_edit_size
+            max_chunks, max_sessions, paint_area, chunk_size
             FROM t_wall_settings;
         "#,
         (),
@@ -208,7 +185,6 @@ pub fn start(settings: Settings) -> eyre::Result<Database> {
                 max_sessions: row.get(1)?,
                 paint_area: row.get(2)?,
                 chunk_size: row.get(3)?,
-                max_edit_size: row.get(4)?,
             })
         },
     )?;

crates/rkgk/src/wall/render.rs

@@ -0,0 +1,113 @@
+//! Implementation of a haku2 canvas based on tiny-skia.
+
+use std::mem;
+
+use tiny_skia::{
+    BlendMode, Color, FillRule, LineCap, Paint, PathBuilder, Shader, Stroke, Transform,
+};
+
+use super::Chunk;
+
+pub struct ChunkCanvas<'c> {
+    chunk: &'c mut Chunk,
+    transform: Transform,
+    pb: PathBuilder,
+}
+
+impl<'c> ChunkCanvas<'c> {
+    pub fn new(chunk: &'c mut Chunk) -> Self {
+        Self {
+            chunk,
+            transform: Transform::identity(),
+            pb: PathBuilder::new(),
+        }
+    }
+
+    pub fn translated(mut self, x: f32, y: f32) -> Self {
+        self.transform = self.transform.post_translate(x, y);
+        self
+    }
+}
+
+impl haku2::Canvas for ChunkCanvas<'_> {
+    fn begin(&mut self) -> Result<(), haku2::RenderError> {
+        self.pb.clear();
+        Ok(())
+    }
+
+    fn line(&mut self, x1: f32, y1: f32, x2: f32, y2: f32) -> Result<(), haku2::RenderError> {
+        self.pb.move_to(x1, y1);
+        self.pb.line_to(x2, y2);
+        Ok(())
+    }
+
+    fn rectangle(
+        &mut self,
+        x: f32,
+        y: f32,
+        width: f32,
+        height: f32,
+    ) -> Result<(), haku2::RenderError> {
+        if let Some(rect) = tiny_skia::Rect::from_xywh(x, y, width, height) {
+            self.pb.push_rect(rect);
+        }
+        Ok(())
+    }
+
+    fn circle(&mut self, x: f32, y: f32, r: f32) -> Result<(), haku2::RenderError> {
+        self.pb.push_circle(x, y, r);
+        Ok(())
+    }
+
+    fn fill(&mut self, r: u8, g: u8, b: u8, a: u8) -> Result<(), haku2::RenderError> {
+        let pb = mem::take(&mut self.pb);
+        if let Some(path) = pb.finish() {
+            let paint = Paint {
+                shader: Shader::SolidColor(Color::from_rgba8(r, g, b, a)),
+                ..default_paint()
+            };
+            self.chunk
+                .pixmap
+                .fill_path(&path, &paint, FillRule::EvenOdd, self.transform, None);
+        }
+        Ok(())
+    }
+
+    fn stroke(
+        &mut self,
+        r: u8,
+        g: u8,
+        b: u8,
+        a: u8,
+        thickness: f32,
+    ) -> Result<(), haku2::RenderError> {
+        let pb = mem::take(&mut self.pb);
+        if let Some(path) = pb.finish() {
+            let paint = Paint {
+                shader: Shader::SolidColor(Color::from_rgba8(r, g, b, a)),
+                ..default_paint()
+            };
+            self.chunk.pixmap.stroke_path(
+                &path,
+                &paint,
+                &Stroke {
+                    width: thickness,
+                    line_cap: LineCap::Round,
+                    ..Default::default()
+                },
+                self.transform,
+                None,
+            );
+        }
+        Ok(())
+    }
+}
+
+fn default_paint() -> Paint<'static> {
+    Paint {
+        shader: Shader::SolidColor(Color::BLACK),
+        blend_mode: BlendMode::SourceOver,
+        anti_alias: false,
+        force_hq_pipeline: false,
+    }
+}

rkgk.toml

@@ -48,11 +48,6 @@ chunk_size = 168
 # can produce.
 paint_area = 504
 
-# Maximum size of a single edit, in chunks.
-# You don't want to make this _too_ large, otherwise the client will try to allocate too many
-# chunks at once. Way more than WebAssembly's 4GiB address space can handle.
-max_edit_size = 256
-
 [wall_broker.auto_save]
 
 # How often should modified chunks be saved to the database.

static/brush-box.js

@@ -318,7 +318,7 @@ export class BrushBox extends HTMLElement {
         if (id == null) {
             // Save a new preset.
             id = `user/${randomId()}`;
-            console.info("saving new brush", id);
+            console.log("saving new brush", id);
             this.userPresets.push({
                 id,
                 name,
@@ -327,7 +327,7 @@ export class BrushBox extends HTMLElement {
         } else {
             // Overwrite an existing one.
             let preset = this.userPresets.find((p) => p.id == id);
-            console.info("overwriting existing brush", preset);
+            console.log("overwriting existing brush", preset);
             preset.code = code;
         }
         this.saveUserPresets();

static/canvas-renderer.js

@@ -1,6 +1,6 @@
-import { listen, Pool } from "rkgk/framework.js";
+import { listen } from "rkgk/framework.js";
 import { Viewport } from "rkgk/viewport.js";
-import { Wall, chunkKey } from "rkgk/wall.js";
+import { Wall } from "rkgk/wall.js";
 
 class CanvasRenderer extends HTMLElement {
     viewport = new Viewport();
@@ -196,8 +196,7 @@ class CanvasRenderer extends HTMLElement {
 
         console.debug("initialized atlas allocator", this.atlasAllocator);
 
-        this.batches = [];
+        this.chunksThisFrame = new Map();
-        this.batchPool = new Pool();
 
         console.debug("GL error state", this.gl.getError());
 
@@ -295,18 +294,13 @@ class CanvasRenderer extends HTMLElement {
 
         this.#collectChunksThisFrame();
 
-        for (let batch of this.batches) {
+        for (let [i, chunks] of this.chunksThisFrame) {
-            for (let [i, chunks] of batch) {
             let atlas = this.atlasAllocator.atlases[i];
             this.gl.bindTexture(this.gl.TEXTURE_2D, atlas.id);
 
             this.#resetRectBuffer();
             for (let chunk of chunks) {
-                    let { i, allocation } = this.getChunkAllocation(
+                let { i, allocation } = this.getChunkAllocation(chunk.x, chunk.y);
-                        chunk.layerId,
-                        chunk.x,
-                        chunk.y,
-                    );
                 let atlas = this.atlasAllocator.atlases[i];
                 this.#pushRect(
                     chunk.x * this.wall.chunkSize,
@@ -323,27 +317,8 @@ class CanvasRenderer extends HTMLElement {
         }
     }
 
-        // TODO: This is a nice debug view.
+    getChunkAllocation(chunkX, chunkY) {
-        // There should be a switch to it somewhere in the app.
+        let key = Wall.chunkKey(chunkX, chunkY);
-        /*
-            let x = 0;
-            let y = 0;
-            for (let atlas of this.atlasAllocator.atlases) {
-                this.#resetRectBuffer();
-                this.gl.bindTexture(this.gl.TEXTURE_2D, atlas.id);
-                this.#pushRect(x, y, atlas.textureSize, atlas.textureSize, 0, 0, 1, 1);
-                this.#drawRects();
-                if (x > atlas.textureSize * 16) {
-                    y += atlas.textureSize;
-                    x = 0;
-                }
-                x += atlas.textureSize;
-            }
-        */
-    }
-
-    getChunkAllocation(layerId, chunkX, chunkY) {
-        let key = `${layerId}/${chunkKey(chunkX, chunkY)}`;
         if (this.chunkAllocations.has(key)) {
             return this.chunkAllocations.get(key);
         } else {
@@ -353,55 +328,37 @@ class CanvasRenderer extends HTMLElement {
         }
     }
 
-    deallocateChunks(layer) {
-        for (let chunkKey of layer.chunks.keys()) {
-            let key = `${layer.id}/${chunkKey}`;
-            if (this.chunkAllocations.has(key)) {
-                let allocation = this.chunkAllocations.get(key);
-                this.atlasAllocator.dealloc(allocation);
-                this.chunkAllocations.delete(key);
-            }
-        }
-    }
-
     #collectChunksThisFrame() {
-        for (let batch of this.batches) {
+        // NOTE: Not optimal that we don't preserve the arrays anyhow; it would be better if we
-            batch.clear();
+        // preserved the allocations.
-            this.batchPool.free(batch);
+        this.chunksThisFrame.clear();
-        }
-        this.batches.splice(0, this.batches.length);
 
         let visibleRect = this.viewport.getVisibleRect(this.getWindowSize());
         let left = Math.floor(visibleRect.x / this.wall.chunkSize);
         let top = Math.floor(visibleRect.y / this.wall.chunkSize);
         let right = Math.ceil((visibleRect.x + visibleRect.width) / this.wall.chunkSize);
         let bottom = Math.ceil((visibleRect.y + visibleRect.height) / this.wall.chunkSize);
-
-        for (let layer of this.wall.layers) {
-            let batch = this.batchPool.alloc(Map);
         for (let chunkY = top; chunkY < bottom; ++chunkY) {
             for (let chunkX = left; chunkX < right; ++chunkX) {
-                    let chunk = layer.getChunk(chunkX, chunkY);
+                let chunk = this.wall.getChunk(chunkX, chunkY);
                 if (chunk != null) {
                     if (chunk.renderDirty) {
-                            this.#updateChunkTexture(layer, chunkX, chunkY);
+                        this.#updateChunkTexture(chunkX, chunkY);
                         chunk.renderDirty = false;
                     }
 
-                        let allocation = this.getChunkAllocation(layer.id, chunkX, chunkY);
+                    let allocation = this.getChunkAllocation(chunkX, chunkY);
 
-                        let array = batch.get(allocation.i);
+                    let array = this.chunksThisFrame.get(allocation.i);
                     if (array == null) {
                         array = [];
-                            batch.set(allocation.i, array);
+                        this.chunksThisFrame.set(allocation.i, array);
                     }
 
-                        array.push({ layerId: layer.id, x: chunkX, y: chunkY });
+                    array.push({ x: chunkX, y: chunkY });
                 }
             }
         }
-            this.batches.push(batch);
-        }
     }
 
     #resetRectBuffer() {
@@ -438,9 +395,9 @@ class CanvasRenderer extends HTMLElement {
         this.gl.drawArraysInstanced(this.gl.TRIANGLES, 0, 6, this.uboRectsNum);
     }
 
-    #updateChunkTexture(layer, chunkX, chunkY) {
+    #updateChunkTexture(chunkX, chunkY) {
-        let allocation = this.getChunkAllocation(layer.id, chunkX, chunkY);
+        let allocation = this.getChunkAllocation(chunkX, chunkY);
-        let chunk = layer.getChunk(chunkX, chunkY);
+        let chunk = this.wall.getChunk(chunkX, chunkY);
         this.atlasAllocator.upload(this.gl, allocation, chunk.pixmap);
     }
 
@@ -517,10 +474,6 @@ class CanvasRenderer extends HTMLElement {
             }
         }
     }
-
-    commitInteraction() {
-        this.dispatchEvent(new Event(".commitInteraction"));
-    }
 }
 
 customElements.define("rkgk-canvas-renderer", CanvasRenderer);
@@ -560,7 +513,6 @@ class InteractEvent extends Event {
 
             if (event.type == "mouseup" && event.button == 0) {
                 // Break the loop.
-                this.canvasRenderer.commitInteraction();
                 return;
             }
         })();
@@ -624,10 +576,6 @@ class Atlas {
         return this.free.pop();
     }
 
-    dealloc(xy) {
-        this.free.push(xy);
-    }
-
     upload(gl, { x, y }, pixmap) {
         gl.bindTexture(gl.TEXTURE_2D, this.id);
         gl.texSubImage2D(
@@ -673,11 +621,6 @@ class AtlasAllocator {
         return { i, allocation };
     }
 
-    dealloc({ i, allocation }) {
-        let atlas = this.atlases[i];
-        atlas.dealloc(allocation);
-    }
-
     upload(gl, { i, allocation }, pixmap) {
         this.atlases[i].upload(gl, allocation, pixmap);
     }

static/framework.js

@@ -54,24 +54,6 @@ export function debounce(time, fn) {
     };
 }
 
-export class Pool {
-    constructor() {
-        this.pool = [];
-    }
-
-    alloc(ctor) {
-        if (this.pool.length > 0) {
-            return this.pool.pop();
-        } else {
-            return new ctor();
-        }
-    }
-
-    free(obj) {
-        this.pool.push(obj);
-    }
-}
-
 export class SaveData {
     constructor(prefix) {
         this.prefix = `rkgk.${prefix}`;

static/index.css

@@ -778,8 +778,6 @@ rkgk-connection-status {
 /* Context menu */
 
 rkgk-context-menu-space {
-    z-index: var(--z-modal);
-
     pointer-events: none;
 
     & > rkgk-context-menu {

static/index.js

@@ -192,7 +192,7 @@ function readUrl(urlString) {
         }
     });
 
-    let sendViewportUpdate = debounce(updateInterval / 4, () => {
+    let sendViewportUpdate = debounce(updateInterval, () => {
         let visibleRect = canvasRenderer.getVisibleChunkRect();
         session.sendViewport(visibleRect);
     });
@@ -213,12 +213,7 @@ function readUrl(urlString) {
                 let blob = chunkData.slice(info.offset, info.offset + info.length, "image/webp");
                 updatePromises.push(
                     createImageBitmap(blob).then((bitmap) => {
-                        let chunk = wall.mainLayer.getOrCreateChunk(
+                        let chunk = wall.getOrCreateChunk(info.position.x, info.position.y);
-                            info.position.x,
-                            info.position.y,
-                        );
-                        if (chunk == null) return;
-
                         chunk.ctx.globalCompositeOperation = "copy";
                         chunk.ctx.drawImage(bitmap, 0, 0);
                         chunk.syncToPixmap();
@@ -235,7 +230,7 @@ function readUrl(urlString) {
         }
     });
 
-    let reportCursor = debounce(updateInterval, (x, y) => session.sendCursor(x, y));
+    let reportCursor = debounce(updateInterval, (x, y) => session.sendCursor(x, y), console.log);
     canvasRenderer.addEventListener(".cursor", async (event) => {
         reportCursor(event.x, event.y);
     });
@@ -253,38 +248,12 @@ function readUrl(urlString) {
     canvasRenderer.addEventListener(".interact", async (event) => {
         if (!currentUser.haku.ok) return;
 
-        let layer = currentUser.getScratchLayer(wall);
         let result = await currentUser.haku.evalBrush(
-            selfController(interactionQueue, wall, layer, event),
+            selfController(interactionQueue, wall, event),
         );
         brushEditor.renderHakuResult(result);
     });
 
-    canvasRenderer.addEventListener(".commitInteraction", async () => {
-        let scratchLayer = currentUser.commitScratchLayer(wall);
-        if (scratchLayer == null) return;
-
-        canvasRenderer.deallocateChunks(scratchLayer);
-        let edits = await scratchLayer.toEdits();
-        scratchLayer.destroy();
-
-        let editRecords = [];
-        let dataParts = [];
-        let cursor = 0;
-        for (let edit of edits) {
-            editRecords.push({
-                chunk: edit.chunk,
-                dataType: edit.data.type,
-                dataOffset: cursor,
-                dataLength: edit.data.size,
-            });
-            dataParts.push(edit.data);
-            cursor += edit.data.size;
-        }
-
-        session.sendEdit(editRecords, new Blob(dataParts));
-    });
-
     canvasRenderer.addEventListener(".viewportUpdate", () => reticleRenderer.render());
     canvasRenderer.addEventListener(".viewportUpdateEnd", () =>
         updateUrl(session, canvasRenderer.viewport),

static/online-users.js

@@ -1,6 +1,5 @@
 import { ContKind, Haku } from "rkgk/haku.js";
 import { renderToChunksInArea, dotterRenderArea } from "rkgk/painter.js";
-import { Layer } from "rkgk/wall.js";
 
 export class User {
     nickname = "";
@@ -10,22 +9,19 @@ export class User {
     isBrushOk = false;
     simulation = null;
 
-    scratchLayer = null;
-
     constructor(wallInfo, nickname) {
         this.nickname = nickname;
         this.haku = new Haku(wallInfo.hakuLimits);
     }
 
     destroy() {
-        console.info("destroying user", this.nickname);
         this.haku.destroy();
     }
 
     setBrush(brush) {
         console.groupCollapsed("setBrush", this.nickname);
         let compileResult = this.haku.setBrush(brush);
-        console.info("compiling brush complete", compileResult);
+        console.log("compiling brush complete", compileResult);
         console.groupEnd();
 
         this.isBrushOk = compileResult.status == "ok";
@@ -36,14 +32,14 @@ export class User {
     renderBrushToChunks(wall, x, y) {
         console.groupCollapsed("renderBrushToChunks", this.nickname);
         let result = this.painter.renderBrushToWall(this.haku, x, y, wall);
-        console.info("rendering brush to chunks complete");
+        console.log("rendering brush to chunks complete");
         console.groupEnd();
 
         return result;
     }
 
     simulate(wall, interactions) {
-        console.group("simulate", this.nickname);
+        console.group("simulate");
         for (let interaction of interactions) {
             if (interaction.kind == "setBrush") {
                 this.simulation = null;
@@ -52,7 +48,7 @@ export class User {
 
             if (this.isBrushOk) {
                 if (this.simulation == null) {
-                    console.info("no simulation -- beginning brush");
+                    console.log("no simulation -- beginning brush");
                     this.simulation = { renderArea: { left: 0, top: 0, right: 0, bottom: 0 } };
                     this.haku.beginBrush();
                 }
@@ -71,13 +67,13 @@ export class User {
 
                 if (interaction.kind == "scribble" && this.#expectContKind(ContKind.Scribble)) {
                     renderToChunksInArea(
-                        this.getScratchLayer(wall),
+                        wall,
                         this.simulation.renderArea,
                         (pixmap, translationX, translationY) => {
                             return this.haku.contScribble(pixmap, translationX, translationY);
                         },
                     );
-                    console.info("ended simulation");
+                    console.log("ended simulation");
                     this.simulation = null;
                 }
             }
@@ -104,34 +100,6 @@ export class User {
             memoryMax: wallInfo.hakuLimits.memory,
         };
     }
-
-    getScratchLayer(wall) {
-        if (this.scratchLayer == null) {
-            this.scratchLayer = wall.addLayer(
-                new Layer({
-                    name: `scratch ${this.nickname}`,
-                    chunkSize: wall.chunkSize,
-                    chunkLimit: wall.maxEditSize,
-                }),
-            );
-        }
-        return this.scratchLayer;
-    }
-
-    // Returns the scratch layer committed to the wall, so that the caller may do additional
-    // processing with the completed layer (i.e. send to the server.)
-    // The layer has to be .destroy()ed once you're done working with it.
-    commitScratchLayer(wall) {
-        if (this.scratchLayer != null) {
-            wall.mainLayer.compositeAlpha(this.scratchLayer);
-            wall.removeLayer(this.scratchLayer);
-            let scratchLayer = this.scratchLayer;
-            this.scratchLayer = null;
-            return scratchLayer;
-        } else {
-            console.error("commitScratchLayer without an active scratch layer", this.nickname);
-        }
-    }
 }
 
 export class OnlineUsers extends EventTarget {

static/painter.js

@@ -1,20 +1,10 @@
 import { listen } from "rkgk/framework.js";
 
-function numChunksInRectangle(rect, chunkSize) {
+function* chunksInRectangle(left, top, right, bottom, chunkSize) {
-    let leftChunk = Math.floor(rect.left / chunkSize);
+    let leftChunk = Math.floor(left / chunkSize);
-    let topChunk = Math.floor(rect.top / chunkSize);
+    let topChunk = Math.floor(top / chunkSize);
-    let rightChunk = Math.ceil(rect.right / chunkSize);
+    let rightChunk = Math.ceil(right / chunkSize);
-    let bottomChunk = Math.ceil(rect.bottom / chunkSize);
+    let bottomChunk = Math.ceil(bottom / chunkSize);
-    let numX = rightChunk - leftChunk;
-    let numY = bottomChunk - topChunk;
-    return numX * numY;
-}
-
-function* chunksInRectangle(rect, chunkSize) {
-    let leftChunk = Math.floor(rect.left / chunkSize);
-    let topChunk = Math.floor(rect.top / chunkSize);
-    let rightChunk = Math.ceil(rect.right / chunkSize);
-    let bottomChunk = Math.ceil(rect.bottom / chunkSize);
     for (let chunkY = topChunk; chunkY < bottomChunk; ++chunkY) {
         for (let chunkX = leftChunk; chunkX < rightChunk; ++chunkX) {
             yield [chunkX, chunkY];
@@ -22,13 +12,17 @@ function* chunksInRectangle(rect, chunkSize) {
     }
 }
 
-export function renderToChunksInArea(layer, renderArea, renderToPixmap) {
+export function renderToChunksInArea(wall, renderArea, renderToPixmap) {
-    for (let [chunkX, chunkY] of chunksInRectangle(renderArea, layer.chunkSize)) {
+    for (let [chunkX, chunkY] of chunksInRectangle(
-        let chunk = layer.getOrCreateChunk(chunkX, chunkY);
+        renderArea.left,
-        if (chunk == null) continue;
+        renderArea.top,
-
+        renderArea.right,
-        let translationX = -chunkX * layer.chunkSize;
+        renderArea.bottom,
-        let translationY = -chunkY * layer.chunkSize;
+        wall.chunkSize,
+    )) {
+        let chunk = wall.getOrCreateChunk(chunkX, chunkY);
+        let translationX = -chunkX * wall.chunkSize;
+        let translationY = -chunkY * wall.chunkSize;
         let result = renderToPixmap(chunk.pixmap, translationX, translationY);
         chunk.markModified();
         if (result.status != "ok") return result;
@@ -47,19 +41,13 @@ export function dotterRenderArea(wall, dotter) {
     };
 }
 
-export function selfController(interactionQueue, wall, layer, event) {
+export function selfController(interactionQueue, wall, event) {
     let renderArea = null;
     return {
         async runScribble(renderToPixmap) {
             interactionQueue.push({ kind: "scribble" });
             if (renderArea != null) {
-                let numChunksToRender = numChunksInRectangle(renderArea, layer.chunkSize);
+                return renderToChunksInArea(wall, renderArea, renderToPixmap);
-                let result = renderToChunksInArea(layer, renderArea, renderToPixmap);
-                if (!layer.canFitNewChunks(numChunksToRender)) {
-                    console.debug("too many chunks rendered; committing interaction early");
-                    event.earlyCommitInteraction();
-                }
-                return result;
             } else {
                 console.debug("render area is empty, nothing will be rendered");
             }

static/session.js

@@ -266,17 +266,6 @@ class Session extends EventTarget {
         });
     }
 
-    sendEdit(edits, data) {
-        this.#sendJson({
-            request: "wall",
-            wallEvent: {
-                event: "edit",
-                edits,
-            },
-        });
-        this.ws.send(data);
-    }
-
     sendInteraction(interactions) {
         this.#sendJson({
             request: "wall",

static/wall.js

@@ -9,10 +9,6 @@ export class Chunk {
         this.renderDirty = false;
     }
 
-    destroy() {
-        this.pixmap.destroy();
-    }
-
     syncFromPixmap() {
         this.ctx.putImageData(this.pixmap.getImageData(), 0, 0);
     }
@@ -27,117 +23,31 @@ export class Chunk {
     }
 }
 
-let layerIdCounter = 0;
-
-export class Layer {
-    chunks = new Map();
-    id = layerIdCounter++;
-
-    constructor({ name, chunkSize, chunkLimit }) {
-        this.name = name;
-        this.chunkSize = chunkSize;
-        this.chunkLimit = chunkLimit;
-
-        console.info("created layer", this.id, this.name);
-    }
-
-    destroy() {
-        for (let { chunk } of this.chunks.values()) {
-            chunk.destroy();
-        }
-    }
-
-    getChunk(x, y) {
-        return this.chunks.get(chunkKey(x, y))?.chunk;
-    }
-
-    getOrCreateChunk(x, y) {
-        let key = chunkKey(x, y);
-        if (this.chunks.has(key)) {
-            return this.chunks.get(key)?.chunk;
-        } else {
-            if (this.chunkLimit != null && this.chunks.size >= this.chunkLimit) return null;
-
-            let chunk = new Chunk(this.chunkSize);
-            this.chunks.set(key, { x, y, chunk });
-            return chunk;
-        }
-    }
-
-    compositeAlpha(src) {
-        for (let { x, y, chunk: srcChunk } of src.chunks.values()) {
-            srcChunk.syncFromPixmap();
-            let dstChunk = this.getOrCreateChunk(x, y);
-            if (dstChunk == null) continue;
-
-            dstChunk.ctx.globalCompositeOperation = "source-over";
-            dstChunk.ctx.drawImage(srcChunk.canvas, 0, 0);
-            dstChunk.syncToPixmap();
-            dstChunk.markModified();
-        }
-    }
-
-    async toEdits() {
-        let edits = [];
-
-        let start = performance.now();
-
-        for (let { x, y, chunk } of this.chunks.values()) {
-            edits.push({
-                chunk: { x, y },
-                data: chunk.canvas.convertToBlob({ type: "image/png" }),
-            });
-        }
-
-        for (let edit of edits) {
-            edit.data = await edit.data;
-        }
-
-        let end = performance.now();
-        console.debug("toEdits done", end - start);
-
-        return edits;
-    }
-}
-
-export function chunkKey(x, y) {
-    return `${x},${y}`;
-}
-
 export class Wall {
-    layers = []; // do not modify directly; only read
+    #chunks = new Map();
-    #layersById = new Map();
 
     constructor(wallInfo) {
         this.chunkSize = wallInfo.chunkSize;
         this.paintArea = wallInfo.paintArea;
-        this.maxEditSize = wallInfo.maxEditSize;
         this.onlineUsers = new OnlineUsers(wallInfo);
-
-        this.mainLayer = new Layer({ name: "main", chunkSize: this.chunkSize });
-        this.addLayer(this.mainLayer);
     }
 
-    addLayer(layer) {
+    static chunkKey(x, y) {
-        if (!this.#layersById.get(layer.id)) {
+        return `(${x},${y})`;
-            this.layers.push(layer);
+    }
-            this.#layersById.set(layer.id, layer);
+
+    getChunk(x, y) {
+        return this.#chunks.get(Wall.chunkKey(x, y));
+    }
+
+    getOrCreateChunk(x, y) {
+        let key = Wall.chunkKey(x, y);
+        if (this.#chunks.has(key)) {
+            return this.#chunks.get(key);
         } else {
-            console.warn("attempt to add layer more than once", layer);
+            let chunk = new Chunk(this.chunkSize);
-        }
+            this.#chunks.set(key, chunk);
-        return layer;
+            return chunk;
-    }
-
-    removeLayer(layer) {
-        if (this.#layersById.delete(layer.id)) {
-            let index = this.layers.findIndex((x) => x == layer);
-            this.layers.splice(index, 1);
-        } else {
-            console.warn("attempt to remove layer more than once", layer);
         }
     }
-
-    getLayerById(id) {
-        return this.#layersById.get(id);
-    }
 }