リキ萌
bff899c9c0
brush rendering is now completely client-side. the server only receives edits the client would like to do, in the form of PNG images of chunks, that are then composited onto the wall known issue: it is possible to brush up against the current 256 chunk edit limit pretty easily. I'm not sure it can be solved very easily though. the perfect solution would involve splitting up the interaction into multiple edits, and I tried to do that, but there's a noticable stutter for some reason that I haven't managed to track down yet. so it'll be kinda crap for the time being.
36 lines
1.1 KiB
Rust
36 lines
1.1 KiB
Rust
#[derive(Debug, Clone, Copy)]
|
|
pub struct Image<'a> {
|
|
pub width: u32,
|
|
pub height: u32,
|
|
pub data: &'a [u8],
|
|
}
|
|
|
|
#[derive(Debug)]
|
|
pub struct ImageMut<'a> {
|
|
pub width: u32,
|
|
pub height: u32,
|
|
pub data: &'a mut [u8],
|
|
}
|
|
|
|
impl ImageMut<'_> {
|
|
pub fn composite_alpha(&mut self, src: &Image<'_>) {
|
|
assert_eq!(self.width, src.width);
|
|
assert_eq!(self.height, src.height);
|
|
|
|
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);
|
|
}
|
|
}
|
|
}
|