53 lines
2.3 KiB
Plaintext
53 lines
2.3 KiB
Plaintext
# haku
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Haku is a little scripting language used by rakugaki for programming brushes.
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Here's a brief tour of the language.
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## Your brush
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Your brush is a piece of code that describes what's to be drawn on the wall.
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For example:
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```haku
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(stroke
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8
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(rgba 0 0 0 1)
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(vec 0 0))
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```
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This is the simplest brush you can write.
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It demonstrates a few things:
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- The brush's task is to produce a description of what's to be drawn.
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Brushes produce *scribbles* - commands that instruct rakugaki draw something on the wall.
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- This brush produces the `(stroke)` scribble.
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This scribble is composed out of three things:
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- The stroke thickness - in this case `8`.
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- The stroke color - in this case `(rgba 0 0 0 1)`.
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Note that unlike most drawing programs, rakugaki brushes represent color channels with decimal numbers from 0 to 1, rather than integers from 0 to 255.
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- The shape to draw - in this case a `(vec 0 0)`.
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- Vectors are aggregations of four generic decimal numbers, most often used to represent positions in the wall's Cartesian coordinate space.
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Although vectors are mathematically not the same as points, brushes always execute in a coordinate space relative to where you want to draw with the brush, so a separate `(point)` type isn't needed.
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- Vectors in haku are four-dimensional, but the wall is two-dimensional, so the extra dimensions are discarded when drawing to the wall.
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- haku permits constructing vectors from zero two four values - from `(vec)`, up to `(vec x y w h)`.
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Any values that you leave out end up being zero.
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- Note that a brush can only produce *one* scribble - this is because scribbles may be composed together using lists (described later.)
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I highly recommend that you play around with the brush to get a feel for editing haku code!
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## Limits
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The wall is infinite, but your brush may only draw in a small area around your cursor (~500 pixels.)
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Drawing outside this area may result in pixels getting dropped in ugly ways, but it can also be used to your advantage in order to produce cool glitch art.
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Additionally, haku code has some pretty strong limitations on what it can do.
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It cannot be too big, it cannot execute for too long, and it cannot consume too much memory.
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It does not have access to the world outside the wall.
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