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• About
  • defOptimized()
  • Tree optimizations
    • Constant folding
• Status
• Installation
• Dependencies
• Usage examples
• API
• Authors
• License

About

Shader AST code/tree optimization passes/strategies. This is a support package for @thi.ng/shader-ast.

defOptimized()

The function defOptimize() can be used as direct replacement for thi.ng/shader-ast's defMain() to define automatically optimized shader main() functions.

Tree optimizations

Currently, only the following operations are supported/considered:

Constant folding

• scalar math operators (incl. some vector versions)
• scalar math built-in functions (incl. some vector versions)
• scalar comparisons
• single component vector swizzling
• literal hoisting

(See tests for some more examples, non-exhaustive...)

Note: The static optimizer throws an error if it detects a division-by-zero...

import {
  add, defn, float, mul, neg, ret, scope, vec2, $x, $y
} from "@thi.ng/shader-ast";
import { targetGLSL } from "@thi.ng/shader-ast-glsl";
import { constantFolding } from "@thi.ng/shader-ast-optimize";

// function def
const foo = defn("float", "foo", ["float"], (x) => [
  ret(mul(x, add(neg(float(10)), 42)))
]);

const bar = vec2(100, 200);

// program def
const prog = scope([
  foo,
  foo(add(float(1), float(2))),
  foo(add($x(bar), $y(bar)))
], true);

// GLSL codegen
const glsl = targetGLSL();

// unoptimized AST as GLSL (see section above)
console.log(glsl(prog));
// #version 300 es
// float foo(in float _s0) {
// return (_s0 * ((-10.0) + 42.0));
// }
// foo((1.0 + 2.0));
// foo((vec2(100.0, 200.0).x + vec2(100.0, 200.0).y));

// with constant folding
console.log(glsl(constantFolding(prog)))
// #version 300 es
// float foo(in float _s0) {
// return (_s0 * 32.0);
// }
// foo(3.0);
// foo(300.0);

const expr = mul(float(4), $x(vec2(2)))

console.log(glsl(expr))
// (4.0 * vec2(2.0).x)

// optimize single expression
console.log(glsl(constantFolding(expr)))
// 8.0

Status

STABLE - used in production

Search or submit any issues for this package

Installation

yarn add @thi.ng/shader-ast-optimize

ESM import:

import * as opt from "@thi.ng/shader-ast-optimize";

Browser ESM import:

<script type="module" src="https://esm.run/@thi.ng/shader-ast-optimize"></script>

JSDelivr documentation

For Node.js REPL:

const opt = await import("@thi.ng/shader-ast-optimize");

Package sizes (brotli'd, pre-treeshake): ESM: 1.27 KB

Dependencies

• @thi.ng/api
• @thi.ng/defmulti
• @thi.ng/errors
• @thi.ng/logger
• @thi.ng/math
• @thi.ng/shader-ast

Note: @thi.ng/api is in most cases a type-only import (not used at runtime)

Usage examples

One project in this repo's /examples directory is using this package:

| Screenshot | Description | Live demo | Source | |:----------------------------------------------------------------------------------------------------------------------|:---------------------------------------------------------|:-----------------------------------------------------|:----------------------------------------------------------------------------------| | | Evolutionary shader generation using genetic programming | Demo | Source |

API

Generated API docs

TODO

Authors

• Karsten Schmidt

If this project contributes to an academic publication, please cite it as:

@misc{thing-shader-ast-optimize,
  title = "@thi.ng/shader-ast-optimize",
  author = "Karsten Schmidt",
  note = "https://thi.ng/shader-ast-optimize",
  year = 2019
}

License

© 2019 - 2026 Karsten Schmidt // Apache License 2.0