WGSL Cheat Sheet

This is a reference to WGSL syntax for users coming from GLSL. It is not meant to be complete, but to cover some common usages.

WGSL is still evolving, so some things may change before the final version. This reference is based on the WGSL draft spec.

Types

Primitives

WGSL	GLSL	Note
bool	bool	true or false
i32	int	32-bit signed integer
u32	uint	32-bit unsigned integer
f32	float	Single-precision float
Not available	double	Double-precision float

Composite Types

WGSL	GLSL	Note
vecN<bool>	bvecN	Vector of N ∈ {2, 3, 4} bools.
vecN<i32>	ivecN	Vector of N ∈ {2, 3, 4} signed integers.
vecN<u32>	uvecN	Vector of N ∈ {2, 3, 4} unsigned integers.
vecN<f32>	vecN	Vector of N ∈ {2, 3, 4} floats.
Not available	dvecN	Vector of N ∈ {2, 3, 4} double-precision vectors.
matNxM<f32>	matNxM, matN	Matrix of NxM ∈ {2, 3, 4} columns and rows (or NxN).

Variables

WGSL	GLSL	Note
var m: i32 = 4;	int m = 4;	var creates a local variable.
let m: i32 = 4;	Not available?	let creates an immutable binding.

Literals

WGSL	GLSL	Note
123	123 (when used in int context)
123u, 123u32	123 (when used in uint context)	WGSL does not infer int type from context; you need to be explicit.

switch syntax

WGSL needs explicit fallthrough to not break at the end of a switch block. my_var must be a u32 (I think?).

WGSL	GLSL
switch (my_var) { case 0: { fallthrough; } case 1: { foo = 1; } case 2: { foo = 4; } }	switch (my_var) { case 0: case 1: foo = 1; break; case 2: foo = 4; }

Shader Function Structure

Vertex Shader

WGSL	GLSL
// Structure of vertex shader output struct VertexOutput { [[builtin(position)]] position: vec4<f32>; [[location(0)]] baz; }; // Vertex shader function [[stage(vertex)]] fn vs_main( [[location(0)]] foo: vec2<f32>, [[location(1)]] bar: vec4<f32>, ) -> VertexOutput { var out: VertexOutput; if (foo.x > foo.y) { discard; } out.baz = vec4<f32>(0.0, 1.0, 0.0, 1.0); out.position = bar; return out; }	// Inputs from vertex buffer. layout(location=0) in vec2 foo; layout(location=1) in vec4 bar; // Output to frag shader. layout(location=0) out vec4 baz; void main() { if (foo.x > foo.y) { discard; } baz = vec4(0.0, 1.0, 0.0, 1.0); gl_Position = bar; }