pixels/examples/custom-shader/shaders/noise.wgsl

50 lines
1.4 KiB
WebGPU Shading Language

// Vertex shader bindings
struct VertexOutput {
@location(0) tex_coord: vec2<f32>,
@builtin(position) position: vec4<f32>,
}
@vertex
fn vs_main(
@location(0) position: vec2<f32>,
) -> VertexOutput {
var out: VertexOutput;
out.tex_coord = fma(position, vec2<f32>(0.5, -0.5), vec2<f32>(0.5, 0.5));
out.position = vec4<f32>(position, 0.0, 1.0);
return out;
}
// Fragment shader bindings
@group(0) @binding(0) var r_tex_color: texture_2d<f32>;
@group(0) @binding(1) var r_tex_sampler: sampler;
struct Locals {
time: f32,
}
@group(0) @binding(2) var<uniform> r_locals: Locals;
const tau = 6.283185307179586476925286766559;
const bias = 0.2376; // Offset the circular time input so it is never 0
// Random functions based on https://thebookofshaders.com/10/
const random_scale = 43758.5453123;
const random_x = 12.9898;
const random_y = 78.233;
fn random(x: f32) -> f32 {
return fract(sin(x) * random_scale);
}
fn random_vec2(st: vec2<f32>) -> f32 {
return random(dot(st, vec2<f32>(random_x, random_y)));
}
@fragment
fn fs_main(@location(0) tex_coord: vec2<f32>) -> @location(0) vec4<f32> {
let sampled_color = textureSample(r_tex_color, r_tex_sampler, tex_coord);
let noise_color = vec3<f32>(random_vec2(tex_coord.xy * vec2<f32>(r_locals.time % tau + bias)));
return vec4<f32>(sampled_color.rgb * noise_color, sampled_color.a);
}