pixels/examples/custom-shader/shaders/noise.wgsl
Jay Oster bd2de37b84
Use Fused-Multiply-Add (#232)
- There are a few places in the `simple-invaders` crate that could use
  `f32::mul_add()` as well.
2021-12-04 09:08:29 -08:00

50 lines
1.4 KiB
WebGPU Shading Language

// Vertex shader bindings
struct VertexOutput {
[[location(0)]] tex_coord: vec2<f32>;
[[builtin(position)]] position: vec4<f32>;
};
[[stage(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;
[[block]] struct Locals {
time: f32;
};
[[group(0), binding(2)]] var<uniform> r_locals: Locals;
let tau: f32 = 6.283185307179586476925286766559;
let bias: f32 = 0.2376; // Offset the circular time input so it is never 0
// Random functions based on https://thebookofshaders.com/10/
let random_scale: f32 = 43758.5453123;
let random_x: f32 = 12.9898;
let random_y: f32 = 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)));
}
[[stage(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);
}