72 lines
1.9 KiB
WebGPU Shading Language
72 lines
1.9 KiB
WebGPU Shading Language
#include globals.wgsl
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#include constants.wgsl
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#include noise.wgsl
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struct FogVertexOutput {
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@builtin(position) clip_position: vec4<f32>,
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@location(0) world_position: vec3<f32>,
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@location(1) light_world_position: vec3<f32>,
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}
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@vertex
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fn vs_main(
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model: VertexInput,
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instance: InstanceInput,
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) -> FogVertexOutput {
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let model_matrix = mat4x4<f32>(
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instance.model_matrix_0,
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instance.model_matrix_1,
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instance.model_matrix_2,
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instance.model_matrix_3,
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);
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let world_position = model_matrix * vec4<f32>(model.position, 1.0);
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var out: FogVertexOutput;
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out.clip_position = camera.proj * camera.view * world_position;
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out.world_position = world_position.xyz / world_position.w;
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out.light_world_position = light.position;
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return out;
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}
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fn fog_noise(pos: vec3<f32>) -> f32 {
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var p = pos * FOG_SCALE;
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p.x += global_uniforms.time * 0.01;
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p.y += global_uniforms.time * 0.1;
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p.z += sin(global_uniforms.time * 0.1) * 0.1;
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return fbm(p);
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}
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fn ray_march(origin: vec3<f32>, direction: vec3<f32>, scene_depth: f32) -> f32 {
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var density = 0.0;
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var depth = 0.0;
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for (var i = 0; i < FOG_MAX_STEPS; i++)
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{
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depth += FOG_MAX_DIST / f32(FOG_MAX_STEPS);
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let p = origin + direction * depth;
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density += fog_noise(p) * FOG_DENSITY / f32(FOG_MAX_STEPS);
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if (density >= 1.0)
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{
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density = 1.0;
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break;
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}
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if (depth >= scene_depth)
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{
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break;
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}
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}
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return density;
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}
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@fragment
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fn fs_main(vert: FogVertexOutput) -> @location(0) vec4<f32> {
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var color = vec4<f32>(0.5, 0.5, 0.5, 1.0);
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let direction = normalize(vert.world_position.xyz - camera.position.xyz);
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let scene_depth = FOG_MAX_DIST; // TODO: sample geometry pass depth buffer
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let density = ray_march(vert.world_position.xyz, direction, scene_depth);
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color.a *= density;
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return color;
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}
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