209 lines
5.4 KiB
WebGPU Shading Language
209 lines
5.4 KiB
WebGPU Shading Language
struct CameraUniform {
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eye: vec4<f32>;
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vp: mat4x4<f32>;
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};
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struct MeshInstance {
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transform: mat4x4<f32>;
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};
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struct MeshData {
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instances: array<MeshInstance>;
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};
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struct PointLight {
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center: vec4<f32>;
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intensity: vec4<f32>;
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};
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struct PointLightData {
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num: i32;
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lights: array<PointLight>;
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};
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struct VertexInput {
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[[location(0)]] position: vec3<f32>;
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[[location(1)]] normal: vec3<f32>;
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[[location(2)]] tex_coords: vec2<f32>;
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};
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struct VertexOutput {
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[[builtin(position)]] clip_position: vec4<f32>;
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[[location(0)]] position: vec3<f32>;
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[[location(1)]] normal: vec3<f32>;
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[[location(2)]] tex_coords: vec2<f32>;
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};
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[[group(0), binding(0)]]
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var<uniform> camera: CameraUniform;
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[[group(0), binding(1)]]
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var<storage,read> point_lights: PointLightData;
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[[group(1), binding(0)]]
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var<storage,read> meshes: MeshData;
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[[group(2), binding(0)]] var m_sampler: sampler;
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[[group(2), binding(1)]] var m_albedo: texture_2d<f32>;
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[[group(2), binding(2)]] var m_metallic_roughness: texture_2d<f32>;
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let PI: f32 = 3.141592;
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fn D_GGX(NoH: f32, roughness: f32) -> f32 {
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let a = roughness * roughness;
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let a2 = a * a;
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let NoH2 = NoH * NoH;
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let f = NoH * (a2 - 1.0) + 1.0;
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return a2 / (PI * f * f);
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}
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fn g1(NoV: f32, roughness: f32, k: f32) -> f32 {
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let denom = NoV * (1.0 - k) + k;
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return NoV / denom;
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}
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fn G_SmithGGXCorrelated(NoV: f32, NoL: f32, roughness: f32) -> f32 {
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let r = roughness + 1.0;
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let k = (r * r) / 8.0;
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let g1l = g1(NoV, roughness, k);
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let g1v = g1(NoL, roughness, k);
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return g1l * g1v;
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}
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fn F_Schlick(u: f32, f0: vec3<f32>) -> vec3<f32> {
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let f = pow(1.0 - u, 5.0);
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return f + f0 * (1.0 - f);
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}
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fn BRDF(
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l: vec3<f32>, // normalized light direction
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n: vec3<f32>, // normalized surface normal
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v: vec3<f32>, // normalized view direction
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albedo: vec3<f32>, // surface albedo
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metallic: f32, // surface metallic
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roughness: f32, // surface roughness
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) -> vec3<f32> {
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let h = normalize(v + l);
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let NoL = max(dot(n, l), 0.0);
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let NoV = max(dot(n, v), 0.0);
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let NoH = max(dot(n, h), 0.0);
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let LoH = max(dot(l, h), 0.0);
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// calculate reflectance at surface incidence
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let f0 = mix(vec3<f32>(0.04), albedo, metallic);
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// specular BRDF
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let D = D_GGX(NoH, roughness);
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let G = G_SmithGGXCorrelated(NoV, NoL, roughness);
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let F = F_Schlick(LoH, f0);
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let numerator = (D * G) * F;
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let denominator = 4.0 * NoV * NoL;
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let Fr = numerator / max(denominator, 0.01);
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// diffuse BRDF
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let diffuse_fresnel =
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(vec3<f32>(1.0) - F_Schlick(NoL, f0)) *
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(vec3<f32>(1.0) - F_Schlick(NoV, f0));
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let lambertian = albedo / PI;
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let Fd = diffuse_fresnel * lambertian;
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// TODO multiple scattering
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return (Fr + Fd) * NoL;
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}
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fn sample_ibl_fake(
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n_color: vec3<f32>,
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s_color: vec3<f32>,
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gradient: f32,
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coords: vec3<f32>,
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) -> vec3<f32> {
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let blend = coords.y / gradient + 0.5;
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return mix(s_color, n_color, clamp(blend, 0.0, 1.0));
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}
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fn F_Schlick_Roughness(cos_theta: f32, f0: vec3<f32>, roughness: f32) -> vec3<f32> {
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return f0 + (max(vec3<f32>(1.0 - roughness), f0) - f0) * pow(clamp(1.0 - cos_theta, 0.0, 1.0), 5.0);
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}
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let N_COLOR = vec3<f32>(0.7, 0.0, 1.0);
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let S_COLOR = vec3<f32>(0.1, 0.1, 0.1);
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let IBL_G = 1.0;
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fn fake_ibl(
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n: vec3<f32>, // normalized surface normal
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v: vec3<f32>, // normalized view direction
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albedo: vec3<f32>, // surface albedo
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metallic: f32, // surface metallic
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roughness: f32, // surface roughness
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) -> vec3<f32> {
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// calculate reflectance at surface incidence
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let f0 = mix(vec3<f32>(0.04), albedo, metallic);
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let kS = F_Schlick_Roughness(max(dot(n, v), 0.0), f0, roughness);
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let kD = 1.0 - kS;
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let diffuse = sample_ibl_fake(N_COLOR, S_COLOR, IBL_G, n);
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let R = normalize(reflect(-v, n));
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let specular = sample_ibl_fake(N_COLOR, S_COLOR, IBL_G, R);
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let received = kD * diffuse + kS * specular;
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return received * albedo;
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}
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[[stage(vertex)]]
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fn vs_main(
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[[builtin(instance_index)]] mesh_idx: u32,
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vertex: VertexInput,
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) -> VertexOutput {
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let transform = meshes.instances[mesh_idx].transform;
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let world_pos = transform * vec4<f32>(vertex.position, 1.0);
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let world_normal = transform * vec4<f32>(vertex.normal, 0.0);
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var out: VertexOutput;
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out.clip_position = camera.vp * world_pos;
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out.position = world_pos.xyz;
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out.normal = world_normal.xyz;
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out.tex_coords = vertex.tex_coords;
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return out;
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}
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[[stage(fragment)]]
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fn fs_main(
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frag: VertexOutput,
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) -> [[location(0)]] vec4<f32> {
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let albedo = textureSample(m_albedo, m_sampler, frag.tex_coords).rgb;
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let normal = normalize(frag.normal);
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let view = normalize(camera.eye.xyz - frag.position);
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let metallic_roughness = textureSample(m_metallic_roughness, m_sampler, frag.tex_coords).bg;
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let metallic = metallic_roughness.x;
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let roughness = metallic_roughness.y;
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var lum = vec3<f32>(0.0);
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for(var i = 0; i < 4; i = i + 1) {
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let light = point_lights.lights[i];
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let light_position = light.center.xyz - frag.position;
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let light_intensity = light.intensity.rgb;
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let light_direction = normalize(light_position);
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let radiance = light_intensity / dot(light_position, light_position);
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let reflected = BRDF(
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light_direction, normal, view,
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albedo, metallic, roughness
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);
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lum = lum + (radiance * reflected);
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}
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lum = lum + fake_ibl(normal, view, albedo, metallic, roughness);
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let tone_mapped = lum / (lum + 1.0);
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return vec4<f32>(tone_mapped, 1.0);
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}
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