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PBR Shader

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This commit is contained in:
Szymon Nowakowski
2025-11-09 21:32:13 +01:00
parent 00b5f9c2b2
commit bcde2e80ff
2 changed files with 204 additions and 16 deletions
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13
src/main.zig
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@@ -46,9 +46,10 @@ fn init() callconv(.c) void {
bindings.vertex_buffers[0] = sg.makeBuffer(.{
.data = sg.asRange(&[_]f32{
0.0, 0.5, 0.5, 1.0, 0.0, 0.0, 1.0,
0.5, -0.5, 0.5, 0.0, 1.0, 0.0, 1.0,
-0.5, -0.5, 0.5, 0.0, 0.0, 1.0, 1.0,
// positionOS texCoord normalOS tangentOS
0.0, 0.5, 0.5, 0.5, 1.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 1.0,
0.5, -0.5, 0.5, 1.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 1.0,
-0.5, -0.5, 0.5, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 1.0,
}),
});
@@ -56,8 +57,10 @@ fn init() callconv(.c) void {
.shader = sg.makeShader(shader.programShaderDesc(sg.queryBackend())),
.layout = blk: {
var ret: sg.VertexLayoutState = .{};
ret.attrs[shader.ATTR_program_position_CS].format = .FLOAT3;
ret.attrs[shader.ATTR_program_color].format = .FLOAT4;
ret.attrs[shader.ATTR_program_positionOS].format = .FLOAT3;
ret.attrs[shader.ATTR_program_texCoord].format = .FLOAT2;
ret.attrs[shader.ATTR_program_normalOS].format = .FLOAT3;
ret.attrs[shader.ATTR_program_tangentOS].format = .FLOAT4;
break :blk ret;
},
});

207
src/shader.glsl
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@@ -1,23 +1,208 @@
@vs vert
in vec4 position_CS;
in vec4 color;
@vs vertex
out vec4 varColor;
layout(location = 0) in vec3 positionOS;
layout(location = 1) in vec2 texCoord;
layout(location = 2) in vec3 normalOS;
layout(location = 3) in vec4 tangentOS;
layout(location = 0) out vec3 var_positionVS;
layout(location = 1) out vec2 var_texCoord;
layout(location = 2) out vec3 var_normalVS;
layout(location = 3) out vec3 var_tangentVS;
layout(location = 4) out vec3 var_bitangentVS;
layout(binding = 0) uniform Global_Uniforms_Vertex {
mat4 _MatrixWStoVS;
mat4 _MatrixVStoCS;
};
layout(binding = 1) uniform Object_Uniforms {
mat4 _MatrixOStoWS;
mat4 _MatrixOStoWSNormal;
};
void main() {
gl_Position = position_CS;
varColor = color;
vec3 positionWS = (_MatrixOStoWS * vec4(positionOS, 1.0)).xyz;
vec3 positionVS = (_MatrixWStoVS * vec4(positionWS, 1.0)).xyz;
vec4 positionCS = _MatrixVStoCS * vec4(positionVS, 1.0);
vec3 normalWS = normalize((_MatrixOStoWSNormal * vec4(normalOS, 0.0)).xyz);
vec3 normalVS = normalize((_MatrixWStoVS * vec4(normalWS, 0.0)).xyz);
vec3 tangentWS = normalize((_MatrixOStoWS * vec4(tangentOS.xyz, 0.0)).xyz);
vec3 tangentVS = normalize((_MatrixWStoVS * vec4(tangentWS, 0.0)).xyz);
vec3 bitangentVS = tangentOS.w * normalize(cross(normalVS, tangentVS));
gl_Position = positionCS;
var_positionVS = positionVS;
var_texCoord = texCoord;
var_normalVS = normalVS;
var_tangentVS = tangentVS;
var_bitangentVS = bitangentVS;
}
@end
@fs frag
in vec4 varColor;
@fs fragment
struct Point_Light {
vec3 positionWS;
vec3 color;
};
struct Directional_Light {
vec3 directionWS;
vec3 color;
};
layout(location = 0) in vec3 var_positionVS;
layout(location = 1) in vec2 var_texCoord;
layout(location = 2) in vec3 var_normalVS;
layout(location = 3) in vec3 var_tangentVS;
layout(location = 4) in vec3 var_bitangentVS;
out vec4 fragColor;
void main() {
fragColor = varColor;
layout(binding = 2) uniform Global_Uniforms_Fragment {
mat4 _MatrixWStoVS;
vec3 _AmbientLight;
int _PointLightCount;
int _DirectionalLightCount;
};
layout(binding = 3) uniform Material_Uniforms {
int _TextureIndex;
};
layout(binding = 0) readonly buffer Point_Lights {
Point_Light _PointLights[];
};
layout(binding = 1) readonly buffer Directional_Lights {
Directional_Light _DirectionalLights[];
};
layout(binding = 2) uniform texture2DArray _BaseColorTexture;
layout(binding = 3) uniform texture2DArray _OcclusionRoughnessMetallicTexture;
layout(binding = 4) uniform texture2DArray _NormalTexture;
layout(binding = 0) uniform sampler _Sampler;
const float INV_PI = 0.31830987;
const float IOR = 1.45;
const vec3 DIELECTRIC_F0 = vec3(pow((IOR - 1.0) / (IOR + 1.0), 2.0));
const vec3 F90 = vec3(1.0);
vec3 fresnelSchlick(float dotVH, vec3 f0) {
return mix(f0, F90, pow(1.0 - dotVH, 5.0));
}
float visibilityGGX(float dotNL, float dotNV, float alpha) {
float alphaSquared = alpha * alpha;
float vGGX = dotNL * sqrt(dotNV * dotNV * (1.0 - alphaSquared) + alphaSquared);
float lGGX = dotNV * sqrt(dotNL * dotNL * (1.0 - alphaSquared) + alphaSquared);
float GGX = vGGX + lGGX;
return mix(0.0, 0.5 / GGX, GGX > 0.0);
}
float distributionGGX(float dotNH, float alpha) {
float alphaSquared = alpha * alpha;
float tmp = dotNH * dotNH * (alphaSquared - 1.0) + 1.0;
return alphaSquared * INV_PI / (tmp * tmp);
}
vec3 toneMapAcesNarkowicz(vec3 color) {
const float A = 2.51;
const float B = 0.03;
const float C = 2.43;
const float D = 0.59;
const float E = 0.14;
return clamp((color * (A * color + B)) / (color * (C * color + D) + E), 0.0, 1.0);
}
vec3 lightOutgoingRadiance(
vec3 viewDirectionVS, vec3 normalVS, float dotNV,
vec3 baseColor, float alpha, float metallic, vec3 f0,
vec3 incomingRadiance, vec3 lightDirectionVS
) {
vec3 halfVectorVS = normalize(lightDirectionVS + viewDirectionVS);
float dotVH = clamp(dot(viewDirectionVS, halfVectorVS), 0.0, 1.0);
float dotNH = clamp(dot(normalVS, halfVectorVS), 0.0, 1.0);
float dotNL = clamp(dot(normalVS, lightDirectionVS), 0.0, 1.0);
vec3 fresnel = fresnelSchlick(dotVH, f0);
float visibility = visibilityGGX(dotNL, dotNV, alpha);
float distribution = distributionGGX(dotNH, alpha);
vec3 scatteredFactor = (1.0 - fresnel) * (1.0 - metallic) * baseColor * INV_PI;
vec3 reflectedFactor = fresnel * visibility * distribution;
return (scatteredFactor + reflectedFactor) * incomingRadiance * dotNL;
}
void main() {
vec4 baseColorTexel = texture(sampler2DArray(_BaseColorTexture, _Sampler), vec3(var_texCoord, float(_TextureIndex)));
vec4 occlusionRoughnessMetallicTexel = texture(sampler2DArray(_OcclusionRoughnessMetallicTexture, _Sampler), vec3(var_texCoord, float(_TextureIndex)));
vec4 normalTextureTexel = texture(sampler2DArray(_NormalTexture, _Sampler), vec3(var_texCoord, float(_TextureIndex)));
vec3 baseColor = baseColorTexel.rgb;
float occlusion = occlusionRoughnessMetallicTexel.r;
float roughness = occlusionRoughnessMetallicTexel.g;
float metallic = occlusionRoughnessMetallicTexel.b;
vec3 tangentVS = normalize(var_tangentVS);
vec3 bitangentVS = normalize(var_bitangentVS);
mat3 matrixTStoVS = mat3(tangentVS, bitangentVS, var_normalVS);
vec3 normalTS = normalTextureTexel.xyz * 2.0 - 1.0;
vec3 normalVS = normalize(matrixTStoVS * normalTS);
vec3 positionVS = var_positionVS;
vec3 viewDirectionVS = normalize(-positionVS);
float dotNV = clamp(dot(normalVS, viewDirectionVS), 0.0, 1.0);
float alpha = roughness * roughness;
vec3 f0 = mix(DIELECTRIC_F0, baseColor, metallic);
vec3 outgoingRadiance = vec3(0.0);
for (int i = 0; i < _PointLightCount; i++) {
Point_Light light = _PointLights[i];
vec3 lightPositionVS = (_MatrixWStoVS * vec4(light.positionWS, 1.0)).xyz;
vec3 lightDirectionVS = normalize(lightPositionVS - positionVS);
float lightDistance = distance(positionVS, lightPositionVS);
float lightAttenuation = 1.0 / (lightDistance * lightDistance);
vec3 incomingRadiance = light.color * lightAttenuation;
outgoingRadiance += lightOutgoingRadiance(
viewDirectionVS, normalVS, dotNV,
baseColor, alpha, metallic, f0,
incomingRadiance, lightDirectionVS
);
}
for (int i = 0; i < _DirectionalLightCount; i++) {
Directional_Light light = _DirectionalLights[i];
vec3 lightDirectionVS = normalize((_MatrixWStoVS * vec4(light.directionWS, 0.0)).xyz);
vec3 incomingRadiance = light.color;
outgoingRadiance += lightOutgoingRadiance(
viewDirectionVS, normalVS, dotNV,
baseColor, alpha, metallic, f0,
incomingRadiance, lightDirectionVS
);
}
outgoingRadiance += _AmbientLight * baseColor * occlusion;
vec3 toneMappedLinearColor = toneMapAcesNarkowicz(outgoingRadiance);
vec3 toneMappedSrgbColor = pow(toneMappedLinearColor, vec3(1.0 / 2.2));
fragColor = vec4(toneMappedSrgbColor, 1.0);
}
@end
@program program vert frag
@program program vertex fragment