60 lines
1.5 KiB
GLSL
60 lines
1.5 KiB
GLSL
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struct GltfMaterial
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{
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int shadingModel; // 0: metallic-roughness, 1: specular-glossiness
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// PbrMetallicRoughness
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vec4 pbrBaseColorFactor;
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int pbrBaseColorTexture;
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float pbrMetallicFactor;
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float pbrRoughnessFactor;
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int pbrMetallicRoughnessTexture;
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// KHR_materials_pbrSpecularGlossiness
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vec4 khrDiffuseFactor;
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int khrDiffuseTexture;
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vec3 khrSpecularFactor;
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float khrGlossinessFactor;
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int khrSpecularGlossinessTexture;
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int emissiveTexture;
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vec3 emissiveFactor;
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int alphaMode;
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float alphaCutoff;
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bool doubleSided;
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int normalTexture;
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float normalTextureScale;
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int occlusionTexture;
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float occlusionTextureStrength;
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};
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struct PrimMeshInfo
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{
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uint indexOffset;
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uint vertexOffset;
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int materialIndex;
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};
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vec3 computeDiffuse(GltfMaterial mat, vec3 lightDir, vec3 normal)
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{
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// Lambertian
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float dotNL = max(dot(normal, lightDir), 0.0);
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return mat.pbrBaseColorFactor.xyz * dotNL;
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}
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vec3 computeSpecular(GltfMaterial mat, vec3 viewDir, vec3 lightDir, vec3 normal)
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{
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// Compute specular only if not in shadow
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const float kPi = 3.14159265;
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const float kShininess = 60.0;
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// Specular
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const float kEnergyConservation = (2.0 + kShininess) / (2.0 * kPi);
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vec3 V = normalize(-viewDir);
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vec3 R = reflect(-lightDir, normal);
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float specular = kEnergyConservation * pow(max(dot(V, R), 0.0), kShininess);
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return vec3(specular);
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}
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