89 lines
2.7 KiB
GLSL
89 lines
2.7 KiB
GLSL
#version 450
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#extension GL_GOOGLE_include_directive : require
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#include "input_structures.glsl"
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layout (location = 0) in vec3 inNormal;
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layout (location = 1) in vec3 inColor;
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layout (location = 2) in vec2 inUV;
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layout (location = 3) in vec3 inWorldPos;
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layout (location = 0) out vec4 outFragColor;
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const float PI = 3.14159265359;
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vec3 fresnelSchlick(float cosTheta, vec3 F0)
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{
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return F0 + (1.0 - F0) * pow(1.0 - cosTheta, 5.0);
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}
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float DistributionGGX(vec3 N, vec3 H, float roughness)
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{
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float a = roughness * roughness;
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float a2 = a * a;
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float NdotH = max(dot(N, H), 0.0);
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float NdotH2 = NdotH * NdotH;
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float num = a2;
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float denom = (NdotH2 * (a2 - 1.0) + 1.0);
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denom = PI * denom * denom;
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return num / max(denom, 0.001);
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}
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float GeometrySchlickGGX(float NdotV, float roughness)
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{
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float r = (roughness + 1.0);
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float k = (r * r) / 8.0;
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float denom = NdotV * (1.0 - k) + k;
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return NdotV / denom;
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}
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float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness)
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{
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float ggx2 = GeometrySchlickGGX(max(dot(N, V), 0.0), roughness);
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float ggx1 = GeometrySchlickGGX(max(dot(N, L), 0.0), roughness);
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return ggx1 * ggx2;
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}
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void main()
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{
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// Base color with material factor and texture
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vec4 baseTex = texture(colorTex, inUV);
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vec3 albedo = inColor * baseTex.rgb * materialData.colorFactors.rgb;
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// glTF: metallicRoughnessTexture uses G=roughness, B=metallic
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vec2 mrTex = texture(metalRoughTex, inUV).gb;
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float roughness = clamp(mrTex.x * materialData.metal_rough_factors.y, 0.04, 1.0);
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float metallic = clamp(mrTex.y * materialData.metal_rough_factors.x, 0.0, 1.0);
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vec3 N = normalize(inNormal);
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vec3 camPos = vec3(inverse(sceneData.view)[3]);
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vec3 V = normalize(camPos - inWorldPos);
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vec3 L = normalize(-sceneData.sunlightDirection.xyz);
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vec3 H = normalize(V + L);
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vec3 F0 = mix(vec3(0.04), albedo, metallic);
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vec3 F = fresnelSchlick(max(dot(H, V), 0.0), F0);
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float NDF = DistributionGGX(N, H, roughness);
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float G = GeometrySmith(N, V, L, roughness);
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vec3 numerator = NDF * G * F;
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float denom = 4.0 * max(dot(N, V), 0.0) * max(dot(N, L), 0.0);
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vec3 specular = numerator / max(denom, 0.001);
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vec3 kS = F;
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vec3 kD = vec3(1.0) - kS;
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kD *= 1.0 - metallic;
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float NdotL = max(dot(N, L), 0.0);
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vec3 irradiance = sceneData.sunlightColor.rgb * sceneData.sunlightColor.a * NdotL;
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vec3 color = (kD * albedo / PI + specular) * irradiance;
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color += albedo * sceneData.ambientColor.rgb;
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// Alpha from baseColor texture and factor (glTF spec)
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float alpha = clamp(baseTex.a * materialData.colorFactors.a, 0.0, 1.0);
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outFragColor = vec4(color, alpha);
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}
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