3 #define mdot(x, y) (max(dot(x, y), 0.f))
5 in vec3 worldPos, normal;
10 uniform sampler2D albedoMap;
11 uniform sampler2D normalMap;
12 uniform sampler2D metallicRoughnessMap;
13 uniform sampler2D aoMap;
14 uniform samplerCube irradianceMap;
15 uniform samplerCube prefilterMap;
16 uniform sampler2D brdfMap;
20 uniform vec3 lightPositions[6];
21 uniform vec3 lightColors[6];
23 const float PI = 3.14159265359;
25 vec3 fresnelSchlick(float cosTheta, vec3 F0) {
26 return F0 + (1.f - F0) * pow(1.f - cosTheta, 5.f);
29 vec3 fresnelSchlickRoughness(float cosTheta, vec3 F0, float roughness) {
30 return F0 + (max(vec3(1.f - roughness), F0) - F0) * pow(1.f - cosTheta, 5.f);
33 float distributionGGX(vec3 N, vec3 H, float roughness) {
34 float a = roughness * roughness;
35 float NdotH = mdot(N, H);
36 float denom = (NdotH * NdotH) * ((a * a) - 1.f) + 1.f;
37 denom = PI * denom * denom;
38 return (a * a) / denom;
41 float geometrySchlickGGX(float NdotV, float roughness) {
42 float r = roughness + 1.f;
43 float k = (r * r) / 8.f;
44 return NdotV / (NdotV * (1.f - k) + k);
47 float geometrySmith(vec3 N, vec3 V, vec3 L, float roughness) {
48 float ggx1 = geometrySchlickGGX(mdot(N, L), roughness);
49 float ggx2 = geometrySchlickGGX(mdot(N, V), roughness);
53 vec3 getNormalFromMap() {
54 vec3 tangentNormal = texture(normalMap, texCoords).xyz * 2.f - 1.f;
55 vec3 Q1 = dFdx(worldPos);
56 vec3 Q2 = dFdy(worldPos);
57 vec2 st1 = dFdx(texCoords);
58 vec2 st2 = dFdy(texCoords);
60 vec3 N = normalize(normal);
61 vec3 T = normalize(Q1 * st2.t - Q2 * st1.t);
62 vec3 B = -normalize(cross(N, T));
63 mat3 TBN = mat3(T, B, N);
65 return normalize(TBN * tangentNormal);
69 vec3 albedo = pow(texture(albedoMap, texCoords).rgb, vec3(2.2));
70 vec3 normal = getNormalFromMap();
71 float metallic = texture(metallicRoughnessMap, texCoords).b;
72 float roughness = texture(metallicRoughnessMap, texCoords).g;
73 float ao = texture(aoMap, texCoords).r;
75 vec3 N = normalize(normal);
76 vec3 V = normalize(camPos - worldPos);
78 vec3 F0 = mix(vec3(0.04), albedo, metallic);
80 vec3 R = reflect(-V, N);
84 for (int i = 0; i < lightPositions.length(); i++) {
85 vec3 L = normalize(lightPositions[i] - worldPos);
86 vec3 H = normalize(V + L);
89 float dist = length(lightPositions[i] - worldPos);
90 float attenuation = 5.f / (dist * dist);
91 vec3 radiance = lightColors[i] * attenuation;
94 vec3 F = fresnelSchlick(mdot(H, V), F0);
95 float NDF = distributionGGX(N, H, roughness);
96 float G = geometrySmith(N, V, L, roughness);
98 float denom = 4.f * mdot(N, V) * mdot(N, L);
99 vec3 specular = (NDF * G * F) / max(denom, 0.0000001);
101 vec3 kS = F; // fresnel = reflection ratio
102 vec3 kD = vec3(1.f) - kS;
103 kD *= 1.f - metallic;
105 Lo += (kD * albedo / PI + specular) * radiance * mdot(N, L);
108 vec3 F = fresnelSchlickRoughness(mdot(N, V), F0, roughness);
111 vec3 kD = (1.f - kS) * (1.f - metallic);
113 vec3 irradiance = texture(irradianceMap, N).rgb;
114 vec3 diffuse = irradiance * albedo;
116 const float maxReflectionLoD = 4.f;
117 vec3 prefilteredColor = textureLod(prefilterMap, R, roughness * maxReflectionLoD).rgb;
118 vec2 envBRDF = texture(brdfMap, vec2(mdot(N, V), roughness)).rg;
119 vec3 specular = prefilteredColor * (F * envBRDF.x + envBRDF.y);
121 vec3 ambient = (kD * diffuse + specular) * ao;
122 vec3 color = ambient + Lo;
124 color = color / (color + vec3(1.f)); // map to HDR
125 color = pow(color, vec3(1.f / 2.2)); // gamma correction
127 fragColor = vec4(color, 1.f);