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 metallicMap;
13 uniform sampler2D roughnessMap;
14 uniform sampler2D aoMap;
15 uniform samplerCube irradianceMap;
16 uniform samplerCube prefilterMap;
17 uniform sampler2D brdfMap;
21 uniform vec3 lightPositions[4];
22 uniform vec3 lightColors[4];
24 const float PI = 3.14159265359;
26 vec3 fresnelSchlick(float cosTheta, vec3 F0) {
27 return F0 + (1.f - F0) * pow(1.f - cosTheta, 5.f);
30 vec3 fresnelSchlickRoughness(float cosTheta, vec3 F0, float roughness) {
31 return F0 + (max(vec3(1.f - roughness), F0) - F0) * pow(1.f - cosTheta, 5.f);
34 float distributionGGX(vec3 N, vec3 H, float roughness) {
35 float a = roughness * roughness;
36 float NdotH = mdot(N, H);
37 float denom = (NdotH * NdotH) * ((a * a) - 1.f) + 1.f;
38 denom = PI * denom * denom;
39 return (a * a) / denom;
42 float geometrySchlickGGX(float NdotV, float roughness) {
43 float r = roughness + 1.f;
44 float k = (r * r) / 8.f;
45 return NdotV / (NdotV * (1.f - k) + k);
48 float geometrySmith(vec3 N, vec3 V, vec3 L, float roughness) {
49 float ggx1 = geometrySchlickGGX(mdot(N, L), roughness);
50 float ggx2 = geometrySchlickGGX(mdot(N, V), roughness);
54 vec3 getNormalFromMap() {
55 vec3 tangentNormal = texture(normalMap, texCoords).xyz * 2.f - 1.f;
56 vec3 Q1 = dFdx(worldPos);
57 vec3 Q2 = dFdy(worldPos);
58 vec2 st1 = dFdx(texCoords);
59 vec2 st2 = dFdy(texCoords);
61 vec3 N = normalize(normal);
62 vec3 T = normalize(Q1 * st2.t - Q2 * st1.t);
63 vec3 B = -normalize(cross(N, T));
64 mat3 TBN = mat3(T, B, N);
66 return normalize(TBN * tangentNormal);
70 vec3 albedo = pow(texture(albedoMap, texCoords).rgb, vec3(2.2));
71 vec3 normal = getNormalFromMap();
72 float metallic = texture(metallicMap, texCoords).r;
73 float roughness = texture(roughnessMap, texCoords).r;
74 float ao = texture(aoMap, texCoords).r;
76 vec3 N = normalize(normal);
77 vec3 V = normalize(camPos - worldPos);
79 vec3 F0 = mix(vec3(0.04), albedo, metallic);
81 vec3 R = reflect(-V, N);
85 for (int i = 0; i < lightPositions.length(); i++) {
86 vec3 L = normalize(lightPositions[i] - worldPos);
87 vec3 H = normalize(V + L);
90 float dist = length(lightPositions[i] - worldPos);
91 float attenuation = 5.f / (dist * dist);
92 vec3 radiance = lightColors[i] * attenuation;
95 vec3 F = fresnelSchlick(mdot(H, V), F0);
96 float NDF = distributionGGX(N, H, roughness);
97 float G = geometrySmith(N, V, L, roughness);
99 float denom = 4.f * mdot(N, V) * mdot(N, L);
100 vec3 specular = (NDF * G * F) / max(denom, 0.0000001);
102 vec3 kS = F; // fresnel = reflection ratio
103 vec3 kD = vec3(1.f) - kS;
104 kD *= 1.f - metallic;
106 Lo += (kD * albedo / PI + specular) * radiance * mdot(N, L);
109 vec3 F = fresnelSchlickRoughness(mdot(N, V), F0, roughness);
112 vec3 kD = (1.f - kS) * (1.f - metallic);
114 vec3 irradiance = texture(irradianceMap, N).rgb;
115 vec3 diffuse = irradiance * albedo;
117 const float maxReflectionLoD = 4.f;
118 vec3 prefilteredColor = textureLod(prefilterMap, R, roughness * maxReflectionLoD).rgb;
119 vec2 envBRDF = texture(brdfMap, vec2(mdot(N, V), roughness)).rg;
120 vec3 specular = prefilteredColor * (F * envBRDF.x + envBRDF.y);
122 vec3 ambient = (kD * diffuse + specular) * ao;
123 vec3 color = ambient + Lo;
125 color = color / (color + vec3(1.f)); // map to HDR
126 color = pow(color, vec3(1.f / 2.2)); // gamma correction
128 fragColor = vec4(color, 1.f);