3 #define mdot(x, y) (max(dot(x, y), 0.f))
5 in vec3 worldPos, normal;
13 sampler2D metallicRoughnessMap;
15 bool hasAlbedo, hasNormal, hasMetallicRoughness, hasAo;
19 uniform samplerCube irradianceMap;
20 uniform samplerCube prefilterMap;
21 uniform sampler2D brdfMap;
25 uniform int numLights;
26 uniform vec3 lightPositions[8];
27 uniform vec3 lightColors[8];
29 const float PI = 3.14159265359;
31 vec3 fresnelSchlick(float cosTheta, vec3 F0) {
32 return F0 + (1.f - F0) * pow(1.f - cosTheta, 5.f);
35 vec3 fresnelSchlickRoughness(float cosTheta, vec3 F0, float roughness) {
36 return F0 + (max(vec3(1.f - roughness), F0) - F0) * pow(1.f - cosTheta, 5.f);
39 float distributionGGX(vec3 N, vec3 H, float roughness) {
40 float a = roughness * roughness;
41 float NdotH = mdot(N, H);
42 float denom = (NdotH * NdotH) * ((a * a) - 1.f) + 1.f;
43 denom = PI * denom * denom;
44 return (a * a) / denom;
47 float geometrySchlickGGX(float NdotV, float roughness) {
48 float r = roughness + 1.f;
49 float k = (r * r) / 8.f;
50 return NdotV / (NdotV * (1.f - k) + k);
53 float geometrySmith(vec3 N, vec3 V, vec3 L, float roughness) {
54 float ggx1 = geometrySchlickGGX(mdot(N, L), roughness);
55 float ggx2 = geometrySchlickGGX(mdot(N, V), roughness);
59 vec3 getNormalFromMap() {
60 vec3 tangentNormal = vec3(0, 0, 1);
62 tangentNormal = texture(mat.normalMap, texCoords).xyz * 2.f - 1.f;
63 vec3 Q1 = dFdx(worldPos);
64 vec3 Q2 = dFdy(worldPos);
65 vec2 st1 = dFdx(texCoords);
66 vec2 st2 = dFdy(texCoords);
68 vec3 N = normalize(normal);
69 vec3 T = normalize(Q1 * st2.t - Q2 * st1.t);
70 vec3 B = -normalize(cross(N, T));
71 mat3 TBN = mat3(T, B, N);
73 return normalize(TBN * tangentNormal);
77 vec3 albedo = vec3(1);
79 albedo = pow(texture(mat.albedoMap, texCoords).rgb, vec3(2.2));
81 vec3 normal = getNormalFromMap();
83 float metallic = 0, roughness = 1;
84 if (mat.hasMetallicRoughness) {
85 metallic = texture(mat.metallicRoughnessMap, texCoords).b;
86 roughness = texture(mat.metallicRoughnessMap, texCoords).g;
88 float ao = mat.hasAo ? texture(mat.aoMap, texCoords).r : 1;
90 vec3 N = normalize(normal);
91 vec3 V = normalize(camPos - worldPos);
93 vec3 F0 = mix(vec3(0.04), albedo, metallic);
95 vec3 R = reflect(-V, N);
99 for (int i = 0; i < numLights; i++) {
100 vec3 L = normalize(lightPositions[i] - worldPos);
101 vec3 H = normalize(V + L);
103 // calculate radiance
104 float dist = length(lightPositions[i] - worldPos);
105 float attenuation = 5.f / (dist * dist);
106 vec3 radiance = lightColors[i] * attenuation;
108 // cook-torrance brdf
109 vec3 F = fresnelSchlick(mdot(H, V), F0);
110 float NDF = distributionGGX(N, H, roughness);
111 float G = geometrySmith(N, V, L, roughness);
113 float denom = 4.f * mdot(N, V) * mdot(N, L);
114 vec3 specular = (NDF * G * F) / max(denom, 0.0000001);
116 vec3 kS = F; // fresnel = reflection ratio
117 vec3 kD = vec3(1.f) - kS;
118 kD *= 1.f - metallic;
120 Lo += (kD * albedo / PI + specular) * radiance * mdot(N, L);
123 vec3 F = fresnelSchlickRoughness(mdot(N, V), F0, roughness);
126 vec3 kD = (1.f - kS) * (1.f - metallic);
128 vec3 irradiance = texture(irradianceMap, N).rgb;
129 vec3 diffuse = irradiance * albedo;
131 const float maxReflectionLoD = 4.f;
132 vec3 prefilteredColor = textureLod(prefilterMap, R, roughness * maxReflectionLoD).rgb;
133 vec2 envBRDF = texture(brdfMap, vec2(mdot(N, V), roughness)).rg;
134 vec3 specular = prefilteredColor * (F * envBRDF.x + envBRDF.y);
136 vec3 ambient = (kD * diffuse + specular) * ao;
137 vec3 color = ambient + Lo;
139 color = color / (color + vec3(1.f)); // map to HDR
140 color = pow(color, vec3(1.f / 2.2)); // gamma correction
142 fragColor = vec4(color, 1.f);