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;
19 uniform vec3 lightPositions[4];
20 uniform vec3 lightColors[4];
22 const float PI = 3.14159265359;
24 vec3 fresnelSchlick(float cosTheta, vec3 F0) {
25 return F0 + (1.f - F0) * pow(1.f - cosTheta, 5.f);
28 vec3 fresnelSchlickRoughness(float cosTheta, vec3 F0, float roughness) {
29 return F0 + (max(vec3(1.f - roughness), F0) - F0) * pow(1.f - cosTheta, 5.f);
32 float distributionGGX(vec3 N, vec3 H, float roughness) {
33 float a = roughness * roughness;
34 float NdotH = mdot(N, H);
35 float denom = (NdotH * NdotH) * ((a * a) - 1.f) + 1.f;
36 denom = PI * denom * denom;
37 return (a * a) / denom;
40 float geometrySchlickGGX(float NdotV, float roughness) {
41 float r = roughness + 1.f;
42 float k = (r * r) / 8.f;
43 return NdotV / (NdotV * (1.f - k) + k);
46 float geometrySmith(vec3 N, vec3 V, vec3 L, float roughness) {
47 float ggx1 = geometrySchlickGGX(mdot(N, L), roughness);
48 float ggx2 = geometrySchlickGGX(mdot(N, V), roughness);
52 vec3 getNormalFromMap() {
53 vec3 tangentNormal = texture(normalMap, texCoords).xyz * 2.f - 1.f;
54 vec3 Q1 = dFdx(worldPos);
55 vec3 Q2 = dFdy(worldPos);
56 vec2 st1 = dFdx(texCoords);
57 vec2 st2 = dFdy(texCoords);
59 vec3 N = normalize(normal);
60 vec3 T = normalize(Q1 * st2.t - Q2 * st1.t);
61 vec3 B = -normalize(cross(N, T));
62 mat3 TBN = mat3(T, B, N);
64 return normalize(TBN * tangentNormal);
68 vec3 albedo = pow(texture(albedoMap, texCoords).rgb, vec3(2.2));
69 vec3 normal = getNormalFromMap();
70 float metallic = texture(metallicMap, texCoords).r;
71 float roughness = texture(roughnessMap, texCoords).r;
72 float ao = texture(aoMap, texCoords).r;
74 vec3 N = normalize(normal);
75 vec3 V = normalize(camPos - worldPos);
77 vec3 F0 = mix(vec3(0.04), albedo, metallic);
81 for (int i = 0; i < lightPositions.length(); i++) {
82 vec3 L = normalize(lightPositions[i] - worldPos);
83 vec3 H = normalize(V + L);
86 float dist = length(lightPositions[i] - worldPos);
87 float attenuation = 5.f / (dist * dist);
88 vec3 radiance = lightColors[i] * attenuation;
91 vec3 F = fresnelSchlick(mdot(H, V), F0);
92 float NDF = distributionGGX(N, H, roughness);
93 float G = geometrySmith(N, V, L, roughness);
95 float denom = 4.f * mdot(N, V) * mdot(N, L);
96 vec3 specular = (NDF * G * F) / max(denom, 0.0000001);
98 vec3 kS = F; // fresnel = reflection ratio
99 vec3 kD = vec3(1.f) - kS;
100 kD *= 1.f - metallic;
102 Lo += (kD * albedo / PI + specular) * radiance * mdot(N, L);
105 vec3 kD = 1.f - fresnelSchlickRoughness(mdot(N, V), F0, roughness);
106 vec3 diffuse = texture(irradianceMap, N).rgb * albedo;
107 vec3 ambient = (kD * diffuse) * ao;
108 vec3 color = ambient + Lo;
110 color = color / (color + vec3(1.f)); // map to HDR
111 color = pow(color, vec3(1.f / 2.2)); // gamma correction
113 fragColor = vec4(color, 1.f);