5 uniform sampler2D sAlbedoMetal;
6 uniform sampler2D sNormalRoughness;
7 uniform samplerCube sDiffuse;
8 uniform samplerCube sSpecular;
10 // Transformation matrix of the cubemap texture
12 // Number of mip map levels in the texture
13 uniform float uMaxLOD;
15 // Number of mip map levels in the texture
16 uniform float uRoughness;
18 // Number of mip map levels in the texture
19 uniform float uMetallic;
30 // Functions for BRDF calculation come from
31 // https://www.unrealengine.com/blog/physically-based-shading-on-mobile
32 // Based on the paper by Dimitar Lazarov
33 // http://blog.selfshadow.com/publications/s2013-shading-course/lazarov/s2013_pbs_black_ops_2_notes.pdf
34 vec3 EnvBRDFApprox( vec3 SpecularColor, float Roughness, float NoV )
36 const vec4 c0 = vec4( -1.0, -0.0275, -0.572, 0.022 );
37 const vec4 c1 = vec4( 1.0, 0.0425, 1.04, -0.04 );
38 vec4 r = Roughness * c0 + c1;
39 float a004 = min( r.x * r.x, exp2( -9.28 * NoV ) ) * r.x + r.y;
40 vec2 AB = vec2( -1.04, 1.04 ) * a004 + r.zw;
42 return SpecularColor * AB.x + AB.y;
47 // We get information from the maps (albedo, normal map, roughness, metalness
48 // I access the maps in the order they will be used
49 vec4 normalRoughness = texture(sNormalRoughness, vUV.st);
50 vec3 normalMap = normalRoughness.rgb;
51 float roughness = normalRoughness.a * uRoughness;
53 vec4 albedoMetal = texture(sAlbedoMetal, vUV.st);
54 vec3 albedoColor = albedoMetal.rgb;
55 float metallic = albedoMetal.a * uMetallic;
58 vec3 normal = normalize(vNormal);
59 vec3 tangent = normalize(vTangent);
60 vec3 bitangent = normalize(vBitangent);
62 vec3 viewVec = normalize(vViewVec);
64 // Create Inverse Local to world matrix
65 mat3 vInvTBN = mat3(tangent, bitangent, normal);
67 // Get normal map info in world space
68 normalMap = normalize((normalMap - 0.5) * 2.0);
69 vec3 newNormal = vInvTBN * normalMap.rgb;
71 // Calculate normal dot view vector
72 float NoV = clamp(dot(newNormal, -viewVec), 0.0, 1.0);
75 vec3 reflectionVec = reflect(viewVec, newNormal);
77 //transform it now to environment coordinates (used when the environment rotates)
78 vec3 reflecCube = (uCubeMatrix * vec4(reflectionVec,0)).xyz;
79 reflecCube = normalize(reflecCube);
81 //transform it now to environment coordinates
82 vec3 normalCube = (uCubeMatrix * vec4(newNormal,0)).xyz;
83 normalCube = normalize(normalCube);
85 // Get irradiance from diffuse cubemap
86 vec3 irradiance = texture(sDiffuse, normalCube).rgb;
88 // Way to access the mip map level - copied from UE
89 const float REFLECTION_CAPTURE_ROUGHEST_MIP = 1.;
90 const float REFLECTION_CAPTURE_ROUGHNESS_MIP_SCALE = 1.2;
91 float LevelFrom1x1 = REFLECTION_CAPTURE_ROUGHEST_MIP - REFLECTION_CAPTURE_ROUGHNESS_MIP_SCALE * log2(roughness);
92 // Note: must match GReflectionCaptureSize
93 // We need to subtract 2 levels from the uMaxLOD because we don't have the smallest mipmaps
94 // (and because these levels are very small 1x1, 2x2, etc.)
95 float finalLod = (uMaxLOD - 2.0) - 1.0 - LevelFrom1x1;
97 // calculate the convexity and increase the reflectance lobe
98 float convexity = length(fwidth(newNormal));
99 finalLod += convexity * (uMaxLOD - 2.0);
101 // Access reflection color using roughness value
102 vec3 reflectionColor = textureLod(sSpecular, reflecCube, finalLod).rgb;
104 // For increasing contrast a little bit - It should be Gamma correction (2.2) but it gets to dark
105 albedoColor = pow(albedoColor,vec3(1.2));
107 // We use DielectricColor of a plastic (almost everything)
108 // http://blog.selfshadow.com/publications/s2014-shading-course/hoffman/s2014_pbs_physics_math_slides.pdf
109 vec3 DielectricSpecular = vec3(0.04);
110 vec3 DiffuseColor = albedoColor - albedoColor * metallic; // 1 mad
111 vec3 SpecularColor = (DielectricSpecular - DielectricSpecular * metallic) + albedoColor * metallic; //2 mad
113 // Calculate specular color using Magic Function (takes original rougness and normal dot view
114 vec3 specColor = reflectionColor.rgb * EnvBRDFApprox(SpecularColor, roughness, NoV);// * irradiance;
116 // Multiply the result by albedo texture and do energy conservation
117 vec3 diffuseColor = irradiance * DiffuseColor;
119 // Final color is the sum of the diffuse and specular term
120 vec3 finalColor = diffuseColor + specColor;
121 //FragColor = vec4(1.0, 1.0, 1.0, 1.0);
122 finalColor = finalColor / (finalColor + vec3(1));
123 FragColor = vec4(finalColor,1.0);