372 lines
9.6 KiB
GLSL
372 lines
9.6 KiB
GLSL
/* clang-format off */
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[vertex]
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layout(location = 0) in highp vec2 vertex;
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/* clang-format on */
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layout(location = 4) in highp vec2 uv;
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out highp vec2 uv_interp;
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void main() {
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uv_interp = uv;
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gl_Position = vec4(vertex, 0, 1);
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}
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/* clang-format off */
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[fragment]
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precision highp float;
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/* clang-format on */
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precision highp int;
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#ifdef USE_SOURCE_PANORAMA
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uniform sampler2D source_panorama; //texunit:0
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#endif
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#ifdef USE_SOURCE_DUAL_PARABOLOID_ARRAY
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uniform sampler2DArray source_dual_paraboloid_array; //texunit:0
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uniform int source_array_index;
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#endif
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#ifdef USE_SOURCE_DUAL_PARABOLOID
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uniform sampler2D source_dual_paraboloid; //texunit:0
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#endif
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#if defined(USE_SOURCE_DUAL_PARABOLOID) || defined(COMPUTE_IRRADIANCE)
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uniform float source_mip_level;
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#endif
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#if !defined(USE_SOURCE_DUAL_PARABOLOID_ARRAY) && !defined(USE_SOURCE_PANORAMA) && !defined(USE_SOURCE_DUAL_PARABOLOID)
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uniform samplerCube source_cube; //texunit:0
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#endif
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uniform int face_id;
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uniform float roughness;
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uniform float source_resolution;
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in highp vec2 uv_interp;
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layout(location = 0) out vec4 frag_color;
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#define M_PI 3.14159265359
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vec3 texelCoordToVec(vec2 uv, int faceID) {
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mat3 faceUvVectors[6];
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/*
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// -x
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faceUvVectors[1][0] = vec3(0.0, 0.0, 1.0); // u -> +z
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faceUvVectors[1][1] = vec3(0.0, -1.0, 0.0); // v -> -y
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faceUvVectors[1][2] = vec3(-1.0, 0.0, 0.0); // -x face
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// +x
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faceUvVectors[0][0] = vec3(0.0, 0.0, -1.0); // u -> -z
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faceUvVectors[0][1] = vec3(0.0, -1.0, 0.0); // v -> -y
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faceUvVectors[0][2] = vec3(1.0, 0.0, 0.0); // +x face
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// -y
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faceUvVectors[3][0] = vec3(1.0, 0.0, 0.0); // u -> +x
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faceUvVectors[3][1] = vec3(0.0, 0.0, -1.0); // v -> -z
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faceUvVectors[3][2] = vec3(0.0, -1.0, 0.0); // -y face
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// +y
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faceUvVectors[2][0] = vec3(1.0, 0.0, 0.0); // u -> +x
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faceUvVectors[2][1] = vec3(0.0, 0.0, 1.0); // v -> +z
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faceUvVectors[2][2] = vec3(0.0, 1.0, 0.0); // +y face
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// -z
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faceUvVectors[5][0] = vec3(-1.0, 0.0, 0.0); // u -> -x
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faceUvVectors[5][1] = vec3(0.0, -1.0, 0.0); // v -> -y
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faceUvVectors[5][2] = vec3(0.0, 0.0, -1.0); // -z face
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// +z
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faceUvVectors[4][0] = vec3(1.0, 0.0, 0.0); // u -> +x
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faceUvVectors[4][1] = vec3(0.0, -1.0, 0.0); // v -> -y
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faceUvVectors[4][2] = vec3(0.0, 0.0, 1.0); // +z face
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*/
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// -x
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faceUvVectors[0][0] = vec3(0.0, 0.0, 1.0); // u -> +z
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faceUvVectors[0][1] = vec3(0.0, -1.0, 0.0); // v -> -y
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faceUvVectors[0][2] = vec3(-1.0, 0.0, 0.0); // -x face
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// +x
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faceUvVectors[1][0] = vec3(0.0, 0.0, -1.0); // u -> -z
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faceUvVectors[1][1] = vec3(0.0, -1.0, 0.0); // v -> -y
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faceUvVectors[1][2] = vec3(1.0, 0.0, 0.0); // +x face
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// -y
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faceUvVectors[2][0] = vec3(1.0, 0.0, 0.0); // u -> +x
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faceUvVectors[2][1] = vec3(0.0, 0.0, -1.0); // v -> -z
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faceUvVectors[2][2] = vec3(0.0, -1.0, 0.0); // -y face
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// +y
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faceUvVectors[3][0] = vec3(1.0, 0.0, 0.0); // u -> +x
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faceUvVectors[3][1] = vec3(0.0, 0.0, 1.0); // v -> +z
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faceUvVectors[3][2] = vec3(0.0, 1.0, 0.0); // +y face
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// -z
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faceUvVectors[4][0] = vec3(-1.0, 0.0, 0.0); // u -> -x
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faceUvVectors[4][1] = vec3(0.0, -1.0, 0.0); // v -> -y
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faceUvVectors[4][2] = vec3(0.0, 0.0, -1.0); // -z face
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// +z
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faceUvVectors[5][0] = vec3(1.0, 0.0, 0.0); // u -> +x
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faceUvVectors[5][1] = vec3(0.0, -1.0, 0.0); // v -> -y
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faceUvVectors[5][2] = vec3(0.0, 0.0, 1.0); // +z face
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// out = u * s_faceUv[0] + v * s_faceUv[1] + s_faceUv[2].
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vec3 result = (faceUvVectors[faceID][0] * uv.x) + (faceUvVectors[faceID][1] * uv.y) + faceUvVectors[faceID][2];
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return normalize(result);
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}
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vec3 ImportanceSampleGGX(vec2 Xi, float Roughness, vec3 N) {
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float a = Roughness * Roughness; // DISNEY'S ROUGHNESS [see Burley'12 siggraph]
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// Compute distribution direction
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float Phi = 2.0 * M_PI * Xi.x;
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float CosTheta = sqrt((1.0 - Xi.y) / (1.0 + (a * a - 1.0) * Xi.y));
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float SinTheta = sqrt(1.0 - CosTheta * CosTheta);
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// Convert to spherical direction
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vec3 H;
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H.x = SinTheta * cos(Phi);
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H.y = SinTheta * sin(Phi);
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H.z = CosTheta;
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vec3 UpVector = abs(N.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(1.0, 0.0, 0.0);
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vec3 TangentX = normalize(cross(UpVector, N));
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vec3 TangentY = cross(N, TangentX);
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// Tangent to world space
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return TangentX * H.x + TangentY * H.y + N * H.z;
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}
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float DistributionGGX(vec3 N, vec3 H, float roughness) {
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float a = roughness * roughness;
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float a2 = a * a;
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float NdotH = max(dot(N, H), 0.0);
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float NdotH2 = NdotH * NdotH;
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float nom = a2;
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float denom = (NdotH2 * (a2 - 1.0) + 1.0);
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denom = M_PI * denom * denom;
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return nom / denom;
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}
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// http://graphicrants.blogspot.com.au/2013/08/specular-brdf-reference.html
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float GGX(float NdotV, float a) {
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float k = a / 2.0;
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return NdotV / (NdotV * (1.0 - k) + k);
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}
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// http://graphicrants.blogspot.com.au/2013/08/specular-brdf-reference.html
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float G_Smith(float a, float nDotV, float nDotL) {
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return GGX(nDotL, a * a) * GGX(nDotV, a * a);
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}
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float radicalInverse_VdC(uint bits) {
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bits = (bits << 16u) | (bits >> 16u);
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bits = ((bits & 0x55555555u) << 1u) | ((bits & 0xAAAAAAAAu) >> 1u);
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bits = ((bits & 0x33333333u) << 2u) | ((bits & 0xCCCCCCCCu) >> 2u);
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bits = ((bits & 0x0F0F0F0Fu) << 4u) | ((bits & 0xF0F0F0F0u) >> 4u);
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bits = ((bits & 0x00FF00FFu) << 8u) | ((bits & 0xFF00FF00u) >> 8u);
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return float(bits) * 2.3283064365386963e-10; // / 0x100000000
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}
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vec2 Hammersley(uint i, uint N) {
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return vec2(float(i) / float(N), radicalInverse_VdC(i));
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}
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#ifdef LOW_QUALITY
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#define SAMPLE_COUNT 64u
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#define SAMPLE_DELTA 0.05
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#else
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#define SAMPLE_COUNT 512u
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#define SAMPLE_DELTA 0.01
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#endif
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uniform bool z_flip;
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#ifdef USE_SOURCE_PANORAMA
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vec4 texturePanorama(vec3 normal, sampler2D pano, float mipLevel) {
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vec2 st = vec2(
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atan(normal.x, normal.z),
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acos(normal.y));
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if (st.x < 0.0)
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st.x += M_PI * 2.0;
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st /= vec2(M_PI * 2.0, M_PI);
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return textureLod(pano, st, mipLevel);
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}
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#endif
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#ifdef USE_SOURCE_DUAL_PARABOLOID_ARRAY
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vec4 textureDualParaboloidArray(vec3 normal) {
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vec3 norm = normalize(normal);
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norm.xy /= 1.0 + abs(norm.z);
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norm.xy = norm.xy * vec2(0.5, 0.25) + vec2(0.5, 0.25);
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if (norm.z < 0.0) {
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norm.y = 0.5 - norm.y + 0.5;
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}
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return textureLod(source_dual_paraboloid_array, vec3(norm.xy, float(source_array_index)), 0.0);
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}
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#endif
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#ifdef USE_SOURCE_DUAL_PARABOLOID
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vec4 textureDualParaboloid(vec3 normal) {
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vec3 norm = normalize(normal);
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norm.xy /= 1.0 + abs(norm.z);
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norm.xy = norm.xy * vec2(0.5, 0.25) + vec2(0.5, 0.25);
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if (norm.z < 0.0) {
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norm.y = 0.5 - norm.y + 0.5;
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}
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return textureLod(source_dual_paraboloid, norm.xy, source_mip_level);
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}
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#endif
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void main() {
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#ifdef USE_DUAL_PARABOLOID
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vec3 N = vec3(uv_interp * 2.0 - 1.0, 0.0);
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N.z = 0.5 - 0.5 * ((N.x * N.x) + (N.y * N.y));
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N = normalize(N);
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if (z_flip) {
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N.y = -N.y; //y is flipped to improve blending between both sides
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N.z = -N.z;
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}
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#else
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vec2 uv = (uv_interp * 2.0) - 1.0;
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vec3 N = texelCoordToVec(uv, face_id);
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#endif
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//vec4 color = color_interp;
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#ifdef USE_DIRECT_WRITE
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#ifdef USE_SOURCE_PANORAMA
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frag_color = vec4(texturePanorama(N, source_panorama, 0.0).rgb, 1.0);
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#endif
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#ifdef USE_SOURCE_DUAL_PARABOLOID_ARRAY
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frag_color = vec4(textureDualParaboloidArray(N).rgb, 1.0);
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#endif
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#ifdef USE_SOURCE_DUAL_PARABOLOID
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frag_color = vec4(textureDualParaboloid(N).rgb, 1.0);
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#endif
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#if !defined(USE_SOURCE_DUAL_PARABOLOID_ARRAY) && !defined(USE_SOURCE_PANORAMA) && !defined(USE_SOURCE_DUAL_PARABOLOID)
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N.y = -N.y;
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frag_color = vec4(texture(N, source_cube).rgb, 1.0);
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#endif
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#else // USE_DIRECT_WRITE
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#ifdef COMPUTE_IRRADIANCE
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vec3 irradiance = vec3(0.0);
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// tangent space calculation from origin point
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vec3 UpVector = vec3(0.0, 1.0, 0.0);
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vec3 TangentX = cross(UpVector, N);
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vec3 TangentY = cross(N, TangentX);
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float num_samples = 0.0f;
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for (float phi = 0.0; phi < 2.0 * M_PI; phi += SAMPLE_DELTA) {
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for (float theta = 0.0; theta < 0.5 * M_PI; theta += SAMPLE_DELTA) {
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// Calculate sample positions
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vec3 tangentSample = vec3(sin(theta) * cos(phi), sin(theta) * sin(phi), cos(theta));
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// Find world vector of sample position
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vec3 H = tangentSample.x * TangentX + tangentSample.y * TangentY + tangentSample.z * N;
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vec2 st = vec2(atan(H.x, H.z), acos(H.y));
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if (st.x < 0.0) {
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st.x += M_PI * 2.0;
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}
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st /= vec2(M_PI * 2.0, M_PI);
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irradiance += texture(source_panorama, st, source_mip_level).rgb * cos(theta) * sin(theta);
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num_samples++;
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}
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}
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irradiance = M_PI * irradiance * (1.0 / float(num_samples));
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frag_color = vec4(irradiance, 1.0);
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#else
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vec4 sum = vec4(0.0, 0.0, 0.0, 0.0);
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for (uint sampleNum = 0u; sampleNum < SAMPLE_COUNT; sampleNum++) {
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vec2 xi = Hammersley(sampleNum, SAMPLE_COUNT);
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vec3 H = normalize(ImportanceSampleGGX(xi, roughness, N));
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vec3 V = N;
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vec3 L = normalize(2.0 * dot(V, H) * H - V);
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float ndotl = max(dot(N, L), 0.0);
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if (ndotl > 0.0) {
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float D = DistributionGGX(N, H, roughness);
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float ndoth = max(dot(N, H), 0.0);
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float hdotv = max(dot(H, V), 0.0);
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float pdf = D * ndoth / (4.0 * hdotv) + 0.0001;
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float saTexel = 4.0 * M_PI / (6.0 * source_resolution * source_resolution);
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float saSample = 1.0 / (float(SAMPLE_COUNT) * pdf + 0.0001);
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float mipLevel = roughness == 0.0 ? 0.0 : 0.5 * log2(saSample / saTexel);
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#ifdef USE_SOURCE_PANORAMA
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sum.rgb += texturePanorama(L, source_panorama, mipLevel).rgb * ndotl;
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#endif
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#ifdef USE_SOURCE_DUAL_PARABOLOID_ARRAY
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sum.rgb += textureDualParaboloidArray(L).rgb * ndotl;
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#endif
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#ifdef USE_SOURCE_DUAL_PARABOLOID
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sum.rgb += textureDualParaboloid(L).rgb * ndotl;
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#endif
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#if !defined(USE_SOURCE_DUAL_PARABOLOID_ARRAY) && !defined(USE_SOURCE_PANORAMA) && !defined(USE_SOURCE_DUAL_PARABOLOID)
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L.y = -L.y;
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sum.rgb += textureLod(source_cube, L, 0.0).rgb * ndotl;
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#endif
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sum.a += ndotl;
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}
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}
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sum /= sum.a;
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frag_color = vec4(sum.rgb, 1.0);
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#endif // COMPUTE_IRRADIANCE
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#endif // USE_DIRECT_WRITE
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}
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