Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 | //This file is automatically rebuilt by the Cesium build process.
export default "uniform samplerCube u_radianceMap;\n\
\n\
in vec2 v_textureCoordinates;\n\
\n\
\n\
const float twoSqrtPi = 2.0 * sqrt(czm_pi);\n\
\n\
// Coutesy of https://www.ppsloan.org/publications/StupidSH36.pdf\n\
float computeShBasis(int index, vec3 s) {\n\
if (index == 0) { // l = 0, m = 0\n\
return 1.0 / twoSqrtPi;\n\
}\n\
\n\
if (index == 1) { // l = 1, m = -1\n\
return -sqrt(3.0) * s.y / twoSqrtPi;\n\
}\n\
\n\
if (index == 2) { // l = 1, m = 0\n\
return sqrt(3.0) * s.z / twoSqrtPi;\n\
}\n\
\n\
if (index == 3) { // l = 1, m = 1\n\
return -sqrt(3.0) * s.x / twoSqrtPi;\n\
}\n\
\n\
if (index == 4) { // l = 2, m = -2\n\
return sqrt(15.0) * s.y * s.x / twoSqrtPi;\n\
}\n\
\n\
if (index == 5) { // l = 2, m = -1\n\
return -sqrt(15.0) * s.y * s.z / twoSqrtPi;\n\
}\n\
\n\
if (index == 6) { // l = 2, m = 0\n\
return sqrt(5.0) * (3.0 * s.z * s.z - 1.0) / 2.0 / twoSqrtPi;\n\
}\n\
\n\
if (index == 7) { // l = 2, m = 1\n\
return -sqrt(15.0) * s.x * s.z / twoSqrtPi;\n\
}\n\
\n\
if (index == 8) { // l = 2, m = 2\n\
return sqrt(15.0) * (s.x * s.x - s.y * s.y) / 2.0 / twoSqrtPi;\n\
}\n\
\n\
return 0.0;\n\
}\n\
\n\
float vdcRadicalInverse(int i)\n\
{\n\
float r;\n\
float base = 2.0;\n\
float value = 0.0;\n\
float invBase = 1.0 / base;\n\
float invBi = invBase;\n\
for (int x = 0; x < 100; x++)\n\
{\n\
if (i <= 0)\n\
{\n\
break;\n\
}\n\
r = mod(float(i), base);\n\
value += r * invBi;\n\
invBi *= invBase;\n\
i = int(float(i) * invBase);\n\
}\n\
return value;\n\
}\n\
\n\
vec2 hammersley2D(int i, int N)\n\
{\n\
return vec2(float(i) / float(N), vdcRadicalInverse(i));\n\
}\n\
\n\
// Sample count is relatively low for the sake of performance, but should still be enough to capture directionality needed for third-order harmonics\n\
const int samples = 256; \n\
const float solidAngle = 1.0 / float(samples);\n\
\n\
void main() {\n\
// Get the current coefficient based on the uv\n\
vec2 uv = v_textureCoordinates.xy * 3.0;\n\
int coefficientIndex = int(floor(uv.y) * 3.0 + floor(uv.x));\n\
\n\
for (int i = 0; i < samples; ++i) {\n\
vec2 xi = hammersley2D(i, samples);\n\
float phi = czm_twoPi * xi.x;\n\
float cosTheta = 1.0 - 2.0 * sqrt(1.0 - xi.y * xi.y);\n\
float sinTheta = sqrt(1.0 - cosTheta * cosTheta);\n\
vec3 direction = normalize(vec3(sinTheta * cos(phi), cosTheta, sinTheta * sin(phi)));\n\
\n\
// Generate the spherical harmonics basis from the direction\n\
float Ylm = computeShBasis(coefficientIndex, direction);\n\
\n\
vec3 lookupDirection = -direction.xyz;\n\
lookupDirection.z = -lookupDirection.z;\n\
\n\
vec4 color = czm_textureCube(u_radianceMap, lookupDirection, 0.0);\n\
\n\
// Use the relevant function for this coefficient\n\
out_FragColor += Ylm * color * solidAngle * sinTheta;\n\
}\n\
\n\
}\n\
";
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