mirror of
https://github.com/X0nk/Bliss-Shader.git
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115 lines
4.1 KiB
GLSL
115 lines
4.1 KiB
GLSL
#define log10(x) log(x) / log(10.0)
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struct SegmentedSplineParams_c5 {
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float coefsLow[6]; // coefs for B-spline between minPoint and midPoint (units of log luminance)
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float coefsHigh[6]; // coefs for B-spline between midPoint and maxPoint (units of log luminance)
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vec2 minPoint; // {luminance, luminance} linear extension below this
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vec2 midPoint; // {luminance, luminance}
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vec2 maxPoint; // {luminance, luminance} linear extension above this
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float slopeLow; // log-log slope of low linear extension
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float slopeHigh; // log-log slope of high linear extension
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};
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struct SegmentedSplineParams_c9 {
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float coefsLow[10]; // coefs for B-spline between minPoint and midPoint (units of log luminance)
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float coefsHigh[10]; // coefs for B-spline between midPoint and maxPoint (units of log luminance)
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float slopeLow; // log-log slope of low linear extension
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float slopeHigh; // log-log slope of high linear extension
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};
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const mat3 M = mat3(
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0.5, -1.0, 0.5,
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-1.0, 1.0, 0.5,
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0.5, 0.0, 0.0
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);
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float segmented_spline_c5_fwd(float x) {
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const SegmentedSplineParams_c5 C = SegmentedSplineParams_c5(
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float[6] ( -4.0000000000, -4.0000000000, -3.1573765773, -0.4852499958, 1.8477324706, 1.8477324706 ),
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float[6] ( -0.7185482425, 2.0810307172, 3.6681241237, 4.0000000000, 4.0000000000, 4.0000000000 ),
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vec2(0.18*exp2(-15.0), 0.0001),
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vec2(0.18, 4.8),
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vec2(0.18*exp2(18.0), 10000.),
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0.0,
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0.0
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);
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const int N_KNOTS_LOW = 4;
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const int N_KNOTS_HIGH = 4;
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// Check for negatives or zero before taking the log. If negative or zero,
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// set to ACESMIN.1
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float xCheck = x <= 0 ? exp2(-14.0) : x;
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float logx = log10( xCheck);
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float logy;
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if (logx <= log10(C.minPoint.x)) {
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logy = logx * C.slopeLow + (log10(C.minPoint.y) - C.slopeLow * log10(C.minPoint.x));
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} else if ((logx > log10(C.minPoint.x)) && (logx < log10(C.midPoint.x))) {
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float knot_coord = (N_KNOTS_LOW-1) * (logx-log10(C.minPoint.x))/(log10(C.midPoint.x)-log10(C.minPoint.x));
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int j = int(knot_coord);
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float t = knot_coord - float(j);
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vec3 cf = vec3( C.coefsLow[ j], C.coefsLow[ j + 1], C.coefsLow[ j + 2]);
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vec3 monomials = vec3(t * t, t, 1.0);
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logy = dot( monomials, M * cf);
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} else if ((logx >= log10(C.midPoint.x)) && (logx < log10(C.maxPoint.x))) {
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float knot_coord = (N_KNOTS_HIGH - 1) * (logx - log10(C.midPoint.x)) / (log10(C.maxPoint.x) - log10(C.midPoint.x));
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int j = int(knot_coord);
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float t = knot_coord - float(j);
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vec3 cf = vec3(C.coefsHigh[j], C.coefsHigh[j + 1], C.coefsHigh[j + 2]);
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vec3 monomials = vec3(t * t, t, 1.0);
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logy = dot(monomials, M * cf);
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} else {
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logy = logx * C.slopeHigh + (log10(C.maxPoint.y) - C.slopeHigh * log10(C.maxPoint.x));
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}
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return pow(10.0, logy);
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}
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float segmented_spline_c9_fwd( float x, const SegmentedSplineParams_c9 C, const mat3x2 toningPoints) {
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const int N_KNOTS_LOW = 8;
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const int N_KNOTS_HIGH = 8;
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// Check for negatives or zero before taking the log. If negative or zero,
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// set to OCESMIN.
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float xCheck = x <= 0 ? 1e-4 : x;
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vec2 minPoint = toningPoints[0];
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vec2 midPoint = toningPoints[1];
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vec2 maxPoint = toningPoints[2];
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float logx = log10(xCheck);
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float logy;
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if (logx <= log10(minPoint.x)) {
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logy = logx * C.slopeLow + (log10(minPoint.y) - C.slopeLow * log10(minPoint.x));
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} else if ((logx > log10(minPoint.x)) && (logx < log10(midPoint.x))) {
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float knot_coord = (N_KNOTS_LOW - 1) * (logx - log10(minPoint.x)) / (log10(midPoint.x) - log10(minPoint.x));
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int j = int(knot_coord);
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float t = knot_coord - float(j);
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vec3 cf = vec3(C.coefsLow[j], C.coefsLow[j + 1], C.coefsLow[j + 2]);
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vec3 monomials = vec3(t * t, t, 1.0);
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logy = dot(monomials, M * cf);
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} else if ((logx >= log10(midPoint.x)) && (logx < log10(maxPoint.x))) {
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float knot_coord = (N_KNOTS_HIGH - 1) * (logx - log10(midPoint.x)) / (log10(maxPoint.x) - log10(midPoint.x));
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int j = int(knot_coord);
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float t = knot_coord - float(j);
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vec3 cf = vec3(C.coefsHigh[j], C.coefsHigh[j + 1], C.coefsHigh[j + 2]);
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vec3 monomials = vec3(t * t, t, 1.0);
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logy = dot(monomials, M * cf);
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} else {
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logy = logx * C.slopeHigh + (log10(maxPoint.y) - C.slopeHigh * log10(maxPoint.x));
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}
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return pow(10.0, logy);
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} |