diff --git a/kitty/shaders/hsluv.slang b/kitty/shaders/hsluv.slang new file mode 100644 index 000000000..9c69fadb9 --- /dev/null +++ b/kitty/shaders/hsluv.slang @@ -0,0 +1,216 @@ +#language slang 2026 +// Copyright (C) 2026 Kovid Goyal +// Distributed under terms of the GPLv3 license. + +module hsluv; + +// Helper Functions +float divide(float num, float denom) { + return num / (abs(denom) + 1e-15) * sign(denom); +} + +float3 divide(float3 num, float3 denom) { + return num / (abs(denom) + 1e-15) * sign(denom); +} + +float3 hsluv_intersectLineLine(float3 line1x, float3 line1y, float3 line2x, float3 line2y) { + return (line1y - line2y) / (line2x - line1x); +} + +float3 hsluv_distanceFromPole(float3 pointx, float3 pointy) { + return sqrt(pointx * pointx + pointy * pointy); +} + +float3 hsluv_lengthOfRayUntilIntersect(float theta, float3 x, float3 y) { + float3 len = divide(y, sin(theta) - x * cos(theta)); + len = lerp(len, (float3)1000.0, step(len, (float3)0.0)); + return len; +} + +float hsluv_maxSafeChromaForL(float L) { + // Transposed from GLSL column-major constructor to Slang row-major layout + float3x3 m2 = float3x3( + 3.2409699419045214, -1.5373831775700935, -0.49861076029300328, + -0.96924363628087983, 1.8759675015077207, 0.041555057407175613, + 0.055630079696993609,-0.20397695888897657, 1.0569715142428786 + ); + + float sub0 = L + 16.0; + float sub1 = sub0 * sub0 * sub0 * 0.000000641; + float sub2 = lerp(L / 903.2962962962963, sub1, step(0.0088564516790356308, sub1)); + + float3 top1 = (284517.0 * m2[0] - 94839.0 * m2[2]) * sub2; + float3 bottom = (632260.0 * m2[2] - 126452.0 * m2[1]) * sub2; + float3 top2 = (838422.0 * m2[2] + 769860.0 * m2[1] + 731718.0 * m2[0]) * L * sub2; + + float3 bounds0x = top1 / bottom; + float3 bounds0y = top2 / bottom; + + float3 bounds1x = top1 / (bottom + 126452.0); + float3 bounds1y = (top2 - 769860.0 * L) / (bottom + 126452.0); + + float3 xs0 = hsluv_intersectLineLine(bounds0x, bounds0y, -1.0 / bounds0x, (float3)0.0); + float3 xs1 = hsluv_intersectLineLine(bounds1x, bounds1y, -1.0 / bounds1x, (float3)0.0); + + float3 lengths0 = hsluv_distanceFromPole(xs0, bounds0y + xs0 * bounds0x); + float3 lengths1 = hsluv_distanceFromPole(xs1, bounds1y + xs1 * bounds1x); + + return min(lengths0.x, + min(lengths1.x, + min(lengths0.y, + min(lengths1.y, + min(lengths0.z, + lengths1.z))))); +} + +float hsluv_maxChromaForLH(float L, float H) { + float hrad = radians(H); + + // Transposed from GLSL column-major constructor to Slang row-major layout + float3x3 m2 = float3x3( + 3.2409699419045214, -1.5373831775700935, -0.49861076029300328, + -0.96924363628087983, 1.8759675015077207, 0.041555057407175613, + 0.055630079696993609,-0.20397695888897657, 1.0569715142428786 + ); + + float sub1 = pow(L + 16.0, 3.0) / 1560896.0; + float sub2 = lerp(L / 903.2962962962963, sub1, step(0.0088564516790356308, sub1)); + + float3 top1 = (284517.0 * m2[0] - 94839.0 * m2[2]) * sub2; + float3 bottom = (632260.0 * m2[2] - 126452.0 * m2[1]) * sub2; + float3 top2 = (838422.0 * m2[2] + 769860.0 * m2[1] + 731718.0 * m2[0]) * L * sub2; + + float3 bound0x = top1 / bottom; + float3 bound0y = top2 / bottom; + + float3 bound1x = top1 / (bottom + 126452.0); + float3 bound1y = (top2 - 769860.0 * L) / (bottom + 126452.0); + + float3 lengths0 = hsluv_lengthOfRayUntilIntersect(hrad, bound0x, bound0y); + float3 lengths1 = hsluv_lengthOfRayUntilIntersect(hrad, bound1x, bound1y); + + return min(lengths0.x, + min(lengths1.x, + min(lengths0.y, + min(lengths1.y, + min(lengths0.z, + lengths1.z))))); +} + +float3 hsluv_fromLinear(float3 c) { + return lerp(c * 12.92, 1.055 * pow(max(c, (float3)0), (float3)(1.0 / 2.4)) - 0.055, step(0.0031308, c)); +} + +float3 hsluv_toLinear(float3 c) { + return lerp(c / 12.92, pow(max((c + 0.055) / (1.0 + 0.055), (float3)0), (float3)2.4), step(0.04045, c)); +} + +float hsluv_yToL(float Y) { + return lerp(Y * 903.2962962962963, 116.0 * pow(max(Y, 0), 1.0 / 3.0) - 16.0, step(0.0088564516790356308, Y)); +} + +float hsluv_lToY(float L) { + return lerp(L / 903.2962962962963, pow((max(L, 0) + 16.0) / 116.0, 3.0), step(8.0, L)); +} + +float3 xyzToRgb(float3 tuple) { + // Transposed layout from GLSL column-major matrix construction + const float3x3 m = float3x3( + 3.2409699419045214, -0.96924363628087983, 0.055630079696993609, + -1.5373831775700935, 1.8759675015077207, -0.20397695888897657, + -0.49861076029300328, 0.041555057407175613, 1.0569715142428786 + ); + // GLSL `tuple * m` is transformed to Slang/HLSL `mul(m, tuple)` + return hsluv_fromLinear(mul(m, tuple)); +} + +float3 rgbToXyz(float3 tuple) { + // Transposed layout from GLSL column-major matrix construction + const float3x3 m = float3x3( + 0.41239079926595948, 0.21263900587151036, 0.019330818715591851, + 0.35758433938387796, 0.71516867876775593, 0.11919477979462599, + 0.18048078840183429, 0.072192315360733715, 0.95053215224966058 + ); + // GLSL `tuple * m` is transformed to Slang/HLSL `mul(m, tuple)` + return mul(m, hsluv_toLinear(tuple)); +} + +float3 xyzToLuv(float3 tuple) { + float X = tuple.x; + float Y = tuple.y; + float Z = tuple.z; + + float L = hsluv_yToL(Y); + float div = 1.0 / max(dot(tuple, float3(1, 15, 3)), 1e-15); + + return float3( + 1.0, + (52.0 * (X * div) - 2.57179), + (117.0 * (Y * div) - 6.08816) + ) * L; +} + +float3 luvToXyz(float3 tuple) { + float L = tuple.x; + + float U = divide(tuple.y, 13.0 * L) + 0.19783000664283681; + float V = divide(tuple.z, 13.0 * L) + 0.468319994938791; + + float Y = hsluv_lToY(L); + float X = 2.25 * U * Y / V; + float Z = (3.0 / V - 5.0) * Y - (X / 3.0); + + return float3(X, Y, Z); +} + +float3 luvToLch(float3 tuple) { + float L = tuple.x; + float U = tuple.y; + float V = tuple.z; + + float C = length(tuple.yz); + float H = degrees(atan2(V, U)); // Slang standard library uses atan2(y, x) + H += 360.0 * step(H, 0.0); + + return float3(L, C, H); +} + +float3 lchToLuv(float3 tuple) { + float hrad = radians(tuple.z); + return float3( + tuple.x, + cos(hrad) * tuple.y, + sin(hrad) * tuple.y + ); +} + +float3 hsluvToLch(float3 tuple) { + tuple.y *= hsluv_maxChromaForLH(tuple.z, tuple.x) * 0.01; + return tuple.zyx; +} + +float3 lchToHsluv(float3 tuple) { + tuple.y = divide(tuple.y, hsluv_maxChromaForLH(tuple.x, tuple.z) * 0.01); + return tuple.zyx; +} + +float3 lchToRgb(float3 tuple) { + return xyzToRgb(luvToXyz(lchToLuv(tuple))); +} + +float3 rgbToLch(float3 tuple) { + return luvToLch(xyzToLuv(rgbToXyz(tuple))); +} + +public float3 hsluvToRgb(float3 tuple) { + return lchToRgb(hsluvToLch(tuple)); +} + +public float3 rgbToHsluv(float3 tuple) { + return lchToHsluv(rgbToLch(tuple)); +} + +float3 luvToRgb(float3 tuple) { + return xyzToRgb(luvToXyz(tuple)); +} +