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test/intern/cycles/util/color.h

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9.6 KiB
C++

/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
*
* SPDX-License-Identifier: Apache-2.0 */
#pragma once
#include "util/math.h"
#include "util/types.h"
CCL_NAMESPACE_BEGIN
ccl_device uchar float_to_byte(const float val)
{
return ((val <= 0.0f) ?
0 :
((val > (1.0f - 0.5f / 255.0f)) ? 255 : (uchar)((255.0f * val) + 0.5f))); // NOLINT
}
ccl_device float byte_to_float(const uchar val)
{
return val * (1.0f / 255.0f);
}
ccl_device uchar4 color_float_to_byte(const float3 c)
{
uchar r;
uchar g;
uchar b;
r = float_to_byte(c.x);
g = float_to_byte(c.y);
b = float_to_byte(c.z);
return make_uchar4(r, g, b, 0);
}
ccl_device uchar4 color_float4_to_uchar4(const float4 c)
{
uchar r;
uchar g;
uchar b;
uchar a;
r = float_to_byte(c.x);
g = float_to_byte(c.y);
b = float_to_byte(c.z);
a = float_to_byte(c.w);
return make_uchar4(r, g, b, a);
}
ccl_device_inline float3 color_byte_to_float(const uchar4 c)
{
return make_float3(c.x * (1.0f / 255.0f), c.y * (1.0f / 255.0f), c.z * (1.0f / 255.0f));
}
ccl_device_inline float4 color_uchar4_to_float4(const uchar4 c)
{
return make_float4(
c.x * (1.0f / 255.0f), c.y * (1.0f / 255.0f), c.z * (1.0f / 255.0f), c.w * (1.0f / 255.0f));
}
ccl_device float color_srgb_to_linear(const float c)
{
if (c < 0.04045f) {
return (c < 0.0f) ? 0.0f : c * (1.0f / 12.92f);
}
return powf((c + 0.055f) * (1.0f / 1.055f), 2.4f);
}
ccl_device float color_linear_to_srgb(const float c)
{
if (c < 0.0031308f) {
return (c < 0.0f) ? 0.0f : c * 12.92f;
}
return 1.055f * powf(c, 1.0f / 2.4f) - 0.055f;
}
ccl_device float3 rgb_to_hsv(const float3 rgb)
{
float cmax;
float cmin;
float h;
float s;
float v;
float cdelta;
float3 c;
cmax = fmaxf(rgb.x, fmaxf(rgb.y, rgb.z));
cmin = min(rgb.x, min(rgb.y, rgb.z));
cdelta = cmax - cmin;
v = cmax;
if (cmax != 0.0f) {
s = cdelta / cmax;
}
else {
s = 0.0f;
h = 0.0f;
}
if (s != 0.0f) {
const float3 cmax3 = make_float3(cmax, cmax, cmax);
c = (cmax3 - rgb) / cdelta;
if (rgb.x == cmax) {
h = c.z - c.y;
}
else if (rgb.y == cmax) {
h = 2.0f + c.x - c.z;
}
else {
h = 4.0f + c.y - c.x;
}
h /= 6.0f;
if (h < 0.0f) {
h += 1.0f;
}
}
else {
h = 0.0f;
}
return make_float3(h, s, v);
}
ccl_device float3 hsv_to_rgb(const float3 hsv)
{
float i;
float f;
float p;
float q;
float t;
float h;
float s;
float v;
float3 rgb;
h = hsv.x;
s = hsv.y;
v = hsv.z;
if (s != 0.0f) {
if (h == 1.0f) {
h = 0.0f;
}
h *= 6.0f;
i = floorf(h);
f = h - i;
rgb = make_float3(f, f, f);
p = v * (1.0f - s);
q = v * (1.0f - (s * f));
t = v * (1.0f - (s * (1.0f - f)));
if (i == 0.0f) {
rgb = make_float3(v, t, p);
}
else if (i == 1.0f) {
rgb = make_float3(q, v, p);
}
else if (i == 2.0f) {
rgb = make_float3(p, v, t);
}
else if (i == 3.0f) {
rgb = make_float3(p, q, v);
}
else if (i == 4.0f) {
rgb = make_float3(t, p, v);
}
else {
rgb = make_float3(v, p, q);
}
}
else {
rgb = make_float3(v, v, v);
}
return rgb;
}
ccl_device float3 rgb_to_hsl(const float3 rgb)
{
float cmax;
float cmin;
float h;
float s;
float l;
cmax = fmaxf(rgb.x, fmaxf(rgb.y, rgb.z));
cmin = min(rgb.x, min(rgb.y, rgb.z));
l = min(1.0f, (cmax + cmin) / 2.0f);
if (cmax == cmin) {
h = s = 0.0f; /* achromatic */
}
else {
const float cdelta = cmax - cmin;
s = l > 0.5f ? cdelta / (2.0f - cmax - cmin) : cdelta / (cmax + cmin);
if (cmax == rgb.x) {
h = (rgb.y - rgb.z) / cdelta + (rgb.y < rgb.z ? 6.0f : 0.0f);
}
else if (cmax == rgb.y) {
h = (rgb.z - rgb.x) / cdelta + 2.0f;
}
else {
h = (rgb.x - rgb.y) / cdelta + 4.0f;
}
}
h /= 6.0f;
return make_float3(h, s, l);
}
ccl_device float3 hsl_to_rgb(const float3 hsl)
{
float nr;
float ng;
float nb;
float chroma;
float h;
float s;
float l;
h = hsl.x;
s = hsl.y;
l = hsl.z;
nr = fabsf(h * 6.0f - 3.0f) - 1.0f;
ng = 2.0f - fabsf(h * 6.0f - 2.0f);
nb = 2.0f - fabsf(h * 6.0f - 4.0f);
nr = clamp(nr, 0.0f, 1.0f);
nb = clamp(nb, 0.0f, 1.0f);
ng = clamp(ng, 0.0f, 1.0f);
chroma = (1.0f - fabsf(2.0f * l - 1.0f)) * s;
return make_float3((nr - 0.5f) * chroma + l, (ng - 0.5f) * chroma + l, (nb - 0.5f) * chroma + l);
}
ccl_device float3 xyY_to_xyz(const float x, const float y, float Y)
{
float X;
float Z;
if (y != 0.0f) {
X = (x / y) * Y;
}
else {
X = 0.0f;
}
if (y != 0.0f && Y != 0.0f) {
Z = (1.0f - x - y) / y * Y;
}
else {
Z = 0.0f;
}
return make_float3(X, Y, Z);
}
#ifdef __KERNEL_SSE2__
/*
* Calculate initial guess for arg^exp based on float representation
* This method gives a constant bias,
* which can be easily compensated by multiplication with bias_coeff.
* Gives better results for exponents near 1 (e. g. 4/5).
* exp = exponent, encoded as uint32_t
* e2coeff = 2^(127/exponent - 127) * bias_coeff^(1/exponent), encoded as uint32_t
*/
template<unsigned exp, unsigned e2coeff> ccl_device_inline float4 fastpow_sse2(const float4 &arg)
{
float4 ret = arg * cast(make_int4(e2coeff));
ret = make_float4(cast(ret));
ret = ret * cast(make_int4(exp));
ret = cast(make_int4(ret));
return ret;
}
/* Improve x ^ 1.0f/5.0f solution with Newton-Raphson method */
ccl_device_inline float4 improve_5throot_solution_sse2(const float4 &old_result, const float4 &x)
{
const float4 approx2 = old_result * old_result;
const float4 approx4 = approx2 * approx2;
const float4 t = x / approx4;
const float4 summ = madd(make_float4(4.0f), old_result, t);
return summ * make_float4(1.0f / 5.0f);
}
/* Calculate powf(x, 2.4). Working domain: 1e-10 < x < 1e+10 */
ccl_device_inline float4 fastpow24_sse2(const float4 &arg)
{
/* `max`, `avg` and |avg| errors were calculated in GCC without FMA instructions.
* The final precision should be better than `powf` in GLIBC. */
/* Calculate x^4/5, coefficient 0.994 was constructed manually to minimize avg error */
/* 0x3F4CCCCD = 4/5 */
/* 0x4F55A7FB = 2^(127/(4/5) - 127) * 0.994^(1/(4/5)) */
float4 x = fastpow_sse2<0x3F4CCCCD, 0x4F55A7FB>(
arg); // error max = 0.17 avg = 0.0018 |avg| = 0.05
const float4 arg2 = arg * arg;
const float4 arg4 = arg2 * arg2;
/* error max = 0.018 avg = 0.0031 |avg| = 0.0031 */
x = improve_5throot_solution_sse2(x, arg4);
/* error max = 0.00021 avg = 1.6e-05 |avg| = 1.6e-05 */
x = improve_5throot_solution_sse2(x, arg4);
/* error max = 6.1e-07 avg = 5.2e-08 |avg| = 1.1e-07 */
x = improve_5throot_solution_sse2(x, arg4);
return x * (x * x);
}
ccl_device float4 color_srgb_to_linear_sse2(const float4 &c)
{
const int4 cmp = c < make_float4(0.04045f);
const float4 lt = max(c * make_float4(1.0f / 12.92f), make_float4(0.0f));
const float4 gtebase = (c + make_float4(0.055f)) * make_float4(1.0f / 1.055f); /* fma */
const float4 gte = fastpow24_sse2(gtebase);
return select(cmp, lt, gte);
}
#endif /* __KERNEL_SSE2__ */
ccl_device float3 color_srgb_to_linear_v3(const float3 c)
{
return make_float3(
color_srgb_to_linear(c.x), color_srgb_to_linear(c.y), color_srgb_to_linear(c.z));
}
ccl_device float3 color_linear_to_srgb_v3(const float3 c)
{
return make_float3(
color_linear_to_srgb(c.x), color_linear_to_srgb(c.y), color_linear_to_srgb(c.z));
}
ccl_device float4 color_linear_to_srgb_v4(const float4 c)
{
return make_float4(
color_linear_to_srgb(c.x), color_linear_to_srgb(c.y), color_linear_to_srgb(c.z), c.w);
}
ccl_device float4 color_srgb_to_linear_v4(const float4 c)
{
#ifdef __KERNEL_SSE2__
float4 r = c;
r = color_srgb_to_linear_sse2(r);
r.w = c.w;
return r;
#else
return make_float4(
color_srgb_to_linear(c.x), color_srgb_to_linear(c.y), color_srgb_to_linear(c.z), c.w);
#endif
}
ccl_device float3 color_highlight_compress(float3 color, ccl_private float3 *variance)
{
color += one_float3();
if (variance) {
*variance *= sqr(one_float3() / color);
}
return log(color);
}
ccl_device float3 color_highlight_uncompress(const float3 color)
{
return exp(color) - one_float3();
}
/* Color division */
ccl_device_inline Spectrum safe_invert_color(Spectrum a)
{
FOREACH_SPECTRUM_CHANNEL (i) {
GET_SPECTRUM_CHANNEL(a, i) = (GET_SPECTRUM_CHANNEL(a, i) != 0.0f) ?
1.0f / GET_SPECTRUM_CHANNEL(a, i) :
0.0f;
}
return a;
}
/* Returns `a/b`, and replace the channel value with `fallback` if `b == 0`. */
ccl_device_inline Spectrum safe_divide_color(Spectrum a, Spectrum b, const float fallback = 0.0f)
{
FOREACH_SPECTRUM_CHANNEL (i) {
GET_SPECTRUM_CHANNEL(a, i) = (GET_SPECTRUM_CHANNEL(b, i) != 0.0f) ?
GET_SPECTRUM_CHANNEL(a, i) / GET_SPECTRUM_CHANNEL(b, i) :
fallback;
}
return a;
}
ccl_device_inline float3 safe_divide_even_color(const float3 a, const float3 b)
{
float x;
float y;
float z;
x = (b.x != 0.0f) ? a.x / b.x : 0.0f;
y = (b.y != 0.0f) ? a.y / b.y : 0.0f;
z = (b.z != 0.0f) ? a.z / b.z : 0.0f;
/* try to get gray even if b is zero */
if (b.x == 0.0f) {
if (b.y == 0.0f) {
x = z;
y = z;
}
else if (b.z == 0.0f) {
x = y;
z = y;
}
else {
x = 0.5f * (y + z);
}
}
else if (b.y == 0.0f) {
if (b.z == 0.0f) {
y = x;
z = x;
}
else {
y = 0.5f * (x + z);
}
}
else if (b.z == 0.0f) {
z = 0.5f * (x + y);
}
return make_float3(x, y, z);
}
CCL_NAMESPACE_END