diff options
Diffstat (limited to 'source/blender/blenlib/intern/math_color.c')
| -rw-r--r-- | source/blender/blenlib/intern/math_color.c | 149 |
1 files changed, 138 insertions, 11 deletions
diff --git a/source/blender/blenlib/intern/math_color.c b/source/blender/blenlib/intern/math_color.c index e149fdb2d26..6d7d24c79c3 100644 --- a/source/blender/blenlib/intern/math_color.c +++ b/source/blender/blenlib/intern/math_color.c @@ -455,7 +455,7 @@ void minmax_rgb(short c[3]) else if (c[2] < 0) c[2] = 0; } -/*If the requested RGB shade contains a negative weight for +/* If the requested RGB shade contains a negative weight for * one of the primaries, it lies outside the color gamut * accessible from the given triple of primaries. Desaturate * it by adding white, equal quantities of R, G, and B, enough @@ -463,21 +463,15 @@ void minmax_rgb(short c[3]) * components were modified, zero otherwise.*/ int constrain_rgb(float *r, float *g, float *b) { - float w; - - /* Amount of white needed is w = - min(0, *r, *g, *b) */ - - w = (0 < *r) ? 0 : *r; - w = (w < *g) ? w : *g; - w = (w < *b) ? w : *b; - w = -w; + /* Amount of white needed */ + const float w = -min_ffff(0.0f, *r, *g, *b); /* Add just enough white to make r, g, b all positive. */ - - if (w > 0) { + if (w > 0.0f) { *r += w; *g += w; *b += w; + return 1; /* Color modified to fit RGB gamut */ } @@ -659,3 +653,136 @@ void rgb_to_lab(float r, float g, float b, float *ll, float *la, float *lb) rgb_to_xyz(r, g, b, &x, &y, &z); xyz_to_lab(x, y, z, ll, la, lb); } + +static void xyz_to_lms(float x, float y, float z, float *l, float *m, float *s) +{ + *l = 0.3897f * x + 0.6890f * y - 0.0787f * z; + *m = -0.2298f * x + 1.1834f * y + 0.0464f * z; + *s = z; +} + +static void lms_to_xyz(float l, float m, float s, float *x, float *y, float *z) +{ + *x = 1.9102f * l - 1.1121f * m + 0.2019f * s; + *y = 0.3709f * l + 0.6290f * m + 0.0000f * s; + *z = s; +} + +static void normalize_rgb(float rgb[3]) +{ + const float max = max_fff(rgb[0], rgb[1], rgb[2]); + + if (max > 0.0f) { + mul_v3_fl(rgb, 1.0f / max); + } +} + +/* Color rendering of spectra, adapted from public domain code by John Walker, + * http://www.fourmilab.ch/ + */ + +static void spectrum_to_xyz(float temperature, float xyz[3]) +{ + int i; + float lambda, x = 0.0f, y = 0.0f, z = 0.0f, xyz_sum; + + /* CIE colour matching functions xBar, yBar, and zBar for wavelengths from + * 380 through 780 nanometers, every 5 nanometers. + * For a wavelength lambda in this range: + * + * cie_colour_match[(lambda - 380) / 5][0] = xBar + * cie_colour_match[(lambda - 380) / 5][1] = yBar + * cie_colour_match[(lambda - 380) / 5][2] = zBar + */ + + const float cie_colour_match[81][3] = { + {0.0014f, 0.0000f, 0.0065f}, {0.0022f, 0.0001f, 0.0105f}, {0.0042f, 0.0001f, 0.0201f}, + {0.0076f, 0.0002f, 0.0362f}, {0.0143f, 0.0004f, 0.0679f}, {0.0232f, 0.0006f, 0.1102f}, + {0.0435f, 0.0012f, 0.2074f}, {0.0776f, 0.0022f, 0.3713f}, {0.1344f, 0.0040f, 0.6456f}, + {0.2148f, 0.0073f, 1.0391f}, {0.2839f, 0.0116f, 1.3856f}, {0.3285f, 0.0168f, 1.6230f}, + {0.3483f, 0.0230f, 1.7471f}, {0.3481f, 0.0298f, 1.7826f}, {0.3362f, 0.0380f, 1.7721f}, + {0.3187f, 0.0480f, 1.7441f}, {0.2908f, 0.0600f, 1.6692f}, {0.2511f, 0.0739f, 1.5281f}, + {0.1954f, 0.0910f, 1.2876f}, {0.1421f, 0.1126f, 1.0419f}, {0.0956f, 0.1390f, 0.8130f}, + {0.0580f, 0.1693f, 0.6162f}, {0.0320f, 0.2080f, 0.4652f}, {0.0147f, 0.2586f, 0.3533f}, + {0.0049f, 0.3230f, 0.2720f}, {0.0024f, 0.4073f, 0.2123f}, {0.0093f, 0.5030f, 0.1582f}, + {0.0291f, 0.6082f, 0.1117f}, {0.0633f, 0.7100f, 0.0782f}, {0.1096f, 0.7932f, 0.0573f}, + {0.1655f, 0.8620f, 0.0422f}, {0.2257f, 0.9149f, 0.0298f}, {0.2904f, 0.9540f, 0.0203f}, + {0.3597f, 0.9803f, 0.0134f}, {0.4334f, 0.9950f, 0.0087f}, {0.5121f, 1.0000f, 0.0057f}, + {0.5945f, 0.9950f, 0.0039f}, {0.6784f, 0.9786f, 0.0027f}, {0.7621f, 0.9520f, 0.0021f}, + {0.8425f, 0.9154f, 0.0018f}, {0.9163f, 0.8700f, 0.0017f}, {0.9786f, 0.8163f, 0.0014f}, + {1.0263f, 0.7570f, 0.0011f}, {1.0567f, 0.6949f, 0.0010f}, {1.0622f, 0.6310f, 0.0008f}, + {1.0456f, 0.5668f, 0.0006f}, {1.0026f, 0.5030f, 0.0003f}, {0.9384f, 0.4412f, 0.0002f}, + {0.8544f, 0.3810f, 0.0002f}, {0.7514f, 0.3210f, 0.0001f}, {0.6424f, 0.2650f, 0.0000f}, + {0.5419f, 0.2170f, 0.0000f}, {0.4479f, 0.1750f, 0.0000f}, {0.3608f, 0.1382f, 0.0000f}, + {0.2835f, 0.1070f, 0.0000f}, {0.2187f, 0.0816f, 0.0000f}, {0.1649f, 0.0610f, 0.0000f}, + {0.1212f, 0.0446f, 0.0000f}, {0.0874f, 0.0320f, 0.0000f}, {0.0636f, 0.0232f, 0.0000f}, + {0.0468f, 0.0170f, 0.0000f}, {0.0329f, 0.0119f, 0.0000f}, {0.0227f, 0.0082f, 0.0000f}, + {0.0158f, 0.0057f, 0.0000f}, {0.0114f, 0.0041f, 0.0000f}, {0.0081f, 0.0029f, 0.0000f}, + {0.0058f, 0.0021f, 0.0000f}, {0.0041f, 0.0015f, 0.0000f}, {0.0029f, 0.0010f, 0.0000f}, + {0.0020f, 0.0007f, 0.0000f}, {0.0014f, 0.0005f, 0.0000f}, {0.0010f, 0.0004f, 0.0000f}, + {0.0007f, 0.0002f, 0.0000f}, {0.0005f, 0.0002f, 0.0000f}, {0.0003f, 0.0001f, 0.0000f}, + {0.0002f, 0.0001f, 0.0000f}, {0.0002f, 0.0001f, 0.0000f}, {0.0001f, 0.0000f, 0.0000f}, + {0.0001f, 0.0000f, 0.0000f}, {0.0001f, 0.0000f, 0.0000f}, {0.0000f, 0.0000f, 0.0000f} + }; + + for (i = 0, lambda = 380.0f; lambda < 780.1f; i++, lambda += 5.0f) { + /* wavelength in meter */ + const float wlm = lambda * 1e-9f; + const float Me = (3.74183e-16f * powf(wlm, -5.0f)) / (expf(1.4388e-2f / (wlm * temperature)) - 1.0f); + + x += Me * cie_colour_match[i][0]; + y += Me * cie_colour_match[i][1]; + z += Me * cie_colour_match[i][2]; + } + + xyz_sum = (x + y + z); + + xyz[0] = x / xyz_sum; + xyz[1] = y / xyz_sum; + xyz[2] = z / xyz_sum; +} + +void blackbody_temperature_to_rgb_table(float *r_table, int width, float min, float max) +{ + int i, j = 0, dj = 1; + float rgb[3], xyz[3], lms[3], lms_w[3]; + float bb_temp; + + if (min < max) { + SWAP(float, min, max); + j = width - 1; + dj = -1; + } + + for (i = 0; i < width; i++, j += dj) { + bb_temp = min + (max - min) / (float)width * (float)i; + + /* integrate blackbody radiation spectrum to XYZ */ + spectrum_to_xyz(bb_temp, xyz); + + /* normalize highest temperature to white (in LMS system) */ + xyz_to_lms(xyz[0], xyz[1], xyz[2], &lms[0], &lms[1], &lms[2]); + + if (i == 0) { + lms_w[0] = 1.0f / lms[0]; + lms_w[1] = 1.0f / lms[1]; + lms_w[2] = 1.0f / lms[2]; + } + + mul_v3_v3(lms, lms_w); + + lms_to_xyz(lms[0], lms[1], lms[2], &xyz[0], &xyz[1], &xyz[2]); + + /* convert to RGB */ + xyz_to_rgb(xyz[0], xyz[1], xyz[2], &rgb[0], &rgb[1], &rgb[2], BLI_XYZ_CIE); + constrain_rgb(&rgb[0], &rgb[1], &rgb[2]); + normalize_rgb(rgb); + + copy_v3_v3(&r_table[(j << 2)], rgb); + + if (rgb[2] > 0.1f) + r_table[(j << 2) + 3] = rgb[2]; + else + r_table[(j << 2) + 3] = 0.0f; + } +} |