diff options
Diffstat (limited to 'source/blender/blenlib/intern/math_color.c')
-rw-r--r-- | source/blender/blenlib/intern/math_color.c | 191 |
1 files changed, 69 insertions, 122 deletions
diff --git a/source/blender/blenlib/intern/math_color.c b/source/blender/blenlib/intern/math_color.c index ef9e46fc62d..9399646bedf 100644 --- a/source/blender/blenlib/intern/math_color.c +++ b/source/blender/blenlib/intern/math_color.c @@ -380,8 +380,10 @@ void xyz_to_rgb(float xc, float yc, float zc, float *r, float *g, float *b, int } } -/* we define a 'cpack' here as a (3 byte color code) number that can be expressed like 0xFFAA66 or so. - * for that reason it is sensitive for endianness... with this function it works correctly +/** + * We define a 'cpack' here as a (3 byte color code) number that can be expressed like 0xFFAA66 or so. + * for that reason it is sensitive for endianness... with this function it works correctly. + * \see #imm_cpack */ unsigned int hsv_to_cpack(float h, float s, float v) @@ -675,135 +677,80 @@ void rgb_to_lab(float r, float g, float b, float *ll, float *la, float *lb) 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); - } -} +/* ****************************** blackbody ******************************** */ -/* Color rendering of spectra, adapted from public domain code by John Walker, - * http://www.fourmilab.ch/ +/* Calculate color in range 800..12000 using an approximation + * a/x+bx+c for R and G and ((at + b)t + c)t + d) for B + * Max absolute error for RGB is (0.00095, 0.00077, 0.00057), + * which is enough to get the same 8 bit/channel color. */ -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]; +static const float blackbody_table_r[6][3] = { + { 2.52432244e+03f, -1.06185848e-03f, 3.11067539e+00f }, + { 3.37763626e+03f, -4.34581697e-04f, 1.64843306e+00f }, + { 4.10671449e+03f, -8.61949938e-05f, 6.41423749e-01f }, + { 4.66849800e+03f, 2.85655028e-05f, 1.29075375e-01f }, + { 4.60124770e+03f, 2.89727618e-05f, 1.48001316e-01f }, + { 3.78765709e+03f, 9.36026367e-06f, 3.98995841e-01f }, +}; + +static const float blackbody_table_g[6][3] = { + { -7.50343014e+02f, 3.15679613e-04f, 4.73464526e-01f }, + { -1.00402363e+03f, 1.29189794e-04f, 9.08181524e-01f }, + { -1.22075471e+03f, 2.56245413e-05f, 1.20753416e+00f }, + { -1.42546105e+03f, -4.01730887e-05f, 1.44002695e+00f }, + { -1.18134453e+03f, -2.18913373e-05f, 1.30656109e+00f }, + { -5.00279505e+02f, -4.59745390e-06f, 1.09090465e+00f }, +}; + +static const float blackbody_table_b[6][4] = { + { 0.0f, 0.0f, 0.0f, 0.0f }, + { 0.0f, 0.0f, 0.0f, 0.0f }, + { 0.0f, 0.0f, 0.0f, 0.0f }, + { -2.02524603e-11f, 1.79435860e-07f, -2.60561875e-04f, -1.41761141e-02f }, + { -2.22463426e-13f, -1.55078698e-08f, 3.81675160e-04f, -7.30646033e-01f }, + { 6.72595954e-13f, -2.73059993e-08f, 4.24068546e-04f, -7.52204323e-01f }, +}; + +static void blackbody_temperature_to_rgb(float rgb[3], float t) +{ + if (t >= 12000.0f) { + rgb[0] = 0.826270103f; + rgb[1] = 0.994478524f; + rgb[2] = 1.56626022f; + } + else if (t < 965.0f) { + rgb[0] = 4.70366907f; + rgb[1] = 0.0f; + rgb[2] = 0.0f; + } + else { + int i = (t >= 6365.0f) ? 5 : + (t >= 3315.0f) ? 4 : + (t >= 1902.0f) ? 3 : + (t >= 1449.0f) ? 2 : + (t >= 1167.0f) ? 1 : 0; + + const float *r = blackbody_table_r[i]; + const float *g = blackbody_table_g[i]; + const float *b = blackbody_table_b[i]; + + const float t_inv = 1.0f / t; + rgb[0] = r[0] * t_inv + r[1] * t + r[2]; + rgb[1] = g[0] * t_inv + g[1] * t + g[2]; + rgb[2] = ((b[0] * t + b[1]) * t + b[2]) * t + b[3]; } - - 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 (int i = 0; i < width; i++) { + float temperature = min + (max - min) / (float)width * (float)i; - for (i = 0; i < width; i++, j += dj) { - bb_temp = min + (max - min) / (float)width * (float)i; + float rgb[3]; + blackbody_temperature_to_rgb(rgb, temperature); - /* 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; + copy_v3_v3(&r_table[i * 4], rgb); + r_table[i * 4 + 3] = 0.0f; } } |