1 | |
2 | // |
3 | // This source file is part of appleseed. |
4 | // Visit http://appleseedhq.net/ for additional information and resources. |
5 | // |
6 | // This software is released under the MIT license. |
7 | // |
8 | // Copyright (c) 2010-2013 Francois Beaune, Jupiter Jazz Limited |
9 | // Copyright (c) 2014-2017 Francois Beaune, The appleseedhq Organization |
10 | // |
11 | // Permission is hereby granted, free of charge, to any person obtaining a copy |
12 | // of this software and associated documentation files (the "Software"), to deal |
13 | // in the Software without restriction, including without limitation the rights |
14 | // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
15 | // copies of the Software, and to permit persons to whom the Software is |
16 | // furnished to do so, subject to the following conditions: |
17 | // |
18 | // The above copyright notice and this permission notice shall be included in |
19 | // all copies or substantial portions of the Software. |
20 | // |
21 | // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
22 | // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
23 | // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
24 | // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
25 | // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
26 | // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
27 | // THE SOFTWARE. |
28 | // |
29 | |
30 | #ifndef APPLESEED_FOUNDATION_IMAGE_COLORSPACE_H |
31 | #define APPLESEED_FOUNDATION_IMAGE_COLORSPACE_H |
32 | |
33 | // appleseed.foundation headers. |
34 | #include "foundation/image/color.h" |
35 | #include "foundation/image/regularspectrum.h" |
36 | #include "foundation/math/fastmath.h" |
37 | #include "foundation/math/scalar.h" |
38 | #include "foundation/math/spline.h" |
39 | #include "foundation/platform/compiler.h" |
40 | #ifdef APPLESEED_USE_SSE |
41 | #include "foundation/platform/sse.h" |
42 | #endif |
43 | #include "foundation/utility/otherwise.h" |
44 | |
45 | // appleseed.main headers. |
46 | #include "main/dllsymbol.h" |
47 | |
48 | // Boost headers. |
49 | #include "boost/static_assert.hpp" |
50 | |
51 | // Standard headers. |
52 | #include <algorithm> |
53 | #include <cmath> |
54 | #include <cstddef> |
55 | |
56 | namespace foundation |
57 | { |
58 | |
59 | // |
60 | // Enumeration of all supported color spaces. |
61 | // |
62 | |
63 | enum ColorSpace |
64 | { |
65 | ColorSpaceLinearRGB, // linear RGB |
66 | ColorSpaceSRGB, // sRGB |
67 | ColorSpaceHSV, // Hue Saturation Value (HSV, or HSB) |
68 | ColorSpaceHLS, // Hue Lightness Saturation (HLS, or HSL) |
69 | ColorSpaceCIEXYZ, // CIE XYZ |
70 | ColorSpaceCIExyY, // CIE xyY |
71 | ColorSpaceSpectral // spectral |
72 | }; |
73 | |
74 | // Return a string identifying a color space. |
75 | APPLESEED_DLLSYMBOL const char* color_space_name(const ColorSpace color_space); |
76 | |
77 | |
78 | // |
79 | // Transform a tristimulus value from one 3D color space to another 3D color space. |
80 | // |
81 | |
82 | template <typename T> |
83 | Color<T, 3> transform_color( |
84 | const Color<T, 3>& color, |
85 | const ColorSpace from, |
86 | const ColorSpace to); |
87 | |
88 | |
89 | // |
90 | // Basis vectors to convert the CIE xy chromaticity of a D series (daylight) illuminant to a spectrum. |
91 | // |
92 | // Reference: |
93 | // |
94 | // http://en.wikipedia.org/wiki/Standard_illuminant#Illuminant_series_D |
95 | // |
96 | |
97 | extern const RegularSpectrum31f DaylightS0; // mean spectral radiant power |
98 | extern const RegularSpectrum31f DaylightS1; // first characteristic vector (yellow-blue variation) |
99 | extern const RegularSpectrum31f DaylightS2; // second characteristic vector (pink-green variation) |
100 | |
101 | |
102 | // |
103 | // Standard illuminants. |
104 | // |
105 | // References: |
106 | // |
107 | // http://en.wikipedia.org/wiki/Standard_illuminant |
108 | // http://cvrl.ioo.ucl.ac.uk/ |
109 | // |
110 | |
111 | // Daylight illuminants. |
112 | extern const RegularSpectrum31f IlluminantCIED65; // CIE D65 |
113 | |
114 | // Incandescent lighting illuminants. |
115 | extern const RegularSpectrum31f IlluminantCIEA; // CIE A (black body radiator at 2856 K) |
116 | |
117 | |
118 | // |
119 | // Color Matching Functions (CMF). |
120 | // |
121 | // References: |
122 | // |
123 | // http://en.wikipedia.org/wiki/CIE_1931_color_space |
124 | // http://cvrl.ioo.ucl.ac.uk/ |
125 | // |
126 | |
127 | // XYZ color matching functions. |
128 | extern const RegularSpectrum31f XYZCMFCIE19312Deg[3]; // CIE 1931 2-deg |
129 | extern const RegularSpectrum31f XYZCMFCIE1931Judd2Deg[3]; // CIE 1931 2-deg, modified by Judd (1951) |
130 | extern const RegularSpectrum31f XYZCMFCIE1931JuddVos2Deg[3]; // CIE 1931 2-deg, modified by Judd (1951) and Vos (1978) |
131 | extern const RegularSpectrum31f XYZCMFCIE196410Deg[3]; // CIE 1964 10-deg (recommended) |
132 | |
133 | // RGB color matching functions. |
134 | extern const RegularSpectrum31f RGBCMFStilesBurch19552Deg[3]; // Stiles and Burch (1955) 2-deg |
135 | extern const RegularSpectrum31f RGBCMFStilesBurch195910Deg[3]; // Stiles and Burch (1959) 10-deg (recommended) |
136 | |
137 | |
138 | // |
139 | // Basis spectra for RGB-to-spectrum conversion. |
140 | // |
141 | |
142 | // Basis spectra for reflectance conversions. |
143 | extern const RegularSpectrum31f RGBToSpectrumWhiteReflectance; |
144 | extern const RegularSpectrum31f RGBToSpectrumCyanReflectance; |
145 | extern const RegularSpectrum31f RGBToSpectrumMagentaReflectance; |
146 | extern const RegularSpectrum31f RGBToSpectrumYellowReflectance; |
147 | extern const RegularSpectrum31f RGBToSpectrumRedReflectance; |
148 | extern const RegularSpectrum31f RGBToSpectrumGreenReflectance; |
149 | extern const RegularSpectrum31f RGBToSpectrumBlueReflectance; |
150 | |
151 | // Basis spectra for illuminance conversions. |
152 | extern const RegularSpectrum31f RGBToSpectrumWhiteIlluminance; |
153 | extern const RegularSpectrum31f RGBToSpectrumCyanIlluminance; |
154 | extern const RegularSpectrum31f RGBToSpectrumMagentaIlluminance; |
155 | extern const RegularSpectrum31f RGBToSpectrumYellowIlluminance; |
156 | extern const RegularSpectrum31f RGBToSpectrumRedIlluminance; |
157 | extern const RegularSpectrum31f RGBToSpectrumGreenIlluminance; |
158 | extern const RegularSpectrum31f RGBToSpectrumBlueIlluminance; |
159 | |
160 | |
161 | // |
162 | // Lighting conditions, defined as a set of color matching functions and an illuminant. |
163 | // |
164 | |
165 | class LightingConditions |
166 | { |
167 | public: |
168 | APPLESEED_SIMD4_ALIGN Color4f m_cmf[32]; // precomputed values of (cmf[0], cmf[1], cmf[2]) * illuminant |
169 | |
170 | LightingConditions(); // leaves the object uninitialized |
171 | |
172 | LightingConditions( |
173 | const RegularSpectrum31f& illuminant, // illuminant |
174 | const RegularSpectrum31f cmf[3]); // color matching functions |
175 | }; |
176 | |
177 | |
178 | // |
179 | // HSV <-> linear RGB transformations. |
180 | // |
181 | // References: |
182 | // |
183 | // http://en.literateprograms.org/RGB_to_HSV_color_space_conversion_%28C%29 |
184 | // http://en.wikipedia.org/wiki/HLS_color_space |
185 | // |
186 | // Note: |
187 | // |
188 | // If hsv is a three-component color expressed in the HSV color space, then: |
189 | // |
190 | // hsv[0] is the Hue in [0, 360) |
191 | // hsv[1] is the Saturation in [0, 1] |
192 | // hsv[2] is the Value in [0, 1] |
193 | // |
194 | |
195 | // Convert a color from the HSV color space to the linear RGB color space. |
196 | template <typename T> |
197 | Color<T, 3> hsv_to_linear_rgb(const Color<T, 3>& hsv); |
198 | |
199 | // Convert a color from the linear RGB color space to the HSV color space. |
200 | template <typename T> |
201 | Color<T, 3> linear_rgb_to_hsv(const Color<T, 3>& linear_rgb); |
202 | |
203 | |
204 | // |
205 | // HSL <-> linear RGB transformations. |
206 | // |
207 | // Reference: |
208 | // |
209 | // http://en.wikipedia.org/wiki/HLS_color_space |
210 | // |
211 | // Note: |
212 | // |
213 | // If hsl is a three-component color expressed in the HSL color space, then: |
214 | // |
215 | // hsl[0] is the Hue in [0, 360) |
216 | // hsl[1] is the Saturation in [0, 1] |
217 | // hsl[2] is the Lightness in [0, 1] |
218 | // |
219 | |
220 | // Convert a color from the HSL color space to the linear RGB color space. |
221 | template <typename T> |
222 | Color<T, 3> hsl_to_linear_rgb(const Color<T, 3>& hsl); |
223 | |
224 | // Convert a color from the linear RGB color space to the HSL color space. |
225 | template <typename T> |
226 | Color<T, 3> linear_rgb_to_hsl(const Color<T, 3>& linear_rgb); |
227 | |
228 | |
229 | // |
230 | // CIE XYZ <-> linear RGB transformations. |
231 | // |
232 | // References: |
233 | // |
234 | // http://en.wikipedia.org/wiki/SRGB_color_space |
235 | // http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.txt |
236 | // http://graphics.stanford.edu/courses/cs148-10-summer/docs/2010--kerr--cie_xyz.pdf |
237 | // |
238 | |
239 | // Convert a color from the CIE XYZ color space to the linear RGB color space. |
240 | template <typename T> |
241 | Color<T, 3> ciexyz_to_linear_rgb(const Color<T, 3>& xyz); |
242 | |
243 | // Convert a color from the linear RGB color space to the CIE XYZ color space. |
244 | template <typename T> |
245 | Color<T, 3> linear_rgb_to_ciexyz(const Color<T, 3>& linear_rgb); |
246 | |
247 | |
248 | // |
249 | // CIE XYZ <-> CIE xyY transformations. |
250 | // |
251 | // Reference: |
252 | // |
253 | // http://en.wikipedia.org/wiki/CIE_1931_color_space#The_CIE_xy_chromaticity_diagram_and_the_CIE_xyY_color_space |
254 | // |
255 | |
256 | // Convert a color from the CIE XYZ color space to the CIE xyY color space. |
257 | template <typename T> |
258 | Color<T, 3> ciexyz_to_ciexyy(const Color<T, 3>& xyz); |
259 | |
260 | // Convert a color from the CIE xyY color space to the CIE XYZ color space. |
261 | template <typename T> |
262 | Color<T, 3> ciexyy_to_ciexyz(const Color<T, 3>& xyy); |
263 | |
264 | |
265 | // |
266 | // Linear RGB <-> sRGB transformations. |
267 | // |
268 | // Reference: |
269 | // |
270 | // http://en.wikipedia.org/wiki/SRGB_color_space |
271 | // |
272 | |
273 | // Convert a color component from the linear RGB color space to the sRGB color space. |
274 | template <typename T> |
275 | T linear_rgb_to_srgb(const T c); |
276 | |
277 | // Convert a color component from the sRGB color space to the linear RGB color space. |
278 | template <typename T> |
279 | T srgb_to_linear_rgb(const T c); |
280 | |
281 | // Convert a color from the linear RGB color space to the sRGB color space. |
282 | template <typename T> |
283 | Color<T, 3> linear_rgb_to_srgb(const Color<T, 3>& linear_rgb); |
284 | |
285 | // Convert a color from the sRGB color space to the linear RGB color space. |
286 | template <typename T> |
287 | Color<T, 3> srgb_to_linear_rgb(const Color<T, 3>& srgb); |
288 | |
289 | // Variants of the above functions using a fast approximation of the power function. |
290 | float fast_linear_rgb_to_srgb(const float c); |
291 | float fast_srgb_to_linear_rgb(const float c); |
292 | #ifdef APPLESEED_USE_SSE |
293 | inline __m128 fast_linear_rgb_to_srgb(const __m128 linear_rgb); |
294 | #endif |
295 | Color3f fast_linear_rgb_to_srgb(const Color3f& linear_rgb); |
296 | Color3f fast_srgb_to_linear_rgb(const Color3f& srgb); |
297 | |
298 | // Variants of the above functions using an even faster approximation of the power function. |
299 | float faster_linear_rgb_to_srgb(const float c); |
300 | float faster_srgb_to_linear_rgb(const float c); |
301 | #ifdef APPLESEED_USE_SSE |
302 | inline __m128 faster_linear_rgb_to_srgb(const __m128 linear_rgb); |
303 | #endif |
304 | Color3f faster_linear_rgb_to_srgb(const Color3f& linear_rgb); |
305 | Color3f faster_srgb_to_linear_rgb(const Color3f& srgb); |
306 | |
307 | |
308 | // |
309 | // Compute the relative luminance of a linear RGB triplet as defined |
310 | // in the ITU-R Recommendation BT.709 (Rec. 709): |
311 | // |
312 | // Y = 0.212671 R + 0.715160 G + 0.072169 B |
313 | // |
314 | // This is equivalent to transforming the linear RGB triplet to the |
315 | // CIE XYZ color space and keeping the Y component. |
316 | // |
317 | // References: |
318 | // |
319 | // http://en.wikipedia.org/wiki/Rec._709 |
320 | // http://en.wikipedia.org/wiki/Luminance_(relative) |
321 | // |
322 | |
323 | template <typename T> |
324 | T luminance(const Color<T, 3>& linear_rgb); |
325 | |
326 | |
327 | // |
328 | // Spectrum <-> CIE XYZ transformations. |
329 | // |
330 | |
331 | // Convert a spectrum to a color in the CIE XYZ color space. |
332 | template <typename T, typename SpectrumType> |
333 | Color<T, 3> spectrum_to_ciexyz( |
334 | const LightingConditions& lighting, |
335 | const SpectrumType& spectrum); |
336 | |
337 | // Convert a spectrum to a color in the CIE XYZ color space using the CIE D65 illuminant |
338 | // and the CIE 1964 10-deg color matching functions. |
339 | APPLESEED_DLLSYMBOL void spectrum_to_ciexyz_standard( |
340 | const float spectrum[], |
341 | float ciexyz[3]); |
342 | |
343 | // Convert a reflectance in the CIE XYZ color space to a spectrum. |
344 | template <typename T, typename SpectrumType> |
345 | void ciexyz_reflectance_to_spectrum( |
346 | const Color<T, 3>& xyz, |
347 | SpectrumType& spectrum); |
348 | |
349 | // Convert an illuminance in the CIE XYZ color space to a spectrum. |
350 | template <typename T, typename SpectrumType> |
351 | void ciexyz_illuminance_to_spectrum( |
352 | const Color<T, 3>& xyz, |
353 | SpectrumType& spectrum); |
354 | |
355 | |
356 | // |
357 | // Convert the CIE xy chromaticity of a D series (daylight) illuminant to a spectrum. |
358 | // |
359 | |
360 | template <typename T, typename SpectrumType> |
361 | void daylight_ciexy_to_spectrum( |
362 | const T x, |
363 | const T y, |
364 | SpectrumType& spectrum); |
365 | |
366 | |
367 | // |
368 | // Linear RGB to spectrum transformation. |
369 | // |
370 | // The spectrum to linear RGB transformation can be obtained by first |
371 | // converting the spectrum to the CIE XYZ color space, then converting |
372 | // the resulting CIE XYZ color to the linear RGB color space. |
373 | // |
374 | // Reference: |
375 | // |
376 | // An RGB to Spectrum Conversion for Reflectances, Brian Smits, University of Utah |
377 | // http://www.cs.utah.edu/~bes/papers/color/ |
378 | // |
379 | |
380 | // Convert a linear RGB reflectance value to a spectrum, |
381 | // without clamping the spectrum values. |
382 | template <typename T, typename SpectrumType> |
383 | void linear_rgb_reflectance_to_spectrum_unclamped( |
384 | const Color<T, 3>& linear_rgb, |
385 | SpectrumType& spectrum); |
386 | |
387 | // Convert a linear RGB reflectance value to a spectrum. |
388 | template <typename T, typename SpectrumType> |
389 | void linear_rgb_reflectance_to_spectrum( |
390 | const Color<T, 3>& linear_rgb, |
391 | SpectrumType& spectrum); |
392 | |
393 | // Convert a linear RGB illuminance value to a spectrum. |
394 | template <typename T, typename SpectrumType> |
395 | void linear_rgb_illuminance_to_spectrum( |
396 | const Color<T, 3>& linear_rgb, |
397 | SpectrumType& spectrum); |
398 | |
399 | |
400 | // |
401 | // Spectrum <-> Spectrum transformation. |
402 | // |
403 | |
404 | // Resample a spectrum from one set of wavelengths to another. |
405 | template <typename T> |
406 | void spectrum_to_spectrum( |
407 | const size_t input_count, |
408 | const T input_wavelength[], |
409 | const T input_spectrum[], |
410 | const size_t output_count, |
411 | const T output_wavelength[], |
412 | T output_spectrum[], |
413 | T working_storage[] = 0); |
414 | |
415 | |
416 | // |
417 | // Transform a tristimulus value from one 3D color space to another 3D color space. |
418 | // |
419 | |
420 | template <typename T> |
421 | Color<T, 3> transform_color( |
422 | const Color<T, 3>& color, |
423 | const ColorSpace from, |
424 | const ColorSpace to) |
425 | { |
426 | switch (from) |
427 | { |
428 | case ColorSpaceLinearRGB: |
429 | switch (to) |
430 | { |
431 | case ColorSpaceLinearRGB: return color; |
432 | case ColorSpaceSRGB: return linear_rgb_to_srgb(color); |
433 | case ColorSpaceCIEXYZ: return linear_rgb_to_ciexyz(color); |
434 | assert_otherwise; |
435 | } |
436 | |
437 | case ColorSpaceSRGB: |
438 | switch (to) |
439 | { |
440 | case ColorSpaceLinearRGB: return srgb_to_linear_rgb(color); |
441 | case ColorSpaceSRGB: return color; |
442 | case ColorSpaceCIEXYZ: return linear_rgb_to_ciexyz(srgb_to_linear_rgb(color)); |
443 | assert_otherwise; |
444 | } |
445 | |
446 | case ColorSpaceCIEXYZ: |
447 | switch (to) |
448 | { |
449 | case ColorSpaceLinearRGB: return ciexyz_to_linear_rgb(color); |
450 | case ColorSpaceSRGB: return linear_rgb_to_srgb(ciexyz_to_linear_rgb(color)); |
451 | case ColorSpaceCIEXYZ: return color; |
452 | assert_otherwise; |
453 | } |
454 | |
455 | assert_otherwise; |
456 | } |
457 | |
458 | // Keep the compiler happy. |
459 | return color; |
460 | } |
461 | |
462 | |
463 | // |
464 | // HSV <-> linear RGB transformations implementation. |
465 | // |
466 | |
467 | template <typename T> |
468 | inline Color<T, 3> hsv_to_linear_rgb(const Color<T, 3>& hsv) |
469 | { |
470 | // Compute chroma. |
471 | const T c = hsv[1] * hsv[2]; |
472 | |
473 | // Compute value. |
474 | Color<T, 3> linear_rgb(hsv[2] - c); |
475 | |
476 | // Compute RGB color. |
477 | const T hprime = hsv[0] * T(1.0 / 60.0); |
478 | const T x = c * (T(1.0) - std::abs(mod(hprime, T(2.0)) - T(1.0))); |
479 | switch (truncate<int>(hprime)) |
480 | { |
481 | case 0: linear_rgb[0] += c; linear_rgb[1] += x; break; |
482 | case 1: linear_rgb[0] += x; linear_rgb[1] += c; break; |
483 | case 2: linear_rgb[1] += c; linear_rgb[2] += x; break; |
484 | case 3: linear_rgb[1] += x; linear_rgb[2] += c; break; |
485 | case 4: linear_rgb[0] += x; linear_rgb[2] += c; break; |
486 | case 5: linear_rgb[0] += c; linear_rgb[2] += x; break; |
487 | assert_otherwise; |
488 | } |
489 | |
490 | return linear_rgb; |
491 | } |
492 | |
493 | template <typename T> |
494 | inline Color<T, 3> linear_rgb_to_hsv(const Color<T, 3>& linear_rgb) |
495 | { |
496 | // Compute value. |
497 | const T value = max_value(linear_rgb); |
498 | |
499 | // Value is zero: return black. |
500 | if (value == T(0.0)) |
501 | return Color<T, 3>(0.0, 0.0, 0.0); |
502 | |
503 | // Compute chroma. |
504 | const T chroma = value - min_value(linear_rgb); |
505 | |
506 | // Chroma is zero: return gray. |
507 | if (chroma == T(0.0)) |
508 | return Color<T, 3>(0.0, 0.0, value); |
509 | |
510 | // Compute hue. |
511 | const T h = |
512 | value == linear_rgb[0] ? (linear_rgb[1] - linear_rgb[2]) / chroma : |
513 | value == linear_rgb[1] ? (linear_rgb[2] - linear_rgb[0]) / chroma + T(2.0) : |
514 | (linear_rgb[0] - linear_rgb[1]) / chroma + T(4.0); |
515 | const T hue = mod(h * T(60.0), T(360.0)); |
516 | |
517 | // Compute saturation. |
518 | const T saturation = chroma / value; |
519 | |
520 | return Color<T, 3>(hue, saturation, value); |
521 | } |
522 | |
523 | |
524 | // |
525 | // HSL <-> linear RGB transformations implementation. |
526 | // |
527 | |
528 | template <typename T> |
529 | inline Color<T, 3> hsl_to_linear_rgb(const Color<T, 3>& hsl) |
530 | { |
531 | // Compute chroma. |
532 | const T c = hsl[1] * (T(1.0) - std::abs(hsl[2] + hsl[2] - T(1.0))); |
533 | |
534 | // Compute lightness. |
535 | Color<T, 3> linear_rgb(hsl[2] - T(0.5) * c); |
536 | |
537 | // Compute RGB color. |
538 | const T hprime = hsl[0] * T(1.0 / 60.0); |
539 | const T x = c * (T(1.0) - std::abs(mod(hprime, T(2.0)) - T(1.0))); |
540 | switch (truncate<int>(hprime)) |
541 | { |
542 | case 6: // fallthrough |
543 | case 0: linear_rgb[0] += c; linear_rgb[1] += x; break; |
544 | case 1: linear_rgb[0] += x; linear_rgb[1] += c; break; |
545 | case 2: linear_rgb[1] += c; linear_rgb[2] += x; break; |
546 | case 3: linear_rgb[1] += x; linear_rgb[2] += c; break; |
547 | case 4: linear_rgb[0] += x; linear_rgb[2] += c; break; |
548 | case 5: linear_rgb[0] += c; linear_rgb[2] += x; break; |
549 | assert_otherwise; |
550 | } |
551 | |
552 | return linear_rgb; |
553 | } |
554 | |
555 | template <typename T> |
556 | inline Color<T, 3> linear_rgb_to_hsl(const Color<T, 3>& linear_rgb) |
557 | { |
558 | // Compute chroma. |
559 | const T max_val = max_value(linear_rgb); |
560 | const T min_val = min_value(linear_rgb); |
561 | const T c = max_val - min_val; |
562 | |
563 | // Special case for zero chroma. |
564 | if (c == T(0.0)) |
565 | return Color<T, 3>(0.0); |
566 | |
567 | // Compute hue. |
568 | const T hprime = |
569 | max_val == linear_rgb[0] ? mod((linear_rgb[1] - linear_rgb[2]) / c, T(6.0)) : |
570 | max_val == linear_rgb[1] ? (linear_rgb[2] - linear_rgb[0]) / c + T(2.0) : |
571 | (linear_rgb[0] - linear_rgb[1]) / c + T(4.0); |
572 | const T hue = hprime * T(60.0); |
573 | |
574 | // Compute lightness and saturation. |
575 | const T lightness = T(0.5) * (min_val + max_val); |
576 | const T saturation = c / (T(1.0) - std::abs(lightness + lightness - T(1.0))); |
577 | |
578 | return Color<T, 3>(hue, saturation, lightness); |
579 | } |
580 | |
581 | |
582 | // |
583 | // CIE XYZ <-> linear RGB transformations implementation. |
584 | // |
585 | |
586 | template <typename T> |
587 | inline Color<T, 3> ciexyz_to_linear_rgb(const Color<T, 3>& xyz) |
588 | { |
589 | return |
590 | clamp_low( |
591 | Color<T, 3>( |
592 | T( 3.240479) * xyz[0] + T(-1.537150) * xyz[1] + T(-0.498535) * xyz[2], |
593 | T(-0.969256) * xyz[0] + T( 1.875991) * xyz[1] + T( 0.041556) * xyz[2], |
594 | T( 0.055648) * xyz[0] + T(-0.204043) * xyz[1] + T( 1.057311) * xyz[2]), |
595 | T(0.0)); |
596 | } |
597 | |
598 | template <typename T> |
599 | inline Color<T, 3> linear_rgb_to_ciexyz(const Color<T, 3>& linear_rgb) |
600 | { |
601 | return |
602 | clamp_low( |
603 | Color<T, 3>( |
604 | T(0.412453) * linear_rgb[0] + T(0.357580) * linear_rgb[1] + T(0.180423) * linear_rgb[2], |
605 | T(0.212671) * linear_rgb[0] + T(0.715160) * linear_rgb[1] + T(0.072169) * linear_rgb[2], |
606 | T(0.019334) * linear_rgb[0] + T(0.119193) * linear_rgb[1] + T(0.950227) * linear_rgb[2]), |
607 | T(0.0)); |
608 | } |
609 | |
610 | |
611 | // |
612 | // CIE XYZ <-> CIE xyY transformations implementation. |
613 | // |
614 | |
615 | template <typename T> |
616 | inline Color<T, 3> ciexyz_to_ciexyy(const Color<T, 3>& xyz) |
617 | { |
618 | const T rcp_sum = T(1.0) / (xyz[0] + xyz[1] + xyz[2]); |
619 | return Color<T, 3>(xyz[0] * rcp_sum, xyz[1] * rcp_sum, xyz[1]); |
620 | } |
621 | |
622 | template <typename T> |
623 | inline Color<T, 3> ciexyy_to_ciexyz(const Color<T, 3>& xyy) |
624 | { |
625 | const T y = xyy[2] / xyy[1]; |
626 | return Color<T, 3>(y * xyy[0], xyy[2], y * (T(1.0) - xyy[0] - xyy[1])); |
627 | } |
628 | |
629 | |
630 | // |
631 | // Linear RGB <-> sRGB transformations implementation. |
632 | // |
633 | |
634 | template <typename T> |
635 | inline T linear_rgb_to_srgb(const T c) |
636 | { |
637 | return c <= T(0.0031308) |
638 | ? T(12.92) * c |
639 | : T(1.055) * std::pow(c, T(1.0 / 2.4)) - T(0.055); |
640 | } |
641 | |
642 | template <typename T> |
643 | inline T srgb_to_linear_rgb(const T c) |
644 | { |
645 | return c <= T(0.04045) |
646 | ? T(1.0 / 12.92) * c |
647 | : std::pow((c + T(0.055)) * T(1.0 / 1.055), T(2.4)); |
648 | } |
649 | |
650 | template <typename T> |
651 | inline Color<T, 3> linear_rgb_to_srgb(const Color<T, 3>& linear_rgb) |
652 | { |
653 | return Color<T, 3>( |
654 | linear_rgb_to_srgb(linear_rgb[0]), |
655 | linear_rgb_to_srgb(linear_rgb[1]), |
656 | linear_rgb_to_srgb(linear_rgb[2])); |
657 | } |
658 | |
659 | template <typename T> |
660 | inline Color<T, 3> srgb_to_linear_rgb(const Color<T, 3>& srgb) |
661 | { |
662 | return Color<T, 3>( |
663 | srgb_to_linear_rgb(srgb[0]), |
664 | srgb_to_linear_rgb(srgb[1]), |
665 | srgb_to_linear_rgb(srgb[2])); |
666 | } |
667 | |
668 | inline float fast_linear_rgb_to_srgb(const float c) |
669 | { |
670 | return c <= 0.0031308f |
671 | ? 12.92f * c |
672 | : 1.055f * fast_pow(c, 1.0f / 2.4f) - 0.055f; |
673 | } |
674 | |
675 | inline float fast_srgb_to_linear_rgb(const float c) |
676 | { |
677 | return c <= 0.04045f |
678 | ? (1.0f / 12.92f) * c |
679 | : fast_pow((c + 0.055f) * (1.0f / 1.055f), 2.4f); |
680 | } |
681 | |
682 | #ifdef APPLESEED_USE_SSE |
683 | |
684 | inline __m128 fast_linear_rgb_to_srgb(const __m128 linear_rgb) |
685 | { |
686 | // Apply 2.4 gamma correction. |
687 | const __m128 y = fast_pow(linear_rgb, _mm_set1_ps(1.0f / 2.4f)); |
688 | |
689 | // Compute both outcomes of the branch. |
690 | const __m128 a = _mm_mul_ps(_mm_set1_ps(12.92f), linear_rgb); |
691 | const __m128 b = _mm_sub_ps(_mm_mul_ps(_mm_set1_ps(1.055f), y), _mm_set1_ps(0.055f)); |
692 | |
693 | // Interleave them based on the comparison result. |
694 | const __m128 mask = _mm_cmple_ps(linear_rgb, _mm_set1_ps(0.0031308f)); |
695 | return _mm_add_ps(_mm_and_ps(mask, a), _mm_andnot_ps(mask, b)); |
696 | } |
697 | |
698 | inline Color3f fast_linear_rgb_to_srgb(const Color3f& linear_rgb) |
699 | { |
700 | APPLESEED_SIMD4_ALIGN float transfer[4] = |
701 | { |
702 | linear_rgb[0], |
703 | linear_rgb[1], |
704 | linear_rgb[2], |
705 | linear_rgb[2] |
706 | }; |
707 | |
708 | _mm_store_ps(transfer, fast_linear_rgb_to_srgb(_mm_load_ps(transfer))); |
709 | |
710 | return Color3f(transfer[0], transfer[1], transfer[2]); |
711 | } |
712 | |
713 | #else |
714 | |
715 | inline Color3f fast_linear_rgb_to_srgb(const Color3f& linear_rgb) |
716 | { |
717 | return Color3f( |
718 | fast_linear_rgb_to_srgb(linear_rgb[0]), |
719 | fast_linear_rgb_to_srgb(linear_rgb[1]), |
720 | fast_linear_rgb_to_srgb(linear_rgb[2])); |
721 | } |
722 | |
723 | #endif // APPLESEED_USE_SSE |
724 | |
725 | inline Color3f fast_srgb_to_linear_rgb(const Color3f& srgb) |
726 | { |
727 | return Color3f( |
728 | fast_srgb_to_linear_rgb(srgb[0]), |
729 | fast_srgb_to_linear_rgb(srgb[1]), |
730 | fast_srgb_to_linear_rgb(srgb[2])); |
731 | } |
732 | |
733 | inline float faster_linear_rgb_to_srgb(const float c) |
734 | { |
735 | return c <= 0.0031308f |
736 | ? 12.92f * c |
737 | : 1.055f * faster_pow(c, 1.0f / 2.4f) - 0.055f; |
738 | } |
739 | |
740 | inline float faster_srgb_to_linear_rgb(const float c) |
741 | { |
742 | return c <= 0.04045f |
743 | ? (1.0f / 12.92f) * c |
744 | : faster_pow((c + 0.055f) * (1.0f / 1.055f), 2.4f); |
745 | } |
746 | |
747 | #ifdef APPLESEED_USE_SSE |
748 | |
749 | inline __m128 faster_linear_rgb_to_srgb(const __m128 linear_rgb) |
750 | { |
751 | // Apply 2.4 gamma correction. |
752 | const __m128 y = faster_pow(linear_rgb, _mm_set1_ps(1.0f / 2.4f)); |
753 | |
754 | // Compute both outcomes of the branch. |
755 | const __m128 a = _mm_mul_ps(_mm_set1_ps(12.92f), linear_rgb); |
756 | const __m128 b = _mm_sub_ps(_mm_mul_ps(_mm_set1_ps(1.055f), y), _mm_set1_ps(0.055f)); |
757 | |
758 | // Interleave them based on the comparison result. |
759 | const __m128 mask = _mm_cmple_ps(linear_rgb, _mm_set1_ps(0.0031308f)); |
760 | return _mm_add_ps(_mm_and_ps(mask, a), _mm_andnot_ps(mask, b)); |
761 | } |
762 | |
763 | inline Color3f faster_linear_rgb_to_srgb(const Color3f& linear_rgb) |
764 | { |
765 | APPLESEED_SIMD4_ALIGN float transfer[4] = |
766 | { |
767 | linear_rgb[0], |
768 | linear_rgb[1], |
769 | linear_rgb[2], |
770 | linear_rgb[2] |
771 | }; |
772 | |
773 | _mm_store_ps(transfer, faster_linear_rgb_to_srgb(_mm_load_ps(transfer))); |
774 | |
775 | return Color3f(transfer[0], transfer[1], transfer[2]); |
776 | } |
777 | |
778 | #else |
779 | |
780 | inline Color3f faster_linear_rgb_to_srgb(const Color3f& linear_rgb) |
781 | { |
782 | return Color3f( |
783 | faster_linear_rgb_to_srgb(linear_rgb[0]), |
784 | faster_linear_rgb_to_srgb(linear_rgb[1]), |
785 | faster_linear_rgb_to_srgb(linear_rgb[2])); |
786 | } |
787 | |
788 | #endif // APPLESEED_USE_SSE |
789 | |
790 | inline Color3f faster_srgb_to_linear_rgb(const Color3f& srgb) |
791 | { |
792 | return Color3f( |
793 | faster_srgb_to_linear_rgb(srgb[0]), |
794 | faster_srgb_to_linear_rgb(srgb[1]), |
795 | faster_srgb_to_linear_rgb(srgb[2])); |
796 | } |
797 | |
798 | |
799 | // |
800 | // Relative luminance function implementation. |
801 | // |
802 | |
803 | template <typename T> |
804 | inline T luminance(const Color<T, 3>& linear_rgb) |
805 | { |
806 | return |
807 | T(0.212671) * linear_rgb[0] + |
808 | T(0.715160) * linear_rgb[1] + |
809 | T(0.072169) * linear_rgb[2]; |
810 | } |
811 | |
812 | |
813 | // |
814 | // Spectrum <-> CIE XYZ transformations implementation. |
815 | // |
816 | |
817 | template <typename T, typename SpectrumType> |
818 | Color<T, 3> spectrum_to_ciexyz( |
819 | const LightingConditions& lighting, |
820 | const SpectrumType& spectrum) |
821 | { |
822 | BOOST_STATIC_ASSERT(SpectrumType::Samples == 31); |
823 | |
824 | T x = T(0.0); |
825 | T y = T(0.0); |
826 | T z = T(0.0); |
827 | |
828 | for (size_t w = 0; w < 31; ++w) |
829 | { |
830 | const T val = spectrum[w]; |
831 | x += lighting.m_cmf[w][0] * val; |
832 | y += lighting.m_cmf[w][1] * val; |
833 | z += lighting.m_cmf[w][2] * val; |
834 | } |
835 | |
836 | return Color<T, 3>(x, y, z); |
837 | } |
838 | |
839 | #ifdef APPLESEED_USE_SSE |
840 | |
841 | template <> |
842 | inline Color3f spectrum_to_ciexyz<float, RegularSpectrum31f>( |
843 | const LightingConditions& lighting, |
844 | const RegularSpectrum31f& spectrum) |
845 | { |
846 | __m128 xyz1 = _mm_setzero_ps(); |
847 | __m128 xyz2 = _mm_setzero_ps(); |
848 | __m128 xyz3 = _mm_setzero_ps(); |
849 | __m128 xyz4 = _mm_setzero_ps(); |
850 | |
851 | for (size_t w = 0; w < 8; ++w) |
852 | { |
853 | xyz1 = _mm_add_ps(xyz1, _mm_mul_ps(_mm_set1_ps(spectrum[4 * w + 0]), _mm_load_ps(&lighting.m_cmf[4 * w + 0][0]))); |
854 | xyz2 = _mm_add_ps(xyz2, _mm_mul_ps(_mm_set1_ps(spectrum[4 * w + 1]), _mm_load_ps(&lighting.m_cmf[4 * w + 1][0]))); |
855 | xyz3 = _mm_add_ps(xyz3, _mm_mul_ps(_mm_set1_ps(spectrum[4 * w + 2]), _mm_load_ps(&lighting.m_cmf[4 * w + 2][0]))); |
856 | xyz4 = _mm_add_ps(xyz4, _mm_mul_ps(_mm_set1_ps(spectrum[4 * w + 3]), _mm_load_ps(&lighting.m_cmf[4 * w + 3][0]))); |
857 | } |
858 | |
859 | xyz1 = _mm_add_ps(xyz1, xyz2); |
860 | xyz3 = _mm_add_ps(xyz3, xyz4); |
861 | xyz1 = _mm_add_ps(xyz1, xyz3); |
862 | |
863 | APPLESEED_SIMD4_ALIGN float transfer[4]; |
864 | _mm_store_ps(transfer, xyz1); |
865 | |
866 | return Color3f(transfer[0], transfer[1], transfer[2]); |
867 | } |
868 | |
869 | #endif // APPLESEED_USE_SSE |
870 | |
871 | template <typename T, typename SpectrumType> |
872 | void ciexyz_reflectance_to_spectrum( |
873 | const Color<T, 3>& xyz, |
874 | SpectrumType& spectrum) |
875 | { |
876 | linear_rgb_reflectance_to_spectrum( |
877 | ciexyz_to_linear_rgb(xyz), |
878 | spectrum); |
879 | } |
880 | |
881 | template <typename T, typename SpectrumType> |
882 | void ciexyz_illuminance_to_spectrum( |
883 | const Color<T, 3>& xyz, |
884 | SpectrumType& spectrum) |
885 | { |
886 | linear_rgb_illuminance_to_spectrum( |
887 | ciexyz_to_linear_rgb(xyz), |
888 | spectrum); |
889 | } |
890 | |
891 | |
892 | // |
893 | // Convert the CIE xy chromaticity of a D series (daylight) illuminant to a spectrum. |
894 | // |
895 | |
896 | template <> |
897 | inline void daylight_ciexy_to_spectrum<float, RegularSpectrum31f>( |
898 | const float x, |
899 | const float y, |
900 | RegularSpectrum31f& spectrum) |
901 | { |
902 | const float rcp_m = 1.0f / (0.0241f + 0.2562f * x - 0.7341f * y); |
903 | const float m1 = (-1.3515f - 1.7703f * x + 5.9114f * y) * rcp_m; |
904 | const float m2 = (0.0300f - 31.4424f * x + 30.0717f * y) * rcp_m; |
905 | |
906 | spectrum = DaylightS0; |
907 | |
908 | RegularSpectrum31f s1 = DaylightS1; |
909 | s1 *= m1; |
910 | spectrum += s1; |
911 | |
912 | RegularSpectrum31f s2 = DaylightS2; |
913 | s2 *= m2; |
914 | spectrum += s2; |
915 | } |
916 | |
917 | |
918 | // |
919 | // Linear RGB to spectrum transformation implementation. |
920 | // |
921 | |
922 | namespace impl |
923 | { |
924 | template <typename T, typename SpectrumType> |
925 | void linear_rgb_to_spectrum_approximation( |
926 | const Color<T, 3>& linear_rgb, |
927 | SpectrumType& spectrum) |
928 | { |
929 | for (size_t w = 0; w < 10; ++w) |
930 | spectrum[w] = static_cast<T>(linear_rgb[2]); |
931 | |
932 | for (size_t w = 10; w < 20; ++w) |
933 | spectrum[w] = static_cast<T>(linear_rgb[1]); |
934 | |
935 | for (size_t w = 20; w < 31; ++w) |
936 | spectrum[w] = static_cast<T>(linear_rgb[0]); |
937 | } |
938 | |
939 | template <typename T, typename SpectrumType> |
940 | void linear_rgb_to_spectrum( |
941 | const Color<T, 3>& linear_rgb, |
942 | const SpectrumType& white, |
943 | const SpectrumType& cyan, |
944 | const SpectrumType& magenta, |
945 | const SpectrumType& yellow, |
946 | const SpectrumType& red, |
947 | const SpectrumType& green, |
948 | const SpectrumType& blue, |
949 | SpectrumType& spectrum) |
950 | { |
951 | const T r = linear_rgb[0]; |
952 | const T g = linear_rgb[1]; |
953 | const T b = linear_rgb[2]; |
954 | SpectrumType tmp; |
955 | |
956 | if (r <= g && r <= b) |
957 | { |
958 | spectrum = white; |
959 | spectrum *= r; |
960 | |
961 | if (g <= b) |
962 | { |
963 | tmp = cyan; |
964 | tmp *= g - r; |
965 | spectrum += tmp; |
966 | |
967 | tmp = blue; |
968 | tmp *= b - g; |
969 | spectrum += tmp; |
970 | } |
971 | else |
972 | { |
973 | tmp = cyan; |
974 | tmp *= b - r; |
975 | spectrum += tmp; |
976 | |
977 | tmp = green; |
978 | tmp *= g - b; |
979 | spectrum += tmp; |
980 | } |
981 | } |
982 | else if (g <= r && g <= b) |
983 | { |
984 | spectrum = white; |
985 | spectrum *= g; |
986 | |
987 | if (r <= b) |
988 | { |
989 | tmp = magenta; |
990 | tmp *= r - g; |
991 | spectrum += tmp; |
992 | |
993 | tmp = blue; |
994 | tmp *= b - r; |
995 | spectrum += tmp; |
996 | } |
997 | else |
998 | { |
999 | tmp = magenta; |
1000 | tmp *= b - g; |
1001 | spectrum += tmp; |
1002 | |
1003 | tmp = red; |
1004 | tmp *= r - b; |
1005 | spectrum += tmp; |
1006 | } |
1007 | } |
1008 | else |
1009 | { |
1010 | spectrum = white; |
1011 | spectrum *= b; |
1012 | |
1013 | if (r <= g) |
1014 | { |
1015 | tmp = yellow; |
1016 | tmp *= r - b; |
1017 | spectrum += tmp; |
1018 | |
1019 | tmp = green; |
1020 | tmp *= g - r; |
1021 | spectrum += tmp; |
1022 | } |
1023 | else |
1024 | { |
1025 | tmp = yellow; |
1026 | tmp *= g - b; |
1027 | spectrum += tmp; |
1028 | |
1029 | tmp = red; |
1030 | tmp *= r - g; |
1031 | spectrum += tmp; |
1032 | } |
1033 | } |
1034 | } |
1035 | } |
1036 | |
1037 | template <typename T, typename SpectrumType> |
1038 | void linear_rgb_reflectance_to_spectrum_unclamped( |
1039 | const Color<T, 3>& linear_rgb, |
1040 | SpectrumType& spectrum) |
1041 | { |
1042 | impl::linear_rgb_to_spectrum( |
1043 | linear_rgb, |
1044 | RGBToSpectrumWhiteReflectance, |
1045 | RGBToSpectrumCyanReflectance, |
1046 | RGBToSpectrumMagentaReflectance, |
1047 | RGBToSpectrumYellowReflectance, |
1048 | RGBToSpectrumRedReflectance, |
1049 | RGBToSpectrumGreenReflectance, |
1050 | RGBToSpectrumBlueReflectance, |
1051 | spectrum); |
1052 | } |
1053 | |
1054 | template <typename T, typename SpectrumType> |
1055 | void linear_rgb_reflectance_to_spectrum( |
1056 | const Color<T, 3>& linear_rgb, |
1057 | SpectrumType& spectrum) |
1058 | { |
1059 | linear_rgb_reflectance_to_spectrum_unclamped(linear_rgb, spectrum); |
1060 | clamp_low_in_place(spectrum, T(0.0)); |
1061 | } |
1062 | |
1063 | template <typename T, typename SpectrumType> |
1064 | void linear_rgb_illuminance_to_spectrum( |
1065 | const Color<T, 3>& linear_rgb, |
1066 | SpectrumType& spectrum) |
1067 | { |
1068 | /* This gives an undesirable blue tint... |
1069 | impl::linear_rgb_to_spectrum( |
1070 | linear_rgb, |
1071 | RGBToSpectrumWhiteIlluminance, |
1072 | RGBToSpectrumCyanIlluminance, |
1073 | RGBToSpectrumMagentaIlluminance, |
1074 | RGBToSpectrumYellowIlluminance, |
1075 | RGBToSpectrumRedIlluminance, |
1076 | RGBToSpectrumGreenIlluminance, |
1077 | RGBToSpectrumBlueIlluminance, |
1078 | spectrum); */ |
1079 | |
1080 | impl::linear_rgb_to_spectrum( |
1081 | linear_rgb, |
1082 | RGBToSpectrumWhiteReflectance, |
1083 | RGBToSpectrumCyanReflectance, |
1084 | RGBToSpectrumMagentaReflectance, |
1085 | RGBToSpectrumYellowReflectance, |
1086 | RGBToSpectrumRedReflectance, |
1087 | RGBToSpectrumGreenReflectance, |
1088 | RGBToSpectrumBlueReflectance, |
1089 | spectrum); |
1090 | |
1091 | clamp_low_in_place(spectrum, T(0.0)); |
1092 | } |
1093 | |
1094 | |
1095 | // |
1096 | // Spectrum <-> Spectrum transformation implementation. |
1097 | // |
1098 | |
1099 | template <typename T> |
1100 | void spectrum_to_spectrum( |
1101 | const size_t input_count, |
1102 | const T input_wavelength[], |
1103 | const T input_spectrum[], |
1104 | const size_t output_count, |
1105 | const T output_wavelength[], |
1106 | T output_spectrum[], |
1107 | T working_storage[]) |
1108 | { |
1109 | const bool own_memory = (working_storage == 0); |
1110 | |
1111 | if (own_memory) |
1112 | working_storage = new T[input_count]; |
1113 | |
1114 | compute_cardinal_spline_tangents( |
1115 | input_count, // [in] knot count |
1116 | input_wavelength, // [in] knot x |
1117 | &input_spectrum[0], // [in] knot y |
1118 | T(0.0), // [in] tension |
1119 | working_storage); // [out] knot derivatives |
1120 | |
1121 | cubic_hermite_spline( |
1122 | input_count, // [in] knot count |
1123 | input_wavelength, // [in] knot x |
1124 | &input_spectrum[0], // [in] knot y |
1125 | working_storage, // [in] knot derivatives |
1126 | output_count, // [in] point count |
1127 | output_wavelength, // [in] point x |
1128 | &output_spectrum[0]); // [out] point y |
1129 | |
1130 | if (own_memory) |
1131 | delete [] working_storage; |
1132 | } |
1133 | |
1134 | } // namespace foundation |
1135 | |
1136 | #endif // !APPLESEED_FOUNDATION_IMAGE_COLORSPACE_H |
1137 | |