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Color management: add functions to detect scene linear and sRGB color spaces 

Same as the ones in Cycles, but intended for GPU textures.
This commit is contained in:
Brecht Van Lommel 2019-05-05 13:14:37 +02:00
parent 8794779a2d
commit 2c0da4a3db
6 changed files with 139 additions and 11 deletions
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24
intern/cycles/render/colorspace.cpp
View File

@ -114,11 +114,11 @@ ustring ColorSpaceManager::detect_known_colorspace(ustring colorspace,
}
/* Detect if it matches a simple builtin colorspace. */
bool is_no_op, is_srgb;
is_builtin_colorspace(colorspace, is_no_op, is_srgb);
bool is_scene_linear, is_srgb;
is_builtin_colorspace(colorspace, is_scene_linear, is_srgb);
thread_scoped_lock cache_lock(cache_mutex);
if (is_no_op) {
if (is_scene_linear) {
VLOG(1) << "Colorspace " << colorspace.string() << " is no-op";
cached_colorspaces[colorspace] = u_colorspace_raw;
return u_colorspace_raw;
@ -154,17 +154,19 @@ ustring ColorSpaceManager::detect_known_colorspace(ustring colorspace,
}
}
void ColorSpaceManager::is_builtin_colorspace(ustring colorspace, bool &is_no_op, bool &is_srgb)
void ColorSpaceManager::is_builtin_colorspace(ustring colorspace,
bool &is_scene_linear,
bool &is_srgb)
{
#ifdef WITH_OCIO
const OCIO::Processor *processor = (const OCIO::Processor *)get_processor(colorspace);
if (!processor) {
is_no_op = false;
is_scene_linear = false;
is_srgb = false;
return;
}
is_no_op = true;
is_scene_linear = true;
is_srgb = true;
for (int i = 0; i < 256; i++) {
float v = i / 255.0f;
@ -181,27 +183,27 @@ void ColorSpaceManager::is_builtin_colorspace(ustring colorspace, bool &is_no_op
/* Make sure that there is no channel crosstalk. */
if (fabsf(cR[1]) > 1e-5f || fabsf(cR[2]) > 1e-5f || fabsf(cG[0]) > 1e-5f ||
fabsf(cG[2]) > 1e-5f || fabsf(cB[0]) > 1e-5f || fabsf(cB[1]) > 1e-5f) {
is_no_op = false;
is_scene_linear = false;
is_srgb = false;
break;
}
/* Make sure that the three primaries combine linearly. */
if (!compare_floats(cR[0], cW[0], 1e-6f, 64) || !compare_floats(cG[1], cW[1], 1e-6f, 64) ||
!compare_floats(cB[2], cW[2], 1e-6f, 64)) {
is_no_op = false;
is_scene_linear = false;
is_srgb = false;
break;
}
/* Make sure that the three channels behave identically. */
if (!compare_floats(cW[0], cW[1], 1e-6f, 64) || !compare_floats(cW[1], cW[2], 1e-6f, 64)) {
is_no_op = false;
is_scene_linear = false;
is_srgb = false;
break;
}
float out_v = average(make_float3(cW[0], cW[1], cW[2]));
if (!compare_floats(v, out_v, 1e-6f, 64)) {
is_no_op = false;
is_scene_linear = false;
}
if (!compare_floats(color_srgb_to_linear(v), out_v, 1e-6f, 64)) {
is_srgb = false;
@ -209,7 +211,7 @@ void ColorSpaceManager::is_builtin_colorspace(ustring colorspace, bool &is_no_op
}
#else
(void)colorspace;
is_no_op = false;
is_scene_linear = false;
is_srgb = false;
#endif
}

19
intern/opencolorio/fallback_impl.cc
View File

@ -363,6 +363,25 @@ int FallbackImpl::colorSpaceIsData(OCIO_ConstColorSpaceRcPtr * /*cs*/)
return 0;
}
void FallbackImpl::colorSpaceIsBuiltin(OCIO_ConstConfigRcPtr * /*config*/,
OCIO_ConstColorSpaceRcPtr *cs,
bool &is_scene_linear,
bool &is_srgb)
{
if (cs == COLORSPACE_LINEAR) {
is_scene_linear = true;
is_srgb = false;
}
else if (cs == COLORSPACE_SRGB) {
is_scene_linear = false;
is_srgb = true;
}
else {
is_scene_linear = false;
is_srgb = false;
}
}
void FallbackImpl::colorSpaceRelease(OCIO_ConstColorSpaceRcPtr * /*cs*/)
{
}

8
intern/opencolorio/ocio_capi.cc
View File

@ -174,6 +174,14 @@ int OCIO_colorSpaceIsData(OCIO_ConstColorSpaceRcPtr *cs)
return impl->colorSpaceIsData(cs);
}
void OCIO_colorSpaceIsBuiltin(OCIO_ConstConfigRcPtr *config,
OCIO_ConstColorSpaceRcPtr *cs,
bool *is_scene_linear,
bool *is_srgb)
{
impl->colorSpaceIsBuiltin(config, cs, *is_scene_linear, *is_srgb);
}
void OCIO_colorSpaceRelease(OCIO_ConstColorSpaceRcPtr *cs)
{
impl->colorSpaceRelease(cs);

4
intern/opencolorio/ocio_capi.h
View File

@ -130,6 +130,10 @@ int OCIO_configGetIndexForColorSpace(OCIO_ConstConfigRcPtr *config, const char *
int OCIO_colorSpaceIsInvertible(OCIO_ConstColorSpaceRcPtr *cs);
int OCIO_colorSpaceIsData(OCIO_ConstColorSpaceRcPtr *cs);
void OCIO_colorSpaceIsBuiltin(OCIO_ConstConfigRcPtr *config,
OCIO_ConstColorSpaceRcPtr *cs,
bool *is_scene_linear,
bool *is_srgb);
void OCIO_colorSpaceRelease(OCIO_ConstColorSpaceRcPtr *cs);

83
intern/opencolorio/ocio_impl.cc
View File

@ -18,6 +18,7 @@
*/
#include <iostream>
#include <math.h>
#include <sstream>
#include <string.h>
@ -34,6 +35,8 @@ using namespace OCIO_NAMESPACE;
#include "MEM_guardedalloc.h"
#include "BLI_math_color.h"
#include "ocio_impl.h"
#if !defined(WITH_ASSERT_ABORT)
@ -520,6 +523,86 @@ int OCIOImpl::colorSpaceIsData(OCIO_ConstColorSpaceRcPtr *cs)
return (*(ConstColorSpaceRcPtr *)cs)->isData();
}
static float compare_floats(float a, float b, float abs_diff, int ulp_diff)
{
/* Returns true if the absolute difference is smaller than abs_diff (for numbers near zero)
* or their relative difference is less than ulp_diff ULPs. Based on:
* https://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/ */
if (fabsf(a - b) < abs_diff) {
return true;
}
if ((a < 0.0f) != (b < 0.0f)) {
return false;
}
return (abs((*(int *)&a) - (*(int *)&b)) < ulp_diff);
}
void OCIOImpl::colorSpaceIsBuiltin(OCIO_ConstConfigRcPtr *config_,
OCIO_ConstColorSpaceRcPtr *cs_,
bool &is_scene_linear,
bool &is_srgb)
{
ConstConfigRcPtr *config = (ConstConfigRcPtr *)config_;
ConstColorSpaceRcPtr *cs = (ConstColorSpaceRcPtr *)cs_;
ConstProcessorRcPtr processor;
try {
processor = (*config)->getProcessor((*cs)->getName(), "scene_linear");
}
catch (Exception &exception) {
OCIO_reportException(exception);
is_scene_linear = false;
is_srgb = false;
return;
}
is_scene_linear = true;
is_srgb = true;
for (int i = 0; i < 256; i++) {
float v = i / 255.0f;
float cR[3] = {v, 0, 0};
float cG[3] = {0, v, 0};
float cB[3] = {0, 0, v};
float cW[3] = {v, v, v};
processor->applyRGB(cR);
processor->applyRGB(cG);
processor->applyRGB(cB);
processor->applyRGB(cW);
/* Make sure that there is no channel crosstalk. */
if (fabsf(cR[1]) > 1e-5f || fabsf(cR[2]) > 1e-5f || fabsf(cG[0]) > 1e-5f ||
fabsf(cG[2]) > 1e-5f || fabsf(cB[0]) > 1e-5f || fabsf(cB[1]) > 1e-5f) {
is_scene_linear = false;
is_srgb = false;
break;
}
/* Make sure that the three primaries combine linearly. */
if (!compare_floats(cR[0], cW[0], 1e-6f, 64) || !compare_floats(cG[1], cW[1], 1e-6f, 64) ||
!compare_floats(cB[2], cW[2], 1e-6f, 64)) {
is_scene_linear = false;
is_srgb = false;
break;
}
/* Make sure that the three channels behave identically. */
if (!compare_floats(cW[0], cW[1], 1e-6f, 64) || !compare_floats(cW[1], cW[2], 1e-6f, 64)) {
is_scene_linear = false;
is_srgb = false;
break;
}
float out_v = (cW[0] + cW[1] + cW[2]) * (1.0f / 3.0f);
if (!compare_floats(v, out_v, 1e-6f, 64)) {
is_scene_linear = false;
}
if (!compare_floats(srgb_to_linearrgb(v), out_v, 1e-6f, 64)) {
is_srgb = false;
}
}
}
void OCIOImpl::colorSpaceRelease(OCIO_ConstColorSpaceRcPtr *cs)
{
OBJECT_GUARDED_DELETE((ConstColorSpaceRcPtr *)cs, ConstColorSpaceRcPtr);

12
intern/opencolorio/ocio_impl.h
View File

@ -44,6 +44,10 @@ class IOCIOImpl {
virtual int colorSpaceIsInvertible(OCIO_ConstColorSpaceRcPtr *cs) = 0;
virtual int colorSpaceIsData(OCIO_ConstColorSpaceRcPtr *cs) = 0;
virtual void colorSpaceIsBuiltin(OCIO_ConstConfigRcPtr *config,
OCIO_ConstColorSpaceRcPtr *cs,
bool &is_scene_linear,
bool &is_srgb) = 0;
virtual void colorSpaceRelease(OCIO_ConstColorSpaceRcPtr *cs) = 0;
@ -160,6 +164,10 @@ class FallbackImpl : public IOCIOImpl {
int colorSpaceIsInvertible(OCIO_ConstColorSpaceRcPtr *cs);
int colorSpaceIsData(OCIO_ConstColorSpaceRcPtr *cs);
void colorSpaceIsBuiltin(OCIO_ConstConfigRcPtr *config,
OCIO_ConstColorSpaceRcPtr *cs,
bool &is_scene_linear,
bool &is_srgb);
void colorSpaceRelease(OCIO_ConstColorSpaceRcPtr *cs);
@ -266,6 +274,10 @@ class OCIOImpl : public IOCIOImpl {
int colorSpaceIsInvertible(OCIO_ConstColorSpaceRcPtr *cs);
int colorSpaceIsData(OCIO_ConstColorSpaceRcPtr *cs);
void colorSpaceIsBuiltin(OCIO_ConstConfigRcPtr *config,
OCIO_ConstColorSpaceRcPtr *cs,
bool &is_scene_linear,
bool &is_srgb);
void colorSpaceRelease(OCIO_ConstColorSpaceRcPtr *cs);