Color management: add OCIO aware utility functions for transform to/from XYZ.

5 files changed, 50 insertions, 0 deletions

diff --git a/intern/opencolorio/fallback_impl.cc b/intern/opencolorio/fallback_impl.cc
index 87629422013..7bf8134b41c 100644
--- a/intern/opencolorio/fallback_impl.cc
+++ b/intern/opencolorio/fallback_impl.cc
@@ -333,6 +333,13 @@ void FallbackImpl::configGetDefaultLumaCoefs(OCIO_ConstConfigRcPtr * /*config*/,
 	rgb[2] = 0.0722f;
 }
 
+void FallbackImpl::configGetXYZtoRGB(OCIO_ConstConfigRcPtr * /*config*/,
+                                     float xyz_to_rgb[3][3])
+{
+	/* Default to ITU-BT.709. */
+	memcpy(xyz_to_rgb, OCIO_XYZ_TO_LINEAR_SRGB, sizeof(OCIO_XYZ_TO_LINEAR_SRGB));
+}
+
 int FallbackImpl::configGetNumLooks(OCIO_ConstConfigRcPtr * /*config*/)
 {
 	return 0;
diff --git a/intern/opencolorio/ocio_capi.cc b/intern/opencolorio/ocio_capi.cc
index 7a0b9faa5fc..25e1b31630c 100644
--- a/intern/opencolorio/ocio_capi.cc
+++ b/intern/opencolorio/ocio_capi.cc
@@ -137,6 +137,11 @@ void OCIO_configGetDefaultLumaCoefs(OCIO_ConstConfigRcPtr *config, float *rgb)
 	impl->configGetDefaultLumaCoefs(config, rgb);
 }
 
+void OCIO_configGetXYZtoRGB(OCIO_ConstConfigRcPtr *config, float xyz_to_rgb[3][3])
+{
+	impl->configGetXYZtoRGB(config, xyz_to_rgb);
+}
+
 int OCIO_configGetNumLooks(OCIO_ConstConfigRcPtr *config)
 {
 	return impl->configGetNumLooks(config);
diff --git a/intern/opencolorio/ocio_capi.h b/intern/opencolorio/ocio_capi.h
index 52a86727902..5bed24d64b1 100644
--- a/intern/opencolorio/ocio_capi.h
+++ b/intern/opencolorio/ocio_capi.h
@@ -54,6 +54,13 @@ OCIO_DECLARE_HANDLE(OCIO_ExponentTransformRcPtr);
 OCIO_DECLARE_HANDLE(OCIO_MatrixTransformRcPtr);
 OCIO_DECLARE_HANDLE(OCIO_ConstLookRcPtr);
 
+/* Standard XYZ to linear sRGB transform, for fallback. */
+static const float OCIO_XYZ_TO_LINEAR_SRGB[3][3] = {
+	{3.2404542f, -0.9692660f, 0.0556434f},
+	{-1.5371385f, 1.8760108f, -0.2040259f},
+	{-0.4985314f, 0.0415560f, 1.0572252f}};
+
+
 /* This structure is used to pass curve mapping settings from
  * blender's DNA structure stored in view transform settings
  * to a generic OpenColorIO C-API.
@@ -141,6 +148,7 @@ const char *OCIO_configGetView(OCIO_ConstConfigRcPtr *config, const char *displa
 const char *OCIO_configGetDisplayColorSpaceName(OCIO_ConstConfigRcPtr *config, const char *display, const char *view);
 
 void        OCIO_configGetDefaultLumaCoefs(OCIO_ConstConfigRcPtr *config, float *rgb);
+void        OCIO_configGetXYZtoRGB(OCIO_ConstConfigRcPtr *config, float xyz_to_rgb[3][3]);
 
 int                  OCIO_configGetNumLooks(OCIO_ConstConfigRcPtr *config);
 const char          *OCIO_configGetLookNameByIndex(OCIO_ConstConfigRcPtr *config, int index);
diff --git a/intern/opencolorio/ocio_impl.cc b/intern/opencolorio/ocio_impl.cc
index 4c9115af810..ac167692647 100644
--- a/intern/opencolorio/ocio_impl.cc
+++ b/intern/opencolorio/ocio_impl.cc
@@ -419,6 +419,33 @@ void OCIOImpl::configGetDefaultLumaCoefs(OCIO_ConstConfigRcPtr *config, float *r
 	}
 }
 
+void OCIOImpl::configGetXYZtoRGB(OCIO_ConstConfigRcPtr *config_, float xyz_to_rgb[3][3])
+{
+	ConstConfigRcPtr config = (*(ConstConfigRcPtr *) config_);
+
+	/* Default to ITU-BT.709 in case no appropriate transform found. */
+	memcpy(xyz_to_rgb, OCIO_XYZ_TO_LINEAR_SRGB, sizeof(OCIO_XYZ_TO_LINEAR_SRGB));
+
+	/* Auto estimate from XYZ and scene_linear roles, assumed to be a linear transform. */
+	if(config->hasRole("XYZ") && config->hasRole("scene_linear")) {
+		ConstProcessorRcPtr to_rgb_processor = config->getProcessor("XYZ", "scene_linear");
+		if(to_rgb_processor) {
+			xyz_to_rgb[0][0] = 1.0f;
+			xyz_to_rgb[0][1] = 0.0f;
+			xyz_to_rgb[0][2] = 0.0f;
+			xyz_to_rgb[1][0] = 0.0f;
+			xyz_to_rgb[1][1] = 1.0f;
+			xyz_to_rgb[1][2] = 0.0f;
+			xyz_to_rgb[2][0] = 0.0f;
+			xyz_to_rgb[2][1] = 0.0f;
+			xyz_to_rgb[2][2] = 1.0f;
+			to_rgb_processor->applyRGB(xyz_to_rgb[0]);
+			to_rgb_processor->applyRGB(xyz_to_rgb[1]);
+			to_rgb_processor->applyRGB(xyz_to_rgb[2]);
+		}
+	}
+}
+
 int OCIOImpl::configGetNumLooks(OCIO_ConstConfigRcPtr *config)
 {
 	try {
diff --git a/intern/opencolorio/ocio_impl.h b/intern/opencolorio/ocio_impl.h
index f086bbb1a26..4e844584bca 100644
--- a/intern/opencolorio/ocio_impl.h
+++ b/intern/opencolorio/ocio_impl.h
@@ -59,6 +59,7 @@ public:
 	virtual const char *configGetDisplayColorSpaceName(OCIO_ConstConfigRcPtr *config, const char *display, const char *view) = 0;
 
 	virtual void configGetDefaultLumaCoefs(OCIO_ConstConfigRcPtr *config, float *rgb) = 0;
+	virtual void configGetXYZtoRGB(OCIO_ConstConfigRcPtr *config, float xyz_to_rgb[3][3]) = 0;
 
 	virtual int                  configGetNumLooks(OCIO_ConstConfigRcPtr *config) = 0;
 	virtual const char          *configGetLookNameByIndex(OCIO_ConstConfigRcPtr *config, int index) = 0;
@@ -148,6 +149,7 @@ public:
 	const char *configGetDisplayColorSpaceName(OCIO_ConstConfigRcPtr *config, const char *display, const char *view);
 
 	void configGetDefaultLumaCoefs(OCIO_ConstConfigRcPtr *config, float *rgb);
+	void configGetXYZtoRGB(OCIO_ConstConfigRcPtr *config, float xyz_to_rgb[3][3]);
 
 	int                  configGetNumLooks(OCIO_ConstConfigRcPtr *config);
 	const char          *configGetLookNameByIndex(OCIO_ConstConfigRcPtr *config, int index);
@@ -238,6 +240,7 @@ public:
 	const char *configGetDisplayColorSpaceName(OCIO_ConstConfigRcPtr *config, const char *display, const char *view);
 
 	void configGetDefaultLumaCoefs(OCIO_ConstConfigRcPtr *config, float *rgb);
+	void configGetXYZtoRGB(OCIO_ConstConfigRcPtr *config, float xyz_to_rgb[3][3]);
 
 	int                  configGetNumLooks(OCIO_ConstConfigRcPtr *config);
 	const char          *configGetLookNameByIndex(OCIO_ConstConfigRcPtr *config, int index);