Cycles: Query XYZ to/from Scene Linear conversion from OCIO instead of assuming sRGB

I've limited it to just the RGB<->XYZ stuff for now, correct image handling is the next step.

Reviewers: brecht, sergey

Differential Revision: https://developer.blender.org/D3478

7 files changed, 74 insertions, 9 deletions

diff --git a/intern/cycles/render/constant_fold.cpp b/intern/cycles/render/constant_fold.cpp
index 943b218f0e4..98c3e99996c 100644
--- a/intern/cycles/render/constant_fold.cpp
+++ b/intern/cycles/render/constant_fold.cpp
@@ -22,8 +22,8 @@
 
 CCL_NAMESPACE_BEGIN
 
-ConstantFolder::ConstantFolder(ShaderGraph *graph, ShaderNode *node, ShaderOutput *output)
-: graph(graph), node(node), output(output)
+ConstantFolder::ConstantFolder(ShaderGraph *graph, ShaderNode *node, ShaderOutput *output, Scene *scene)
+: graph(graph), node(node), output(output), scene(scene)
 {
 }
 
diff --git a/intern/cycles/render/constant_fold.h b/intern/cycles/render/constant_fold.h
index 33f93b8c0ab..cc24d614206 100644
--- a/intern/cycles/render/constant_fold.h
+++ b/intern/cycles/render/constant_fold.h
@@ -22,6 +22,7 @@
 
 CCL_NAMESPACE_BEGIN
 
+class Scene;
 class ShaderGraph;
 class ShaderInput;
 class ShaderNode;
@@ -33,7 +34,9 @@ public:
 	ShaderNode *const node;
 	ShaderOutput *const output;
 
-	ConstantFolder(ShaderGraph *graph, ShaderNode *node, ShaderOutput *output);
+	Scene *scene;
+
+	ConstantFolder(ShaderGraph *graph, ShaderNode *node, ShaderOutput *output, Scene *scene);
 
 	bool all_inputs_constant() const;
 
diff --git a/intern/cycles/render/graph.cpp b/intern/cycles/render/graph.cpp
index e1c09373004..8b179f742c4 100644
--- a/intern/cycles/render/graph.cpp
+++ b/intern/cycles/render/graph.cpp
@@ -496,7 +496,7 @@ void ShaderGraph::remove_proxy_nodes()
  * Try to constant fold some nodes, and pipe result directly to
  * the input socket of connected nodes.
  */
-void ShaderGraph::constant_fold()
+void ShaderGraph::constant_fold(Scene *scene)
 {
 	ShaderNodeSet done, scheduled;
 	queue<ShaderNode*> traverse_queue;
@@ -536,7 +536,7 @@ void ShaderGraph::constant_fold()
 				}
 			}
 			/* Optimize current node. */
-			ConstantFolder folder(this, node, output);
+			ConstantFolder folder(this, node, output, scene);
 			node->constant_fold(folder);
 		}
 	}
@@ -734,7 +734,7 @@ void ShaderGraph::clean(Scene *scene)
 	/* Graph simplification */
 
 	/* NOTE: Remove proxy nodes was already done. */
-	constant_fold();
+	constant_fold(scene);
 	simplify_settings(scene);
 	deduplicate_nodes();
 	verify_volume_output();
diff --git a/intern/cycles/render/graph.h b/intern/cycles/render/graph.h
index 2c134932b3c..5d986ae4827 100644
--- a/intern/cycles/render/graph.h
+++ b/intern/cycles/render/graph.h
@@ -285,7 +285,7 @@ protected:
 
 	/* Graph simplification routines. */
 	void clean(Scene *scene);
-	void constant_fold();
+	void constant_fold(Scene *scene);
 	void simplify_settings(Scene *scene);
 	void deduplicate_nodes();
 	void verify_volume_output();
diff --git a/intern/cycles/render/nodes.cpp b/intern/cycles/render/nodes.cpp
index 3dad4d1a346..0f2581b2a2e 100644
--- a/intern/cycles/render/nodes.cpp
+++ b/intern/cycles/render/nodes.cpp
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+#include "render/film.h"
 #include "render/image.h"
 #include "render/integrator.h"
 #include "render/light.h"
@@ -1673,7 +1674,8 @@ RGBToBWNode::RGBToBWNode()
 void RGBToBWNode::constant_fold(const ConstantFolder& folder)
 {
 	if(folder.all_inputs_constant()) {
-		folder.make_constant(linear_rgb_to_gray(color));
+		float val = folder.scene->shader_manager->linear_rgb_to_gray(color);
+		folder.make_constant(val);
 	}
 }
 
@@ -1769,7 +1771,8 @@ void ConvertNode::constant_fold(const ConstantFolder& folder)
 			if(to == SocketType::FLOAT) {
 				if(from == SocketType::COLOR) {
 					/* color to float */
-					folder.make_constant(linear_rgb_to_gray(value_color));
+					float val = folder.scene->shader_manager->linear_rgb_to_gray(value_color);
+					folder.make_constant(val);
 				}
 				else {
 					/* vector/point/normal to float */
diff --git a/intern/cycles/render/shader.cpp b/intern/cycles/render/shader.cpp
index ec52c51e337..e34f272d9b6 100644
--- a/intern/cycles/render/shader.cpp
+++ b/intern/cycles/render/shader.cpp
@@ -31,6 +31,11 @@
 
 #include "util/util_foreach.h"
 
+#ifdef WITH_OCIO
+#  include <OpenColorIO/OpenColorIO.h>
+namespace OCIO = OCIO_NAMESPACE;
+#endif
+
 CCL_NAMESPACE_BEGIN
 
 thread_mutex ShaderManager::lookup_table_mutex;
@@ -338,6 +343,40 @@ ShaderManager::ShaderManager()
 {
 	need_update = true;
 	beckmann_table_offset = TABLE_OFFSET_INVALID;
+
+	xyz_to_r = make_float3( 3.2404542f, -1.5371385f, -0.4985314f);
+	xyz_to_g = make_float3(-0.9692660f,  1.8760108f,  0.0415560f);
+	xyz_to_b = make_float3( 0.0556434f, -0.2040259f,  1.0572252f);
+	rgb_to_y = make_float3( 0.2126729f,  0.7151522f,  0.0721750f);
+
+#ifdef WITH_OCIO
+	OCIO::ConstConfigRcPtr config = OCIO::GetCurrentConfig();
+	if(config) {
+		if(config->hasRole("XYZ") && config->hasRole("scene_linear")) {
+			OCIO::ConstProcessorRcPtr to_rgb_processor = config->getProcessor("XYZ", "scene_linear");
+			OCIO::ConstProcessorRcPtr to_xyz_processor = config->getProcessor("scene_linear", "XYZ");
+			if(to_rgb_processor && to_xyz_processor) {
+				float r[] = {1.0f, 0.0f, 0.0f};
+				float g[] = {0.0f, 1.0f, 0.0f};
+				float b[] = {0.0f, 0.0f, 1.0f};
+				to_xyz_processor->applyRGB(r);
+				to_xyz_processor->applyRGB(g);
+				to_xyz_processor->applyRGB(b);
+				rgb_to_y = make_float3(r[1], g[1], b[1]);
+
+				float x[] = {1.0f, 0.0f, 0.0f};
+				float y[] = {0.0f, 1.0f, 0.0f};
+				float z[] = {0.0f, 0.0f, 1.0f};
+				to_rgb_processor->applyRGB(x);
+				to_rgb_processor->applyRGB(y);
+				to_rgb_processor->applyRGB(z);
+				xyz_to_r = make_float3(x[0], y[0], z[0]);
+				xyz_to_g = make_float3(x[1], y[1], z[1]);
+				xyz_to_b = make_float3(x[2], y[2], z[2]);
+			}
+		}
+	}
+#endif
 }
 
 ShaderManager::~ShaderManager()
@@ -518,6 +557,14 @@ void ShaderManager::device_update_common(Device *device,
 	kintegrator->use_volumes = has_volumes;
 	/* TODO(sergey): De-duplicate with flags set in integrator.cpp. */
 	kintegrator->transparent_shadows = has_transparent_shadow;
+
+	/* film */
+	KernelFilm *kfilm = &dscene->data.film;
+	/* color space, needs to be here because e.g. displacement shaders could depend on it */
+	kfilm->xyz_to_r = xyz_to_r;
+	kfilm->xyz_to_g = xyz_to_g;
+	kfilm->xyz_to_b = xyz_to_b;
+	kfilm->rgb_to_y = rgb_to_y;
 }
 
 void ShaderManager::device_free_common(Device *, DeviceScene *dscene, Scene *scene)
@@ -643,5 +690,10 @@ void ShaderManager::free_memory()
 	beckmann_table.free_memory();
 }
 
+float ShaderManager::linear_rgb_to_gray(float3 c)
+{
+	return dot(c, rgb_to_y);
+}
+
 CCL_NAMESPACE_END
 
diff --git a/intern/cycles/render/shader.h b/intern/cycles/render/shader.h
index abd483caabc..0353da90013 100644
--- a/intern/cycles/render/shader.h
+++ b/intern/cycles/render/shader.h
@@ -195,6 +195,8 @@ public:
 
 	static void free_memory();
 
+	float linear_rgb_to_gray(float3 c);
+
 protected:
 	ShaderManager();
 
@@ -211,6 +213,11 @@ protected:
 	                                  DeviceRequestedFeatures *requested_features);
 
 	thread_spin_lock attribute_lock_;
+
+	float3 xyz_to_r;
+	float3 xyz_to_g;
+	float3 xyz_to_b;
+	float3 rgb_to_y;
 };
 
 CCL_NAMESPACE_END