Cycles: Constant fold for the Gamma Node.

4 files changed, 33 insertions, 6 deletions

diff --git a/intern/cycles/kernel/svm/svm_gamma.h b/intern/cycles/kernel/svm/svm_gamma.h
index b645ff3f0f9..171945a60bc 100644
--- a/intern/cycles/kernel/svm/svm_gamma.h
+++ b/intern/cycles/kernel/svm/svm_gamma.h
@@ -21,12 +21,7 @@ ccl_device void svm_node_gamma(ShaderData *sd, float *stack, uint in_gamma, uint
 	float3 color = stack_load_float3(stack, in_color);
 	float gamma = stack_load_float(stack, in_gamma);
 
-	if(color.x > 0.0f)
-		color.x = powf(color.x, gamma);
-	if(color.y > 0.0f)
-		color.y = powf(color.y, gamma);
-	if(color.z > 0.0f)
-		color.z = powf(color.z, gamma);
+	color = svm_math_gamma_color(color, gamma);
 
 	if(stack_valid(out_color))
 		stack_store_float3(stack, out_color, color);
diff --git a/intern/cycles/kernel/svm/svm_math_util.h b/intern/cycles/kernel/svm/svm_math_util.h
index 645cbd3fc73..3f7d18a02fe 100644
--- a/intern/cycles/kernel/svm/svm_math_util.h
+++ b/intern/cycles/kernel/svm/svm_math_util.h
@@ -166,5 +166,17 @@ ccl_device float3 svm_math_blackbody_color(float t) {
 	return make_float3(4.70366907f, 0.0f, 0.0f);
 }
 
+ccl_device_inline float3 svm_math_gamma_color(float3 color, float gamma)
+{
+	if(color.x > 0.0f)
+		color.x = powf(color.x, gamma);
+	if(color.y > 0.0f)
+		color.y = powf(color.y, gamma);
+	if(color.z > 0.0f)
+		color.z = powf(color.z, gamma);
+
+	return color;
+}
+
 CCL_NAMESPACE_END
 
diff --git a/intern/cycles/render/nodes.cpp b/intern/cycles/render/nodes.cpp
index 2771d35990e..678f7b31334 100644
--- a/intern/cycles/render/nodes.cpp
+++ b/intern/cycles/render/nodes.cpp
@@ -3516,6 +3516,23 @@ GammaNode::GammaNode()
 	add_output("Color", SHADER_SOCKET_COLOR);
 }
 
+bool GammaNode::constant_fold(ShaderOutput *socket, float3 *optimized_value)
+{
+	ShaderInput *color_in = input("Color");
+	ShaderInput *gamma_in = input("Gamma");
+
+	if(socket == output("Color")) {
+		if(color_in->link == NULL && gamma_in->link == NULL) {
+			*optimized_value = svm_math_gamma_color(color_in->value,
+			                                        gamma_in->value.x);
+
+			return true;
+		}
+	}
+
+	return false;
+}
+
 void GammaNode::compile(SVMCompiler& compiler)
 {
 	ShaderInput *color_in = input("Color");
diff --git a/intern/cycles/render/nodes.h b/intern/cycles/render/nodes.h
index 51efbc37f38..8c5f6651463 100644
--- a/intern/cycles/render/nodes.h
+++ b/intern/cycles/render/nodes.h
@@ -557,6 +557,9 @@ public:
 class GammaNode : public ShaderNode {
 public:
 	SHADER_NODE_CLASS(GammaNode)
+
+	bool constant_fold(ShaderOutput *socket, float3 *optimized_value);
+
 	virtual int get_group() { return NODE_GROUP_LEVEL_1; }
 };