Cycles/Compositor: Add arctan2 operation to the Math node

The Math node currently has the normal atan() function, but for
actual angles this is fairly useless without additional nodes to handle the signs.

Since the node has two inputs anyways, it only makes sense to add an arctan2 option.

Reviewers: sergey, brecht

Differential Revision: https://developer.blender.org/D3430

3 files changed, 22 insertions, 0 deletions

diff --git a/source/blender/compositor/nodes/COM_MathNode.cpp b/source/blender/compositor/nodes/COM_MathNode.cpp
index eb6bb2caf56..0fb6933afe7 100644
--- a/source/blender/compositor/nodes/COM_MathNode.cpp
+++ b/source/blender/compositor/nodes/COM_MathNode.cpp
@@ -86,6 +86,9 @@ void MathNode::convertToOperations(NodeConverter &converter, const CompositorCon
 		case NODE_MATH_ABS:
 			operation = new MathAbsoluteOperation();
 			break;
+		case NODE_MATH_ATAN2:
+			operation = new MathArcTan2Operation();
+			break;
 	}
 	
 	if (operation) {
diff --git a/source/blender/compositor/operations/COM_MathBaseOperation.cpp b/source/blender/compositor/operations/COM_MathBaseOperation.cpp
index 32a1e77b9a7..dbc91980acd 100644
--- a/source/blender/compositor/operations/COM_MathBaseOperation.cpp
+++ b/source/blender/compositor/operations/COM_MathBaseOperation.cpp
@@ -343,3 +343,16 @@ void MathAbsoluteOperation::executePixelSampled(float output[4], float x, float
 
 	clampIfNeeded(output);
 }
+
+void MathArcTan2Operation::executePixelSampled(float output[4], float x, float y, PixelSampler sampler)
+{
+	float inputValue1[4];
+	float inputValue2[4];
+
+	this->m_inputValue1Operation->readSampled(inputValue1, x, y, sampler);
+	this->m_inputValue2Operation->readSampled(inputValue2, x, y, sampler);
+
+	output[0] = atan2(inputValue1[0], inputValue2[0]);
+
+	clampIfNeeded(output);
+}
\ No newline at end of file
diff --git a/source/blender/compositor/operations/COM_MathBaseOperation.h b/source/blender/compositor/operations/COM_MathBaseOperation.h
index 32cd19f1fb9..04019372711 100644
--- a/source/blender/compositor/operations/COM_MathBaseOperation.h
+++ b/source/blender/compositor/operations/COM_MathBaseOperation.h
@@ -169,4 +169,10 @@ public:
 	void executePixelSampled(float output[4], float x, float y, PixelSampler sampler);
 };
 
+class MathArcTan2Operation : public MathBaseOperation {
+public:
+	MathArcTan2Operation() : MathBaseOperation() {}
+	void executePixelSampled(float output[4], float x, float y, PixelSampler sampler);
+};
+
 #endif