Pica: Add triangle clipper.

src/video_core/clipper.h

@@ -0,0 +1,21 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#pragma once
+
+namespace Pica {
+
+namespace VertexShader {
+    struct OutputVertex;
+}
+
+namespace Clipper {
+
+using VertexShader::OutputVertex;
+
+void ProcessTriangle(OutputVertex& v0, OutputVertex& v1, OutputVertex& v2);
+
+} // namespace
+
+} // namespace