VideoCore: Unify interface to OpenGL and SW rasterizers

This removes explicit checks sprinkled all over the codebase to instead
just have the SW rasterizer expose an implementation with no-ops for
most operations.

src/video_core/rasterizer_interface.h

@@ -0,0 +1,48 @@
+// Copyright 2015 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/common_types.h"
+
+namespace Pica {
+namespace Shader {
+struct OutputVertex;
+}
+}
+
+namespace VideoCore {
+
+class RasterizerInterface {
+public:
+    virtual ~RasterizerInterface() {}
+
+    /// Initialize API-specific GPU objects
+    virtual void InitObjects() = 0;
+
+    /// Reset the rasterizer, such as flushing all caches and updating all state
+    virtual void Reset() = 0;
+
+    /// Queues the primitive formed by the given vertices for rendering
+    virtual void AddTriangle(const Pica::Shader::OutputVertex& v0,
+                             const Pica::Shader::OutputVertex& v1,
+                             const Pica::Shader::OutputVertex& v2) = 0;
+
+    /// Draw the current batch of triangles
+    virtual void DrawTriangles() = 0;
+
+    /// Commit the rasterizer's framebuffer contents immediately to the current 3DS memory framebuffer
+    virtual void FlushFramebuffer() = 0;
+
+    /// Notify rasterizer that the specified PICA register has been changed
+    virtual void NotifyPicaRegisterChanged(u32 id) = 0;
+
+    /// Notify rasterizer that any caches of the specified region should be flushed to 3DS memory.
+    virtual void FlushRegion(PAddr addr, u32 size) = 0;
+
+    /// Notify rasterizer that any caches of the specified region should be discraded and reloaded from 3DS memory.
+    virtual void InvalidateRegion(PAddr addr, u32 size) = 0;
+};
+
+}