Minor refactoring to pull GrClipMaskManager into its own files

http://codereview.appspot.com/5978055/



git-svn-id: http://skia.googlecode.com/svn/trunk@3697 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 81 insertions, 0 deletions

diff --git a/src/gpu/GrClipMaskManager.h b/src/gpu/GrClipMaskManager.h
new file mode 100644
index 0000000000..d3f0d159e9
--- /dev/null
+++ b/src/gpu/GrClipMaskManager.h
@@ -0,0 +1,81 @@
+
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrClipMaskManager_DEFINED
+#define GrClipMaskManager_DEFINED
+
+#include "GrRect.h"
+
+class GrGpu;
+class GrClip;
+class GrPathRenderer;
+class GrPathRendererChain;
+class SkPath;
+
+/**
+ * Scissoring needs special handling during stencil clip mask creation
+ * since the creation process re-entrantly invokes setupClipAndFlushState.
+ * During this process the call stack is used to keep 
+ * track of (and apply to the GPU) the current scissor settings.
+ */
+struct ScissoringSettings {
+    bool    fEnableScissoring;
+    GrIRect fScissorRect;
+
+    void setupScissoring(GrGpu* gpu);
+};
+
+
+/**
+ * The clip mask creator handles the generation of the clip mask. If anti 
+ * aliasing is requested it will (in the future) generate a single channel 
+ * (8bit) mask. If no anti aliasing is requested it will generate a 1-bit 
+ * mask in the stencil buffer. In the non anti-aliasing case, if the clip
+ * mask can be represented as a rectangle then scissoring is used. In all
+ * cases scissoring is used to bound the range of the clip mask.
+ */
+class GrClipMaskManager {
+public:
+    GrClipMaskManager()
+        : fClipMaskInStencil(false)
+        , fPathRendererChain(NULL) {
+    }
+
+    bool createClipMask(GrGpu* gpu, 
+                        const GrClip& clip, 
+                        ScissoringSettings* scissorSettings);
+
+    void freeResources();
+
+    bool isClipInStencil() const { return fClipMaskInStencil; }
+
+    void resetMask() {
+        fClipMaskInStencil = false;
+    }
+
+protected:
+private:
+    bool fClipMaskInStencil;        // is the clip mask in the stencil buffer?
+
+    // must be instantiated after GrGpu object has been given its owning
+    // GrContext ptr. (GrGpu is constructed first then handed off to GrContext).
+    GrPathRendererChain*        fPathRendererChain;
+
+    bool createStencilClipMask(GrGpu* gpu, 
+                               const GrClip& clip, 
+                               const GrRect& bounds,
+                               ScissoringSettings* scissorSettings);
+
+    // determines the path renderer used to draw a clip path element.
+    GrPathRenderer* getClipPathRenderer(GrGpu* gpu,
+                                        const SkPath& path, 
+                                        GrPathFill fill);
+
+};
+
+#endif // GrClipMaskManager_DEFINED