michael@0: /*
michael@0:  * Copyright 2012 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #ifndef GrClipMaskCache_DEFINED
michael@0: #define GrClipMaskCache_DEFINED
michael@0: 
michael@0: #include "GrContext.h"
michael@0: #include "SkClipStack.h"
michael@0: #include "SkTypes.h"
michael@0: 
michael@0: class GrTexture;
michael@0: 
michael@0: /**
michael@0:  * The stencil buffer stores the last clip path - providing a single entry
michael@0:  * "cache". This class provides similar functionality for AA clip paths
michael@0:  */
michael@0: class GrClipMaskCache : public SkNoncopyable {
michael@0: public:
michael@0:     GrClipMaskCache();
michael@0: 
michael@0:     ~GrClipMaskCache() {
michael@0: 
michael@0:         while (!fStack.empty()) {
michael@0:             GrClipStackFrame* temp = (GrClipStackFrame*) fStack.back();
michael@0:             temp->~GrClipStackFrame();
michael@0:             fStack.pop_back();
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     bool canReuse(int32_t clipGenID, const SkIRect& bounds) {
michael@0: 
michael@0:         SkASSERT(clipGenID != SkClipStack::kWideOpenGenID);
michael@0:         SkASSERT(clipGenID != SkClipStack::kEmptyGenID);
michael@0: 
michael@0:         GrClipStackFrame* back = (GrClipStackFrame*) fStack.back();
michael@0: 
michael@0:         // We could reuse the mask if bounds is a subset of last bounds. We'd have to communicate
michael@0:         // an offset to the caller.
michael@0:         if (back->fLastMask.texture() &&
michael@0:             back->fLastBound == bounds &&
michael@0:             back->fLastClipGenID == clipGenID) {
michael@0:             return true;
michael@0:         }
michael@0: 
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     void reset() {
michael@0:         if (fStack.empty()) {
michael@0: //            SkASSERT(false);
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         GrClipStackFrame* back = (GrClipStackFrame*) fStack.back();
michael@0: 
michael@0:         back->reset();
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * After a "push" the clip state is entirely open. Currently, the
michael@0:      * entire clip stack will be re-rendered into a new clip mask.
michael@0:      * TODO: can we take advantage of the nested nature of the clips to
michael@0:      * reduce the mask creation cost?
michael@0:      */
michael@0:     void push();
michael@0: 
michael@0:     void pop() {
michael@0:         //SkASSERT(!fStack.empty());
michael@0: 
michael@0:         if (!fStack.empty()) {
michael@0:             GrClipStackFrame* back = (GrClipStackFrame*) fStack.back();
michael@0: 
michael@0:             back->~GrClipStackFrame();
michael@0:             fStack.pop_back();
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     int32_t getLastClipGenID() const {
michael@0: 
michael@0:         if (fStack.empty()) {
michael@0:             return SkClipStack::kInvalidGenID;
michael@0:         }
michael@0: 
michael@0:         return ((GrClipStackFrame*) fStack.back())->fLastClipGenID;
michael@0:     }
michael@0: 
michael@0:     GrTexture* getLastMask() {
michael@0: 
michael@0:         if (fStack.empty()) {
michael@0:             SkASSERT(false);
michael@0:             return NULL;
michael@0:         }
michael@0: 
michael@0:         GrClipStackFrame* back = (GrClipStackFrame*) fStack.back();
michael@0: 
michael@0:         return back->fLastMask.texture();
michael@0:     }
michael@0: 
michael@0:     const GrTexture* getLastMask() const {
michael@0: 
michael@0:         if (fStack.empty()) {
michael@0:             SkASSERT(false);
michael@0:             return NULL;
michael@0:         }
michael@0: 
michael@0:         GrClipStackFrame* back = (GrClipStackFrame*) fStack.back();
michael@0: 
michael@0:         return back->fLastMask.texture();
michael@0:     }
michael@0: 
michael@0:     void acquireMask(int32_t clipGenID,
michael@0:                      const GrTextureDesc& desc,
michael@0:                      const SkIRect& bound) {
michael@0: 
michael@0:         if (fStack.empty()) {
michael@0:             SkASSERT(false);
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         GrClipStackFrame* back = (GrClipStackFrame*) fStack.back();
michael@0: 
michael@0:         back->acquireMask(fContext, clipGenID, desc, bound);
michael@0:     }
michael@0: 
michael@0:     int getLastMaskWidth() const {
michael@0: 
michael@0:         if (fStack.empty()) {
michael@0:             SkASSERT(false);
michael@0:             return -1;
michael@0:         }
michael@0: 
michael@0:         GrClipStackFrame* back = (GrClipStackFrame*) fStack.back();
michael@0: 
michael@0:         if (NULL == back->fLastMask.texture()) {
michael@0:             return -1;
michael@0:         }
michael@0: 
michael@0:         return back->fLastMask.texture()->width();
michael@0:     }
michael@0: 
michael@0:     int getLastMaskHeight() const {
michael@0: 
michael@0:         if (fStack.empty()) {
michael@0:             SkASSERT(false);
michael@0:             return -1;
michael@0:         }
michael@0: 
michael@0:         GrClipStackFrame* back = (GrClipStackFrame*) fStack.back();
michael@0: 
michael@0:         if (NULL == back->fLastMask.texture()) {
michael@0:             return -1;
michael@0:         }
michael@0: 
michael@0:         return back->fLastMask.texture()->height();
michael@0:     }
michael@0: 
michael@0:     void getLastBound(SkIRect* bound) const {
michael@0: 
michael@0:         if (fStack.empty()) {
michael@0:             SkASSERT(false);
michael@0:             bound->setEmpty();
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         GrClipStackFrame* back = (GrClipStackFrame*) fStack.back();
michael@0: 
michael@0:         *bound = back->fLastBound;
michael@0:     }
michael@0: 
michael@0:     void setContext(GrContext* context) {
michael@0:         fContext = context;
michael@0:     }
michael@0: 
michael@0:     GrContext* getContext() {
michael@0:         return fContext;
michael@0:     }
michael@0: 
michael@0:     void releaseResources() {
michael@0: 
michael@0:         SkDeque::F2BIter iter(fStack);
michael@0:         for (GrClipStackFrame* frame = (GrClipStackFrame*) iter.next();
michael@0:                 frame != NULL;
michael@0:                 frame = (GrClipStackFrame*) iter.next()) {
michael@0:             frame->reset();
michael@0:         }
michael@0:     }
michael@0: 
michael@0: private:
michael@0:     struct GrClipStackFrame {
michael@0: 
michael@0:         GrClipStackFrame() {
michael@0:             this->reset();
michael@0:         }
michael@0: 
michael@0:         void acquireMask(GrContext* context,
michael@0:                          int32_t clipGenID,
michael@0:                          const GrTextureDesc& desc,
michael@0:                          const SkIRect& bound) {
michael@0: 
michael@0:             fLastClipGenID = clipGenID;
michael@0: 
michael@0:             fLastMask.set(context, desc);
michael@0: 
michael@0:             fLastBound = bound;
michael@0:         }
michael@0: 
michael@0:         void reset () {
michael@0:             fLastClipGenID = SkClipStack::kInvalidGenID;
michael@0: 
michael@0:             GrTextureDesc desc;
michael@0: 
michael@0:             fLastMask.set(NULL, desc);
michael@0:             fLastBound.setEmpty();
michael@0:         }
michael@0: 
michael@0:         int32_t                 fLastClipGenID;
michael@0:         // The mask's width & height values are used by GrClipMaskManager to correctly scale the
michael@0:         // texture coords for the geometry drawn with this mask.
michael@0:         GrAutoScratchTexture    fLastMask;
michael@0:         // fLastBound stores the bounding box of the clip mask in clip-stack space. This rect is
michael@0:         // used by GrClipMaskManager to position a rect and compute texture coords for the mask.
michael@0:         SkIRect                 fLastBound;
michael@0:     };
michael@0: 
michael@0:     GrContext*   fContext;
michael@0:     SkDeque      fStack;
michael@0: 
michael@0:     typedef SkNoncopyable INHERITED;
michael@0: };
michael@0: 
michael@0: #endif // GrClipMaskCache_DEFINED