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 GrClipMaskManager_DEFINED
michael@0: #define GrClipMaskManager_DEFINED
michael@0: 
michael@0: #include "GrClipMaskCache.h"
michael@0: #include "GrContext.h"
michael@0: #include "GrDrawState.h"
michael@0: #include "GrReducedClip.h"
michael@0: #include "GrStencil.h"
michael@0: #include "GrTexture.h"
michael@0: 
michael@0: #include "SkClipStack.h"
michael@0: #include "SkDeque.h"
michael@0: #include "SkPath.h"
michael@0: #include "SkRefCnt.h"
michael@0: #include "SkTLList.h"
michael@0: #include "SkTypes.h"
michael@0: 
michael@0: class GrGpu;
michael@0: class GrPathRenderer;
michael@0: class GrPathRendererChain;
michael@0: class GrTexture;
michael@0: class SkPath;
michael@0: 
michael@0: /**
michael@0:  * The clip mask creator handles the generation of the clip mask. If anti
michael@0:  * aliasing is requested it will (in the future) generate a single channel
michael@0:  * (8bit) mask. If no anti aliasing is requested it will generate a 1-bit
michael@0:  * mask in the stencil buffer. In the non anti-aliasing case, if the clip
michael@0:  * mask can be represented as a rectangle then scissoring is used. In all
michael@0:  * cases scissoring is used to bound the range of the clip mask.
michael@0:  */
michael@0: class GrClipMaskManager : public SkNoncopyable {
michael@0: public:
michael@0:     GrClipMaskManager()
michael@0:         : fGpu(NULL)
michael@0:         , fCurrClipMaskType(kNone_ClipMaskType) {
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Creates a clip mask if necessary as a stencil buffer or alpha texture
michael@0:      * and sets the GrGpu's scissor and stencil state. If the return is false
michael@0:      * then the draw can be skipped. The AutoRestoreEffects is initialized by
michael@0:      * the manager when it must install additional effects to implement the
michael@0:      * clip. devBounds is optional but can help optimize clipping.
michael@0:      */
michael@0:     bool setupClipping(const GrClipData* clipDataIn, GrDrawState::AutoRestoreEffects*,
michael@0:                        const SkRect* devBounds);
michael@0: 
michael@0:     void releaseResources();
michael@0: 
michael@0:     bool isClipInStencil() const {
michael@0:         return kStencil_ClipMaskType == fCurrClipMaskType;
michael@0:     }
michael@0:     bool isClipInAlpha() const {
michael@0:         return kAlpha_ClipMaskType == fCurrClipMaskType;
michael@0:     }
michael@0: 
michael@0:     void invalidateStencilMask() {
michael@0:         if (kStencil_ClipMaskType == fCurrClipMaskType) {
michael@0:             fCurrClipMaskType = kNone_ClipMaskType;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     GrContext* getContext() {
michael@0:         return fAACache.getContext();
michael@0:     }
michael@0: 
michael@0:     void setGpu(GrGpu* gpu);
michael@0: 
michael@0:     void adjustPathStencilParams(GrStencilSettings* settings);
michael@0: private:
michael@0:     /**
michael@0:      * Informs the helper function adjustStencilParams() about how the stencil
michael@0:      * buffer clip is being used.
michael@0:      */
michael@0:     enum StencilClipMode {
michael@0:         // Draw to the clip bit of the stencil buffer
michael@0:         kModifyClip_StencilClipMode,
michael@0:         // Clip against the existing representation of the clip in the high bit
michael@0:         // of the stencil buffer.
michael@0:         kRespectClip_StencilClipMode,
michael@0:         // Neither writing to nor clipping against the clip bit.
michael@0:         kIgnoreClip_StencilClipMode,
michael@0:     };
michael@0: 
michael@0:     GrGpu* fGpu;
michael@0: 
michael@0:     /**
michael@0:      * We may represent the clip as a mask in the stencil buffer or as an alpha
michael@0:      * texture. It may be neither because the scissor rect suffices or we
michael@0:      * haven't yet examined the clip.
michael@0:      */
michael@0:     enum ClipMaskType {
michael@0:         kNone_ClipMaskType,
michael@0:         kStencil_ClipMaskType,
michael@0:         kAlpha_ClipMaskType,
michael@0:     } fCurrClipMaskType;
michael@0: 
michael@0:     GrClipMaskCache fAACache;       // cache for the AA path
michael@0: 
michael@0:     // Attempts to install a series of coverage effects to implement the clip. Return indicates
michael@0:     // whether the element list was successfully converted to effects.
michael@0:     bool installClipEffects(const GrReducedClip::ElementList&,
michael@0:                             GrDrawState::AutoRestoreEffects*,
michael@0:                             const SkVector& clipOffset,
michael@0:                             const SkRect* devBounds);
michael@0: 
michael@0:     // Draws the clip into the stencil buffer
michael@0:     bool createStencilClipMask(int32_t elementsGenID,
michael@0:                                GrReducedClip::InitialState initialState,
michael@0:                                const GrReducedClip::ElementList& elements,
michael@0:                                const SkIRect& clipSpaceIBounds,
michael@0:                                const SkIPoint& clipSpaceToStencilOffset);
michael@0:     // Creates an alpha mask of the clip. The mask is a rasterization of elements through the
michael@0:     // rect specified by clipSpaceIBounds.
michael@0:     GrTexture* createAlphaClipMask(int32_t elementsGenID,
michael@0:                                    GrReducedClip::InitialState initialState,
michael@0:                                    const GrReducedClip::ElementList& elements,
michael@0:                                    const SkIRect& clipSpaceIBounds);
michael@0:     // Similar to createAlphaClipMask but it rasterizes in SW and uploads to the result texture.
michael@0:     GrTexture* createSoftwareClipMask(int32_t elementsGenID,
michael@0:                                       GrReducedClip::InitialState initialState,
michael@0:                                       const GrReducedClip::ElementList& elements,
michael@0:                                       const SkIRect& clipSpaceIBounds);
michael@0: 
michael@0:     // Gets a texture to use for the clip mask. If true is returned then a cached mask was found
michael@0:     // that already contains the rasterization of the clip stack, otherwise an uninitialized texture
michael@0:     // is returned. 'willUpload' is set when the alpha mask needs to be uploaded from the CPU.
michael@0:     bool getMaskTexture(int32_t elementsGenID,
michael@0:                         const SkIRect& clipSpaceIBounds,
michael@0:                         GrTexture** result,
michael@0:                         bool willUpload);
michael@0: 
michael@0:     bool useSWOnlyPath(const GrReducedClip::ElementList& elements);
michael@0: 
michael@0:     // Draws a clip element into the target alpha mask. The caller should have already setup the
michael@0:     // desired blend operation. Optionally if the caller already selected a path renderer it can
michael@0:     // be passed. Otherwise the function will select one if the element is a path.
michael@0:     bool drawElement(GrTexture* target, const SkClipStack::Element*, GrPathRenderer* = NULL);
michael@0: 
michael@0:     // Determines whether it is possible to draw the element to both the stencil buffer and the
michael@0:     // alpha mask simultaneously. If so and the element is a path a compatible path renderer is
michael@0:     // also returned.
michael@0:     bool canStencilAndDrawElement(GrTexture* target, const SkClipStack::Element*, GrPathRenderer**);
michael@0: 
michael@0:     void mergeMask(GrTexture* dstMask,
michael@0:                    GrTexture* srcMask,
michael@0:                    SkRegion::Op op,
michael@0:                    const SkIRect& dstBound,
michael@0:                    const SkIRect& srcBound);
michael@0: 
michael@0:     void getTemp(int width, int height, GrAutoScratchTexture* temp);
michael@0: 
michael@0:     void setupCache(const SkClipStack& clip,
michael@0:                     const SkIRect& bounds);
michael@0: 
michael@0:     /**
michael@0:      * Called prior to return control back the GrGpu in setupClipping. It
michael@0:      * updates the GrGpu with stencil settings that account stencil-based
michael@0:      * clipping.
michael@0:      */
michael@0:     void setGpuStencil();
michael@0: 
michael@0:     /**
michael@0:      * Adjusts the stencil settings to account for interaction with stencil
michael@0:      * clipping.
michael@0:      */
michael@0:     void adjustStencilParams(GrStencilSettings* settings,
michael@0:                              StencilClipMode mode,
michael@0:                              int stencilBitCnt);
michael@0: 
michael@0:     typedef SkNoncopyable INHERITED;
michael@0: };
michael@0: 
michael@0: #endif // GrClipMaskManager_DEFINED