1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/gpu/GrClipMaskManager.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,182 @@
1.4 +/*
1.5 + * Copyright 2012 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#ifndef GrClipMaskManager_DEFINED
1.12 +#define GrClipMaskManager_DEFINED
1.13 +
1.14 +#include "GrClipMaskCache.h"
1.15 +#include "GrContext.h"
1.16 +#include "GrDrawState.h"
1.17 +#include "GrReducedClip.h"
1.18 +#include "GrStencil.h"
1.19 +#include "GrTexture.h"
1.20 +
1.21 +#include "SkClipStack.h"
1.22 +#include "SkDeque.h"
1.23 +#include "SkPath.h"
1.24 +#include "SkRefCnt.h"
1.25 +#include "SkTLList.h"
1.26 +#include "SkTypes.h"
1.27 +
1.28 +class GrGpu;
1.29 +class GrPathRenderer;
1.30 +class GrPathRendererChain;
1.31 +class GrTexture;
1.32 +class SkPath;
1.33 +
1.34 +/**
1.35 + * The clip mask creator handles the generation of the clip mask. If anti
1.36 + * aliasing is requested it will (in the future) generate a single channel
1.37 + * (8bit) mask. If no anti aliasing is requested it will generate a 1-bit
1.38 + * mask in the stencil buffer. In the non anti-aliasing case, if the clip
1.39 + * mask can be represented as a rectangle then scissoring is used. In all
1.40 + * cases scissoring is used to bound the range of the clip mask.
1.41 + */
1.42 +class GrClipMaskManager : public SkNoncopyable {
1.43 +public:
1.44 + GrClipMaskManager()
1.45 + : fGpu(NULL)
1.46 + , fCurrClipMaskType(kNone_ClipMaskType) {
1.47 + }
1.48 +
1.49 + /**
1.50 + * Creates a clip mask if necessary as a stencil buffer or alpha texture
1.51 + * and sets the GrGpu's scissor and stencil state. If the return is false
1.52 + * then the draw can be skipped. The AutoRestoreEffects is initialized by
1.53 + * the manager when it must install additional effects to implement the
1.54 + * clip. devBounds is optional but can help optimize clipping.
1.55 + */
1.56 + bool setupClipping(const GrClipData* clipDataIn, GrDrawState::AutoRestoreEffects*,
1.57 + const SkRect* devBounds);
1.58 +
1.59 + void releaseResources();
1.60 +
1.61 + bool isClipInStencil() const {
1.62 + return kStencil_ClipMaskType == fCurrClipMaskType;
1.63 + }
1.64 + bool isClipInAlpha() const {
1.65 + return kAlpha_ClipMaskType == fCurrClipMaskType;
1.66 + }
1.67 +
1.68 + void invalidateStencilMask() {
1.69 + if (kStencil_ClipMaskType == fCurrClipMaskType) {
1.70 + fCurrClipMaskType = kNone_ClipMaskType;
1.71 + }
1.72 + }
1.73 +
1.74 + GrContext* getContext() {
1.75 + return fAACache.getContext();
1.76 + }
1.77 +
1.78 + void setGpu(GrGpu* gpu);
1.79 +
1.80 + void adjustPathStencilParams(GrStencilSettings* settings);
1.81 +private:
1.82 + /**
1.83 + * Informs the helper function adjustStencilParams() about how the stencil
1.84 + * buffer clip is being used.
1.85 + */
1.86 + enum StencilClipMode {
1.87 + // Draw to the clip bit of the stencil buffer
1.88 + kModifyClip_StencilClipMode,
1.89 + // Clip against the existing representation of the clip in the high bit
1.90 + // of the stencil buffer.
1.91 + kRespectClip_StencilClipMode,
1.92 + // Neither writing to nor clipping against the clip bit.
1.93 + kIgnoreClip_StencilClipMode,
1.94 + };
1.95 +
1.96 + GrGpu* fGpu;
1.97 +
1.98 + /**
1.99 + * We may represent the clip as a mask in the stencil buffer or as an alpha
1.100 + * texture. It may be neither because the scissor rect suffices or we
1.101 + * haven't yet examined the clip.
1.102 + */
1.103 + enum ClipMaskType {
1.104 + kNone_ClipMaskType,
1.105 + kStencil_ClipMaskType,
1.106 + kAlpha_ClipMaskType,
1.107 + } fCurrClipMaskType;
1.108 +
1.109 + GrClipMaskCache fAACache; // cache for the AA path
1.110 +
1.111 + // Attempts to install a series of coverage effects to implement the clip. Return indicates
1.112 + // whether the element list was successfully converted to effects.
1.113 + bool installClipEffects(const GrReducedClip::ElementList&,
1.114 + GrDrawState::AutoRestoreEffects*,
1.115 + const SkVector& clipOffset,
1.116 + const SkRect* devBounds);
1.117 +
1.118 + // Draws the clip into the stencil buffer
1.119 + bool createStencilClipMask(int32_t elementsGenID,
1.120 + GrReducedClip::InitialState initialState,
1.121 + const GrReducedClip::ElementList& elements,
1.122 + const SkIRect& clipSpaceIBounds,
1.123 + const SkIPoint& clipSpaceToStencilOffset);
1.124 + // Creates an alpha mask of the clip. The mask is a rasterization of elements through the
1.125 + // rect specified by clipSpaceIBounds.
1.126 + GrTexture* createAlphaClipMask(int32_t elementsGenID,
1.127 + GrReducedClip::InitialState initialState,
1.128 + const GrReducedClip::ElementList& elements,
1.129 + const SkIRect& clipSpaceIBounds);
1.130 + // Similar to createAlphaClipMask but it rasterizes in SW and uploads to the result texture.
1.131 + GrTexture* createSoftwareClipMask(int32_t elementsGenID,
1.132 + GrReducedClip::InitialState initialState,
1.133 + const GrReducedClip::ElementList& elements,
1.134 + const SkIRect& clipSpaceIBounds);
1.135 +
1.136 + // Gets a texture to use for the clip mask. If true is returned then a cached mask was found
1.137 + // that already contains the rasterization of the clip stack, otherwise an uninitialized texture
1.138 + // is returned. 'willUpload' is set when the alpha mask needs to be uploaded from the CPU.
1.139 + bool getMaskTexture(int32_t elementsGenID,
1.140 + const SkIRect& clipSpaceIBounds,
1.141 + GrTexture** result,
1.142 + bool willUpload);
1.143 +
1.144 + bool useSWOnlyPath(const GrReducedClip::ElementList& elements);
1.145 +
1.146 + // Draws a clip element into the target alpha mask. The caller should have already setup the
1.147 + // desired blend operation. Optionally if the caller already selected a path renderer it can
1.148 + // be passed. Otherwise the function will select one if the element is a path.
1.149 + bool drawElement(GrTexture* target, const SkClipStack::Element*, GrPathRenderer* = NULL);
1.150 +
1.151 + // Determines whether it is possible to draw the element to both the stencil buffer and the
1.152 + // alpha mask simultaneously. If so and the element is a path a compatible path renderer is
1.153 + // also returned.
1.154 + bool canStencilAndDrawElement(GrTexture* target, const SkClipStack::Element*, GrPathRenderer**);
1.155 +
1.156 + void mergeMask(GrTexture* dstMask,
1.157 + GrTexture* srcMask,
1.158 + SkRegion::Op op,
1.159 + const SkIRect& dstBound,
1.160 + const SkIRect& srcBound);
1.161 +
1.162 + void getTemp(int width, int height, GrAutoScratchTexture* temp);
1.163 +
1.164 + void setupCache(const SkClipStack& clip,
1.165 + const SkIRect& bounds);
1.166 +
1.167 + /**
1.168 + * Called prior to return control back the GrGpu in setupClipping. It
1.169 + * updates the GrGpu with stencil settings that account stencil-based
1.170 + * clipping.
1.171 + */
1.172 + void setGpuStencil();
1.173 +
1.174 + /**
1.175 + * Adjusts the stencil settings to account for interaction with stencil
1.176 + * clipping.
1.177 + */
1.178 + void adjustStencilParams(GrStencilSettings* settings,
1.179 + StencilClipMode mode,
1.180 + int stencilBitCnt);
1.181 +
1.182 + typedef SkNoncopyable INHERITED;
1.183 +};
1.184 +
1.185 +#endif // GrClipMaskManager_DEFINED
