The Tor Browser: gfx/skia/trunk/src/gpu/GrClipMaskManager.cpp@6474c204b198 (annotated)

gfx/skia/trunk/src/gpu/GrClipMaskManager.cpp@6474c204b198 (annotated)

gfx/skia/trunk/src/gpu/GrClipMaskManager.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "GrClipMaskManager.h"
 #include "GrAAConvexPathRenderer.h"
 #include "GrAAHairLinePathRenderer.h"
 #include "GrAARectRenderer.h"
 #include "GrDrawTargetCaps.h"
 #include "GrGpu.h"
 #include "GrPaint.h"
 #include "GrPathRenderer.h"
 #include "GrRenderTarget.h"
 #include "GrStencilBuffer.h"
 #include "GrSWMaskHelper.h"
 #include "effects/GrTextureDomain.h"
 #include "effects/GrConvexPolyEffect.h"
 #include "effects/GrRRectEffect.h"
 #include "SkRasterClip.h"
 #include "SkStrokeRec.h"
 #include "SkTLazy.h"
 #define GR_AA_CLIP 1
 typedef SkClipStack::Element Element;
 using namespace GrReducedClip;
 ////////////////////////////////////////////////////////////////////////////////
 namespace {
 // set up the draw state to enable the aa clipping mask. Besides setting up the
 // stage matrix this also alters the vertex layout
 void setup_drawstate_aaclip(GrGpu* gpu,
                             GrTexture* result,
                             const SkIRect &devBound) {
     GrDrawState* drawState = gpu->drawState();
     SkASSERT(drawState);
     SkMatrix mat;
     // We want to use device coords to compute the texture coordinates. We set our matrix to be
     // equal to the view matrix followed by an offset to the devBound, and then a scaling matrix to
     // normalized coords. We apply this matrix to the vertex positions rather than local coords.
     mat.setIDiv(result->width(), result->height());
     mat.preTranslate(SkIntToScalar(-devBound.fLeft),
                      SkIntToScalar(-devBound.fTop));
     mat.preConcat(drawState->getViewMatrix());
     SkIRect domainTexels = SkIRect::MakeWH(devBound.width(), devBound.height());
     // This could be a long-lived effect that is cached with the alpha-mask.
     drawState->addCoverageEffect(
         GrTextureDomainEffect::Create(result,
                                       mat,
                                       GrTextureDomain::MakeTexelDomain(result, domainTexels),
                                       GrTextureDomain::kDecal_Mode,
                                       GrTextureParams::kNone_FilterMode,
                                       kPosition_GrCoordSet))->unref();
 }
 bool path_needs_SW_renderer(GrContext* context,
                             GrGpu* gpu,
                             const SkPath& origPath,
                             const SkStrokeRec& stroke,
                             bool doAA) {
     // the gpu alpha mask will draw the inverse paths as non-inverse to a temp buffer
     SkTCopyOnFirstWrite<SkPath> path(origPath);
     if (path->isInverseFillType()) {
         path.writable()->toggleInverseFillType();
     }
     // last (false) parameter disallows use of the SW path renderer
     GrPathRendererChain::DrawType type = doAA ?
                                          GrPathRendererChain::kColorAntiAlias_DrawType :
                                          GrPathRendererChain::kColor_DrawType;
     return NULL == context->getPathRenderer(*path, stroke, gpu, false, type);
 }
 }
 /*
  * This method traverses the clip stack to see if the GrSoftwarePathRenderer
  * will be used on any element. If so, it returns true to indicate that the
  * entire clip should be rendered in SW and then uploaded en masse to the gpu.
  */
 bool GrClipMaskManager::useSWOnlyPath(const ElementList& elements) {
     // TODO: generalize this function so that when
     // a clip gets complex enough it can just be done in SW regardless
     // of whether it would invoke the GrSoftwarePathRenderer.
     SkStrokeRec stroke(SkStrokeRec::kFill_InitStyle);
     for (ElementList::Iter iter(elements.headIter()); iter.get(); iter.next()) {
         const Element* element = iter.get();
         // rects can always be drawn directly w/o using the software path
         // Skip rrects once we're drawing them directly.
         if (Element::kRect_Type != element->getType()) {
             SkPath path;
             element->asPath(&path);
             if (path_needs_SW_renderer(this->getContext(), fGpu, path, stroke, element->isAA())) {
                 return true;
             }
         }
     }
     return false;
 }
 bool GrClipMaskManager::installClipEffects(const ElementList& elements,
                                            GrDrawState::AutoRestoreEffects* are,
                                            const SkVector& clipToRTOffset,
                                            const SkRect* drawBounds) {
     GrDrawState* drawState = fGpu->drawState();
     SkRect boundsInClipSpace;
     if (NULL != drawBounds) {
         boundsInClipSpace = *drawBounds;
         boundsInClipSpace.offset(-clipToRTOffset.fX, -clipToRTOffset.fY);
     }
     are->set(drawState);
     GrRenderTarget* rt = drawState->getRenderTarget();
     ElementList::Iter iter(elements);
     bool setARE = false;
     bool failed = false;
     while (NULL != iter.get()) {
         SkRegion::Op op = iter.get()->getOp();
         bool invert;
         bool skip = false;
         switch (op) {
             case SkRegion::kReplace_Op:
                 SkASSERT(iter.get() == elements.head());
                 // Fallthrough, handled same as intersect.
             case SkRegion::kIntersect_Op:
                 invert = false;
                 if (NULL != drawBounds && iter.get()->contains(boundsInClipSpace)) {
                     skip = true;
                 }
                 break;
             case SkRegion::kDifference_Op:
                 invert = true;
                 // We don't currently have a cheap test for whether a rect is fully outside an
                 // element's primitive, so don't attempt to set skip.
                 break;
             default:
                 failed = true;
                 break;
         }
         if (failed) {
             break;
         }
         if (!skip) {
             GrEffectEdgeType edgeType;
             if (GR_AA_CLIP && iter.get()->isAA()) {
                 if (rt->isMultisampled()) {
                     // Coverage based AA clips don't place nicely with MSAA.
                     failed = true;
                     break;
                 }
                 edgeType = invert ? kInverseFillAA_GrEffectEdgeType : kFillAA_GrEffectEdgeType;
             } else {
                 edgeType = invert ? kInverseFillBW_GrEffectEdgeType : kFillBW_GrEffectEdgeType;
             }
             SkAutoTUnref<GrEffectRef> effect;
             switch (iter.get()->getType()) {
                 case SkClipStack::Element::kPath_Type:
                     effect.reset(GrConvexPolyEffect::Create(edgeType, iter.get()->getPath(),
                         &clipToRTOffset));
                     break;
                 case SkClipStack::Element::kRRect_Type: {
                     SkRRect rrect = iter.get()->getRRect();
                     rrect.offset(clipToRTOffset.fX, clipToRTOffset.fY);
                     effect.reset(GrRRectEffect::Create(edgeType, rrect));
                     break;
                 }
                 case SkClipStack::Element::kRect_Type: {
                     SkRect rect = iter.get()->getRect();
                     rect.offset(clipToRTOffset.fX, clipToRTOffset.fY);
                     effect.reset(GrConvexPolyEffect::Create(edgeType, rect));
                     break;
                 }
                 default:
                     break;
             }
             if (effect) {
                 if (!setARE) {
                     are->set(fGpu->drawState());
                     setARE = true;
                 }
                 fGpu->drawState()->addCoverageEffect(effect);
             } else {
                 failed = true;
                 break;
             }
         }
         iter.next();
     }
     if (failed) {
         are->set(NULL);
     }
     return !failed;
 }
 ////////////////////////////////////////////////////////////////////////////////
 // sort out what kind of clip mask needs to be created: alpha, stencil,
 // scissor, or entirely software
 bool GrClipMaskManager::setupClipping(const GrClipData* clipDataIn,
                                       GrDrawState::AutoRestoreEffects* are,
                                       const SkRect* devBounds) {
     fCurrClipMaskType = kNone_ClipMaskType;
     ElementList elements(16);
     int32_t genID;
     InitialState initialState;
     SkIRect clipSpaceIBounds;
     bool requiresAA;
     bool isRect = false;
     GrDrawState* drawState = fGpu->drawState();
     const GrRenderTarget* rt = drawState->getRenderTarget();
     // GrDrawTarget should have filtered this for us
     SkASSERT(NULL != rt);
     bool ignoreClip = !drawState->isClipState() || clipDataIn->fClipStack->isWideOpen();
     if (!ignoreClip) {
         SkIRect clipSpaceRTIBounds = SkIRect::MakeWH(rt->width(), rt->height());
         clipSpaceRTIBounds.offset(clipDataIn->fOrigin);
         ReduceClipStack(*clipDataIn->fClipStack,
                         clipSpaceRTIBounds,
                         &elements,
                         &genID,
                         &initialState,
                         &clipSpaceIBounds,
                         &requiresAA);
         if (elements.isEmpty()) {
             if (kAllIn_InitialState == initialState) {
                 ignoreClip = clipSpaceIBounds == clipSpaceRTIBounds;
                 isRect = true;
             } else {
                 return false;
             }
         }
     }
     if (ignoreClip) {
         fGpu->disableScissor();
         this->setGpuStencil();
         return true;
     }
     // An element count of 4 was chosen because of the common pattern in Blink of:
     //   isect RR
     //   diff  RR
     //   isect convex_poly
     //   isect convex_poly
     // when drawing rounded div borders. This could probably be tuned based on a
     // configuration's relative costs of switching RTs to generate a mask vs
     // longer shaders.
     if (elements.count() <= 4) {
         SkVector clipToRTOffset = { SkIntToScalar(-clipDataIn->fOrigin.fX),
                                     SkIntToScalar(-clipDataIn->fOrigin.fY) };
         if (elements.isEmpty() ||
             this->installClipEffects(elements, are, clipToRTOffset, devBounds)) {
             SkIRect scissorSpaceIBounds(clipSpaceIBounds);
             scissorSpaceIBounds.offset(-clipDataIn->fOrigin);
             if (NULL == devBounds ||
                 !SkRect::Make(scissorSpaceIBounds).contains(*devBounds)) {
                 fGpu->enableScissor(scissorSpaceIBounds);
             } else {
                 fGpu->disableScissor();
             }
             this->setGpuStencil();
             return true;
         }
     }
 #if GR_AA_CLIP
     // If MSAA is enabled we can do everything in the stencil buffer.
     if (0 == rt->numSamples() && requiresAA) {
         GrTexture* result = NULL;
         if (this->useSWOnlyPath(elements)) {
             // The clip geometry is complex enough that it will be more efficient to create it
             // entirely in software
             result = this->createSoftwareClipMask(genID,
                                                   initialState,
                                                   elements,
                                                   clipSpaceIBounds);
         } else {
             result = this->createAlphaClipMask(genID,
                                                initialState,
                                                elements,
                                                clipSpaceIBounds);
         }
         if (NULL != result) {
             // The mask's top left coord should be pinned to the rounded-out top left corner of
             // clipSpace bounds. We determine the mask's position WRT to the render target here.
             SkIRect rtSpaceMaskBounds = clipSpaceIBounds;
             rtSpaceMaskBounds.offset(-clipDataIn->fOrigin);
             are->set(fGpu->drawState());
             setup_drawstate_aaclip(fGpu, result, rtSpaceMaskBounds);
             fGpu->disableScissor();
             this->setGpuStencil();
             return true;
         }
         // if alpha clip mask creation fails fall through to the non-AA code paths
     }
 #endif // GR_AA_CLIP
     // Either a hard (stencil buffer) clip was explicitly requested or an anti-aliased clip couldn't
     // be created. In either case, free up the texture in the anti-aliased mask cache.
     // TODO: this may require more investigation. Ganesh performs a lot of utility draws (e.g.,
     // clears, InOrderDrawBuffer playbacks) that hit the stencil buffer path. These may be
     // "incorrectly" clearing the AA cache.
     fAACache.reset();
     // If the clip is a rectangle then just set the scissor. Otherwise, create
     // a stencil mask.
     if (isRect) {
         SkIRect clipRect = clipSpaceIBounds;
         clipRect.offset(-clipDataIn->fOrigin);
         fGpu->enableScissor(clipRect);
         this->setGpuStencil();
         return true;
     }
     // use the stencil clip if we can't represent the clip as a rectangle.
     SkIPoint clipSpaceToStencilSpaceOffset = -clipDataIn->fOrigin;
     this->createStencilClipMask(genID,
                                 initialState,
                                 elements,
                                 clipSpaceIBounds,
                                 clipSpaceToStencilSpaceOffset);
     // This must occur after createStencilClipMask. That function may change the scissor. Also, it
     // only guarantees that the stencil mask is correct within the bounds it was passed, so we must
     // use both stencil and scissor test to the bounds for the final draw.
     SkIRect scissorSpaceIBounds(clipSpaceIBounds);
     scissorSpaceIBounds.offset(clipSpaceToStencilSpaceOffset);
     fGpu->enableScissor(scissorSpaceIBounds);
     this->setGpuStencil();
     return true;
 }
 #define VISUALIZE_COMPLEX_CLIP 0
 #if VISUALIZE_COMPLEX_CLIP
     #include "SkRandom.h"
     SkRandom gRandom;
     #define SET_RANDOM_COLOR drawState->setColor(0xff000000 | gRandom.nextU());
 #else
     #define SET_RANDOM_COLOR
 #endif
 namespace {
 ////////////////////////////////////////////////////////////////////////////////
 // set up the OpenGL blend function to perform the specified
 // boolean operation for alpha clip mask creation
 void setup_boolean_blendcoeffs(GrDrawState* drawState, SkRegion::Op op) {
     switch (op) {
         case SkRegion::kReplace_Op:
             drawState->setBlendFunc(kOne_GrBlendCoeff, kZero_GrBlendCoeff);
             break;
         case SkRegion::kIntersect_Op:
             drawState->setBlendFunc(kDC_GrBlendCoeff, kZero_GrBlendCoeff);
             break;
         case SkRegion::kUnion_Op:
             drawState->setBlendFunc(kOne_GrBlendCoeff, kISC_GrBlendCoeff);
             break;
         case SkRegion::kXOR_Op:
             drawState->setBlendFunc(kIDC_GrBlendCoeff, kISC_GrBlendCoeff);
             break;
         case SkRegion::kDifference_Op:
             drawState->setBlendFunc(kZero_GrBlendCoeff, kISC_GrBlendCoeff);
             break;
         case SkRegion::kReverseDifference_Op:
             drawState->setBlendFunc(kIDC_GrBlendCoeff, kZero_GrBlendCoeff);
             break;
         default:
             SkASSERT(false);
             break;
     }
 }
 }
 ////////////////////////////////////////////////////////////////////////////////
 bool GrClipMaskManager::drawElement(GrTexture* target,
                                     const SkClipStack::Element* element,
                                     GrPathRenderer* pr) {
     GrDrawState* drawState = fGpu->drawState();
     drawState->setRenderTarget(target->asRenderTarget());
     // TODO: Draw rrects directly here.
     switch (element->getType()) {
         case Element::kEmpty_Type:
             SkDEBUGFAIL("Should never get here with an empty element.");
             break;
         case Element::kRect_Type:
             // TODO: Do rects directly to the accumulator using a aa-rect GrEffect that covers the
             // entire mask bounds and writes 0 outside the rect.
             if (element->isAA()) {
                 getContext()->getAARectRenderer()->fillAARect(fGpu,
                                                               fGpu,
                                                               element->getRect(),
                                                               SkMatrix::I(),
                                                               element->getRect(),
                                                               false);
             } else {
                 fGpu->drawSimpleRect(element->getRect(), NULL);
             }
             return true;
         default: {
             SkPath path;
             element->asPath(&path);
             if (path.isInverseFillType()) {
                 path.toggleInverseFillType();
             }
             SkStrokeRec stroke(SkStrokeRec::kFill_InitStyle);
             if (NULL == pr) {
                 GrPathRendererChain::DrawType type;
                 type = element->isAA() ? GrPathRendererChain::kColorAntiAlias_DrawType :
                                          GrPathRendererChain::kColor_DrawType;
                 pr = this->getContext()->getPathRenderer(path, stroke, fGpu, false, type);
             }
             if (NULL == pr) {
                 return false;
             }
             pr->drawPath(path, stroke, fGpu, element->isAA());
             break;
         }
     }
     return true;
 }
 bool GrClipMaskManager::canStencilAndDrawElement(GrTexture* target,
                                                  const SkClipStack::Element* element,
                                                  GrPathRenderer** pr) {
     GrDrawState* drawState = fGpu->drawState();
     drawState->setRenderTarget(target->asRenderTarget());
     if (Element::kRect_Type == element->getType()) {
         return true;
     } else {
         // We shouldn't get here with an empty clip element.
         SkASSERT(Element::kEmpty_Type != element->getType());
         SkPath path;
         element->asPath(&path);
         if (path.isInverseFillType()) {
             path.toggleInverseFillType();
         }
         SkStrokeRec stroke(SkStrokeRec::kFill_InitStyle);
         GrPathRendererChain::DrawType type = element->isAA() ?
             GrPathRendererChain::kStencilAndColorAntiAlias_DrawType :
             GrPathRendererChain::kStencilAndColor_DrawType;
         *pr = this->getContext()->getPathRenderer(path, stroke, fGpu, false, type);
         return NULL != *pr;
     }
 }
 void GrClipMaskManager::mergeMask(GrTexture* dstMask,
                                   GrTexture* srcMask,
                                   SkRegion::Op op,
                                   const SkIRect& dstBound,
                                   const SkIRect& srcBound) {
     GrDrawState::AutoViewMatrixRestore avmr;
     GrDrawState* drawState = fGpu->drawState();
     SkAssertResult(avmr.setIdentity(drawState));
     GrDrawState::AutoRestoreEffects are(drawState);
     drawState->setRenderTarget(dstMask->asRenderTarget());
     setup_boolean_blendcoeffs(drawState, op);
     SkMatrix sampleM;
     sampleM.setIDiv(srcMask->width(), srcMask->height());
     drawState->addColorEffect(
         GrTextureDomainEffect::Create(srcMask,
                                       sampleM,
                                       GrTextureDomain::MakeTexelDomain(srcMask, srcBound),
                                       GrTextureDomain::kDecal_Mode,
                                       GrTextureParams::kNone_FilterMode))->unref();
     fGpu->drawSimpleRect(SkRect::Make(dstBound), NULL);
 }
 // get a texture to act as a temporary buffer for AA clip boolean operations
 // TODO: given the expense of createTexture we may want to just cache this too
 void GrClipMaskManager::getTemp(int width, int height, GrAutoScratchTexture* temp) {
     if (NULL != temp->texture()) {
         // we've already allocated the temp texture
         return;
     }
     GrTextureDesc desc;
     desc.fFlags = kRenderTarget_GrTextureFlagBit|kNoStencil_GrTextureFlagBit;
     desc.fWidth = width;
     desc.fHeight = height;
     desc.fConfig = kAlpha_8_GrPixelConfig;
     temp->set(this->getContext(), desc);
 }
 ////////////////////////////////////////////////////////////////////////////////
 // Handles caching & allocation (if needed) of a clip alpha-mask texture for both the sw-upload
 // or gpu-rendered cases. Returns true if there is no more work to be done (i.e., we got a cache
 // hit)
 bool GrClipMaskManager::getMaskTexture(int32_t elementsGenID,
                                        const SkIRect& clipSpaceIBounds,
                                        GrTexture** result,
                                        bool willUpload) {
     bool cached = fAACache.canReuse(elementsGenID, clipSpaceIBounds);
     if (!cached) {
         // There isn't a suitable entry in the cache so we create a new texture to store the mask.
         // Since we are setting up the cache we know the last lookup was a miss. Free up the
         // currently cached mask so it can be reused.
         fAACache.reset();
         GrTextureDesc desc;
         desc.fFlags = willUpload ? kNone_GrTextureFlags : kRenderTarget_GrTextureFlagBit;
         desc.fWidth = clipSpaceIBounds.width();
         desc.fHeight = clipSpaceIBounds.height();
         desc.fConfig = kRGBA_8888_GrPixelConfig;
         if (willUpload || this->getContext()->isConfigRenderable(kAlpha_8_GrPixelConfig, false)) {
             // We would always like A8 but it isn't supported on all platforms
             desc.fConfig = kAlpha_8_GrPixelConfig;
         }
         fAACache.acquireMask(elementsGenID, desc, clipSpaceIBounds);
     }
     *result = fAACache.getLastMask();
     return cached;
 }
 ////////////////////////////////////////////////////////////////////////////////
 // Create a 8-bit clip mask in alpha
 GrTexture* GrClipMaskManager::createAlphaClipMask(int32_t elementsGenID,
                                                   InitialState initialState,
                                                   const ElementList& elements,
                                                   const SkIRect& clipSpaceIBounds) {
     SkASSERT(kNone_ClipMaskType == fCurrClipMaskType);
     GrTexture* result;
     if (this->getMaskTexture(elementsGenID, clipSpaceIBounds, &result, false)) {
         fCurrClipMaskType = kAlpha_ClipMaskType;
         return result;
     }
     if (NULL == result) {
         fAACache.reset();
         return NULL;
     }
     // The top-left of the mask corresponds to the top-left corner of the bounds.
     SkVector clipToMaskOffset = {
         SkIntToScalar(-clipSpaceIBounds.fLeft),
         SkIntToScalar(-clipSpaceIBounds.fTop)
     };
     // The texture may be larger than necessary, this rect represents the part of the texture
     // we populate with a rasterization of the clip.
     SkIRect maskSpaceIBounds = SkIRect::MakeWH(clipSpaceIBounds.width(), clipSpaceIBounds.height());
     // Set the matrix so that rendered clip elements are transformed to mask space from clip space.
     SkMatrix translate;
     translate.setTranslate(clipToMaskOffset);
     GrDrawTarget::AutoGeometryAndStatePush agasp(fGpu, GrDrawTarget::kReset_ASRInit, &translate);
     GrDrawState* drawState = fGpu->drawState();
     // We're drawing a coverage mask and want coverage to be run through the blend function.
     drawState->enableState(GrDrawState::kCoverageDrawing_StateBit);
     // The scratch texture that we are drawing into can be substantially larger than the mask. Only
     // clear the part that we care about.
     fGpu->clear(&maskSpaceIBounds,
                 kAllIn_InitialState == initialState ? 0xffffffff : 0x00000000,
                 true,
                 result->asRenderTarget());
     // When we use the stencil in the below loop it is important to have this clip installed.
     // The second pass that zeros the stencil buffer renders the rect maskSpaceIBounds so the first
     // pass must not set values outside of this bounds or stencil values outside the rect won't be
     // cleared.
     GrDrawTarget::AutoClipRestore acr(fGpu, maskSpaceIBounds);
     drawState->enableState(GrDrawState::kClip_StateBit);
     GrAutoScratchTexture temp;
     // walk through each clip element and perform its set op
     for (ElementList::Iter iter = elements.headIter(); iter.get(); iter.next()) {
         const Element* element = iter.get();
         SkRegion::Op op = element->getOp();
         bool invert = element->isInverseFilled();
         if (invert || SkRegion::kIntersect_Op == op || SkRegion::kReverseDifference_Op == op) {
             GrPathRenderer* pr = NULL;
             bool useTemp = !this->canStencilAndDrawElement(result, element, &pr);
             GrTexture* dst;
             // This is the bounds of the clip element in the space of the alpha-mask. The temporary
             // mask buffer can be substantially larger than the actually clip stack element. We
             // touch the minimum number of pixels necessary and use decal mode to combine it with
             // the accumulator.
             SkIRect maskSpaceElementIBounds;
             if (useTemp) {
                 if (invert) {
                     maskSpaceElementIBounds = maskSpaceIBounds;
                 } else {
                     SkRect elementBounds = element->getBounds();
                     elementBounds.offset(clipToMaskOffset);
                     elementBounds.roundOut(&maskSpaceElementIBounds);
                 }
                 this->getTemp(maskSpaceIBounds.fRight, maskSpaceIBounds.fBottom, &temp);
                 if (NULL == temp.texture()) {
                     fAACache.reset();
                     return NULL;
                 }
                 dst = temp.texture();
                 // clear the temp target and set blend to replace
                 fGpu->clear(&maskSpaceElementIBounds,
                             invert ? 0xffffffff : 0x00000000,
                             true,
                             dst->asRenderTarget());
                 setup_boolean_blendcoeffs(drawState, SkRegion::kReplace_Op);
             } else {
                 // draw directly into the result with the stencil set to make the pixels affected
                 // by the clip shape be non-zero.
                 dst = result;
                 GR_STATIC_CONST_SAME_STENCIL(kStencilInElement,
                                              kReplace_StencilOp,
                                              kReplace_StencilOp,
                                              kAlways_StencilFunc,
 xffff,
 xffff,
 xffff);
                 drawState->setStencil(kStencilInElement);
                 setup_boolean_blendcoeffs(drawState, op);
             }
             drawState->setAlpha(invert ? 0x00 : 0xff);
             if (!this->drawElement(dst, element, pr)) {
                 fAACache.reset();
                 return NULL;
             }
             if (useTemp) {
                 // Now draw into the accumulator using the real operation and the temp buffer as a
                 // texture
                 this->mergeMask(result,
                                 temp.texture(),
                                 op,
                                 maskSpaceIBounds,
                                 maskSpaceElementIBounds);
             } else {
                 // Draw to the exterior pixels (those with a zero stencil value).
                 drawState->setAlpha(invert ? 0xff : 0x00);
                 GR_STATIC_CONST_SAME_STENCIL(kDrawOutsideElement,
                                              kZero_StencilOp,
                                              kZero_StencilOp,
                                              kEqual_StencilFunc,
 xffff,
 x0000,
 xffff);
                 drawState->setStencil(kDrawOutsideElement);
                 fGpu->drawSimpleRect(clipSpaceIBounds);
                 drawState->disableStencil();
             }
         } else {
             // all the remaining ops can just be directly draw into the accumulation buffer
             drawState->setAlpha(0xff);
             setup_boolean_blendcoeffs(drawState, op);
             this->drawElement(result, element);
         }
     }
     fCurrClipMaskType = kAlpha_ClipMaskType;
     return result;
 }
 ////////////////////////////////////////////////////////////////////////////////
 // Create a 1-bit clip mask in the stencil buffer. 'devClipBounds' are in device
 // (as opposed to canvas) coordinates
 bool GrClipMaskManager::createStencilClipMask(int32_t elementsGenID,
                                               InitialState initialState,
                                               const ElementList& elements,
                                               const SkIRect& clipSpaceIBounds,
                                               const SkIPoint& clipSpaceToStencilOffset) {
     SkASSERT(kNone_ClipMaskType == fCurrClipMaskType);
     GrDrawState* drawState = fGpu->drawState();
     SkASSERT(drawState->isClipState());
     GrRenderTarget* rt = drawState->getRenderTarget();
     SkASSERT(NULL != rt);
     // TODO: dynamically attach a SB when needed.
     GrStencilBuffer* stencilBuffer = rt->getStencilBuffer();
     if (NULL == stencilBuffer) {
         return false;
     }
     if (stencilBuffer->mustRenderClip(elementsGenID, clipSpaceIBounds, clipSpaceToStencilOffset)) {
         stencilBuffer->setLastClip(elementsGenID, clipSpaceIBounds, clipSpaceToStencilOffset);
         // Set the matrix so that rendered clip elements are transformed from clip to stencil space.
         SkVector translate = {
             SkIntToScalar(clipSpaceToStencilOffset.fX),
             SkIntToScalar(clipSpaceToStencilOffset.fY)
         };
         SkMatrix matrix;
         matrix.setTranslate(translate);
         GrDrawTarget::AutoGeometryAndStatePush agasp(fGpu, GrDrawTarget::kReset_ASRInit, &matrix);
         drawState = fGpu->drawState();
         drawState->setRenderTarget(rt);
         // We set the current clip to the bounds so that our recursive draws are scissored to them.
         SkIRect stencilSpaceIBounds(clipSpaceIBounds);
         stencilSpaceIBounds.offset(clipSpaceToStencilOffset);
         GrDrawTarget::AutoClipRestore acr(fGpu, stencilSpaceIBounds);
         drawState->enableState(GrDrawState::kClip_StateBit);
 #if !VISUALIZE_COMPLEX_CLIP
         drawState->enableState(GrDrawState::kNoColorWrites_StateBit);
 #endif
         int clipBit = stencilBuffer->bits();
         SkASSERT((clipBit <= 16) && "Ganesh only handles 16b or smaller stencil buffers");
         clipBit = (1 << (clipBit-1));
         fGpu->clearStencilClip(stencilSpaceIBounds, kAllIn_InitialState == initialState);
         // walk through each clip element and perform its set op
         // with the existing clip.
         for (ElementList::Iter iter(elements.headIter()); NULL != iter.get(); iter.next()) {
             const Element* element = iter.get();
             bool fillInverted = false;
             // enabled at bottom of loop
             drawState->disableState(GrGpu::kModifyStencilClip_StateBit);
             // if the target is MSAA then we want MSAA enabled when the clip is soft
             if (rt->isMultisampled()) {
                 drawState->setState(GrDrawState::kHWAntialias_StateBit, element->isAA());
             }
             // This will be used to determine whether the clip shape can be rendered into the
             // stencil with arbitrary stencil settings.
             GrPathRenderer::StencilSupport stencilSupport;
             SkStrokeRec stroke(SkStrokeRec::kFill_InitStyle);
             SkRegion::Op op = element->getOp();
             GrPathRenderer* pr = NULL;
             SkPath clipPath;
             if (Element::kRect_Type == element->getType()) {
                 stencilSupport = GrPathRenderer::kNoRestriction_StencilSupport;
                 fillInverted = false;
             } else {
                 element->asPath(&clipPath);
                 fillInverted = clipPath.isInverseFillType();
                 if (fillInverted) {
                     clipPath.toggleInverseFillType();
                 }
                 pr = this->getContext()->getPathRenderer(clipPath,
                                                          stroke,
                                                          fGpu,
                                                          false,
                                                          GrPathRendererChain::kStencilOnly_DrawType,
                                                          &stencilSupport);
                 if (NULL == pr) {
                     return false;
                 }
             }
             int passes;
             GrStencilSettings stencilSettings[GrStencilSettings::kMaxStencilClipPasses];
             bool canRenderDirectToStencil =
                 GrPathRenderer::kNoRestriction_StencilSupport == stencilSupport;
             bool canDrawDirectToClip; // Given the renderer, the element,
                                       // fill rule, and set operation can
                                       // we render the element directly to
                                       // stencil bit used for clipping.
             canDrawDirectToClip = GrStencilSettings::GetClipPasses(op,
                                                                    canRenderDirectToStencil,
                                                                    clipBit,
                                                                    fillInverted,
                                                                    &passes,
                                                                    stencilSettings);
             // draw the element to the client stencil bits if necessary
             if (!canDrawDirectToClip) {
                 GR_STATIC_CONST_SAME_STENCIL(gDrawToStencil,
                                              kIncClamp_StencilOp,
                                              kIncClamp_StencilOp,
                                              kAlways_StencilFunc,
 xffff,
 x0000,
 xffff);
                 SET_RANDOM_COLOR
                 if (Element::kRect_Type == element->getType()) {
                     *drawState->stencil() = gDrawToStencil;
                     fGpu->drawSimpleRect(element->getRect(), NULL);
                 } else {
                     if (!clipPath.isEmpty()) {
                         if (canRenderDirectToStencil) {
                             *drawState->stencil() = gDrawToStencil;
                             pr->drawPath(clipPath, stroke, fGpu, false);
                         } else {
                             pr->stencilPath(clipPath, stroke, fGpu);
                         }
                     }
                 }
             }
             // now we modify the clip bit by rendering either the clip
             // element directly or a bounding rect of the entire clip.
             drawState->enableState(GrGpu::kModifyStencilClip_StateBit);
             for (int p = 0; p < passes; ++p) {
                 *drawState->stencil() = stencilSettings[p];
                 if (canDrawDirectToClip) {
                     if (Element::kRect_Type == element->getType()) {
                         SET_RANDOM_COLOR
                         fGpu->drawSimpleRect(element->getRect(), NULL);
                     } else {
                         SET_RANDOM_COLOR
                         pr->drawPath(clipPath, stroke, fGpu, false);
                     }
                 } else {
                     SET_RANDOM_COLOR
                     // The view matrix is setup to do clip space -> stencil space translation, so
                     // draw rect in clip space.
                     fGpu->drawSimpleRect(SkRect::Make(clipSpaceIBounds), NULL);
                 }
             }
         }
     }
     // set this last because recursive draws may overwrite it back to kNone.
     SkASSERT(kNone_ClipMaskType == fCurrClipMaskType);
     fCurrClipMaskType = kStencil_ClipMaskType;
     return true;
 }
 // mapping of clip-respecting stencil funcs to normal stencil funcs
 // mapping depends on whether stencil-clipping is in effect.
 static const GrStencilFunc
     gSpecialToBasicStencilFunc[2][kClipStencilFuncCount] = {
     {// Stencil-Clipping is DISABLED,  we are effectively always inside the clip
         // In the Clip Funcs
         kAlways_StencilFunc,          // kAlwaysIfInClip_StencilFunc
         kEqual_StencilFunc,           // kEqualIfInClip_StencilFunc
         kLess_StencilFunc,            // kLessIfInClip_StencilFunc
         kLEqual_StencilFunc,          // kLEqualIfInClip_StencilFunc
         // Special in the clip func that forces user's ref to be 0.
         kNotEqual_StencilFunc,        // kNonZeroIfInClip_StencilFunc
                                       // make ref 0 and do normal nequal.
     },
     {// Stencil-Clipping is ENABLED
         // In the Clip Funcs
         kEqual_StencilFunc,           // kAlwaysIfInClip_StencilFunc
                                       // eq stencil clip bit, mask
                                       // out user bits.
         kEqual_StencilFunc,           // kEqualIfInClip_StencilFunc
                                       // add stencil bit to mask and ref
         kLess_StencilFunc,            // kLessIfInClip_StencilFunc
         kLEqual_StencilFunc,          // kLEqualIfInClip_StencilFunc
                                       // for both of these we can add
                                       // the clip bit to the mask and
                                       // ref and compare as normal
         // Special in the clip func that forces user's ref to be 0.
         kLess_StencilFunc,            // kNonZeroIfInClip_StencilFunc
                                       // make ref have only the clip bit set
                                       // and make comparison be less
                                       // 10..0 < 1..user_bits..
     }
 };
 namespace {
 // Sets the settings to clip against the stencil buffer clip while ignoring the
 // client bits.
 const GrStencilSettings& basic_apply_stencil_clip_settings() {
     // stencil settings to use when clip is in stencil
     GR_STATIC_CONST_SAME_STENCIL_STRUCT(gSettings,
         kKeep_StencilOp,
         kKeep_StencilOp,
         kAlwaysIfInClip_StencilFunc,
 x0000,
 x0000,
 x0000);
     return *GR_CONST_STENCIL_SETTINGS_PTR_FROM_STRUCT_PTR(&gSettings);
 }
 }
 void GrClipMaskManager::setGpuStencil() {
     // We make two copies of the StencilSettings here (except in the early
     // exit scenario. One copy from draw state to the stack var. Then another
     // from the stack var to the gpu. We could make this class hold a ptr to
     // GrGpu's fStencilSettings and eliminate the stack copy here.
     const GrDrawState& drawState = fGpu->getDrawState();
     // use stencil for clipping if clipping is enabled and the clip
     // has been written into the stencil.
     GrClipMaskManager::StencilClipMode clipMode;
     if (this->isClipInStencil() && drawState.isClipState()) {
         clipMode = GrClipMaskManager::kRespectClip_StencilClipMode;
         // We can't be modifying the clip and respecting it at the same time.
         SkASSERT(!drawState.isStateFlagEnabled(
                     GrGpu::kModifyStencilClip_StateBit));
     } else if (drawState.isStateFlagEnabled(
                     GrGpu::kModifyStencilClip_StateBit)) {
         clipMode = GrClipMaskManager::kModifyClip_StencilClipMode;
     } else {
         clipMode = GrClipMaskManager::kIgnoreClip_StencilClipMode;
     }
     GrStencilSettings settings;
     // The GrGpu client may not be using the stencil buffer but we may need to
     // enable it in order to respect a stencil clip.
     if (drawState.getStencil().isDisabled()) {
         if (GrClipMaskManager::kRespectClip_StencilClipMode == clipMode) {
             settings = basic_apply_stencil_clip_settings();
         } else {
             fGpu->disableStencil();
             return;
         }
     } else {
         settings = drawState.getStencil();
     }
     // TODO: dynamically attach a stencil buffer
     int stencilBits = 0;
     GrStencilBuffer* stencilBuffer =
         drawState.getRenderTarget()->getStencilBuffer();
     if (NULL != stencilBuffer) {
         stencilBits = stencilBuffer->bits();
     }
     SkASSERT(fGpu->caps()->stencilWrapOpsSupport() || !settings.usesWrapOp());
     SkASSERT(fGpu->caps()->twoSidedStencilSupport() || !settings.isTwoSided());
     this->adjustStencilParams(&settings, clipMode, stencilBits);
     fGpu->setStencilSettings(settings);
 }
 void GrClipMaskManager::adjustStencilParams(GrStencilSettings* settings,
                                             StencilClipMode mode,
                                             int stencilBitCnt) {
     SkASSERT(stencilBitCnt > 0);
     if (kModifyClip_StencilClipMode == mode) {
         // We assume that this clip manager itself is drawing to the GrGpu and
         // has already setup the correct values.
         return;
     }
     unsigned int clipBit = (1 << (stencilBitCnt - 1));
     unsigned int userBits = clipBit - 1;
     GrStencilSettings::Face face = GrStencilSettings::kFront_Face;
     bool twoSided = fGpu->caps()->twoSidedStencilSupport();
     bool finished = false;
     while (!finished) {
         GrStencilFunc func = settings->func(face);
         uint16_t writeMask = settings->writeMask(face);
         uint16_t funcMask = settings->funcMask(face);
         uint16_t funcRef = settings->funcRef(face);
         SkASSERT((unsigned) func < kStencilFuncCount);
         writeMask &= userBits;
         if (func >= kBasicStencilFuncCount) {
             int respectClip = kRespectClip_StencilClipMode == mode;
             if (respectClip) {
                 // The GrGpu class should have checked this
                 SkASSERT(this->isClipInStencil());
                 switch (func) {
                     case kAlwaysIfInClip_StencilFunc:
                         funcMask = clipBit;
                         funcRef = clipBit;
                         break;
                     case kEqualIfInClip_StencilFunc:
                     case kLessIfInClip_StencilFunc:
                     case kLEqualIfInClip_StencilFunc:
                         funcMask = (funcMask & userBits) | clipBit;
                         funcRef  = (funcRef  & userBits) | clipBit;
                         break;
                     case kNonZeroIfInClip_StencilFunc:
                         funcMask = (funcMask & userBits) | clipBit;
                         funcRef = clipBit;
                         break;
                     default:
                         GrCrash("Unknown stencil func");
                 }
             } else {
                 funcMask &= userBits;
                 funcRef &= userBits;
             }
             const GrStencilFunc* table =
                 gSpecialToBasicStencilFunc[respectClip];
             func = table[func - kBasicStencilFuncCount];
             SkASSERT(func >= 0 && func < kBasicStencilFuncCount);
         } else {
             funcMask &= userBits;
             funcRef &= userBits;
         }
         settings->setFunc(face, func);
         settings->setWriteMask(face, writeMask);
         settings->setFuncMask(face, funcMask);
         settings->setFuncRef(face, funcRef);
         if (GrStencilSettings::kFront_Face == face) {
             face = GrStencilSettings::kBack_Face;
             finished = !twoSided;
         } else {
             finished = true;
         }
     }
     if (!twoSided) {
         settings->copyFrontSettingsToBack();
     }
 }
 ////////////////////////////////////////////////////////////////////////////////
 GrTexture* GrClipMaskManager::createSoftwareClipMask(int32_t elementsGenID,
                                                      GrReducedClip::InitialState initialState,
                                                      const GrReducedClip::ElementList& elements,
                                                      const SkIRect& clipSpaceIBounds) {
     SkASSERT(kNone_ClipMaskType == fCurrClipMaskType);
     GrTexture* result;
     if (this->getMaskTexture(elementsGenID, clipSpaceIBounds, &result, true)) {
         return result;
     }
     if (NULL == result) {
         fAACache.reset();
         return NULL;
     }
     // The mask texture may be larger than necessary. We round out the clip space bounds and pin
     // the top left corner of the resulting rect to the top left of the texture.
     SkIRect maskSpaceIBounds = SkIRect::MakeWH(clipSpaceIBounds.width(), clipSpaceIBounds.height());
     GrSWMaskHelper helper(this->getContext());
     SkMatrix matrix;
     matrix.setTranslate(SkIntToScalar(-clipSpaceIBounds.fLeft),
                         SkIntToScalar(-clipSpaceIBounds.fTop));
     helper.init(maskSpaceIBounds, &matrix);
     helper.clear(kAllIn_InitialState == initialState ? 0xFF : 0x00);
     SkStrokeRec stroke(SkStrokeRec::kFill_InitStyle);
     for (ElementList::Iter iter(elements.headIter()) ; NULL != iter.get(); iter.next()) {
         const Element* element = iter.get();
         SkRegion::Op op = element->getOp();
         if (SkRegion::kIntersect_Op == op || SkRegion::kReverseDifference_Op == op) {
             // Intersect and reverse difference require modifying pixels outside of the geometry
             // that is being "drawn". In both cases we erase all the pixels outside of the geometry
             // but leave the pixels inside the geometry alone. For reverse difference we invert all
             // the pixels before clearing the ones outside the geometry.
             if (SkRegion::kReverseDifference_Op == op) {
                 SkRect temp = SkRect::Make(clipSpaceIBounds);
                 // invert the entire scene
                 helper.draw(temp, SkRegion::kXOR_Op, false, 0xFF);
             }
             SkPath clipPath;
             element->asPath(&clipPath);
             clipPath.toggleInverseFillType();
             helper.draw(clipPath, stroke, SkRegion::kReplace_Op, element->isAA(), 0x00);
             continue;
         }
         // The other ops (union, xor, diff) only affect pixels inside
         // the geometry so they can just be drawn normally
         if (Element::kRect_Type == element->getType()) {
             helper.draw(element->getRect(), op, element->isAA(), 0xFF);
         } else {
             SkPath path;
             element->asPath(&path);
             helper.draw(path, stroke, op, element->isAA(), 0xFF);
         }
     }
     helper.toTexture(result);
     fCurrClipMaskType = kAlpha_ClipMaskType;
     return result;
 }
 ////////////////////////////////////////////////////////////////////////////////
 void GrClipMaskManager::releaseResources() {
     fAACache.releaseResources();
 }
 void GrClipMaskManager::setGpu(GrGpu* gpu) {
     fGpu = gpu;
     fAACache.setContext(gpu->getContext());
 }
 void GrClipMaskManager::adjustPathStencilParams(GrStencilSettings* settings) {
     const GrDrawState& drawState = fGpu->getDrawState();
     GrClipMaskManager::StencilClipMode clipMode;
     if (this->isClipInStencil() && drawState.isClipState()) {
         clipMode = GrClipMaskManager::kRespectClip_StencilClipMode;
         // We can't be modifying the clip and respecting it at the same time.
         SkASSERT(!drawState.isStateFlagEnabled(
                     GrGpu::kModifyStencilClip_StateBit));
     } else if (drawState.isStateFlagEnabled(
                     GrGpu::kModifyStencilClip_StateBit)) {
         clipMode = GrClipMaskManager::kModifyClip_StencilClipMode;
     } else {
         clipMode = GrClipMaskManager::kIgnoreClip_StencilClipMode;
     }
     // TODO: dynamically attach a stencil buffer
     int stencilBits = 0;
     GrStencilBuffer* stencilBuffer =
         drawState.getRenderTarget()->getStencilBuffer();
     if (NULL != stencilBuffer) {
         stencilBits = stencilBuffer->bits();
         this->adjustStencilParams(settings, clipMode, stencilBits);
     }
 }

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gfx/skia/trunk/src/gpu/GrClipMaskManager.cpp@6474c204b198 (annotated)

gfx/skia/trunk/src/gpu/GrClipMaskManager.cpp