C++ GrDrawState::disableStencil方法代码示例

//.........这里部分代码省略.........
    // 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.
            GrIRect maskSpaceElementIBounds;

            if (useTemp) {
                if (invert) {
                    maskSpaceElementIBounds = maskSpaceIBounds;
                } else {
                    GrRect 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,
                            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,
                                             0xffff,
                                             0xffff,
                                             0xffff);
                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,
                                             0xffff,
                                             0x0000,
                                             0xffff);
                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;
}