C++ GrRenderTarget::isStencilBufferMultisampled方法代码示例

//.........这里部分代码省略.........
                        return true;
                    }
                } else {
                    return false;
                }
            }
        } break;
    }

    // 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() <= kMaxAnalyticElements) {
        SkVector clipToRTOffset = { SkIntToScalar(-clip.origin().fX),
                                    SkIntToScalar(-clip.origin().fY) };
        // When there are multiple samples we want to do per-sample clipping, not compute a
        // fractional pixel coverage.
        bool disallowAnalyticAA = rt->isUnifiedMultisampled() || pipelineBuilder.hasMixedSamples();
        const GrFragmentProcessor* clipFP = nullptr;
        if (elements.isEmpty() ||
            (requiresAA &&
             this->getAnalyticClipProcessor(elements, disallowAnalyticAA, clipToRTOffset, devBounds,
                                            &clipFP))) {
            SkIRect scissorSpaceIBounds(clipSpaceIBounds);
            scissorSpaceIBounds.offset(-clip.origin());
            if (nullptr == devBounds ||
                !SkRect::Make(scissorSpaceIBounds).contains(*devBounds)) {
                out->fScissorState.set(scissorSpaceIBounds);
            }
            this->setPipelineBuilderStencil(pipelineBuilder, ars);
            out->fClipCoverageFP.reset(clipFP);
            return true;
        }
    }

    // If the stencil buffer is multisampled we can use it to do everything.
    if (!rt->isStencilBufferMultisampled() && requiresAA) {
        SkAutoTUnref<GrTexture> result;

        // The top-left of the mask corresponds to the top-left corner of the bounds.
        SkVector clipToMaskOffset = {
            SkIntToScalar(-clipSpaceIBounds.fLeft),
            SkIntToScalar(-clipSpaceIBounds.fTop)
        };

        if (UseSWOnlyPath(this->getContext(), pipelineBuilder, rt, clipToMaskOffset, elements)) {
            // The clip geometry is complex enough that it will be more efficient to create it
            // entirely in software
            result.reset(CreateSoftwareClipMask(this->getContext(),
                                                genID,
                                                initialState,
                                                elements,
                                                clipToMaskOffset,
                                                clipSpaceIBounds));
        } else {
            result.reset(CreateAlphaClipMask(this->getContext(),
                                             genID,
                                             initialState,
                                             elements,
                                             clipToMaskOffset,
                                             clipSpaceIBounds));
            // If createAlphaClipMask fails it means UseSWOnlyPath has a bug
            SkASSERT(result);
        }

        if (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(-clip.origin());
            out->fClipCoverageFP.reset(create_fp_for_mask(result, rtSpaceMaskBounds));
            this->setPipelineBuilderStencil(pipelineBuilder, ars);
            return true;
        }
        // if alpha clip mask creation fails fall through to the non-AA code paths
    }

    // use the stencil clip if we can't represent the clip as a rectangle.
    SkIPoint clipSpaceToStencilSpaceOffset = -clip.origin();
    this->createStencilClipMask(rt,
                                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);
    out->fScissorState.set(scissorSpaceIBounds);
    this->setPipelineBuilderStencil(pipelineBuilder, ars);
    return true;
}