Enable blend optimizations with instanced draws

src/gpu/instanced/InstancedRendering.cpp

Index: src/gpu/instanced/InstancedRendering.cpp
diff --git a/src/gpu/instanced/InstancedRendering.cpp b/src/gpu/instanced/InstancedRendering.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..d96bb397862c60e03ade568ad79534710a3bbd16
--- /dev/null
+++ b/src/gpu/instanced/InstancedRendering.cpp
@@ -0,0 +1,488 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "InstancedRendering.h"
+
+#include "GrBatchFlushState.h"
+#include "GrPipeline.h"
+#include "GrResourceProvider.h"
+#include "instanced/InstanceProcessor.h"
+
+namespace gr_instanced {
+
+InstancedRendering::InstancedRendering(GrGpu* gpu, AntialiasMode lastSupportedAAMode,
+                                       bool canRenderToFloat)
+    : fGpu(SkRef(gpu)),
+      fLastSupportedAAMode(lastSupportedAAMode),
+      fCanRenderToFloat(canRenderToFloat),
+      fState(State::kRecordingDraws),
+      fDrawPool(1024 * sizeof(Batch::Draw), 1024 * sizeof(Batch::Draw)) {
+}
+
+GrDrawBatch* InstancedRendering::recordRect(const SkRect& rect, const SkMatrix& viewMatrix,
+                                            GrColor color, bool antialias,
+                                            const GrInstancedPipelineInfo& info, bool* useHWAA) {
+    return this->recordShape(ShapeType::kRect, rect, viewMatrix, color, rect, antialias, info,
+                             useHWAA);
+}
+
+GrDrawBatch* InstancedRendering::recordRect(const SkRect& rect, const SkMatrix& viewMatrix,
+                                            GrColor color, const SkRect& localRect, bool antialias,
+                                            const GrInstancedPipelineInfo& info, bool* useHWAA) {
+    return this->recordShape(ShapeType::kRect, rect, viewMatrix, color, localRect, antialias, info,
+                             useHWAA);
+}
+
+GrDrawBatch* InstancedRendering::recordRect(const SkRect& rect, const SkMatrix& viewMatrix,
+                                            GrColor color, const SkMatrix& localMatrix,
+                                            bool antialias, const GrInstancedPipelineInfo& info,
+                                            bool* useHWAA) {
+    if (localMatrix.hasPerspective()) {
+        return nullptr; // Perspective is not yet supported in the local matrix.
+    }
+    if (Batch* batch = this->recordShape(ShapeType::kRect, rect, viewMatrix, color, rect, antialias,
+                                         info, useHWAA)) {
+        batch->getSingleInstance().fInfo |= kLocalMatrix_InfoFlag;
+        batch->appendParamsTexel(localMatrix.getScaleX(), localMatrix.getSkewX(),
+                                 localMatrix.getTranslateX());
+        batch->appendParamsTexel(localMatrix.getSkewY(), localMatrix.getScaleY(),
+                                 localMatrix.getTranslateY());
+        batch->fInfo.fHasLocalMatrix = true;
+        return batch;
+    }
+    return nullptr;
+}
+
+GrDrawBatch* InstancedRendering::recordOval(const SkRect& oval, const SkMatrix& viewMatrix,
+                                            GrColor color, bool antialias,
+                                            const GrInstancedPipelineInfo& info, bool* useHWAA) {
+    return this->recordShape(ShapeType::kOval, oval, viewMatrix, color, oval, antialias, info,
+                             useHWAA);
+}
+
+GrDrawBatch* InstancedRendering::recordRRect(const SkRRect& rrect, const SkMatrix& viewMatrix,
+                                             GrColor color, bool antialias,
+                                             const GrInstancedPipelineInfo& info, bool* useHWAA) {
+    if (Batch* batch = this->recordShape(GetRRectShapeType(rrect), rrect.rect(), viewMatrix, color,
+                                         rrect.rect(), antialias, info, useHWAA)) {
+        batch->appendRRectParams(rrect);
+        return batch;
+    }
+    return nullptr;
+}
+
+GrDrawBatch* InstancedRendering::recordDRRect(const SkRRect& outer, const SkRRect& inner,
+                                              const SkMatrix& viewMatrix, GrColor color,
+                                              bool antialias, const GrInstancedPipelineInfo& info,
+                                              bool* useHWAA) {
+    if (inner.getType() > SkRRect::kSimple_Type) {
+       return nullptr; // Complex inner round rects are not yet supported.
+    }
+    if (SkRRect::kEmpty_Type == inner.getType()) {
+        return this->recordRRect(outer, viewMatrix, color, antialias, info, useHWAA);
+    }
+    if (Batch* batch = this->recordShape(GetRRectShapeType(outer), outer.rect(), viewMatrix, color,
+                                         outer.rect(), antialias, info, useHWAA)) {
+        batch->appendRRectParams(outer);
+        ShapeType innerShapeType = GetRRectShapeType(inner);
+        batch->fInfo.fInnerShapeTypes |= GetShapeFlag(innerShapeType);
+        batch->getSingleInstance().fInfo |= ((int)innerShapeType << kInnerShapeType_InfoBit);
+        batch->appendParamsTexel(inner.rect().asScalars(), 4);
+        batch->appendRRectParams(inner);
+        return batch;
+    }
+    return nullptr;
+}
+
+InstancedRendering::Batch* InstancedRendering::recordShape(ShapeType type, const SkRect& bounds,
+                                                           const SkMatrix& viewMatrix,
+                                                           GrColor color, const SkRect& localRect,
+                                                           bool antialias,
+                                                           const GrInstancedPipelineInfo& info,
+                                                           bool* useHWAA) {
+    SkASSERT(State::kRecordingDraws == fState);
+
+    if (info.fIsRenderingToFloat && !fCanRenderToFloat) {
+        return nullptr;
+    }
+
+    AntialiasMode antialiasMode;
+    if (!this->selectAntialiasMode(viewMatrix, antialias, info, useHWAA, &antialiasMode)) {
+        return nullptr;
+    }
+
+    Batch* batch = this->createBatch();
+    batch->fInfo.fAntialiasMode = antialiasMode;
+    batch->fInfo.fShapeTypes = GetShapeFlag(type);
+    batch->fInfo.fCannotDiscard = !info.fCanDiscard;
+
+    Instance& instance = batch->getSingleInstance();
+    instance.fInfo = (int)type << kShapeType_InfoBit;
+
+    // The instanced shape renderer draws rectangles of [-1, -1, +1, +1], so we find the matrix that
+    // will map this rectangle to the same device coordinates as "viewMatrix * bounds".
+    float sx = 0.5f * bounds.width();
+    float sy = 0.5f * bounds.height();
+    float tx = sx + bounds.fLeft;
+    float ty = sy + bounds.fTop;
+    if (!viewMatrix.hasPerspective()) {
+        float* m = instance.fShapeMatrix2x3;
+        m[0] = viewMatrix.getScaleX() * sx;
+        m[1] = viewMatrix.getSkewX() * sy;
+        m[2] = viewMatrix.getTranslateX() +
+               viewMatrix.getScaleX() * tx + viewMatrix.getSkewX() * ty;
+
+        m[3] = viewMatrix.getSkewY() * sx;
+        m[4] = viewMatrix.getScaleY() * sy;
+        m[5] = viewMatrix.getTranslateY() +
+               viewMatrix.getSkewY() * tx + viewMatrix.getScaleY() * ty;
+
+        // Since 'm' is a 2x3 matrix that maps the rect [-1, +1] into the shape's device-space quad,
+        // it's quite simple to find the bounding rectangle:
+        float devBoundsHalfWidth = fabsf(m[0]) + fabsf(m[1]);
+        float devBoundsHalfHeight = fabsf(m[3]) + fabsf(m[4]);
+        batch->fBounds.fLeft = m[2] - devBoundsHalfWidth;
+        batch->fBounds.fRight = m[2] + devBoundsHalfWidth;
+        batch->fBounds.fTop = m[5] - devBoundsHalfHeight;
+        batch->fBounds.fBottom = m[5] + devBoundsHalfHeight;
+
+        // TODO: Is this worth the CPU overhead?
+        batch->fInfo.fNonSquare =
+            fabsf(devBoundsHalfHeight - devBoundsHalfWidth) > 0.5f || // Early out.
+            fabs(m[0] * m[3] + m[1] * m[4]) > 1e-3f || // Skew?
+            fabs(m[0] * m[0] + m[1] * m[1] - m[3] * m[3] - m[4] * m[4]) > 1e-2f; // Diff. lengths?
+    } else {
+        SkMatrix shapeMatrix(viewMatrix);
+        shapeMatrix.preTranslate(tx, ty);
+        shapeMatrix.preScale(sx, sy);
+        instance.fInfo |= kPerspective_InfoFlag;
+
+        float* m = instance.fShapeMatrix2x3;
+        m[0] = SkScalarToFloat(shapeMatrix.getScaleX());
+        m[1] = SkScalarToFloat(shapeMatrix.getSkewX());
+        m[2] = SkScalarToFloat(shapeMatrix.getTranslateX());
+        m[3] = SkScalarToFloat(shapeMatrix.getSkewY());
+        m[4] = SkScalarToFloat(shapeMatrix.getScaleY());
+        m[5] = SkScalarToFloat(shapeMatrix.getTranslateY());
+
+        // Send the perspective column as a param.
+        batch->appendParamsTexel(shapeMatrix[SkMatrix::kMPersp0], shapeMatrix[SkMatrix::kMPersp1],
+                                 shapeMatrix[SkMatrix::kMPersp2]);
+        batch->fInfo.fHasPerspective = true;
+
+        viewMatrix.mapRect(&batch->fBounds, bounds);
+
+        batch->fInfo.fNonSquare = true;
+    }
+
+    instance.fColor = color;
+
+    const float* rectAsFloats = localRect.asScalars(); // Ensure SkScalar == float.
+    memcpy(&instance.fLocalRect, rectAsFloats, 4 * sizeof(float));
+
+    batch->fPixelLoad = batch->fBounds.height() * batch->fBounds.width();
+    return batch;
+}
+
+inline bool InstancedRendering::selectAntialiasMode(const SkMatrix& viewMatrix, bool antialias,
+                                                    const GrInstancedPipelineInfo& info,
+                                                    bool* useHWAA, AntialiasMode* antialiasMode) {
+    SkASSERT(!info.fColorDisabled || info.fDrawingShapeToStencil);
+    SkASSERT(!info.fIsMixedSampled || info.fIsMultisampled);
+
+    if (!info.fIsMultisampled || fGpu->caps()->multisampleDisableSupport()) {
+        SkASSERT(fLastSupportedAAMode >= AntialiasMode::kCoverage);
+        if (!antialias) {
+            if (info.fDrawingShapeToStencil && !info.fCanDiscard) {
+                // We can't draw to the stencil buffer without discard (or sample mask if MSAA).
+                return false;
+            }
+            *antialiasMode = AntialiasMode::kNone;
+            *useHWAA = false;
+            return true;
+        }
+
+        if (info.canUseCoverageAA() && viewMatrix.preservesRightAngles()) {
+            *antialiasMode = AntialiasMode::kCoverage;
+            *useHWAA = false;
+            return true;
+        }
+    }
+
+    if (info.fIsMultisampled && fLastSupportedAAMode >= AntialiasMode::kMSAA) {
+        if (!info.fIsMixedSampled || info.fColorDisabled) {
+            *antialiasMode = AntialiasMode::kMSAA;
+            *useHWAA = true;
+            return true;
+        }
+        if (fLastSupportedAAMode >= AntialiasMode::kMixedSamples) {
+            *antialiasMode = AntialiasMode::kMixedSamples;
+            *useHWAA = true;
+            return true;
+        }
+    }
+
+    return false;
+}
+
+InstancedRendering::Batch::Batch(uint32_t classID, InstancedRendering* ir)
+    : INHERITED(classID),
+      fInstancedRendering(ir),
+      fIsTracked(false),
+      fNumDraws(1),
+      fNumChangesInGeometry(0) {
+    fHeadDraw = fTailDraw = (Draw*)fInstancedRendering->fDrawPool.allocate(sizeof(Draw));
+#ifdef SK_DEBUG
+    fHeadDraw->fGeometry = {-1, 0};
+#endif
+    fHeadDraw->fNext = nullptr;
+}
+
+InstancedRendering::Batch::~Batch() {
+    if (fIsTracked) {
+        fInstancedRendering->fTrackedBatches.remove(this);
+    }
+
+    Draw* draw = fHeadDraw;
+    while (draw) {
+        Draw* next = draw->fNext;
+        fInstancedRendering->fDrawPool.release(draw);
+        draw = next;
+    }
+}
+
+void InstancedRendering::Batch::appendRRectParams(const SkRRect& rrect) {
+    SkASSERT(!fIsTracked);
+    switch (rrect.getType()) {
+        case SkRRect::kSimple_Type: {
+            const SkVector& radii = rrect.getSimpleRadii();
+            this->appendParamsTexel(radii.x(), radii.y(), rrect.width(), rrect.height());
+            return;
+        }
+        case SkRRect::kNinePatch_Type: {
+            float twoOverW = 2 / rrect.width();
+            float twoOverH = 2 / rrect.height();
+            const SkVector& radiiTL = rrect.radii(SkRRect::kUpperLeft_Corner);
+            const SkVector& radiiBR = rrect.radii(SkRRect::kLowerRight_Corner);
+            this->appendParamsTexel(radiiTL.x() * twoOverW, radiiBR.x() * twoOverW,
+                                    radiiTL.y() * twoOverH, radiiBR.y() * twoOverH);
+            return;
+        }
+        case SkRRect::kComplex_Type: {
+            /**
+             * The x and y radii of each arc are stored in separate vectors,
+             * in the following order:
+             *
+             *        __x1 _ _ _ x3__
+             *    y1 |               | y2
+             *
+             *       |               |
+             *
+             *    y3 |__   _ _ _   __| y4
+             *          x2       x4
+             *
+             */
+            float twoOverW = 2 / rrect.width();
+            float twoOverH = 2 / rrect.height();
+            const SkVector& radiiTL = rrect.radii(SkRRect::kUpperLeft_Corner);
+            const SkVector& radiiTR = rrect.radii(SkRRect::kUpperRight_Corner);
+            const SkVector& radiiBR = rrect.radii(SkRRect::kLowerRight_Corner);
+            const SkVector& radiiBL = rrect.radii(SkRRect::kLowerLeft_Corner);
+            this->appendParamsTexel(radiiTL.x() * twoOverW, radiiBL.x() * twoOverW,
+                                    radiiTR.x() * twoOverW, radiiBR.x() * twoOverW);
+            this->appendParamsTexel(radiiTL.y() * twoOverH, radiiTR.y() * twoOverH,
+                                    radiiBL.y() * twoOverH, radiiBR.y() * twoOverH);
+            return;
+        }
+        default: return;
+    }
+}
+
+void InstancedRendering::Batch::appendParamsTexel(const SkScalar* vals, int count) {
+    SkASSERT(!fIsTracked);
+    SkASSERT(count <= 4 && count >= 0);
+    const float* valsAsFloats = vals; // Ensure SkScalar == float.
+    memcpy(&fParams.push_back(), valsAsFloats, count * sizeof(float));
+    fInfo.fHasParams = true;
+}
+
+void InstancedRendering::Batch::appendParamsTexel(SkScalar x, SkScalar y, SkScalar z, SkScalar w) {
+    SkASSERT(!fIsTracked);
+    ParamsTexel& texel = fParams.push_back();
+    texel.fX = SkScalarToFloat(x);
+    texel.fY = SkScalarToFloat(y);
+    texel.fZ = SkScalarToFloat(z);
+    texel.fW = SkScalarToFloat(w);
+    fInfo.fHasParams = true;
+}
+
+void InstancedRendering::Batch::appendParamsTexel(SkScalar x, SkScalar y, SkScalar z) {
+    SkASSERT(!fIsTracked);
+    ParamsTexel& texel = fParams.push_back();
+    texel.fX = SkScalarToFloat(x);
+    texel.fY = SkScalarToFloat(y);
+    texel.fZ = SkScalarToFloat(z);
+    fInfo.fHasParams = true;
+}
+
+void InstancedRendering::Batch::computePipelineOptimizations(GrInitInvariantOutput* color,
+                                                            GrInitInvariantOutput* coverage,
+                                                            GrBatchToXPOverrides* overrides) const {
+    color->setKnownFourComponents(this->getSingleInstance().fColor);
+
+    if (AntialiasMode::kCoverage == fInfo.fAntialiasMode ||
+        (AntialiasMode::kNone == fInfo.fAntialiasMode &&
+         !fInfo.isSimpleRects() && fInfo.fCannotDiscard)) {
+        coverage->setUnknownSingleComponent();
+    } else {
+        coverage->setKnownSingleComponent(255);
+    }
+}
+
+void InstancedRendering::Batch::initBatchTracker(const GrXPOverridesForBatch& overrides) {
+    Draw& draw = this->getSingleDraw(); // This will assert if we have > 1 command.
+    SkASSERT(draw.fGeometry.isEmpty());
+    SkASSERT(SkIsPow2(fInfo.fShapeTypes));
+    SkASSERT(!fIsTracked);
+
+    if (kRect_ShapeFlag == fInfo.fShapeTypes) {
+        draw.fGeometry = InstanceProcessor::GetIndexRangeForRect(fInfo.fAntialiasMode);
+    } else if (kOval_ShapeFlag == fInfo.fShapeTypes) {
+        draw.fGeometry = InstanceProcessor::GetIndexRangeForOval(fInfo.fAntialiasMode, fBounds);
+    } else {
+        draw.fGeometry = InstanceProcessor::GetIndexRangeForRRect(fInfo.fAntialiasMode);
+    }
+
+    if (!fParams.empty()) {
+        SkASSERT(fInstancedRendering->fParams.count() < (int)kParamsIdx_InfoMask); // TODO: cleaner.
+        this->getSingleInstance().fInfo |= fInstancedRendering->fParams.count();
+        fInstancedRendering->fParams.push_back_n(fParams.count(), fParams.begin());
+    }
+
+    GrColor overrideColor;
+    if (overrides.getOverrideColorIfSet(&overrideColor)) {
+        SkASSERT(State::kRecordingDraws == fInstancedRendering->fState);
+        this->getSingleInstance().fColor = overrideColor;
+    }
+    fInfo.fUsesLocalCoords = overrides.readsLocalCoords();
+    fInfo.fCannotTweakAlphaForCoverage = !overrides.canTweakAlphaForCoverage();
+
+    fInstancedRendering->fTrackedBatches.addToTail(this);
+    fIsTracked = true;
+}
+
+bool InstancedRendering::Batch::onCombineIfPossible(GrBatch* other, const GrCaps& caps) {
+    Batch* that = static_cast<Batch*>(other);
+    SkASSERT(fInstancedRendering == that->fInstancedRendering);
+    SkASSERT(fTailDraw);
+    SkASSERT(that->fTailDraw);
+
+    if (!BatchInfo::CanCombine(fInfo, that->fInfo) ||
+        !GrPipeline::CanCombine(*this->pipeline(), this->bounds(),
+                                *that->pipeline(), that->bounds(), caps)) {
+        return false;
+    }
+
+    BatchInfo combinedInfo = fInfo | that->fInfo;
+    if (!combinedInfo.isSimpleRects()) {
+        // This threshold was chosen with the "shapes_mixed" bench on a MacBook with Intel graphics.
+        // There seems to be a wide range where it doesn't matter if we combine or not. What matters
+        // is that the itty bitty rects combine with other shapes and the giant ones don't.
+        constexpr SkScalar kMaxPixelsToGeneralizeRects = 256 * 256;
+        if (fInfo.isSimpleRects() && fPixelLoad > kMaxPixelsToGeneralizeRects) {
+            return false;
+        }
+        if (that->fInfo.isSimpleRects() && that->fPixelLoad > kMaxPixelsToGeneralizeRects) {
+            return false;
+        }
+    }
+
+    fBounds.join(that->fBounds);
+    fInfo = combinedInfo;
+    fPixelLoad += that->fPixelLoad;
+
+    // Adopt the other batch's draws.
+    fNumDraws += that->fNumDraws;
+    fNumChangesInGeometry += that->fNumChangesInGeometry;
+    if (fTailDraw->fGeometry != that->fHeadDraw->fGeometry) {
+        ++fNumChangesInGeometry;
+    }
+    fTailDraw->fNext = that->fHeadDraw;
+    fTailDraw = that->fTailDraw;
+
+    that->fHeadDraw = that->fTailDraw = nullptr;
+
+    return true;
+}
+
+void InstancedRendering::beginFlush(GrResourceProvider* rp) {
+    SkASSERT(State::kRecordingDraws == fState);
+    fState = State::kFlushing;
+
+    if (fTrackedBatches.isEmpty()) {
+        return;
+    }
+
+    if (!fVertexBuffer) {
+        fVertexBuffer.reset(InstanceProcessor::FindOrCreateVertexBuffer(fGpu));
+        if (!fVertexBuffer) {
+            return;
+        }
+    }
+
+    if (!fIndexBuffer) {
+      fIndexBuffer.reset(InstanceProcessor::FindOrCreateIndex8Buffer(fGpu));
+        if (!fIndexBuffer) {
+            return;
+        }
+    }
+
+    if (!fParams.empty()) {
+        fParamsBuffer.reset(rp->createBuffer(fParams.count() * sizeof(ParamsTexel),
+                                             kTexel_GrBufferType, kDynamic_GrAccessPattern,
+                                             GrResourceProvider::kNoPendingIO_Flag,
+                                             fParams.begin()));
+        if (!fParamsBuffer) {
+            return;
+        }
+    }
+
+    this->onBeginFlush(rp);
+}
+
+void InstancedRendering::Batch::onDraw(GrBatchFlushState* state) {
+    SkASSERT(State::kFlushing == fInstancedRendering->fState);
+    SkASSERT(state->gpu() == fInstancedRendering->gpu());
+
+    state->gpu()->handleDirtyContext();
+    if (GrXferBarrierType barrierType = this->pipeline()->xferBarrierType(*state->gpu()->caps())) {
+        state->gpu()->xferBarrier(this->pipeline()->getRenderTarget(), barrierType);
+    }
+
+    InstanceProcessor instProc(fInfo, fInstancedRendering->fParamsBuffer);
+    fInstancedRendering->onDraw(*this->pipeline(), instProc, this);
+}
+
+void InstancedRendering::endFlush() {
+    // The caller is expected to delete all tracked batches (i.e. batches whose initBatchTracker
+    // method has been called) before ending the flush.
+    SkASSERT(fTrackedBatches.isEmpty());
+    fParams.reset();
+    fParamsBuffer.reset();
+    this->onEndFlush();
+    fState = State::kRecordingDraws;
+    // Hold on to the shape coords and index buffers.
+}
+
+void InstancedRendering::resetGpuResources(ResetType resetType) {
+    fVertexBuffer.reset();
+    fIndexBuffer.reset();
+    fParamsBuffer.reset();
+    this->onResetGpuResources(resetType);
+}
+
+}