src/gpu/batches/GrRectBatch.cpp

/*
 * Copyright 2015 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "GrRectBatch.h"

#include "GrBatchTarget.h"
#include "GrDefaultGeoProcFactory.h"
#include "GrPrimitiveProcessor.h"

void GrRectBatch::initBatchTracker(const GrPipelineOptimizations& init) {
    // Handle any color overrides
    if (!init.readsColor()) {
        fGeoData[0].fColor = GrColor_ILLEGAL;
    }
    init.getOverrideColorIfSet(&fGeoData[0].fColor);

    // setup batch properties
    fBatch.fColorIgnored = !init.readsColor();
    fBatch.fColor = fGeoData[0].fColor;
    fBatch.fUsesLocalCoords = init.readsLocalCoords();
    fBatch.fCoverageIgnored = !init.readsCoverage();
}

void GrRectBatch::generateGeometry(GrBatchTarget* batchTarget) {
    SkAutoTUnref<const GrGeometryProcessor> gp(this->createRectGP());
    if (!gp) {
        SkDebugf("Could not create GrGeometryProcessor\n");
        return;
    }

    batchTarget->initDraw(gp, this->pipeline());

    int instanceCount = fGeoData.count();
    size_t vertexStride = gp->getVertexStride();
    SkASSERT(this->hasLocalRect() ?
             vertexStride == sizeof(GrDefaultGeoProcFactory::PositionColorLocalCoordAttr) :
             vertexStride == sizeof(GrDefaultGeoProcFactory::PositionColorAttr));
    QuadHelper helper;
    void* vertices = helper.init(batchTarget, vertexStride, instanceCount);

    if (!vertices) {
        return;
    }

    for (int i = 0; i < instanceCount; i++) {
        const Geometry& geom = fGeoData[i];

        intptr_t offset = reinterpret_cast<intptr_t>(vertices) +
                          kVerticesPerQuad * i * vertexStride;
        SkPoint* positions = reinterpret_cast<SkPoint*>(offset);

        positions->setRectFan(geom.fRect.fLeft, geom.fRect.fTop,
                              geom.fRect.fRight, geom.fRect.fBottom, vertexStride);
        geom.fViewMatrix.mapPointsWithStride(positions, vertexStride, kVerticesPerQuad);

        // TODO we should only do this if local coords are being read
        if (geom.fHasLocalRect) {
            static const int kLocalOffset = sizeof(SkPoint) + sizeof(GrColor);
            SkPoint* coords = reinterpret_cast<SkPoint*>(offset + kLocalOffset);
            coords->setRectFan(geom.fLocalRect.fLeft, geom.fLocalRect.fTop,
                               geom.fLocalRect.fRight, geom.fLocalRect.fBottom,
                               vertexStride);
            if (geom.fHasLocalMatrix) {
                geom.fLocalMatrix.mapPointsWithStride(coords, vertexStride, kVerticesPerQuad);
            }
        }

        static const int kColorOffset = sizeof(SkPoint);
        GrColor* vertColor = reinterpret_cast<GrColor*>(offset + kColorOffset);
        for (int j = 0; j < 4; ++j) {
            *vertColor = geom.fColor;
            vertColor = (GrColor*) ((intptr_t) vertColor + vertexStride);
        }
    }

    helper.issueDraw(batchTarget);
}

bool GrRectBatch::onCombineIfPossible(GrBatch* t, const GrCaps& caps) {
    if (!GrPipeline::CanCombine(*this->pipeline(), this->bounds(), *t->pipeline(), t->bounds(),
                                caps)) {
        return false;
    }

    GrRectBatch* that = t->cast<GrRectBatch>();

    if (this->hasLocalRect() != that->hasLocalRect()) {
        return false;
    }

    SkASSERT(this->usesLocalCoords() == that->usesLocalCoords());
    if (!this->hasLocalRect() && this->usesLocalCoords()) {
        if (!this->viewMatrix().cheapEqualTo(that->viewMatrix())) {
            return false;
        }

        if (this->hasLocalMatrix() != that->hasLocalMatrix()) {
            return false;
        }

        if (this->hasLocalMatrix() && !this->localMatrix().cheapEqualTo(that->localMatrix())) {
            return false;
        }
    }

    if (this->color() != that->color()) {
        fBatch.fColor = GrColor_ILLEGAL;
    }
    fGeoData.push_back_n(that->geoData()->count(), that->geoData()->begin());
    this->joinBounds(that->bounds());
    return true;
}

/** We always use per-vertex colors so that rects can be batched across color changes. Sometimes
    we  have explicit local coords and sometimes not. We *could* always provide explicit local
    coords and just duplicate the positions when the caller hasn't provided a local coord rect,
    but we haven't seen a use case which frequently switches between local rect and no local
    rect draws.

    The color param is used to determine whether the opaque hint can be set on the draw state.
    The caller must populate the vertex colors itself.

    The vertex attrib order is always pos, color, [local coords].
 */
const GrGeometryProcessor* GrRectBatch::createRectGP() {
    using namespace GrDefaultGeoProcFactory;
    Color color(Color::kAttribute_Type);
    Coverage coverage(this->coverageIgnored() ? Coverage::kNone_Type : Coverage::kSolid_Type);

    // if we have a local rect, then we apply the localMatrix directly to the localRect to
    // generate vertex local coords
    if (this->hasLocalRect()) {
        LocalCoords localCoords(LocalCoords::kHasExplicit_Type);
        return GrDefaultGeoProcFactory::Create(color, coverage, localCoords, SkMatrix::I());
    } else {
        LocalCoords localCoords(LocalCoords::kUsePosition_Type,
                                this->hasLocalMatrix() ? &this->localMatrix() : NULL);
        return GrDefaultGeoProcFactory::CreateForDeviceSpace(color, coverage, localCoords,
                                                             this->viewMatrix());
    }
}

///////////////////////////////////////////////////////////////////////////////////////////////////

#ifdef GR_TEST_UTILS

#include "GrBatchTest.h"

BATCH_TEST_DEFINE(RectBatch) {
    GrRectBatch::Geometry geometry;
    geometry.fColor = GrRandomColor(random);

    geometry.fRect = GrTest::TestRect(random);
    geometry.fHasLocalRect = random->nextBool();

    if (geometry.fHasLocalRect) {
        geometry.fViewMatrix = GrTest::TestMatrixInvertible(random);
        geometry.fLocalRect = GrTest::TestRect(random);
    } else {
        geometry.fViewMatrix = GrTest::TestMatrix(random);
    }

    geometry.fHasLocalMatrix = random->nextBool();
    if (geometry.fHasLocalMatrix) {
        geometry.fLocalMatrix = GrTest::TestMatrix(random);
    }

    return GrRectBatch::Create(geometry);
}

#endif