/*
 * Copyright 2021 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "src/gpu/tessellate/GrAtlasRenderTask.h"

#include "src/core/SkBlendModePriv.h"
#include "src/core/SkIPoint16.h"
#include "src/gpu/GrGpu.h"
#include "src/gpu/GrOpFlushState.h"
#include "src/gpu/GrOpsTypes.h"
#include "src/gpu/ops/GrFillRectOp.h"
#include "src/gpu/tessellate/GrPathStencilCoverOp.h"

GrAtlasRenderTask::GrAtlasRenderTask(GrRecordingContext* rContext,
                                     sk_sp<GrArenas> arenas,
                                     std::unique_ptr<GrDynamicAtlas> dynamicAtlas)
        : GrOpsTask(rContext->priv().drawingManager(),
                    dynamicAtlas->writeView(*rContext->priv().caps()),
                    rContext->priv().auditTrail(),
                    std::move(arenas))
        , fDynamicAtlas(std::move(dynamicAtlas)) {
}

bool GrAtlasRenderTask::addPath(const SkMatrix& viewMatrix, const SkPath& path,
                                SkIPoint pathDevTopLeft, int widthInAtlas, int heightInAtlas,
                                bool transposedInAtlas, SkIPoint16* locationInAtlas) {
    SkASSERT(!this->isClosed());
    SkASSERT(this->isEmpty());
    SkASSERT(!fDynamicAtlas->isInstantiated());  // Paths can't be added after instantiate().

    if (!fDynamicAtlas->addRect(widthInAtlas, heightInAtlas, locationInAtlas)) {
        return false;
    }

    SkMatrix pathToAtlasMatrix = viewMatrix;
    if (transposedInAtlas) {
        std::swap(pathToAtlasMatrix[0], pathToAtlasMatrix[3]);
        std::swap(pathToAtlasMatrix[1], pathToAtlasMatrix[4]);
        float tx=pathToAtlasMatrix.getTranslateX(), ty=pathToAtlasMatrix.getTranslateY();
        pathToAtlasMatrix.setTranslateX(ty - pathDevTopLeft.y() + locationInAtlas->x());
        pathToAtlasMatrix.setTranslateY(tx - pathDevTopLeft.x() + locationInAtlas->y());
    } else {
        pathToAtlasMatrix.postTranslate(locationInAtlas->x() - pathDevTopLeft.x(),
                                        locationInAtlas->y() - pathDevTopLeft.y());
    }

    // Concatenate this path onto our uber path that matches its fill rule.
    SkPath* uberPath = this->getUberPath(GrFillRuleForSkPath(path));
    uberPath->moveTo(locationInAtlas->x(), locationInAtlas->y());  // Implicit moveTo(0,0).
    uberPath->addPath(path, pathToAtlasMatrix);
    return true;
}

GrRenderTask::ExpectedOutcome GrAtlasRenderTask::onMakeClosed(GrRecordingContext* rContext,
                                                              SkIRect* targetUpdateBounds) {
    // We don't add our ops until now, at which point we know the atlas is done being built.
    SkASSERT(this->isEmpty());
    SkASSERT(!fDynamicAtlas->isInstantiated());  // Instantiation happens after makeClosed().

    const GrCaps& caps = *rContext->priv().caps();

    // Set our dimensions now. GrOpsTask will need them when we add our ops.
    this->target(0)->priv().setLazyDimensions(fDynamicAtlas->drawBounds());
    this->target(0)->asRenderTargetProxy()->setNeedsStencil();
    SkRect drawRect = target(0)->getBoundsRect();

    // Clear the atlas.
    if (caps.performColorClearsAsDraws() || caps.performStencilClearsAsDraws()) {
        this->setColorLoadOp(GrLoadOp::kDiscard);
        this->setInitialStencilContent(GrOpsTask::StencilContent::kDontCare);

        constexpr static GrUserStencilSettings kClearStencil(
            GrUserStencilSettings::StaticInit<
                0x0000,
                GrUserStencilTest::kAlways,
                0xffff,
                GrUserStencilOp::kReplace,
                GrUserStencilOp::kReplace,
                0xffff>());

        this->stencilAtlasRect(rContext, drawRect, SK_PMColor4fTRANSPARENT, &kClearStencil);
    } else {
        this->setColorLoadOp(GrLoadOp::kClear);
        this->setInitialStencilContent(GrOpsTask::StencilContent::kUserBitsCleared);
    }

    // Add ops to stencil the atlas paths.
    for (auto fillRule : {GrFillRule::kNonzero, GrFillRule::kEvenOdd}) {
        SkPath* uberPath = this->getUberPath(fillRule);
        if (uberPath->isEmpty()) {
            continue;
        }
        uberPath->setFillType(fillRule == GrFillRule::kNonzero ? SkPathFillType::kWinding
                                                               : SkPathFillType::kEvenOdd);
        auto op = GrOp::Make<GrPathStencilCoverOp>(
                rContext, SkMatrix::I(), *uberPath, GrPaint(), GrAAType::kMSAA,
                GrTessellationPathRenderer::PathFlags::kStencilOnly, drawRect);
        this->addAtlasDrawOp(std::move(op), caps);
    }

    // Finally, draw a fullscreen rect to cover our stencilled paths.
    const GrUserStencilSettings* stencil;
    if (caps.discardStencilValuesAfterRenderPass()) {
        constexpr static GrUserStencilSettings kTestStencil(
            GrUserStencilSettings::StaticInit<
                0x0000,
                GrUserStencilTest::kNotEqual,
                0xffff,
                GrUserStencilOp::kKeep,
                GrUserStencilOp::kKeep,
                0xffff>());

        // This is the final op in the task. Since Ganesh is planning to discard the stencil values
        // anyway, there is no need to reset the stencil values back to 0.
        stencil = &kTestStencil;
    } else {
        constexpr static GrUserStencilSettings kTestAndResetStencil(
            GrUserStencilSettings::StaticInit<
                0x0000,
                GrUserStencilTest::kNotEqual,
                0xffff,
                GrUserStencilOp::kZero,
                GrUserStencilOp::kKeep,
                0xffff>());

        // Outset the cover rect to make extra sure we clear every stencil value touched by the
        // atlas.
        drawRect.outset(1, 1);
        stencil = &kTestAndResetStencil;
    }
    this->stencilAtlasRect(rContext, drawRect, SK_PMColor4fWHITE, stencil);

    this->GrOpsTask::onMakeClosed(rContext, targetUpdateBounds);

    // Don't mark msaa dirty. Since this op defers being closed, the drawing manager's dirty
    // tracking doesn't work anyway. We will just resolve msaa manually during onExecute.
    return ExpectedOutcome::kTargetUnchanged;
}

void GrAtlasRenderTask::stencilAtlasRect(GrRecordingContext* rContext, const SkRect& rect,
                                         const SkPMColor4f& color,
                                         const GrUserStencilSettings* stencil) {
    GrPaint paint;
    paint.setColor4f(color);
    paint.setXPFactory(SkBlendMode_AsXPFactory(SkBlendMode::kSrc));
    GrQuad quad(rect);
    DrawQuad drawQuad{quad, quad, GrQuadAAFlags::kAll};
    auto op = GrFillRectOp::Make(rContext, std::move(paint), GrAAType::kMSAA, &drawQuad, stencil);
    this->addAtlasDrawOp(std::move(op), *rContext->priv().caps());
}

void GrAtlasRenderTask::addAtlasDrawOp(GrOp::Owner op, const GrCaps& caps) {
    SkASSERT(!this->isClosed());

    auto drawOp = static_cast<GrDrawOp*>(op.get());
    SkDEBUGCODE(drawOp->fAddDrawOpCalled = true;)

    auto processorAnalysis = drawOp->finalize(caps, nullptr,
                                              GrColorTypeClampType(fDynamicAtlas->colorType()));
    SkASSERT(!processorAnalysis.requiresDstTexture());
    SkASSERT(!processorAnalysis.usesNonCoherentHWBlending());

    drawOp->setClippedBounds(drawOp->bounds());
    this->recordOp(std::move(op), true/*usesMSAA*/, processorAnalysis, nullptr, nullptr, caps);
}

bool GrAtlasRenderTask::onExecute(GrOpFlushState* flushState) {
    if (!this->GrOpsTask::onExecute(flushState)) {
        return false;
    }
    if (this->target(0)->requiresManualMSAAResolve()) {
        // Since atlases don't get closed until they are done being built, the drawingManager
        // doesn't detect that they need an MSAA resolve. Do it here manually.
        auto nativeRect = GrNativeRect::MakeIRectRelativeTo(
                GrDynamicAtlas::kTextureOrigin,
                this->target(0)->backingStoreDimensions().height(),
                SkIRect::MakeSize(fDynamicAtlas->drawBounds()));
        flushState->gpu()->resolveRenderTarget(this->target(0)->peekRenderTarget(), nativeRect);
    }
    return true;
}