src/gpu/GrDrawingManager.h

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

#ifndef GrDrawingManager_DEFINED
#define GrDrawingManager_DEFINED

#include "include/core/SkSurface.h"
#include "include/private/SkTArray.h"
#include "include/private/SkTHash.h"
#include "src/core/SkSpan.h"
#include "src/gpu/GrBufferAllocPool.h"
#include "src/gpu/GrDeferredUpload.h"
#include "src/gpu/GrHashMapWithCache.h"
#include "src/gpu/GrPathRenderer.h"
#include "src/gpu/GrPathRendererChain.h"
#include "src/gpu/GrResourceCache.h"
#include "src/gpu/GrSurfaceProxy.h"

// Enabling this will print out which path renderers are being chosen
#define GR_PATH_RENDERER_SPEW 0

class GrCoverageCountingPathRenderer;
class GrGpuBuffer;
class GrOnFlushCallbackObject;
class GrOpFlushState;
class GrOpsTask;
class GrRecordingContext;
class GrRenderTargetContext;
class GrRenderTargetProxy;
class GrRenderTask;
class GrSemaphore;
class GrSoftwarePathRenderer;
class GrSurfaceContext;
class GrSurfaceProxyView;
class GrTextureResolveRenderTask;
class SkDeferredDisplayList;

class GrDrawingManager {
public:
    ~GrDrawingManager();

    void freeGpuResources();

    // A managed opsTask is controlled by the drawing manager (i.e., sorted & flushed with the
    // others). An unmanaged one is created and used by the onFlushCallback.
    sk_sp<GrOpsTask> newOpsTask(GrSurfaceProxyView, bool managedOpsTask);

    // Create a render task that can resolve MSAA and/or regenerate mipmap levels on proxies. This
    // method will only add the new render task to the list. It is up to the caller to call
    // addProxy() on the returned object.
    GrTextureResolveRenderTask* newTextureResolveRenderTask(const GrCaps&);

    // Create a new render task that will cause the gpu to wait on semaphores before executing any
    // more RenderTasks that target proxy. It is possible for this wait to also block additional
    // work (even to other proxies) that has already been recorded or will be recorded later. The
    // only guarantee is that future work to the passed in proxy will wait on the semaphores to be
    // signaled.
    void newWaitRenderTask(sk_sp<GrSurfaceProxy> proxy,
                           std::unique_ptr<std::unique_ptr<GrSemaphore>[]>,
                           int numSemaphores);

    // Create a new render task which copies the pixels from the srcProxy into the dstBuffer. This
    // is used to support the asynchronous readback API. The srcRect is the region of the srcProxy
    // to be copied. The surfaceColorType says how we should interpret the data when reading back
    // from the source. DstColorType describes how the data should be stored in the dstBuffer.
    // DstOffset is the offset into the dstBuffer where we will start writing data.
    void newTransferFromRenderTask(sk_sp<GrSurfaceProxy> srcProxy, const SkIRect& srcRect,
                                   GrColorType surfaceColorType, GrColorType dstColorType,
                                   sk_sp<GrGpuBuffer> dstBuffer, size_t dstOffset);

    // Creates a new render task which copies a pixel rectangle from srcView into dstView. The src
    // pixels copied are specified by srcRect. They are copied to a rect of the same size in
    // dstProxy with top left at dstPoint. If the src rect is clipped by the src bounds then  pixel
    // values in the dst rect corresponding to the area clipped by the src rect are not overwritten.
    // This method is not guaranteed to succeed depending on the type of surface, formats, etc, and
    // the backend-specific limitations.
    bool newCopyRenderTask(GrSurfaceProxyView srcView, const SkIRect& srcRect,
                           GrSurfaceProxyView dstView, const SkIPoint& dstPoint);

    GrRecordingContext* getContext() { return fContext; }

    GrPathRenderer* getPathRenderer(const GrPathRenderer::CanDrawPathArgs& args,
                                    bool allowSW,
                                    GrPathRendererChain::DrawType drawType,
                                    GrPathRenderer::StencilSupport* stencilSupport = nullptr);

    GrPathRenderer* getSoftwarePathRenderer();

    // Returns a direct pointer to the coverage counting path renderer, or null if it is not
    // supported and turned on.
    GrCoverageCountingPathRenderer* getCoverageCountingPathRenderer();

    void flushIfNecessary();

    static bool ProgramUnitTest(GrDirectContext*, int maxStages, int maxLevels);

    GrSemaphoresSubmitted flushSurfaces(SkSpan<GrSurfaceProxy*>,
                                        SkSurface::BackendSurfaceAccess,
                                        const GrFlushInfo&,
                                        const GrBackendSurfaceMutableState* newState);

    void addOnFlushCallbackObject(GrOnFlushCallbackObject*);

#if GR_TEST_UTILS
    void testingOnly_removeOnFlushCallbackObject(GrOnFlushCallbackObject*);
    GrPathRendererChain::Options testingOnly_getOptionsForPathRendererChain() {
        return fOptionsForPathRendererChain;
    }
#endif

    GrRenderTask* getLastRenderTask(const GrSurfaceProxy*) const;
    GrOpsTask* getLastOpsTask(const GrSurfaceProxy*) const;
    void setLastRenderTask(const GrSurfaceProxy*, GrRenderTask*);

    void moveRenderTasksToDDL(SkDeferredDisplayList* ddl);
    void copyRenderTasksFromDDL(sk_sp<const SkDeferredDisplayList>, GrRenderTargetProxy* newDest);

private:
    // This class encapsulates maintenance and manipulation of the drawing manager's DAG of
    // renderTasks.
    class RenderTaskDAG {
    public:
        // This call will topologically sort the GrRenderTasks.
        void prepForFlush();

        void closeAll(const GrCaps* caps);

        void gatherIDs(SkSTArray<8, uint32_t, true>* idArray) const;

        void reset();

        // This call forceably removes GrRenderTasks from the DAG. It is problematic bc it
        // just removes the GrRenderTasks but doesn't cleanup any referring pointers (i.e.
        // dependency pointers in the DAG). It works right now bc it is only called after the
        // topological sort is complete (so the dangling pointers aren't used).
        void rawRemoveRenderTasks(int startIndex, int stopIndex);

        bool empty() const { return fRenderTasks.empty(); }
        int numRenderTasks() const { return fRenderTasks.count(); }

        bool isUsed(GrSurfaceProxy*) const;

        GrRenderTask* renderTask(int index) { return fRenderTasks[index].get(); }
        const GrRenderTask* renderTask(int index) const { return fRenderTasks[index].get(); }

        GrRenderTask* back() { return fRenderTasks.back().get(); }
        const GrRenderTask* back() const { return fRenderTasks.back().get(); }

        GrRenderTask* add(sk_sp<GrRenderTask>);
        GrRenderTask* addBeforeLast(sk_sp<GrRenderTask>);
        void add(const SkTArray<sk_sp<GrRenderTask>>&);

        void swap(SkTArray<sk_sp<GrRenderTask>>* renderTasks);

    private:
        SkTArray<sk_sp<GrRenderTask>> fRenderTasks;
    };

    GrDrawingManager(GrRecordingContext*,
                     const GrPathRendererChain::Options&,
                     bool reduceOpsTaskSplitting);

    bool wasAbandoned() const;

    // Closes the target's dependent render tasks (or, if not in sorting/opsTask-splitting-reduction
    // mode, closes fActiveOpsTask) in preparation for us opening a new opsTask that will write to
    // 'target'.
    void closeRenderTasksForNewRenderTask(GrSurfaceProxy* target);

    // return true if any GrRenderTasks were actually executed; false otherwise
    bool executeRenderTasks(int startIndex, int stopIndex, GrOpFlushState*,
                            int* numRenderTasksExecuted);

    void removeRenderTasks(int startIndex, int stopIndex);

    bool flush(SkSpan<GrSurfaceProxy*> proxies,
               SkSurface::BackendSurfaceAccess access,
               const GrFlushInfo&,
               const GrBackendSurfaceMutableState* newState);

    bool submitToGpu(bool syncToCpu);

    SkDEBUGCODE(void validate() const);

    friend class GrDirectContext; // access to: flush & cleanup
    friend class GrDirectContextPriv; // access to: flush
    friend class GrOnFlushResourceProvider; // this is just a shallow wrapper around this class
    friend class GrRecordingContext;  // access to: ctor
    friend class SkImage; // for access to: flush

    static const int kNumPixelGeometries = 5; // The different pixel geometries
    static const int kNumDFTOptions = 2;      // DFT or no DFT

    GrRecordingContext*               fContext;
    GrPathRendererChain::Options      fOptionsForPathRendererChain;

    // This cache is used by both the vertex and index pools. It reuses memory across multiple
    // flushes.
    sk_sp<GrBufferAllocPool::CpuBufferCache> fCpuBufferCache;

    RenderTaskDAG                     fDAG;
    GrOpsTask*                        fActiveOpsTask = nullptr;
    // These are the IDs of the opsTask currently being flushed (in internalFlush)
    SkSTArray<8, uint32_t, true>      fFlushingRenderTaskIDs;
    // These are the new renderTasks generated by the onFlush CBs
    SkSTArray<4, sk_sp<GrRenderTask>> fOnFlushRenderTasks;

    std::unique_ptr<GrPathRendererChain> fPathRendererChain;
    sk_sp<GrSoftwarePathRenderer>     fSoftwarePathRenderer;

    GrTokenTracker                    fTokenTracker;
    bool                              fFlushing;
    const bool                        fReduceOpsTaskSplitting;

    SkTArray<GrOnFlushCallbackObject*> fOnFlushCBObjects;

    void addDDLTarget(GrSurfaceProxy* newTarget, GrRenderTargetProxy* ddlTarget) {
        fDDLTargets.set(newTarget->uniqueID().asUInt(), ddlTarget);
    }
    bool isDDLTarget(GrSurfaceProxy* newTarget) {
        return SkToBool(fDDLTargets.find(newTarget->uniqueID().asUInt()));
    }
    GrRenderTargetProxy* getDDLTarget(GrSurfaceProxy* newTarget) {
        auto entry = fDDLTargets.find(newTarget->uniqueID().asUInt());
        return entry ? *entry : nullptr;
    }
    void clearDDLTargets() { fDDLTargets.reset(); }

    // We play a trick with lazy proxies to retarget the base target of a DDL to the SkSurface
    // it is replayed on. 'fDDLTargets' stores this mapping from SkSurface unique proxy ID
    // to the DDL's lazy proxy.
    // Note: we do not expect a whole lot of these per flush
    SkTHashMap<uint32_t, GrRenderTargetProxy*> fDDLTargets;

    struct SurfaceIDKeyTraits {
        static uint32_t GetInvalidKey() {
            return GrSurfaceProxy::UniqueID::InvalidID().asUInt();
        }
    };

    GrHashMapWithCache<uint32_t, GrRenderTask*, SurfaceIDKeyTraits, GrCheapHash> fLastRenderTasks;
};

#endif