android/rendering/TransferQueue.h

/*
 * Copyright 2011, The Android Open Source Project
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef TransferQueue_h
#define TransferQueue_h

#if USE(ACCELERATED_COMPOSITING)

#include "GLUtils.h"
#include "ShaderProgram.h"
#include "SkBitmap.h"
#include <utils/StrongPointer.h>
#include <utils/threads.h>

namespace WebCore {

class Tile;
class TilePainter;
class TileTexture;

struct GLState {
    GLint bufferId[1];
    GLint viewport[4];
    GLboolean scissor[1];
    GLboolean depth[1];
    GLfloat clearColor[4];
};


// While in the queue, the Tile can be re-used, the updated bitmap
// can be discarded. In order to track this obsolete base tiles, we save
// the Tile's Info to make the comparison.
// At the time of base tile's dtor or webview destroy, we want to discard
// all the data in the queue. However, we have to do the Surface Texture
// update in the same GL context as the UI thread. So we mark the status
// as pendingDiscard, and delay the Surface Texture operation to the next
// draw call.

enum TransferItemStatus {
    emptyItem = 0, // S.T. buffer ready for new content
    pendingBlit = 1, // Ready for bliting into tile's GL Tex.
    pendingDiscard = 2 // Waiting for the next draw call to discard
};

enum TextureUploadType {
    CpuUpload = 0,
    GpuUpload = 1
};

#define DEFAULT_UPLOAD_TYPE GpuUpload

class TileTransferData {
public:
    TileTransferData()
    : status(emptyItem)
    , savedTilePtr(0)
    , savedTilePainter(0)
    , savedTileTexturePtr(0)
    , uploadType(DEFAULT_UPLOAD_TYPE)
    , bitmap(0)
    {
    }

    ~TileTransferData()
    {
        // Bitmap will be created lazily, need to delete them at dtor.
        delete bitmap;
    }

    TransferItemStatus status;
    Tile* savedTilePtr;
    TilePainter* savedTilePainter; // Ref count the tilePainter to keep the tile alive.
    TileTexture* savedTileTexturePtr;
    TextureUploadType uploadType;
    // This is only useful in Cpu upload code path, so it will be dynamically
    // lazily allocated.
    SkBitmap* bitmap;

    // Specific data to the pure color tiles' queue.
    Color pureColor;
};

class TransferQueue {
public:
    TransferQueue(bool useMinimalMem);
    ~TransferQueue();

    // This will be called by the browser through nativeSetProperty
    void setTextureUploadType(TextureUploadType type);
    void updateDirtyTiles();

    void initGLResources(int width, int height);

    // insert the bitmap into the queue, mark the tile dirty if failing
    void updateQueueWithBitmap(const TileRenderInfo* renderInfo,
                               const SkBitmap& bitmap);

    void addItemInTransferQueue(const TileRenderInfo* info,
                                TextureUploadType type,
                                const SkBitmap* bitmap);
    // Check if the item @ index is ready for update.
    // The lock will be done when returning true.
    bool readyForUpdate();

    void lockQueue() { m_transferQueueItemLocks.lock(); }
    void unlockQueue() { m_transferQueueItemLocks.unlock(); }

    void addItemInPureColorQueue(const TileRenderInfo* renderInfo);

    void cleanupGLResourcesAndQueue();

    bool needsInit() { return !m_sharedSurfaceTextureId; }
    void resetQueue();
    // This queue can be accessed from UI and TexGen thread, therefore, we need
    // a lock to protect its access
    TileTransferData* m_transferQueue;

    android::sp<ANativeWindow> m_ANW;

    // EGL wrapper around m_ANW for use by the GaneshRenderer
    EGLSurface m_eglSurface;

private:
    // return true if successfully inserted into queue
    bool tryUpdateQueueWithBitmap(const TileRenderInfo* renderInfo,
                                  const SkBitmap& bitmap);
    bool getHasGLContext();
    void setHasGLContext(bool hasContext);
    void emptyAndAbandonQueue();

    int getNextTransferQueueIndex();

    // Save and restore the GL State while switching from/to FBO.
    void saveGLState();
    void setGLStateForCopy(int width, int height);
    void restoreGLState();

    // Check the current transfer queue item is obsolete or not.
    bool checkObsolete(const TileTransferData* data);

    void setPendingDiscard();
    // Before each draw call and the blit operation, clean up all the
    // pendingDiscard items.
    void cleanupPendingDiscard();
    void cleanupGLResources();

    void blitTileFromQueue(GLuint fboID, TileTexture* destTex,
                           GLuint srcTexId, GLenum srcTexTarget,
                           int index);

    void clearItemInTranferQueue(int index);
    void addItemCommon(const TileRenderInfo* renderInfo,
                       TextureUploadType type, TileTransferData* data);

    void updatePureColorTiles();
    void clearPureColorQueue();
    // Note that the m_transferQueueIndex only changed in the TexGen thread
    // where we are going to move on to update the next item in the queue.
    int m_transferQueueIndex;

    GLuint m_fboID; // The FBO used for copy the SurfTex to each tile

    GLuint m_sharedSurfaceTextureId;

    // GLContext can be lost when WebView destroyed.
    bool m_hasGLContext;

    GLState m_GLStateBeforeBlit;
    android::sp<android::SurfaceTexture> m_sharedSurfaceTexture;

    int m_emptyItemCount;

    // We are using wait/signal to handle our own queue sync.
    // First of all, if we don't have our own lock, then while WebView is
    // destroyed, the UI thread will wait for the Tex Gen to get out from
    // dequeue operation, which will not succeed. B/c at this moment, we
    // already lost the GL Context.
    // Now we maintain a counter, which is m_emptyItemCount. When this reach
    // 0, then we need the Tex Gen thread to wait. UI thread can signal this
    // wait after calling updateTexImage at the draw call , or after WebView
    // is destroyed.
    android::Mutex m_transferQueueItemLocks;
    android::Condition m_transferQueueItemCond;

    EGLDisplay m_currentDisplay;

    // This should be GpuUpload for production, but for debug purpose or working
    // around driver/HW issue, we can set it to CpuUpload.
    TextureUploadType m_currentUploadType;

    // The non-pure-color tile are 1 to 1 mapping with Surface Texture which is
    // resource limited. To get better performance, it is better to separate
    // the pure color tile into another queue.
    WTF::Vector<TileTransferData> m_pureColorTileQueue;

    // The number of items transfer queue can buffer up.
    int m_transferQueueSize;
};

} // namespace WebCore

#endif // USE(ACCELERATED_COMPOSITING)
#endif // TransferQueue_h