GrBuffer.h

/*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef GrBuffer_DEFINED
#define GrBuffer_DEFINED

#include "GrGpuResource.h"

class GrGpu;

class GrBuffer : public GrGpuResource {
public:
    static SK_WARN_UNUSED_RESULT GrBuffer* CreateCPUBacked(GrGpu*, size_t sizeInBytes, GrBufferType,
                                                           const void* data = nullptr);

    static void ComputeScratchKeyForDynamicVBO(size_t size, GrBufferType, GrScratchKey*);

    GrAccessPattern accessPattern() const { return fAccessPattern; }
    size_t sizeInBytes() const { return fSizeInBytes; }

    bool isCPUBacked() const { return SkToBool(fCPUData); }
    size_t baseOffset() const { return reinterpret_cast<size_t>(fCPUData); }

     void* map() {
         if (!fMapPtr) {
             this->onMap();
         }
         return fMapPtr;
     }

     void unmap() {
         SkASSERT(fMapPtr);
         this->onUnmap();
         fMapPtr = nullptr;
     }

     void* mapPtr() const { return fMapPtr; }

     bool isMapped() const { return SkToBool(fMapPtr); }

    bool updateData(const void* src, size_t srcSizeInBytes) {
        SkASSERT(!this->isMapped());
        SkASSERT(srcSizeInBytes <= fSizeInBytes);
        return this->onUpdateData(src, srcSizeInBytes);
    }

    ~GrBuffer() override {
        sk_free(fCPUData);
    }

protected:
    GrBuffer(GrGpu*, size_t sizeInBytes, GrBufferType, GrAccessPattern);

    void* fMapPtr;

private:
    GrBuffer(GrGpu*, size_t sizeInBytes, GrBufferType, void* cpuData);

    virtual void onMap() { SkASSERT(this->isCPUBacked()); fMapPtr = fCPUData; }
    virtual void onUnmap() { SkASSERT(this->isCPUBacked()); }
    virtual bool onUpdateData(const void* src, size_t srcSizeInBytes);

    size_t onGpuMemorySize() const override { return fSizeInBytes; } // TODO: zero for cpu backed?
    void computeScratchKey(GrScratchKey* key) const override;

    size_t            fSizeInBytes;
    GrAccessPattern   fAccessPattern;
    void*             fCPUData;
    GrBufferType      fIntendedType;

    typedef GrGpuResource INHERITED;
};

#endif