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/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrGeometryBuffer_DEFINED
#define GrGeometryBuffer_DEFINED
#include "GrGpuObject.h"
class GrGpu;
/**
* Parent class for vertex and index buffers
*/
class GrGeometryBuffer : public GrGpuObject {
public:
SK_DECLARE_INST_COUNT(GrGeometryBuffer);
/**
*Retrieves whether the buffer was created with the dynamic flag
*
* @return true if the buffer was created with the dynamic flag
*/
bool dynamic() const { return fDynamic; }
/**
* Returns true if the buffer is a wrapper around a CPU array. If true it
* indicates that map will always succeed and will be free.
*/
bool isCPUBacked() const { return fCPUBacked; }
/**
* Maps the buffer to be written by the CPU.
*
* The previous content of the buffer is invalidated. It is an error
* to draw from the buffer while it is mapped. It is an error to call map
* on an already mapped buffer. It may fail if the backend doesn't support
* mapping the buffer. If the buffer is CPU backed then it will always
* succeed and is a free operation. Must be matched by an unmap() call.
* Currently only one map at a time is supported (no nesting of
* map/unmap).
*
* Note that buffer mapping does not go through GrContext and therefore is
* not serialized with other operations.
*
* @return a pointer to the data or NULL if the map fails.
*/
void* map() { return (fMapPtr = this->onMap()); }
/**
* Unmaps the buffer.
*
* The pointer returned by the previous map call will no longer be valid.
*/
void unmap() {
SkASSERT(NULL != fMapPtr);
this->onUnmap();
fMapPtr = NULL;
}
/**
* Returns the same ptr that map() returned at time of map or NULL if the
* is not mapped.
*
* @return ptr to mapped buffer data or NULL if buffer is not mapped.
*/
void* mapPtr() const { return fMapPtr; }
/**
Queries whether the buffer has been mapped.
@return true if the buffer is mapped, false otherwise.
*/
bool isMapped() const { return NULL != fMapPtr; }
/**
* Updates the buffer data.
*
* The size of the buffer will be preserved. The src data will be
* placed at the beginning of the buffer and any remaining contents will
* be undefined. srcSizeInBytes must be <= to the buffer size.
*
* The buffer must not be mapped.
*
* Note that buffer updates do not go through GrContext and therefore are
* not serialized with other operations.
*
* @return returns true if the update succeeds, false otherwise.
*/
bool updateData(const void* src, size_t srcSizeInBytes) {
SkASSERT(!this->isMapped());
SkASSERT(srcSizeInBytes <= fGpuMemorySize);
return this->onUpdateData(src, srcSizeInBytes);
}
// GrGpuObject overrides
virtual size_t gpuMemorySize() const { return fGpuMemorySize; }
protected:
GrGeometryBuffer(GrGpu* gpu, bool isWrapped, size_t gpuMemorySize, bool dynamic, bool cpuBacked)
: INHERITED(gpu, isWrapped)
, fMapPtr(NULL)
, fGpuMemorySize(gpuMemorySize)
, fDynamic(dynamic)
, fCPUBacked(cpuBacked) {}
private:
virtual void* onMap() = 0;
virtual void onUnmap() = 0;
virtual bool onUpdateData(const void* src, size_t srcSizeInBytes) = 0;
void* fMapPtr;
size_t fGpuMemorySize;
bool fDynamic;
bool fCPUBacked;
typedef GrGpuObject INHERITED;
};
#endif