/*
* Copyright 2010 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrBufferAllocPool_DEFINED
#define GrBufferAllocPool_DEFINED
#include "SkTArray.h"
#include "SkTDArray.h"
#include "SkTypes.h"
class GrGeometryBuffer;
class GrGpu;
/**
* A pool of geometry buffers tied to a GrGpu.
*
* The pool allows a client to make space for geometry and then put back excess
* space if it over allocated. When a client is ready to draw from the pool
* it calls unmap on the pool ensure buffers are ready for drawing. The pool
* can be reset after drawing is completed to recycle space.
*
* At creation time a minimum per-buffer size can be specified. Additionally,
* a number of buffers to preallocate can be specified. These will
* be allocated at the min size and kept around until the pool is destroyed.
*/
class GrBufferAllocPool : SkNoncopyable {
public:
/**
* Ensures all buffers are unmapped and have all data written to them.
* Call before drawing using buffers from the pool.
*/
void unmap();
/**
* Invalidates all the data in the pool, unrefs non-preallocated buffers.
*/
void reset();
/**
* Frees data from makeSpaces in LIFO order.
*/
void putBack(size_t bytes);
protected:
/**
* Used to determine what type of buffers to create. We could make the
* createBuffer a virtual except that we want to use it in the cons for
* pre-allocated buffers.
*/
enum BufferType {
kVertex_BufferType,
kIndex_BufferType,
};
/**
* Constructor
*
* @param gpu The GrGpu used to create the buffers.
* @param bufferType The type of buffers to create.
* @param bufferSize The minimum size of created buffers.
* This value will be clamped to some
* reasonable minimum.
* @param preallocBufferCnt The pool will allocate this number of
* buffers at bufferSize and keep them until it
* is destroyed.
*/
GrBufferAllocPool(GrGpu* gpu,
BufferType bufferType,
size_t bufferSize = 0,
int preallocBufferCnt = 0);
virtual ~GrBufferAllocPool();
/**
* Returns a block of memory to hold data. A buffer designated to hold the
* data is given to the caller. The buffer may or may not be locked. The
* returned ptr remains valid until any of the following:
* *makeSpace is called again.
* *unmap is called.
* *reset is called.
* *this object is destroyed.
*
* Once unmap on the pool is called the data is guaranteed to be in the
* buffer at the offset indicated by offset. Until that time it may be
* in temporary storage and/or the buffer may be locked.
*
* @param size the amount of data to make space for
* @param alignment alignment constraint from start of buffer
* @param buffer returns the buffer that will hold the data.
* @param offset returns the offset into buffer of the data.
* @return pointer to where the client should write the data.
*/
void* makeSpace(size_t size,
size_t alignment,
const GrGeometryBuffer** buffer,
size_t* offset);
GrGeometryBuffer* createBuffer(size_t size);
private:
struct BufferBlock {
size_t fBytesFree;
GrGeometryBuffer* fBuffer;
};
bool createBlock(size_t requestSize);
void destroyBlock();
void flushCpuData(const BufferBlock& block, size_t flushSize);
#ifdef SK_DEBUG
void validate(bool unusedBlockAllowed = false) const;
#endif
size_t fBytesInUse;
GrGpu* fGpu;
SkTDArray<GrGeometryBuffer*> fPreallocBuffers;
size_t fMinBlockSize;
BufferType fBufferType;
SkTArray<BufferBlock> fBlocks;
int fPreallocBuffersInUse;
// We attempt to cycle through the preallocated buffers rather than
// always starting from the first.
int fPreallocBufferStartIdx;
SkAutoMalloc fCpuData;
void* fBufferPtr;
};
class GrVertexBuffer;
/**
* A GrBufferAllocPool of vertex buffers
*/
class GrVertexBufferAllocPool : public GrBufferAllocPool {
public:
/**
* Constructor
*
* @param gpu The GrGpu used to create the vertex buffers.
* @param bufferSize The minimum size of created VBs. This value
* will be clamped to some reasonable minimum.
* @param preallocBufferCnt The pool will allocate this number of VBs at
* bufferSize and keep them until it is
* destroyed.
*/
GrVertexBufferAllocPool(GrGpu* gpu, size_t bufferSize = 0, int preallocBufferCnt = 0);
/**
* Returns a block of memory to hold vertices. A buffer designated to hold
* the vertices given to the caller. The buffer may or may not be locked.
* The returned ptr remains valid until any of the following:
* *makeSpace is called again.
* *unmap is called.
* *reset is called.
* *this object is destroyed.
*
* Once unmap on the pool is called the vertices are guaranteed to be in
* the buffer at the offset indicated by startVertex. Until that time they
* may be in temporary storage and/or the buffer may be locked.
*
* @param vertexSize specifies size of a vertex to allocate space for
* @param vertexCount number of vertices to allocate space for
* @param buffer returns the vertex buffer that will hold the
* vertices.
* @param startVertex returns the offset into buffer of the first vertex.
* In units of the size of a vertex from layout param.
* @return pointer to first vertex.
*/
void* makeSpace(size_t vertexSize,
int vertexCount,
const GrVertexBuffer** buffer,
int* startVertex);
private:
typedef GrBufferAllocPool INHERITED;
};
class GrIndexBuffer;
/**
* A GrBufferAllocPool of index buffers
*/
class GrIndexBufferAllocPool : public GrBufferAllocPool {
public:
/**
* Constructor
*
* @param gpu The GrGpu used to create the index buffers.
* @param bufferSize The minimum size of created IBs. This value
* will be clamped to some reasonable minimum.
* @param preallocBufferCnt The pool will allocate this number of VBs at
* bufferSize and keep them until it is
* destroyed.
*/
GrIndexBufferAllocPool(GrGpu* gpu,
size_t bufferSize = 0,
int preallocBufferCnt = 0);
/**
* Returns a block of memory to hold indices. A buffer designated to hold
* the indices is given to the caller. The buffer may or may not be locked.
* The returned ptr remains valid until any of the following:
* *makeSpace is called again.
* *unmap is called.
* *reset is called.
* *this object is destroyed.
*
* Once unmap on the pool is called the indices are guaranteed to be in the
* buffer at the offset indicated by startIndex. Until that time they may be
* in temporary storage and/or the buffer may be locked.
*
* @param indexCount number of indices to allocate space for
* @param buffer returns the index buffer that will hold the indices.
* @param startIndex returns the offset into buffer of the first index.
* @return pointer to first index.
*/
void* makeSpace(int indexCount,
const GrIndexBuffer** buffer,
int* startIndex);
private:
typedef GrBufferAllocPool INHERITED;
};
#endif