/*
* 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();
/**
* Gets the number of preallocated buffers that are yet to be used.
*/
int preallocatedBuffersRemaining() const;
/**
* gets the number of preallocated buffers
*/
int preallocatedBufferCount() const;
/**
* Frees data from makeSpaces in LIFO order.
*/
void putBack(size_t bytes);
/**
* Gets the GrGpu that this pool is associated with.
*/
GrGpu* getGpu() { return fGpu; }
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 frequentResetHint A hint that indicates that the pool
* should expect frequent unmap() calls
* (as opposed to many makeSpace / acquires
* between resets).
* @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,
bool frequentResetHint,
size_t bufferSize = 0,
int preallocBufferCnt = 0);
virtual ~GrBufferAllocPool();
/**
* Gets the size of the preallocated buffers.
*
* @return the size of preallocated buffers.
*/
size_t preallocatedBufferSize() const {
return fPreallocBuffers.count() ? fMinBlockSize : 0;
}
/**
* 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);
/**
* Gets the number of items of a size that can be added to the current
* buffer without spilling to another buffer. If the pool has been reset, or
* the previous makeSpace completely exhausted a buffer then the returned
* size will be the size of the next available preallocated buffer, or zero
* if no preallocated buffer remains available. It is assumed that items
* should be itemSize-aligned from the start of a buffer.
*
* @return the number of items that would fit in the current buffer.
*/
int currentBufferItems(size_t itemSize) const;
GrGeometryBuffer* createBuffer(size_t size);
private:
// The GrGpu must be able to clear the ref of pools it creates as members
friend class GrGpu;
void releaseGpuRef();
struct BufferBlock {
size_t fBytesFree;
GrGeometryBuffer* fBuffer;
};
bool createBlock(size_t requestSize);
void destroyBlock();
void flushCpuData(GrGeometryBuffer* buffer, size_t flushSize);
#ifdef SK_DEBUG
void validate(bool unusedBlockAllowed = false) const;
#endif
size_t fBytesInUse;
GrGpu* fGpu;
bool fGpuIsReffed;
bool fFrequentResetHint;
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 frequentResetHint A hint that indicates that the pool
* should expect frequent unmap() calls
* (as opposed to many makeSpace / acquires
* between resets).
* @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,
bool frequentResetHint,
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);
/**
* Shortcut to make space and then write verts into the made space.
*/
bool appendVertices(size_t vertexSize,
int vertexCount,
const void* vertices,
const GrVertexBuffer** buffer,
int* startVertex);
/**
* Gets the number of vertices that can be added to the current VB without
* spilling to another VB. If the pool has been reset, or the previous
* makeSpace completely exhausted a VB then the returned number of vertices
* would fit in the next available preallocated buffer. If any makeSpace
* would force a new VB to be created the return value will be zero.
*
* @param the size of a vertex to compute space for.
* @return the number of vertices that would fit in the current buffer.
*/
int currentBufferVertices(size_t vertexSize) const;
/**
* Gets the number of vertices that can fit in a preallocated vertex buffer.
* Zero if no preallocated buffers.
*
* @param the size of a vertex to compute space for.
*
* @return number of vertices that fit in one of the preallocated vertex
* buffers.
*/
int preallocatedBufferVertices(size_t vertexSize) const;
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 frequentResetHint A hint that indicates that the pool
* should expect frequent unmap() calls
* (as opposed to many makeSpace / acquires
* between resets).
* @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,
bool frequentResetHint,
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);
/**
* Shortcut to make space and then write indices into the made space.
*/
bool appendIndices(int indexCount,
const void* indices,
const GrIndexBuffer** buffer,
int* startIndex);
/**
* Gets the number of indices that can be added to the current IB without
* spilling to another IB. If the pool has been reset, or the previous
* makeSpace completely exhausted a IB then the returned number of indices
* would fit in the next available preallocated buffer. If any makeSpace
* would force a new IB to be created the return value will be zero.
*/
int currentBufferIndices() const;
/**
* Gets the number of indices that can fit in a preallocated index buffer.
* Zero if no preallocated buffers.
*
* @return number of indices that fit in one of the preallocated index
* buffers.
*/
int preallocatedBufferIndices() const;
private:
typedef GrBufferAllocPool INHERITED;
};
#endif