GrGeometryBuffer.h revision 8341eb76fbc54593e873f5589961e02793e7f15f 
1
2/*
3 * Copyright 2011 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10#ifndef GrGeometryBuffer_DEFINED
11#define GrGeometryBuffer_DEFINED
12
13#include "GrGpuObject.h"
14
15class GrGpu;
16
17/**
18 * Parent class for vertex and index buffers
19 */
20class GrGeometryBuffer : public GrGpuObject {
21public:
22    SK_DECLARE_INST_COUNT(GrGeometryBuffer);
23
24    /**
25     *Retrieves whether the buffer was created with the dynamic flag
26     *
27     * @return true if the buffer was created with the dynamic flag
28     */
29    bool dynamic() const { return fDynamic; }
30
31    /**
32     * Returns true if the buffer is a wrapper around a CPU array. If true it
33     * indicates that map will always succeed and will be free.
34     */
35    bool isCPUBacked() const { return fCPUBacked; }
36
37    /**
38     * Maps the buffer to be written by the CPU.
39     *
40     * The previous content of the buffer is invalidated. It is an error
41     * to draw from the buffer while it is mapped. It is an error to call map
42     * on an already mapped buffer. It may fail if the backend doesn't support
43     * mapping the buffer. If the buffer is CPU backed then it will always
44     * succeed and is a free operation. Must be matched by an unmap() call.
45     * Currently only one map at a time is supported (no nesting of
46     * map/unmap).
47     *
48     * @return a pointer to the data or NULL if the map fails.
49     */
50    virtual void* map() = 0;
51
52    /**
53     * Returns the same ptr that map() returned at time of map or NULL if the
54     * is not mapped.
55     *
56     * @return ptr to mapped buffer data or undefined if buffer is not mapped.
57     */
58    virtual void* mapPtr() const = 0;
59
60    /**
61     * Unmaps the buffer.
62     *
63     * The pointer returned by the previous map call will no longer be valid.
64     */
65    virtual void unmap() = 0;
66
67    /**
68     Queries whether the buffer has been mapped.
69
70     @return true if the buffer is mapped, false otherwise.
71     */
72    virtual bool isMapped() const = 0;
73
74    /**
75     * Updates the buffer data.
76     *
77     * The size of the buffer will be preserved. The src data will be
78     * placed at the beginning of the buffer and any remaining contents will
79     * be undefined.
80     *
81     * @return returns true if the update succeeds, false otherwise.
82     */
83    virtual bool updateData(const void* src, size_t srcSizeInBytes) = 0;
84
85    // GrGpuObject overrides
86    virtual size_t gpuMemorySize() const { return fGpuMemorySize; }
87
88protected:
89    GrGeometryBuffer(GrGpu* gpu, bool isWrapped, size_t gpuMemorySize, bool dynamic, bool cpuBacked)
90        : INHERITED(gpu, isWrapped)
91        , fGpuMemorySize(gpuMemorySize)
92        , fDynamic(dynamic)
93        , fCPUBacked(cpuBacked) {}
94
95private:
96    size_t   fGpuMemorySize;
97    bool     fDynamic;
98    bool     fCPUBacked;
99
100    typedef GrGpuObject INHERITED;
101};
102
103#endif
104