blob: bd80666fd6d09aa69deaba9d6ea18b227142f34f [file] [log] [blame]
jvanverth73063dc2015-12-03 09:15:47 -08001
2/*
3 * Copyright 2015 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 GrTransferBuffer_DEFINED
11#define GrTransferBuffer_DEFINED
12
13#include "GrGpuResource.h"
14
15class GrTransferBuffer : public GrGpuResource {
16public:
17 /**
18 * Maps the buffer to be written by the CPU.
19 *
20 * The previous content of the buffer is invalidated. It is an error
21 * to transfer to or from the buffer while it is mapped. It is an error to
22 * call map on an already mapped buffer. Must be matched by an unmap() call.
23 * Currently only one map at a time is supported (no nesting of map/unmap).
24 *
25 * Note that buffer mapping does not go through GrContext and therefore is
26 * not serialized with other operations.
27 *
28 * @return a pointer to the data or nullptr if the map fails.
29 */
30 void* map() { return (fMapPtr = this->onMap()); }
31
32 /**
33 * Unmaps the buffer.
34 *
35 * The pointer returned by the previous map call will no longer be valid.
36 */
37 void unmap() {
38 SkASSERT(fMapPtr);
39 this->onUnmap();
40 fMapPtr = nullptr;
41 }
42
43 /**
44 * Returns the same ptr that map() returned at time of map or nullptr if the
45 * is not mapped.
46 *
47 * @return ptr to mapped buffer data or nullptr if buffer is not mapped.
48 */
49 void* mapPtr() const { return fMapPtr; }
50
51 /**
52 Queries whether the buffer has been mapped.
53
54 @return true if the buffer is mapped, false otherwise.
55 */
56 bool isMapped() const { return SkToBool(fMapPtr); }
57
58protected:
59 GrTransferBuffer(GrGpu* gpu, size_t gpuMemorySize)
60 : INHERITED(gpu, kUncached_LifeCycle)
61 , fGpuMemorySize(gpuMemorySize) {
62 }
63
64private:
65 virtual size_t onGpuMemorySize() const { return fGpuMemorySize; }
66
67 virtual void* onMap() = 0;
68 virtual void onUnmap() = 0;
69
70 void* fMapPtr;
71 size_t fGpuMemorySize;
72
73 typedef GrGpuResource INHERITED;
74};
75
76#endif