OffscreenBufferPool.h revision 37413289478a965336239c731ebfea37ac4dde28 
1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ANDROID_HWUI_OFFSCREEN_BUFFER_POOL_H
18#define ANDROID_HWUI_OFFSCREEN_BUFFER_POOL_H
19
20#include <GpuMemoryTracker.h>
21#include "Caches.h"
22#include "Texture.h"
23#include "utils/Macros.h"
24#include <ui/Region.h>
25
26#include <set>
27
28namespace android {
29namespace uirenderer {
30
31class RenderState;
32
33/**
34 * Lightweight alternative to Layer. Owns the persistent state of an offscreen render target, and
35 * encompasses enough information to draw it back on screen (minus paint properties, which are held
36 * by LayerOp).
37 *
38 * Has two distinct sizes - viewportWidth/viewportHeight describe content area,
39 * texture.width/.height are actual allocated texture size. Texture will tend to be larger than the
40 * viewport bounds, since textures are always allocated with width / height as a multiple of 64, for
41 * the purpose of improving reuse.
42 */
43class OffscreenBuffer : GpuMemoryTracker {
44public:
45    OffscreenBuffer(RenderState& renderState, Caches& caches,
46            uint32_t viewportWidth, uint32_t viewportHeight);
47    ~OffscreenBuffer();
48
49    Rect getTextureCoordinates();
50
51    void dirty(Rect dirtyArea);
52
53    // must be called prior to rendering, to construct/update vertex buffer
54    void updateMeshFromRegion();
55
56    // Set by RenderNode for HW layers, TODO for clipped saveLayers
57    void setWindowTransform(const Matrix4& transform) {
58        inverseTransformInWindow.loadInverse(transform);
59    }
60
61    static uint32_t computeIdealDimension(uint32_t dimension);
62
63    uint32_t getSizeInBytes() { return texture.objectSize(); }
64
65    RenderState& renderState;
66
67    uint32_t viewportWidth;
68    uint32_t viewportHeight;
69    Texture texture;
70
71    // Portion of layer that has been drawn to. Used to minimize drawing area when
72    // drawing back to screen / parent FBO.
73    Region region;
74
75    Matrix4 inverseTransformInWindow;
76
77    // vbo / size of mesh
78    GLsizei elementCount = 0;
79    GLuint vbo = 0;
80
81    bool hasRenderedSinceRepaint;
82};
83
84/**
85 * Pool of OffscreenBuffers allocated, but not currently in use.
86 */
87class OffscreenBufferPool {
88public:
89    OffscreenBufferPool();
90    ~OffscreenBufferPool();
91
92    WARN_UNUSED_RESULT OffscreenBuffer* get(RenderState& renderState,
93            const uint32_t width, const uint32_t height);
94
95    WARN_UNUSED_RESULT OffscreenBuffer* resize(OffscreenBuffer* layer,
96            const uint32_t width, const uint32_t height);
97
98    void putOrDelete(OffscreenBuffer* layer);
99
100    /**
101     * Clears the pool. This causes all layers to be deleted.
102     */
103    void clear();
104
105    /**
106     * Returns the maximum size of the pool in bytes.
107     */
108    uint32_t getMaxSize() { return mMaxSize; }
109
110    /**
111     * Returns the current size of the pool in bytes.
112     */
113    uint32_t getSize() { return mSize; }
114
115    size_t getCount() { return mPool.size(); }
116
117    /**
118     * Prints out the content of the pool.
119     */
120    void dump();
121private:
122    struct Entry {
123        Entry() {}
124
125        Entry(const uint32_t layerWidth, const uint32_t layerHeight)
126                : width(OffscreenBuffer::computeIdealDimension(layerWidth))
127                , height(OffscreenBuffer::computeIdealDimension(layerHeight)) {}
128
129        Entry(OffscreenBuffer* layer)
130                : layer(layer)
131                , width(layer->texture.width())
132                , height(layer->texture.height()) {
133        }
134
135        static int compare(const Entry& lhs, const Entry& rhs);
136
137        bool operator==(const Entry& other) const {
138            return compare(*this, other) == 0;
139        }
140
141        bool operator!=(const Entry& other) const {
142            return compare(*this, other) != 0;
143        }
144
145        bool operator<(const Entry& other) const {
146            return Entry::compare(*this, other) < 0;
147        }
148
149        OffscreenBuffer* layer = nullptr;
150        uint32_t width = 0;
151        uint32_t height = 0;
152    }; // struct Entry
153
154    std::multiset<Entry> mPool;
155
156    uint32_t mSize = 0;
157    uint32_t mMaxSize;
158}; // class OffscreenBufferCache
159
160}; // namespace uirenderer
161}; // namespace android
162
163#endif // ANDROID_HWUI_OFFSCREEN_BUFFER_POOL_H
164