OffscreenBufferPool.h revision 7435eb148e72382126e9073183e881357bb38a8b 
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 "Caches.h"
21#include "Texture.h"
22#include "utils/Macros.h"
23
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 {
44public:
45    OffscreenBuffer(RenderState& renderState, Caches& caches,
46            uint32_t viewportWidth, uint32_t viewportHeight);
47    ~OffscreenBuffer();
48
49    Rect getTextureCoordinates();
50
51    // must be called prior to rendering, to construct/update vertex buffer
52    void updateMeshFromRegion();
53
54    // Set by RenderNode for HW layers, TODO for clipped saveLayers
55    void setWindowTransform(const Matrix4& transform) {
56        inverseTransformInWindow.loadInverse(transform);
57    }
58
59    static uint32_t computeIdealDimension(uint32_t dimension);
60
61    uint32_t getSizeInBytes() { return texture.width * texture.height * 4; }
62
63    RenderState& renderState;
64
65    uint32_t viewportWidth;
66    uint32_t viewportHeight;
67    Texture texture;
68
69    // Portion of layer that has been drawn to. Used to minimize drawing area when
70    // drawing back to screen / parent FBO.
71    Region region;
72
73    Matrix4 inverseTransformInWindow;
74
75    // vbo / size of mesh
76    GLsizei elementCount = 0;
77    GLuint vbo = 0;
78};
79
80/**
81 * Pool of OffscreenBuffers allocated, but not currently in use.
82 */
83class OffscreenBufferPool {
84public:
85    OffscreenBufferPool();
86    ~OffscreenBufferPool();
87
88    WARN_UNUSED_RESULT OffscreenBuffer* get(RenderState& renderState,
89            const uint32_t width, const uint32_t height);
90
91    WARN_UNUSED_RESULT OffscreenBuffer* resize(OffscreenBuffer* layer,
92            const uint32_t width, const uint32_t height);
93
94    void putOrDelete(OffscreenBuffer* layer);
95
96    /**
97     * Clears the pool. This causes all layers to be deleted.
98     */
99    void clear();
100
101    /**
102     * Returns the maximum size of the pool in bytes.
103     */
104    uint32_t getMaxSize() { return mMaxSize; }
105
106    /**
107     * Returns the current size of the pool in bytes.
108     */
109    uint32_t getSize() { return mSize; }
110
111    size_t getCount() { return mPool.size(); }
112
113    /**
114     * Prints out the content of the pool.
115     */
116    void dump();
117private:
118    struct Entry {
119        Entry() {}
120
121        Entry(const uint32_t layerWidth, const uint32_t layerHeight)
122                : width(OffscreenBuffer::computeIdealDimension(layerWidth))
123                , height(OffscreenBuffer::computeIdealDimension(layerHeight)) {}
124
125        Entry(OffscreenBuffer* layer)
126                : layer(layer)
127                , width(layer->texture.width)
128                , height(layer->texture.height) {
129        }
130
131        static int compare(const Entry& lhs, const Entry& rhs);
132
133        bool operator==(const Entry& other) const {
134            return compare(*this, other) == 0;
135        }
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 Entry::compare(*this, other) < 0;
143        }
144
145        OffscreenBuffer* layer = nullptr;
146        uint32_t width = 0;
147        uint32_t height = 0;
148    }; // struct Entry
149
150    std::multiset<Entry> mPool;
151
152    uint32_t mSize = 0;
153    uint32_t mMaxSize;
154}; // class OffscreenBufferCache
155
156}; // namespace uirenderer
157}; // namespace android
158
159#endif // ANDROID_HWUI_OFFSCREEN_BUFFER_POOL_H
160