OffscreenBufferPool.cpp revision 9fded232a9548a304e0145011df8849fba0dcda7 
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#include "OffscreenBufferPool.h"
18
19#include "Caches.h"
20#include "Properties.h"
21#include "renderstate/RenderState.h"
22#include "utils/FatVector.h"
23
24#include <utils/Log.h>
25
26#include <GLES2/gl2.h>
27
28namespace android {
29namespace uirenderer {
30
31////////////////////////////////////////////////////////////////////////////////
32// OffscreenBuffer
33////////////////////////////////////////////////////////////////////////////////
34
35OffscreenBuffer::OffscreenBuffer(RenderState& renderState, Caches& caches,
36        uint32_t viewportWidth, uint32_t viewportHeight)
37        : renderState(renderState)
38        , viewportWidth(viewportWidth)
39        , viewportHeight(viewportHeight)
40        , texture(caches) {
41    texture.width = computeIdealDimension(viewportWidth);
42    texture.height = computeIdealDimension(viewportHeight);
43    texture.blend = true;
44
45    caches.textureState().activateTexture(0);
46    glGenTextures(1, &texture.id);
47    caches.textureState().bindTexture(GL_TEXTURE_2D, texture.id);
48
49    texture.setWrap(GL_CLAMP_TO_EDGE, false, false, GL_TEXTURE_2D);
50    // not setting filter on texture, since it's set when drawing, based on transform
51
52    glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
53    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture.width, texture.height, 0,
54            GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
55}
56
57void OffscreenBuffer::updateMeshFromRegion() {
58    // avoid T-junctions as they cause artifacts in between the resultant
59    // geometry when complex transforms occur.
60    // TODO: generate the safeRegion only if necessary based on drawing transform
61    Region safeRegion = Region::createTJunctionFreeRegion(region);
62
63    size_t count;
64    const android::Rect* rects = safeRegion.getArray(&count);
65
66    const float texX = 1.0f / float(texture.width);
67    const float texY = 1.0f / float(texture.height);
68
69    FatVector<TextureVertex, 64> meshVector(count * 4); // uses heap if more than 64 vertices needed
70    TextureVertex* mesh = &meshVector[0];
71    for (size_t i = 0; i < count; i++) {
72        const android::Rect* r = &rects[i];
73
74        const float u1 = r->left * texX;
75        const float v1 = (viewportHeight - r->top) * texY;
76        const float u2 = r->right * texX;
77        const float v2 = (viewportHeight - r->bottom) * texY;
78
79        TextureVertex::set(mesh++, r->left, r->top, u1, v1);
80        TextureVertex::set(mesh++, r->right, r->top, u2, v1);
81        TextureVertex::set(mesh++, r->left, r->bottom, u1, v2);
82        TextureVertex::set(mesh++, r->right, r->bottom, u2, v2);
83    }
84    elementCount = count * 6;
85    renderState.meshState().genOrUpdateMeshBuffer(&vbo,
86            sizeof(TextureVertex) * count * 4,
87            &meshVector[0],
88            GL_DYNAMIC_DRAW); // TODO: GL_STATIC_DRAW if savelayer
89}
90
91uint32_t OffscreenBuffer::computeIdealDimension(uint32_t dimension) {
92    return uint32_t(ceilf(dimension / float(LAYER_SIZE)) * LAYER_SIZE);
93}
94
95OffscreenBuffer::~OffscreenBuffer() {
96    texture.deleteTexture();
97    renderState.meshState().deleteMeshBuffer(vbo);
98    elementCount = 0;
99    vbo = 0;
100}
101
102///////////////////////////////////////////////////////////////////////////////
103// OffscreenBufferPool
104///////////////////////////////////////////////////////////////////////////////
105
106OffscreenBufferPool::OffscreenBufferPool()
107    : mMaxSize(Properties::layerPoolSize) {
108}
109
110OffscreenBufferPool::~OffscreenBufferPool() {
111    clear(); // TODO: unique_ptr?
112}
113
114int OffscreenBufferPool::Entry::compare(const Entry& lhs, const Entry& rhs) {
115    int deltaInt = int(lhs.width) - int(rhs.width);
116    if (deltaInt != 0) return deltaInt;
117
118    return int(lhs.height) - int(rhs.height);
119}
120
121void OffscreenBufferPool::clear() {
122    for (auto entry : mPool) {
123        delete entry.layer;
124    }
125    mPool.clear();
126    mSize = 0;
127}
128
129OffscreenBuffer* OffscreenBufferPool::get(RenderState& renderState,
130        const uint32_t width, const uint32_t height) {
131    OffscreenBuffer* layer = nullptr;
132
133    Entry entry(width, height);
134    auto iter = mPool.find(entry);
135
136    if (iter != mPool.end()) {
137        entry = *iter;
138        mPool.erase(iter);
139
140        layer = entry.layer;
141        layer->viewportWidth = width;
142        layer->viewportHeight = height;
143        mSize -= layer->getSizeInBytes();
144    } else {
145        layer = new OffscreenBuffer(renderState, Caches::getInstance(), width, height);
146    }
147
148    return layer;
149}
150
151OffscreenBuffer* OffscreenBufferPool::resize(OffscreenBuffer* layer,
152        const uint32_t width, const uint32_t height) {
153    RenderState& renderState = layer->renderState;
154    if (layer->texture.width == OffscreenBuffer::computeIdealDimension(width)
155            && layer->texture.height == OffscreenBuffer::computeIdealDimension(height)) {
156        // resize in place
157        layer->viewportWidth = width;
158        layer->viewportHeight = height;
159        return layer;
160    }
161    putOrDelete(layer);
162    return get(renderState, width, height);
163}
164
165void OffscreenBufferPool::dump() {
166    for (auto entry : mPool) {
167        ALOGD("  Layer size %dx%d", entry.width, entry.height);
168    }
169}
170
171void OffscreenBufferPool::putOrDelete(OffscreenBuffer* layer) {
172    const uint32_t size = layer->getSizeInBytes();
173    // Don't even try to cache a layer that's bigger than the cache
174    if (size < mMaxSize) {
175        // TODO: Use an LRU
176        while (mSize + size > mMaxSize) {
177            OffscreenBuffer* victim = mPool.begin()->layer;
178            mSize -= victim->getSizeInBytes();
179            delete victim;
180            mPool.erase(mPool.begin());
181        }
182
183        // clear region, since it's no longer valid
184        layer->region.clear();
185
186        Entry entry(layer);
187
188        mPool.insert(entry);
189        mSize += size;
190    } else {
191        delete layer;
192    }
193}
194
195}; // namespace uirenderer
196}; // namespace android
197