GradientCache.cpp revision 15a65bfee5b0a98664eb5ebadad63c73e2c471f8 
1/*
2 * Copyright (C) 2010 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#define LOG_TAG "OpenGLRenderer"
18
19#include <utils/JenkinsHash.h>
20#include <utils/threads.h>
21
22#include "Caches.h"
23#include "Debug.h"
24#include "GradientCache.h"
25#include "Properties.h"
26
27namespace android {
28namespace uirenderer {
29
30///////////////////////////////////////////////////////////////////////////////
31// Defines
32///////////////////////////////////////////////////////////////////////////////
33
34#define GRADIENT_TEXTURE_HEIGHT 2
35#define GRADIENT_BYTES_PER_PIXEL 4
36
37///////////////////////////////////////////////////////////////////////////////
38// Functions
39///////////////////////////////////////////////////////////////////////////////
40
41template<typename T>
42static inline T min(T a, T b) {
43    return a < b ? a : b;
44}
45
46///////////////////////////////////////////////////////////////////////////////
47// Cache entry
48///////////////////////////////////////////////////////////////////////////////
49
50hash_t GradientCacheEntry::hash() const {
51    uint32_t hash = JenkinsHashMix(0, count);
52    for (uint32_t i = 0; i < count; i++) {
53        hash = JenkinsHashMix(hash, android::hash_type(colors[i]));
54        hash = JenkinsHashMix(hash, android::hash_type(positions[i]));
55    }
56    return JenkinsHashWhiten(hash);
57}
58
59int GradientCacheEntry::compare(const GradientCacheEntry& lhs, const GradientCacheEntry& rhs) {
60    int deltaInt = int(lhs.count) - int(rhs.count);
61    if (deltaInt != 0) return deltaInt;
62
63    deltaInt = memcmp(lhs.colors, rhs.colors, lhs.count * sizeof(uint32_t));
64    if (deltaInt != 0) return deltaInt;
65
66    return memcmp(lhs.positions, rhs.positions, lhs.count * sizeof(float));
67}
68
69///////////////////////////////////////////////////////////////////////////////
70// Constructors/destructor
71///////////////////////////////////////////////////////////////////////////////
72
73GradientCache::GradientCache():
74        mCache(LruCache<GradientCacheEntry, Texture*>::kUnlimitedCapacity),
75        mSize(0), mMaxSize(MB(DEFAULT_GRADIENT_CACHE_SIZE)) {
76    char property[PROPERTY_VALUE_MAX];
77    if (property_get(PROPERTY_GRADIENT_CACHE_SIZE, property, NULL) > 0) {
78        INIT_LOGD("  Setting gradient cache size to %sMB", property);
79        setMaxSize(MB(atof(property)));
80    } else {
81        INIT_LOGD("  Using default gradient cache size of %.2fMB", DEFAULT_GRADIENT_CACHE_SIZE);
82    }
83
84    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &mMaxTextureSize);
85
86    mCache.setOnEntryRemovedListener(this);
87}
88
89GradientCache::GradientCache(uint32_t maxByteSize):
90        mCache(LruCache<GradientCacheEntry, Texture*>::kUnlimitedCapacity),
91        mSize(0), mMaxSize(maxByteSize) {
92    mCache.setOnEntryRemovedListener(this);
93}
94
95GradientCache::~GradientCache() {
96    mCache.clear();
97}
98
99///////////////////////////////////////////////////////////////////////////////
100// Size management
101///////////////////////////////////////////////////////////////////////////////
102
103uint32_t GradientCache::getSize() {
104    return mSize;
105}
106
107uint32_t GradientCache::getMaxSize() {
108    return mMaxSize;
109}
110
111void GradientCache::setMaxSize(uint32_t maxSize) {
112    mMaxSize = maxSize;
113    while (mSize > mMaxSize) {
114        mCache.removeOldest();
115    }
116}
117
118///////////////////////////////////////////////////////////////////////////////
119// Callbacks
120///////////////////////////////////////////////////////////////////////////////
121
122void GradientCache::operator()(GradientCacheEntry& shader, Texture*& texture) {
123    if (texture) {
124        const uint32_t size = texture->width * texture->height * GRADIENT_BYTES_PER_PIXEL;
125        mSize -= size;
126
127        glDeleteTextures(1, &texture->id);
128        delete texture;
129    }
130}
131
132///////////////////////////////////////////////////////////////////////////////
133// Caching
134///////////////////////////////////////////////////////////////////////////////
135
136Texture* GradientCache::get(uint32_t* colors, float* positions, int count) {
137    GradientCacheEntry gradient(colors, positions, count);
138    Texture* texture = mCache.get(gradient);
139
140    if (!texture) {
141        texture = addLinearGradient(gradient, colors, positions, count);
142    }
143
144    return texture;
145}
146
147void GradientCache::clear() {
148    mCache.clear();
149}
150
151void GradientCache::getGradientInfo(const uint32_t* colors, const int count,
152        GradientInfo& info) {
153    uint32_t width = 256 * (count - 1);
154
155    if (!Caches::getInstance().extensions.hasNPot()) {
156        width = 1 << (31 - __builtin_clz(width));
157    }
158
159    bool hasAlpha = false;
160    for (int i = 0; i < count; i++) {
161        if (((colors[i] >> 24) & 0xff) < 255) {
162            hasAlpha = true;
163            break;
164        }
165    }
166
167    info.width = min(width, uint32_t(mMaxTextureSize));
168    info.hasAlpha = hasAlpha;
169}
170
171Texture* GradientCache::addLinearGradient(GradientCacheEntry& gradient,
172        uint32_t* colors, float* positions, int count) {
173
174    GradientInfo info;
175    getGradientInfo(colors, count, info);
176
177    Texture* texture = new Texture;
178    texture->width = info.width;
179    texture->height = GRADIENT_TEXTURE_HEIGHT;
180    texture->blend = info.hasAlpha;
181    texture->generation = 1;
182
183    // Asume the cache is always big enough
184    const uint32_t size = texture->width * texture->height * GRADIENT_BYTES_PER_PIXEL;
185    while (getSize() + size > mMaxSize) {
186        mCache.removeOldest();
187    }
188
189    generateTexture(colors, positions, count, texture);
190
191    mSize += size;
192    mCache.put(gradient, texture);
193
194    return texture;
195}
196
197void GradientCache::generateTexture(uint32_t* colors, float* positions,
198        int count, Texture* texture) {
199
200    const uint32_t width = texture->width;
201    const GLsizei rowBytes = width * GRADIENT_BYTES_PER_PIXEL;
202    uint32_t pixels[width * texture->height];
203
204    int currentPos = 1;
205
206    float startA = (colors[0] >> 24) & 0xff;
207    float startR = (colors[0] >> 16) & 0xff;
208    float startG = (colors[0] >>  8) & 0xff;
209    float startB = (colors[0] >>  0) & 0xff;
210
211    float endA = (colors[1] >> 24) & 0xff;
212    float endR = (colors[1] >> 16) & 0xff;
213    float endG = (colors[1] >>  8) & 0xff;
214    float endB = (colors[1] >>  0) & 0xff;
215
216    float start = positions[0];
217    float distance = positions[1] - start;
218
219    uint8_t* p = (uint8_t*) pixels;
220    for (uint32_t x = 0; x < width; x++) {
221        float pos = x / float(width - 1);
222        if (pos > positions[currentPos]) {
223            startA = endA;
224            startR = endR;
225            startG = endG;
226            startB = endB;
227            start = positions[currentPos];
228
229            currentPos++;
230
231            endA = (colors[currentPos] >> 24) & 0xff;
232            endR = (colors[currentPos] >> 16) & 0xff;
233            endG = (colors[currentPos] >>  8) & 0xff;
234            endB = (colors[currentPos] >>  0) & 0xff;
235            distance = positions[currentPos] - start;
236        }
237
238        float amount = (pos - start) / distance;
239        float oppAmount = 1.0f - amount;
240
241        const float alpha = startA * oppAmount + endA * amount;
242        const float a = alpha / 255.0f;
243        *p++ = uint8_t(a * (startR * oppAmount + endR * amount));
244        *p++ = uint8_t(a * (startG * oppAmount + endG * amount));
245        *p++ = uint8_t(a * (startB * oppAmount + endB * amount));
246        *p++ = uint8_t(alpha);
247    }
248
249    for (int i = 1; i < GRADIENT_TEXTURE_HEIGHT; i++) {
250        memcpy(pixels + width * i, pixels, rowBytes);
251    }
252
253    glGenTextures(1, &texture->id);
254
255    glBindTexture(GL_TEXTURE_2D, texture->id);
256    glPixelStorei(GL_UNPACK_ALIGNMENT, GRADIENT_BYTES_PER_PIXEL);
257
258    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, texture->height, 0,
259            GL_RGBA, GL_UNSIGNED_BYTE, pixels);
260
261    texture->setFilter(GL_LINEAR);
262    texture->setWrap(GL_CLAMP_TO_EDGE);
263}
264
265}; // namespace uirenderer
266}; // namespace android
267