GradientCache.cpp revision ca89e2a68703bd428e8b66547d033a6ed35b3595 
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
21#include "Caches.h"
22#include "Debug.h"
23#include "GradientCache.h"
24#include "Properties.h"
25
26namespace android {
27namespace uirenderer {
28
29///////////////////////////////////////////////////////////////////////////////
30// Defines
31///////////////////////////////////////////////////////////////////////////////
32
33#define GRADIENT_TEXTURE_HEIGHT 2
34#define GRADIENT_BYTES_PER_PIXEL 4
35
36///////////////////////////////////////////////////////////////////////////////
37// Functions
38///////////////////////////////////////////////////////////////////////////////
39
40template<typename T>
41static inline T min(T a, T b) {
42    return a < b ? a : b;
43}
44
45///////////////////////////////////////////////////////////////////////////////
46// Cache entry
47///////////////////////////////////////////////////////////////////////////////
48
49hash_t GradientCacheEntry::hash() const {
50    uint32_t hash = JenkinsHashMix(0, count);
51    for (uint32_t i = 0; i < count; i++) {
52        hash = JenkinsHashMix(hash, android::hash_type(colors[i]));
53        hash = JenkinsHashMix(hash, android::hash_type(positions[i]));
54    }
55    return JenkinsHashWhiten(hash);
56}
57
58int GradientCacheEntry::compare(const GradientCacheEntry& lhs, const GradientCacheEntry& rhs) {
59    int deltaInt = int(lhs.count) - int(rhs.count);
60    if (deltaInt != 0) return deltaInt;
61
62    deltaInt = memcmp(lhs.colors, rhs.colors, lhs.count * sizeof(uint32_t));
63    if (deltaInt != 0) return deltaInt;
64
65    return memcmp(lhs.positions, rhs.positions, lhs.count * sizeof(float));
66}
67
68///////////////////////////////////////////////////////////////////////////////
69// Constructors/destructor
70///////////////////////////////////////////////////////////////////////////////
71
72GradientCache::GradientCache():
73        mCache(LruCache<GradientCacheEntry, Texture*>::kUnlimitedCapacity),
74        mSize(0), mMaxSize(MB(DEFAULT_GRADIENT_CACHE_SIZE)) {
75    char property[PROPERTY_VALUE_MAX];
76    if (property_get(PROPERTY_GRADIENT_CACHE_SIZE, property, NULL) > 0) {
77        INIT_LOGD("  Setting gradient cache size to %sMB", property);
78        setMaxSize(MB(atof(property)));
79    } else {
80        INIT_LOGD("  Using default gradient cache size of %.2fMB", DEFAULT_GRADIENT_CACHE_SIZE);
81    }
82
83    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &mMaxTextureSize);
84
85    mCache.setOnEntryRemovedListener(this);
86}
87
88GradientCache::GradientCache(uint32_t maxByteSize):
89        mCache(LruCache<GradientCacheEntry, Texture*>::kUnlimitedCapacity),
90        mSize(0), mMaxSize(maxByteSize) {
91    mCache.setOnEntryRemovedListener(this);
92}
93
94GradientCache::~GradientCache() {
95    mCache.clear();
96}
97
98///////////////////////////////////////////////////////////////////////////////
99// Size management
100///////////////////////////////////////////////////////////////////////////////
101
102uint32_t GradientCache::getSize() {
103    return mSize;
104}
105
106uint32_t GradientCache::getMaxSize() {
107    return mMaxSize;
108}
109
110void GradientCache::setMaxSize(uint32_t maxSize) {
111    mMaxSize = maxSize;
112    while (mSize > mMaxSize) {
113        mCache.removeOldest();
114    }
115}
116
117///////////////////////////////////////////////////////////////////////////////
118// Callbacks
119///////////////////////////////////////////////////////////////////////////////
120
121void GradientCache::operator()(GradientCacheEntry& shader, Texture*& texture) {
122    if (texture) {
123        const uint32_t size = texture->width * texture->height * GRADIENT_BYTES_PER_PIXEL;
124        mSize -= size;
125
126        glDeleteTextures(1, &texture->id);
127        delete texture;
128    }
129}
130
131///////////////////////////////////////////////////////////////////////////////
132// Caching
133///////////////////////////////////////////////////////////////////////////////
134
135Texture* GradientCache::get(uint32_t* colors, float* positions, int count) {
136    GradientCacheEntry gradient(colors, positions, count);
137    Texture* texture = mCache.get(gradient);
138
139    if (!texture) {
140        texture = addLinearGradient(gradient, colors, positions, count);
141    }
142
143    return texture;
144}
145
146void GradientCache::clear() {
147    mCache.clear();
148}
149
150void GradientCache::getGradientInfo(const uint32_t* colors, const int count,
151        GradientInfo& info) {
152    uint32_t width = 256 * (count - 1);
153
154    if (!Extensions::getInstance().hasNPot()) {
155        width = 1 << (31 - __builtin_clz(width));
156    }
157
158    bool hasAlpha = false;
159    for (int i = 0; i < count; i++) {
160        if (((colors[i] >> 24) & 0xff) < 255) {
161            hasAlpha = true;
162            break;
163        }
164    }
165
166    info.width = min(width, uint32_t(mMaxTextureSize));
167    info.hasAlpha = hasAlpha;
168}
169
170Texture* GradientCache::addLinearGradient(GradientCacheEntry& gradient,
171        uint32_t* colors, float* positions, int count) {
172
173    GradientInfo info;
174    getGradientInfo(colors, count, info);
175
176    Texture* texture = new Texture;
177    texture->width = info.width;
178    texture->height = GRADIENT_TEXTURE_HEIGHT;
179    texture->blend = info.hasAlpha;
180    texture->generation = 1;
181
182    // Asume the cache is always big enough
183    const uint32_t size = texture->width * texture->height * GRADIENT_BYTES_PER_PIXEL;
184    while (getSize() + size > mMaxSize) {
185        mCache.removeOldest();
186    }
187
188    generateTexture(colors, positions, count, texture);
189
190    mSize += size;
191    mCache.put(gradient, texture);
192
193    return texture;
194}
195
196void GradientCache::generateTexture(uint32_t* colors, float* positions,
197        int count, Texture* texture) {
198
199    const uint32_t width = texture->width;
200    const GLsizei rowBytes = width * GRADIENT_BYTES_PER_PIXEL;
201    uint32_t pixels[width * texture->height];
202
203    int currentPos = 1;
204
205    float startA = (colors[0] >> 24) & 0xff;
206    float startR = (colors[0] >> 16) & 0xff;
207    float startG = (colors[0] >>  8) & 0xff;
208    float startB = (colors[0] >>  0) & 0xff;
209
210    float endA = (colors[1] >> 24) & 0xff;
211    float endR = (colors[1] >> 16) & 0xff;
212    float endG = (colors[1] >>  8) & 0xff;
213    float endB = (colors[1] >>  0) & 0xff;
214
215    float start = positions[0];
216    float distance = positions[1] - start;
217
218    uint8_t* p = (uint8_t*) pixels;
219    for (uint32_t x = 0; x < width; x++) {
220        float pos = x / float(width - 1);
221        if (pos > positions[currentPos]) {
222            startA = endA;
223            startR = endR;
224            startG = endG;
225            startB = endB;
226            start = positions[currentPos];
227
228            currentPos++;
229
230            endA = (colors[currentPos] >> 24) & 0xff;
231            endR = (colors[currentPos] >> 16) & 0xff;
232            endG = (colors[currentPos] >>  8) & 0xff;
233            endB = (colors[currentPos] >>  0) & 0xff;
234            distance = positions[currentPos] - start;
235        }
236
237        float amount = (pos - start) / distance;
238        float oppAmount = 1.0f - amount;
239
240        const float alpha = startA * oppAmount + endA * amount;
241        const float a = alpha / 255.0f;
242        *p++ = uint8_t(a * (startR * oppAmount + endR * amount));
243        *p++ = uint8_t(a * (startG * oppAmount + endG * amount));
244        *p++ = uint8_t(a * (startB * oppAmount + endB * amount));
245        *p++ = uint8_t(alpha);
246    }
247
248    for (int i = 1; i < GRADIENT_TEXTURE_HEIGHT; i++) {
249        memcpy(pixels + width * i, pixels, rowBytes);
250    }
251
252    glGenTextures(1, &texture->id);
253
254    glBindTexture(GL_TEXTURE_2D, texture->id);
255    glPixelStorei(GL_UNPACK_ALIGNMENT, GRADIENT_BYTES_PER_PIXEL);
256
257    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, texture->height, 0,
258            GL_RGBA, GL_UNSIGNED_BYTE, pixels);
259
260    texture->setFilter(GL_LINEAR);
261    texture->setWrap(GL_CLAMP_TO_EDGE);
262}
263
264}; // namespace uirenderer
265}; // namespace android
266