Patch.cpp revision 2665b85b2bd08faabf7c520a622a0e4d3465245f 
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 <cmath>
20
21#include <utils/Log.h>
22
23#include "Patch.h"
24#include "Caches.h"
25
26namespace android {
27namespace uirenderer {
28
29class Caches;
30
31///////////////////////////////////////////////////////////////////////////////
32// Constructors/destructor
33///////////////////////////////////////////////////////////////////////////////
34
35Patch::Patch(const uint32_t xCount, const uint32_t yCount, const int8_t emptyQuads) {
36    // 2 triangles per patch, 3 vertices per triangle
37    verticesCount = ((xCount + 1) * (yCount + 1) - emptyQuads) * 2 * 3;
38    mVertices = new TextureVertex[verticesCount];
39
40    glGenBuffers(1, &meshBuffer);
41}
42
43Patch::~Patch() {
44    delete[] mVertices;
45    glDeleteBuffers(1, &meshBuffer);
46}
47
48///////////////////////////////////////////////////////////////////////////////
49// Vertices management
50///////////////////////////////////////////////////////////////////////////////
51
52void Patch::updateVertices(const float bitmapWidth, const float bitmapHeight,
53        float left, float top, float right, float bottom,
54        const int32_t* xDivs, const int32_t* yDivs,
55        const uint32_t width, const uint32_t height, const uint32_t colorKey) {
56    const uint32_t xStretchCount = (width + 1) >> 1;
57    const uint32_t yStretchCount = (height + 1) >> 1;
58
59    float stretchX = 0.0f;
60    float stretchY = 0.0;
61
62    const float meshWidth = right - left;
63
64    if (xStretchCount > 0) {
65        uint32_t stretchSize = 0;
66        for (uint32_t i = 1; i < width; i += 2) {
67            stretchSize += xDivs[i] - xDivs[i - 1];
68        }
69        const float xStretchTex = stretchSize;
70        const float fixed = bitmapWidth - stretchSize;
71        const float xStretch = right - left - fixed;
72        stretchX = xStretch / xStretchTex;
73    }
74
75    if (yStretchCount > 0) {
76        uint32_t stretchSize = 0;
77        for (uint32_t i = 1; i < height; i += 2) {
78            stretchSize += yDivs[i] - yDivs[i - 1];
79        }
80        const float yStretchTex = stretchSize;
81        const float fixed = bitmapHeight - stretchSize;
82        const float yStretch = bottom - top - fixed;
83        stretchY = yStretch / yStretchTex;
84    }
85
86    TextureVertex* vertex = mVertices;
87    uint32_t quadCount = 0;
88
89    float previousStepY = 0.0f;
90
91    float y1 = 0.0f;
92    float v1 = 0.0f;
93
94    for (uint32_t i = 0; i < height; i++) {
95        float stepY = yDivs[i];
96
97        float y2 = 0.0f;
98        if (i & 1) {
99            const float segment = stepY - previousStepY;
100            y2 = y1 + segment * stretchY;
101        } else {
102            y2 = y1 + stepY - previousStepY;
103        }
104        float v2 = fmax(0.0f, stepY - 0.5f) / bitmapHeight;
105
106        generateRow(vertex, y1, y2, v1, v2, xDivs, width, stretchX,
107                right - left, bitmapWidth, quadCount, colorKey);
108
109        y1 = y2;
110        v1 = (stepY + 0.5f) / bitmapHeight;
111
112        previousStepY = stepY;
113    }
114
115    generateRow(vertex, y1, bottom - top, v1, 1.0f, xDivs, width, stretchX,
116            right - left, bitmapWidth, quadCount, colorKey);
117
118    Caches::getInstance().bindMeshBuffer(meshBuffer);
119    glBufferData(GL_ARRAY_BUFFER, sizeof(TextureVertex) * verticesCount,
120                mVertices, GL_STATIC_DRAW);
121}
122
123inline void Patch::generateRow(TextureVertex*& vertex, float y1, float y2, float v1, float v2,
124        const int32_t xDivs[], uint32_t xCount, float stretchX, float width, float bitmapWidth,
125        uint32_t& quadCount, const uint32_t colorKey) {
126    float previousStepX = 0.0f;
127
128    float x1 = 0.0f;
129    float u1 = 0.0f;
130
131    // Generate the row quad by quad
132    for (uint32_t i = 0; i < xCount; i++) {
133        float stepX = xDivs[i];
134
135        float x2 = 0.0f;
136        if (i & 1) {
137            const float segment = stepX - previousStepX;
138            x2 = x1 + segment * stretchX;
139        } else {
140            x2 = x1 + stepX - previousStepX;
141        }
142        float u2 = fmax(0.0f, stepX - 0.5f) / bitmapWidth;
143
144        generateQuad(vertex, x1, y1, x2, y2, u1, v1, u2, v2, quadCount, colorKey);
145
146        x1 = x2;
147        u1 = (stepX + 0.5f) / bitmapWidth;
148
149        previousStepX = stepX;
150    }
151
152    generateQuad(vertex, x1, y1, width, y2, u1, v1, 1.0f, v2, quadCount, colorKey);
153}
154
155inline void Patch::generateQuad(TextureVertex*& vertex, float x1, float y1, float x2, float y2,
156            float u1, float v1, float u2, float v2, uint32_t& quadCount, const uint32_t colorKey) {
157    if (((colorKey >> quadCount++) & 0x1) == 1) {
158        return;
159    }
160
161    // Left triangle
162    TextureVertex::set(vertex++, x1, y1, u1, v1);
163    TextureVertex::set(vertex++, x2, y1, u2, v1);
164    TextureVertex::set(vertex++, x1, y2, u1, v2);
165
166    // Right triangle
167    TextureVertex::set(vertex++, x1, y2, u1, v2);
168    TextureVertex::set(vertex++, x2, y1, u2, v1);
169    TextureVertex::set(vertex++, x2, y2, u2, v2);
170}
171
172}; // namespace uirenderer
173}; // namespace android
174