Patch.cpp revision 5b3b35296e8b2c8d3f07d32bb645d5414db41a1d 
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
29///////////////////////////////////////////////////////////////////////////////
30// Constructors/destructor
31///////////////////////////////////////////////////////////////////////////////
32
33Patch::Patch(const uint32_t xCount, const uint32_t yCount, const int8_t emptyQuads) {
34    // 2 triangles per patch, 3 vertices per triangle
35    verticesCount = ((xCount + 1) * (yCount + 1) - emptyQuads) * 2 * 3;
36    mVertices = new TextureVertex[verticesCount];
37    hasEmptyQuads = emptyQuads > 0;
38
39    glGenBuffers(1, &meshBuffer);
40}
41
42Patch::~Patch() {
43    delete[] mVertices;
44    glDeleteBuffers(1, &meshBuffer);
45}
46
47///////////////////////////////////////////////////////////////////////////////
48// Vertices management
49///////////////////////////////////////////////////////////////////////////////
50
51void Patch::updateVertices(const float bitmapWidth, const float bitmapHeight,
52        float left, float top, float right, float bottom,
53        const int32_t* xDivs, const int32_t* yDivs,
54        const uint32_t width, const uint32_t height, const uint32_t colorKey) {
55    if (hasEmptyQuads) quads.clear();
56
57    const uint32_t xStretchCount = (width + 1) >> 1;
58    const uint32_t yStretchCount = (height + 1) >> 1;
59
60    float stretchX = 0.0f;
61    float stretchY = 0.0;
62
63    const float meshWidth = right - left;
64
65    if (xStretchCount > 0) {
66        uint32_t stretchSize = 0;
67        for (uint32_t i = 1; i < width; i += 2) {
68            stretchSize += xDivs[i] - xDivs[i - 1];
69        }
70        const float xStretchTex = stretchSize;
71        const float fixed = bitmapWidth - stretchSize;
72        const float xStretch = right - left - fixed;
73        stretchX = xStretch / xStretchTex;
74    }
75
76    if (yStretchCount > 0) {
77        uint32_t stretchSize = 0;
78        for (uint32_t i = 1; i < height; i += 2) {
79            stretchSize += yDivs[i] - yDivs[i - 1];
80        }
81        const float yStretchTex = stretchSize;
82        const float fixed = bitmapHeight - stretchSize;
83        const float yStretch = bottom - top - fixed;
84        stretchY = yStretch / yStretchTex;
85    }
86
87    TextureVertex* vertex = mVertices;
88    uint32_t quadCount = 0;
89
90    float previousStepY = 0.0f;
91
92    float y1 = 0.0f;
93    float v1 = 0.0f;
94
95    for (uint32_t i = 0; i < height; i++) {
96        float stepY = yDivs[i];
97
98        float y2 = 0.0f;
99        if (i & 1) {
100            const float segment = stepY - previousStepY;
101            y2 = y1 + segment * stretchY;
102        } else {
103            y2 = y1 + stepY - previousStepY;
104        }
105        float v2 = fmax(0.0f, stepY - 0.5f) / bitmapHeight;
106
107        generateRow(vertex, y1, y2, v1, v2, xDivs, width, stretchX,
108                right - left, bitmapWidth, quadCount, colorKey);
109
110        y1 = y2;
111        v1 = (stepY + 0.5f) / bitmapHeight;
112
113        previousStepY = stepY;
114    }
115
116    generateRow(vertex, y1, bottom - top, v1, 1.0f, xDivs, width, stretchX,
117            right - left, bitmapWidth, quadCount, colorKey);
118
119    Caches::getInstance().bindMeshBuffer(meshBuffer);
120    glBufferData(GL_ARRAY_BUFFER, sizeof(TextureVertex) * verticesCount,
121                mVertices, GL_STATIC_DRAW);
122}
123
124void Patch::generateRow(TextureVertex*& vertex, float y1, float y2, float v1, float v2,
125        const int32_t xDivs[], uint32_t xCount, float stretchX, float width, float bitmapWidth,
126        uint32_t& quadCount, const uint32_t colorKey) {
127    float previousStepX = 0.0f;
128
129    float x1 = 0.0f;
130    float u1 = 0.0f;
131
132    // Generate the row quad by quad
133    for (uint32_t i = 0; i < xCount; i++) {
134        float stepX = xDivs[i];
135
136        float x2 = 0.0f;
137        if (i & 1) {
138            const float segment = stepX - previousStepX;
139            x2 = x1 + segment * stretchX;
140        } else {
141            x2 = x1 + stepX - previousStepX;
142        }
143        float u2 = fmax(0.0f, stepX - 0.5f) / bitmapWidth;
144
145        generateQuad(vertex, x1, y1, x2, y2, u1, v1, u2, v2, quadCount, colorKey);
146
147        x1 = x2;
148        u1 = (stepX + 0.5f) / bitmapWidth;
149
150        previousStepX = stepX;
151    }
152
153    generateQuad(vertex, x1, y1, width, y2, u1, v1, 1.0f, v2, quadCount, colorKey);
154}
155
156void Patch::generateQuad(TextureVertex*& vertex, float x1, float y1, float x2, float y2,
157            float u1, float v1, float u2, float v2, uint32_t& quadCount, const uint32_t colorKey) {
158    if (((colorKey >> quadCount++) & 0x1) == 1) {
159        return;
160    }
161
162    if (hasEmptyQuads) {
163        Rect bounds(x1, y1, x2, y2);
164        quads.add(bounds);
165    }
166
167    // Left triangle
168    TextureVertex::set(vertex++, x1, y1, u1, v1);
169    TextureVertex::set(vertex++, x2, y1, u2, v1);
170    TextureVertex::set(vertex++, x1, y2, u1, v2);
171
172    // Right triangle
173    TextureVertex::set(vertex++, x1, y2, u1, v2);
174    TextureVertex::set(vertex++, x2, y1, u2, v1);
175    TextureVertex::set(vertex++, x2, y2, u2, v2);
176}
177
178}; // namespace uirenderer
179}; // namespace android
180