1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
** the names of its contributors may be used to endorse or promote
** products derived from this software without specific prior written
** permission.
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
** $QT_END_LICENSE$
**
****************************************************************************/
#include "geometryengine.h"
#include <QVector2D>
#include <QVector3D>
struct VertexData
{
QVector3D position;
QVector2D texCoord;
};
GeometryEngine::GeometryEngine() : vboIds(new GLuint[2])
{
}
GeometryEngine::~GeometryEngine()
{
glDeleteBuffers(2, vboIds);
delete[] vboIds;
}
void GeometryEngine::init()
{
initializeGLFunctions();
//! [0]
// Generate 2 VBOs
glGenBuffers(2, vboIds);
//! [0]
// Initializes cube geometry and transfers it to VBOs
initCubeGeometry();
}
void GeometryEngine::initCubeGeometry()
{
// For cube we would need only 8 vertices but we have to
// duplicate vertex for each face because texture coordinate
// is different.
VertexData vertices[] = {
// Vertex data for face 0
{QVector3D(-1.0, -1.0, 1.0), QVector2D(0.0, 0.0)}, // v0
{QVector3D( 1.0, -1.0, 1.0), QVector2D(0.33, 0.0)}, // v1
{QVector3D(-1.0, 1.0, 1.0), QVector2D(0.0, 0.5)}, // v2
{QVector3D( 1.0, 1.0, 1.0), QVector2D(0.33, 0.5)}, // v3
// Vertex data for face 1
{QVector3D( 1.0, -1.0, 1.0), QVector2D( 0.0, 0.5)}, // v4
{QVector3D( 1.0, -1.0, -1.0), QVector2D(0.33, 0.5)}, // v5
{QVector3D( 1.0, 1.0, 1.0), QVector2D(0.0, 1.0)}, // v6
{QVector3D( 1.0, 1.0, -1.0), QVector2D(0.33, 1.0)}, // v7
// Vertex data for face 2
{QVector3D( 1.0, -1.0, -1.0), QVector2D(0.66, 0.5)}, // v8
{QVector3D(-1.0, -1.0, -1.0), QVector2D(1.0, 0.5)}, // v9
{QVector3D( 1.0, 1.0, -1.0), QVector2D(0.66, 1.0)}, // v10
{QVector3D(-1.0, 1.0, -1.0), QVector2D(1.0, 1.0)}, // v11
// Vertex data for face 3
{QVector3D(-1.0, -1.0, -1.0), QVector2D(0.66, 0.0)}, // v12
{QVector3D(-1.0, -1.0, 1.0), QVector2D(1.0, 0.0)}, // v13
{QVector3D(-1.0, 1.0, -1.0), QVector2D(0.66, 0.5)}, // v14
{QVector3D(-1.0, 1.0, 1.0), QVector2D(1.0, 0.5)}, // v15
// Vertex data for face 4
{QVector3D(-1.0, -1.0, -1.0), QVector2D(0.33, 0.0)}, // v16
{QVector3D( 1.0, -1.0, -1.0), QVector2D(0.66, 0.0)}, // v17
{QVector3D(-1.0, -1.0, 1.0), QVector2D(0.33, 0.5)}, // v18
{QVector3D( 1.0, -1.0, 1.0), QVector2D(0.66, 0.5)}, // v19
// Vertex data for face 5
{QVector3D(-1.0, 1.0, 1.0), QVector2D(0.33, 0.5)}, // v20
{QVector3D( 1.0, 1.0, 1.0), QVector2D(0.66, 0.5)}, // v21
{QVector3D(-1.0, 1.0, -1.0), QVector2D(0.33, 1.0)}, // v22
{QVector3D( 1.0, 1.0, -1.0), QVector2D(0.66, 1.0)} // v23
};
// Indices for drawing cube faces using triangle strips.
// Triangle strips can be connected by duplicating indices
// between the strips. If connecting strips have opposite
// vertex order then last index of the first strip and first
// index of the second strip needs to be duplicated. If
// connecting strips have same vertex order then only last
// index of the first strip needs to be duplicated.
GLushort indices[] = {
0, 1, 2, 3, 3, // Face 0 - triangle strip ( v0, v1, v2, v3)
4, 4, 5, 6, 7, 7, // Face 1 - triangle strip ( v4, v5, v6, v7)
8, 8, 9, 10, 11, 11, // Face 2 - triangle strip ( v8, v9, v10, v11)
12, 12, 13, 14, 15, 15, // Face 3 - triangle strip (v12, v13, v14, v15)
16, 16, 17, 18, 19, 19, // Face 4 - triangle strip (v16, v17, v18, v19)
20, 20, 21, 22, 23 // Face 5 - triangle strip (v20, v21, v22, v23)
};
//! [1]
// Transfer vertex data to VBO 0
glBindBuffer(GL_ARRAY_BUFFER, vboIds[0]);
glBufferData(GL_ARRAY_BUFFER, 24 * sizeof(VertexData), vertices, GL_STATIC_DRAW);
// Transfer index data to VBO 1
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vboIds[1]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, 34 * sizeof(GLushort), indices, GL_STATIC_DRAW);
//! [1]
}
//! [2]
void GeometryEngine::drawCubeGeometry(QGLShaderProgram *program)
{
// Tell OpenGL which VBOs to use
glBindBuffer(GL_ARRAY_BUFFER, vboIds[0]);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vboIds[1]);
// Offset for position
int offset = 0;
// Tell OpenGL programmable pipeline how to locate vertex position data
int vertexLocation = program->attributeLocation("a_position");
program->enableAttributeArray(vertexLocation);
glVertexAttribPointer(vertexLocation, 3, GL_FLOAT, GL_FALSE, sizeof(VertexData), (const void *)offset);
// Offset for texture coordinate
offset += sizeof(QVector3D);
// Tell OpenGL programmable pipeline how to locate vertex texture coordinate data
int texcoordLocation = program->attributeLocation("a_texcoord");
program->enableAttributeArray(texcoordLocation);
glVertexAttribPointer(texcoordLocation, 2, GL_FLOAT, GL_FALSE, sizeof(VertexData), (const void *)offset);
// Draw cube geometry using indices from VBO 1
glDrawElements(GL_TRIANGLE_STRIP, 34, GL_UNSIGNED_SHORT, 0);
}
//! [2]
|
