180 lines
7.2 KiB
C++
180 lines
7.2 KiB
C++
/****************************************************************************
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**
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** Copyright (C) 2016 The Qt Company Ltd.
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** Contact: https://www.qt.io/licensing/
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**
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** This file is part of the QtCore module of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:BSD$
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and The Qt Company. For licensing terms
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** and conditions see https://www.qt.io/terms-conditions. For further
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** information use the contact form at https://www.qt.io/contact-us.
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**
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** BSD License Usage
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** Alternatively, you may use this file under the terms of the BSD license
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** as follows:
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**
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** "Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions are
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** met:
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** * Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** * Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in
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** the documentation and/or other materials provided with the
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** distribution.
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** * Neither the name of The Qt Company Ltd nor the names of its
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** contributors may be used to endorse or promote products derived
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** from this software without specific prior written permission.
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**
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**
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** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#include "..\Header\GeometryEngine.h"
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#include <QVector2D>
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#include <QVector3D>
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struct VertexData
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{
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QVector3D position;
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QVector2D texCoord;
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};
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//! [0]
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GeometryEngine::GeometryEngine()
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: indexBuf(QOpenGLBuffer::IndexBuffer)
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{
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initializeOpenGLFunctions();
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// Generate 2 VBOs
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arrayBuf.create();
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indexBuf.create();
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// Initializes cube geometry and transfers it to VBOs
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initCubeGeometry();
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}
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GeometryEngine::~GeometryEngine()
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{
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arrayBuf.destroy();
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indexBuf.destroy();
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}
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//! [0]
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void GeometryEngine::initCubeGeometry()
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{
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// For cube we would need only 8 vertices but we have to
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// duplicate vertex for each face because texture coordinate
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// is different.
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VertexData vertices[] = {
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// Vertex data for face 0
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{QVector3D(-1.0f, -1.0f, 1.0f), QVector2D(0.0f, 0.0f)}, // v0
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{QVector3D( 1.0f, -1.0f, 1.0f), QVector2D(0.33f, 0.0f)}, // v1
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{QVector3D(-1.0f, 1.0f, 1.0f), QVector2D(0.0f, 0.5f)}, // v2
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{QVector3D( 1.0f, 1.0f, 1.0f), QVector2D(0.33f, 0.5f)}, // v3
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// Vertex data for face 1
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{QVector3D( 1.0f, -1.0f, 1.0f), QVector2D( 0.0f, 0.5f)}, // v4
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{QVector3D( 1.0f, -1.0f, -1.0f), QVector2D(0.33f, 0.5f)}, // v5
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{QVector3D( 1.0f, 1.0f, 1.0f), QVector2D(0.0f, 1.0f)}, // v6
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{QVector3D( 1.0f, 1.0f, -1.0f), QVector2D(0.33f, 1.0f)}, // v7
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// Vertex data for face 2
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{QVector3D( 1.0f, -1.0f, -1.0f), QVector2D(0.66f, 0.5f)}, // v8
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{QVector3D(-1.0f, -1.0f, -1.0f), QVector2D(1.0f, 0.5f)}, // v9
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{QVector3D( 1.0f, 1.0f, -1.0f), QVector2D(0.66f, 1.0f)}, // v10
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{QVector3D(-1.0f, 1.0f, -1.0f), QVector2D(1.0f, 1.0f)}, // v11
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// Vertex data for face 3
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{QVector3D(-1.0f, -1.0f, -1.0f), QVector2D(0.66f, 0.0f)}, // v12
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{QVector3D(-1.0f, -1.0f, 1.0f), QVector2D(1.0f, 0.0f)}, // v13
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{QVector3D(-1.0f, 1.0f, -1.0f), QVector2D(0.66f, 0.5f)}, // v14
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{QVector3D(-1.0f, 1.0f, 1.0f), QVector2D(1.0f, 0.5f)}, // v15
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// Vertex data for face 4
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{QVector3D(-1.0f, -1.0f, -1.0f), QVector2D(0.33f, 0.0f)}, // v16
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{QVector3D( 1.0f, -1.0f, -1.0f), QVector2D(0.66f, 0.0f)}, // v17
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{QVector3D(-1.0f, -1.0f, 1.0f), QVector2D(0.33f, 0.5f)}, // v18
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{QVector3D( 1.0f, -1.0f, 1.0f), QVector2D(0.66f, 0.5f)}, // v19
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// Vertex data for face 5
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{QVector3D(-1.0f, 1.0f, 1.0f), QVector2D(0.33f, 0.5f)}, // v20
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{QVector3D( 1.0f, 1.0f, 1.0f), QVector2D(0.66f, 0.5f)}, // v21
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{QVector3D(-1.0f, 1.0f, -1.0f), QVector2D(0.33f, 1.0f)}, // v22
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{QVector3D( 1.0f, 1.0f, -1.0f), QVector2D(0.66f, 1.0f)} // v23
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};
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// Indices for drawing cube faces using triangle strips.
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// Triangle strips can be connected by duplicating indices
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// between the strips. If connecting strips have opposite
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// vertex order then last index of the first strip and first
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// index of the second strip needs to be duplicated. If
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// connecting strips have same vertex order then only last
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// index of the first strip needs to be duplicated.
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GLushort indices[] = {
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0, 1, 2, 3, 3, // Face 0 - triangle strip ( v0, v1, v2, v3)
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4, 4, 5, 6, 7, 7, // Face 1 - triangle strip ( v4, v5, v6, v7)
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8, 8, 9, 10, 11, 11, // Face 2 - triangle strip ( v8, v9, v10, v11)
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12, 12, 13, 14, 15, 15, // Face 3 - triangle strip (v12, v13, v14, v15)
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16, 16, 17, 18, 19, 19, // Face 4 - triangle strip (v16, v17, v18, v19)
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20, 20, 21, 22, 23 // Face 5 - triangle strip (v20, v21, v22, v23)
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};
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//! [1]
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// Transfer vertex data to VBO 0
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arrayBuf.bind();
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arrayBuf.allocate(vertices, 24 * sizeof(VertexData));
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// Transfer index data to VBO 1
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indexBuf.bind();
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indexBuf.allocate(indices, 34 * sizeof(GLushort));
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//! [1]
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}
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//! [2]
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void GeometryEngine::drawCubeGeometry(QOpenGLShaderProgram *program)
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{
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// Tell OpenGL which VBOs to use
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arrayBuf.bind();
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indexBuf.bind();
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// Offset for position
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quintptr offset = 0;
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// Tell OpenGL programmable pipeline how to locate vertex position data
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int vertexLocation = program->attributeLocation("a_position");
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program->enableAttributeArray(vertexLocation);
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program->setAttributeBuffer(vertexLocation, GL_FLOAT, offset, 3, sizeof(VertexData));
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// Offset for texture coordinate
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offset += sizeof(QVector3D);
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// Tell OpenGL programmable pipeline how to locate vertex texture coordinate data
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int texcoordLocation = program->attributeLocation("a_texcoord");
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program->enableAttributeArray(texcoordLocation);
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program->setAttributeBuffer(texcoordLocation, GL_FLOAT, offset, 2, sizeof(VertexData));
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// Draw cube geometry using indices from VBO 1
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glDrawElements(GL_TRIANGLE_STRIP, 34, GL_UNSIGNED_SHORT, 0);
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}
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//! [2]
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