| /**************************************************************************** |
| ** |
| ** Copyright (C) 2016 The Qt Company Ltd. |
| ** Contact: https://www.qt.io/licensing/ |
| ** |
| ** This file is part of the QtCore module of the Qt Toolkit. |
| ** |
| ** $QT_BEGIN_LICENSE:BSD$ |
| ** Commercial License Usage |
| ** Licensees holding valid commercial Qt licenses may use this file in |
| ** accordance with the commercial license agreement provided with the |
| ** Software or, alternatively, in accordance with the terms contained in |
| ** a written agreement between you and The Qt Company. For licensing terms |
| ** and conditions see https://www.qt.io/terms-conditions. For further |
| ** information use the contact form at https://www.qt.io/contact-us. |
| ** |
| ** BSD License Usage |
| ** Alternatively, 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 The Qt Company Ltd 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; |
| }; |
| |
| //! [0] |
| GeometryEngine::GeometryEngine() |
| : indexBuf(QOpenGLBuffer::IndexBuffer) |
| { |
| initializeOpenGLFunctions(); |
| |
| // Generate 2 VBOs |
| arrayBuf.create(); |
| indexBuf.create(); |
| |
| // Initializes cube geometry and transfers it to VBOs |
| initCubeGeometry(); |
| } |
| |
| GeometryEngine::~GeometryEngine() |
| { |
| arrayBuf.destroy(); |
| indexBuf.destroy(); |
| } |
| //! [0] |
| |
| 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(-1.0f, -1.0f, 1.0f), QVector2D(0.0f, 0.0f)}, // v0 |
| {QVector3D( 1.0f, -1.0f, 1.0f), QVector2D(0.33f, 0.0f)}, // v1 |
| {QVector3D(-1.0f, 1.0f, 1.0f), QVector2D(0.0f, 0.5f)}, // v2 |
| {QVector3D( 1.0f, 1.0f, 1.0f), QVector2D(0.33f, 0.5f)}, // v3 |
| |
| // Vertex data for face 1 |
| {QVector3D( 1.0f, -1.0f, 1.0f), QVector2D( 0.0f, 0.5f)}, // v4 |
| {QVector3D( 1.0f, -1.0f, -1.0f), QVector2D(0.33f, 0.5f)}, // v5 |
| {QVector3D( 1.0f, 1.0f, 1.0f), QVector2D(0.0f, 1.0f)}, // v6 |
| {QVector3D( 1.0f, 1.0f, -1.0f), QVector2D(0.33f, 1.0f)}, // v7 |
| |
| // Vertex data for face 2 |
| {QVector3D( 1.0f, -1.0f, -1.0f), QVector2D(0.66f, 0.5f)}, // v8 |
| {QVector3D(-1.0f, -1.0f, -1.0f), QVector2D(1.0f, 0.5f)}, // v9 |
| {QVector3D( 1.0f, 1.0f, -1.0f), QVector2D(0.66f, 1.0f)}, // v10 |
| {QVector3D(-1.0f, 1.0f, -1.0f), QVector2D(1.0f, 1.0f)}, // v11 |
| |
| // Vertex data for face 3 |
| {QVector3D(-1.0f, -1.0f, -1.0f), QVector2D(0.66f, 0.0f)}, // v12 |
| {QVector3D(-1.0f, -1.0f, 1.0f), QVector2D(1.0f, 0.0f)}, // v13 |
| {QVector3D(-1.0f, 1.0f, -1.0f), QVector2D(0.66f, 0.5f)}, // v14 |
| {QVector3D(-1.0f, 1.0f, 1.0f), QVector2D(1.0f, 0.5f)}, // v15 |
| |
| // Vertex data for face 4 |
| {QVector3D(-1.0f, -1.0f, -1.0f), QVector2D(0.33f, 0.0f)}, // v16 |
| {QVector3D( 1.0f, -1.0f, -1.0f), QVector2D(0.66f, 0.0f)}, // v17 |
| {QVector3D(-1.0f, -1.0f, 1.0f), QVector2D(0.33f, 0.5f)}, // v18 |
| {QVector3D( 1.0f, -1.0f, 1.0f), QVector2D(0.66f, 0.5f)}, // v19 |
| |
| // Vertex data for face 5 |
| {QVector3D(-1.0f, 1.0f, 1.0f), QVector2D(0.33f, 0.5f)}, // v20 |
| {QVector3D( 1.0f, 1.0f, 1.0f), QVector2D(0.66f, 0.5f)}, // v21 |
| {QVector3D(-1.0f, 1.0f, -1.0f), QVector2D(0.33f, 1.0f)}, // v22 |
| {QVector3D( 1.0f, 1.0f, -1.0f), QVector2D(0.66f, 1.0f)} // 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 |
| arrayBuf.bind(); |
| arrayBuf.allocate(vertices, 24 * sizeof(VertexData)); |
| |
| // Transfer index data to VBO 1 |
| indexBuf.bind(); |
| indexBuf.allocate(indices, 34 * sizeof(GLushort)); |
| //! [1] |
| } |
| |
| //! [2] |
| void GeometryEngine::drawCubeGeometry(QOpenGLShaderProgram *program) |
| { |
| // Tell OpenGL which VBOs to use |
| arrayBuf.bind(); |
| indexBuf.bind(); |
| |
| // Offset for position |
| quintptr offset = 0; |
| |
| // Tell OpenGL programmable pipeline how to locate vertex position data |
| int vertexLocation = program->attributeLocation("a_position"); |
| program->enableAttributeArray(vertexLocation); |
| program->setAttributeBuffer(vertexLocation, GL_FLOAT, offset, 3, sizeof(VertexData)); |
| |
| // 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); |
| program->setAttributeBuffer(texcoordLocation, GL_FLOAT, offset, 2, sizeof(VertexData)); |
| |
| // Draw cube geometry using indices from VBO 1 |
| glDrawElements(GL_TRIANGLE_STRIP, 34, GL_UNSIGNED_SHORT, nullptr); |
| } |
| //! [2] |