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/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** 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 Digia Plc 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 "mainwidget.h"
#include <QMouseEvent>
#include <math.h>
#include <locale.h>
MainWidget::MainWidget(QWidget *parent) :
QGLWidget(parent),
angularSpeed(0)
{
}
MainWidget::~MainWidget()
{
deleteTexture(texture);
}
//! [0]
void MainWidget::mousePressEvent(QMouseEvent *e)
{
// Save mouse press position
mousePressPosition = QVector2D(e->localPos());
}
void MainWidget::mouseReleaseEvent(QMouseEvent *e)
{
// Mouse release position - mouse press position
QVector2D diff = QVector2D(e->localPos()) - mousePressPosition;
// Rotation axis is perpendicular to the mouse position difference
// vector
QVector3D n = QVector3D(diff.y(), diff.x(), 0.0).normalized();
// Accelerate angular speed relative to the length of the mouse sweep
qreal acc = diff.length() / 100.0;
// Calculate new rotation axis as weighted sum
rotationAxis = (rotationAxis * angularSpeed + n * acc).normalized();
// Increase angular speed
angularSpeed += acc;
}
//! [0]
//! [1]
void MainWidget::timerEvent(QTimerEvent *)
{
// Decrease angular speed (friction)
angularSpeed *= 0.99;
// Stop rotation when speed goes below threshold
if (angularSpeed < 0.01) {
angularSpeed = 0.0;
} else {
// Update rotation
rotation = QQuaternion::fromAxisAndAngle(rotationAxis, angularSpeed) * rotation;
// Update scene
updateGL();
}
}
//! [1]
void MainWidget::initializeGL()
{
initializeGLFunctions();
qglClearColor(Qt::black);
initShaders();
initTextures();
//! [2]
// Enable depth buffer
glEnable(GL_DEPTH_TEST);
// Enable back face culling
glEnable(GL_CULL_FACE);
//! [2]
geometries.init();
// Use QBasicTimer because its faster than QTimer
timer.start(12, this);
}
//! [3]
void MainWidget::initShaders()
{
// Override system locale until shaders are compiled
setlocale(LC_NUMERIC, "C");
// Compile vertex shader
if (!program.addShaderFromSourceFile(QGLShader::Vertex, ":/vshader.glsl"))
close();
// Compile fragment shader
if (!program.addShaderFromSourceFile(QGLShader::Fragment, ":/fshader.glsl"))
close();
// Link shader pipeline
if (!program.link())
close();
// Bind shader pipeline for use
if (!program.bind())
close();
// Restore system locale
setlocale(LC_ALL, "");
}
//! [3]
//! [4]
void MainWidget::initTextures()
{
// Load cube.png image
glEnable(GL_TEXTURE_2D);
texture = bindTexture(QImage(":/cube.png"));
// Set nearest filtering mode for texture minification
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
// Set bilinear filtering mode for texture magnification
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// Wrap texture coordinates by repeating
// f.ex. texture coordinate (1.1, 1.2) is same as (0.1, 0.2)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
}
//! [4]
//! [5]
void MainWidget::resizeGL(int w, int h)
{
// Set OpenGL viewport to cover whole widget
glViewport(0, 0, w, h);
// Calculate aspect ratio
qreal aspect = qreal(w) / qreal(h ? h : 1);
// Set near plane to 3.0, far plane to 7.0, field of view 45 degrees
const qreal zNear = 3.0, zFar = 7.0, fov = 45.0;
// Reset projection
projection.setToIdentity();
// Set perspective projection
projection.perspective(fov, aspect, zNear, zFar);
}
//! [5]
void MainWidget::paintGL()
{
// Clear color and depth buffer
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
//! [6]
// Calculate model view transformation
QMatrix4x4 matrix;
matrix.translate(0.0, 0.0, -5.0);
matrix.rotate(rotation);
// Set modelview-projection matrix
program.setUniformValue("mvp_matrix", projection * matrix);
//! [6]
// Use texture unit 0 which contains cube.png
program.setUniformValue("texture", 0);
// Draw cube geometry
geometries.drawCubeGeometry(&program);
}
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