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#include "mainwidget.h"
#include "geometryengine.h"
#include <QtOpenGL/QGLShaderProgram>
#include <QBasicTimer>
#include <QMouseEvent>
#include <math.h>
#include <QDebug>
MainWidget::MainWidget(QWidget *parent) :
QGLWidget(parent),
timer(new QBasicTimer),
program(new QGLShaderProgram),
geometries(new GeometryEngine)
{
}
MainWidget::~MainWidget()
{
delete timer; timer = 0;
delete program; program = 0;
delete geometries; geometries = 0;
deleteTexture(texture);
}
//! [0]
void MainWidget::mousePressEvent(QMouseEvent *e)
{
// Saving mouse press position
mousePressPosition = QVector2D(e->posF());
}
void MainWidget::mouseReleaseEvent(QMouseEvent *e)
{
// Mouse release position - mouse press position
QVector2D diff = QVector2D(e->posF()) - 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 *e)
{
Q_UNUSED(e);
// 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()
{
qglClearColor(Qt::black);
qDebug() << "Initializing shaders...";
initShaders();
qDebug() << "Initializing textures...";
initTextures();
//! [2]
// Enable depth buffer
glEnable(GL_DEPTH_TEST);
// Enable back face culling
glEnable(GL_CULL_FACE);
//! [2]
qDebug() << "Initializing geometries...";
geometries->init();
// using QBasicTimer because its faster that QTimer
timer->start(12, this);
}
//! [3]
void MainWidget::initShaders()
{
// Overriding system locale until shaders are compiled
setlocale(LC_NUMERIC, "C");
// Compiling vertex shader
if (!program->addShaderFromSourceFile(QGLShader::Vertex, ":/vshader.glsl"))
close();
// Compiling fragment shader
if (!program->addShaderFromSourceFile(QGLShader::Fragment, ":/fshader.glsl"))
close();
// Linking shader pipeline
if (!program->link())
close();
// Binding shader pipeline for use
if (!program->bind())
close();
// Restore system locale
setlocale(LC_ALL, "");
}
//! [3]
//! [4]
void MainWidget::initTextures()
{
// Loading cube.png to texture unit 0
glActiveTexture(GL_TEXTURE0);
glEnable(GL_TEXTURE_2D);
texture = bindTexture(QImage(":/cube.png"));
// Set nearest filtering mode for texture minification
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
// Set bilinear filtering mode for texture magnification
glTexParameterf(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)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameterf(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]
// Using texture unit 0 which contains cube.png
program->setUniformValue("texture", 0);
// Draw cube geometry
geometries->drawCubeGeometry(program);
}
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