158 lines
3.6 KiB
C++
158 lines
3.6 KiB
C++
#include "..\Header\OglViewerWidget.h"
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#include <QMouseEvent>
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#include <math.h>
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OglViewerWidget::OglViewerWidget(QWidget *parent) :
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QOpenGLWidget(parent),
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geometries(0),
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texture(0),
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angularSpeed(0)
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{
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}
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OglViewerWidget::~OglViewerWidget()
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{
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// Make sure the context is current when deleting the texture
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// and the buffers.
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makeCurrent();
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delete texture;
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delete geometries;
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doneCurrent();
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}
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void OglViewerWidget::mousePressEvent(QMouseEvent *e)
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{
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// Save mouse press position
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mousePressPosition = QVector2D(e->localPos());
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}
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void OglViewerWidget::mouseReleaseEvent(QMouseEvent *e)
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{
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// Mouse release position - mouse press position
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QVector2D diff = QVector2D(e->localPos()) - mousePressPosition;
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// Rotation axis is perpendicular to the mouse position difference
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// vector
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QVector3D n = QVector3D(diff.y(), diff.x(), 0.0).normalized();
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// Accelerate angular speed relative to the length of the mouse sweep
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qreal acc = diff.length() / 100.0;
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// Calculate new rotation axis as weighted sum
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rotationAxis = (rotationAxis * angularSpeed + n * acc).normalized();
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// Increase angular speed
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angularSpeed += acc;
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}
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void OglViewerWidget::timerEvent(QTimerEvent *)
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{
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// Decrease angular speed (friction)
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angularSpeed *= 0.99;
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// Stop rotation when speed goes below threshold
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if (angularSpeed < 0.01) {
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angularSpeed = 0.0;
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} else {
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// Update rotation
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rotation = QQuaternion::fromAxisAndAngle(rotationAxis, angularSpeed) * rotation;
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// Request an update
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update();
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}
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}
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void OglViewerWidget::initializeGL()
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{
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initializeOpenGLFunctions();
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glClearColor(0, 0, 0, 1);
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initShaders();
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initTextures();
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// Enable depth buffer
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glEnable(GL_DEPTH_TEST);
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// Enable back face culling
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glEnable(GL_CULL_FACE);
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geometries = new GeometryEngine;
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// Use QBasicTimer because its faster than QTimer
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timer.start(12, this);
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}
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void OglViewerWidget::initShaders()
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{
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// Compile vertex shader
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if (!program.addShaderFromSourceFile(QOpenGLShader::Vertex, ":/shaders/vshader.glsl"))
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close();
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// Compile fragment shader
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if (!program.addShaderFromSourceFile(QOpenGLShader::Fragment, ":/shaders/fshader.glsl"))
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close();
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// Link shader pipeline
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if (!program.link())
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close();
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// Bind shader pipeline for use
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if (!program.bind())
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close();
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}
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void OglViewerWidget::initTextures()
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{
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// Load cube.png image
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texture = new QOpenGLTexture(QImage(":images/cube.png").mirrored());
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// Set nearest filtering mode for texture minification
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texture->setMinificationFilter(QOpenGLTexture::Nearest);
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// Set bilinear filtering mode for texture magnification
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texture->setMagnificationFilter(QOpenGLTexture::Linear);
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// Wrap texture coordinates by repeating
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// f.ex. texture coordinate (1.1, 1.2) is same as (0.1, 0.2)
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texture->setWrapMode(QOpenGLTexture::Repeat);
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}
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void OglViewerWidget::resizeGL(int w, int h)
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{
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// Calculate aspect ratio
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qreal aspect = qreal(w) / qreal(h ? h : 1);
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// Set near plane to 3.0, far plane to 7.0, field of view 45 degrees
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const qreal zNear = 3.0, zFar = 7.0, fov = 45.0;
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// Reset projection
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projection.setToIdentity();
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// Set perspective projection
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projection.perspective(fov, aspect, zNear, zFar);
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}
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void OglViewerWidget::paintGL()
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{
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// Clear color and depth buffer
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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texture->bind();
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// Calculate model view transformation
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QMatrix4x4 matrix;
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matrix.translate(0.0, 0.0, -5.0);
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matrix.rotate(rotation);
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// Set modelview-projection matrix
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program.setUniformValue("mvp_matrix", projection * matrix);
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// Use texture unit 0 which contains cube.png
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program.setUniformValue("texture", 0);
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// Draw cube geometry
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geometries->drawCubeGeometry(&program);
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}
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