From faea3b0737dcfb0decbe8bb46f396145e9ebcb8a Mon Sep 17 00:00:00 2001
From: Anakin <Battlefrontler@t-online.de>
Date: Tue, 27 Dec 2016 14:05:39 +0100
Subject: [PATCH] removed timer rotation, now the user has full control, added
 keyboard support, reset rotation with space

---
 QtMeshViewer/Header/OglViewerWidget.h   | 17 +++---
 QtMeshViewer/Source/OglViewerWidget.cpp | 71 +++++++++++++------------
 2 files changed, 46 insertions(+), 42 deletions(-)

diff --git a/QtMeshViewer/Header/OglViewerWidget.h b/QtMeshViewer/Header/OglViewerWidget.h
index 7cb8bfc..4b62ae0 100644
--- a/QtMeshViewer/Header/OglViewerWidget.h
+++ b/QtMeshViewer/Header/OglViewerWidget.h
@@ -24,7 +24,8 @@ public:
 protected:
 	void mousePressEvent(QMouseEvent *e) Q_DECL_OVERRIDE;
 	void mouseReleaseEvent(QMouseEvent *e) Q_DECL_OVERRIDE;
-	void timerEvent(QTimerEvent *e) Q_DECL_OVERRIDE;
+	void mouseMoveEvent(QMouseEvent *e) Q_DECL_OVERRIDE;
+	void keyPressEvent(QKeyEvent *e) Q_DECL_OVERRIDE;
 
 	void initializeGL() Q_DECL_OVERRIDE;
 	void resizeGL(int w, int h) Q_DECL_OVERRIDE;
@@ -34,17 +35,17 @@ protected:
 	void initTextures();
 
 private:
-	QBasicTimer timer;
+	struct {
+		bool left = false;
+		bool right = false;
+		QVector2D position;
+	} m_mouse;
 	QOpenGLShaderProgram program;
 	GeometryEngine *geometries;
 
 	QOpenGLTexture *texture;
 
-	QMatrix4x4 projection;
-
-	QVector2D mousePressPosition;
-	QVector3D rotationAxis;
-	qreal angularSpeed;
-	QQuaternion rotation;
+	QMatrix4x4 m_projection;
+	QQuaternion m_rotation;
 };
 
diff --git a/QtMeshViewer/Source/OglViewerWidget.cpp b/QtMeshViewer/Source/OglViewerWidget.cpp
index e83c85f..76554c2 100644
--- a/QtMeshViewer/Source/OglViewerWidget.cpp
+++ b/QtMeshViewer/Source/OglViewerWidget.cpp
@@ -2,13 +2,14 @@
 
 #include <QMouseEvent>
 #include <math.h>
+#include <iostream>
 
 OglViewerWidget::OglViewerWidget(QWidget *parent) :
 	QOpenGLWidget(parent),
 	geometries(0),
-	texture(0),
-	angularSpeed(0)
+	texture(0)
 {
+	setFocus();
 }
 
 OglViewerWidget::~OglViewerWidget()
@@ -24,45 +25,49 @@ OglViewerWidget::~OglViewerWidget()
 void OglViewerWidget::mousePressEvent(QMouseEvent *e)
 {
 	// Save mouse press position
-	mousePressPosition = QVector2D(e->localPos());
+	m_mouse.position = QVector2D(e->localPos());
+
+	// Which button has been pressed?
+	if (e->button() == Qt::LeftButton)
+		m_mouse.left = true;
+	else if (e->button() == Qt::RightButton)
+		m_mouse.right = true;
 }
 
 void OglViewerWidget::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;
+	if (e->button() == Qt::LeftButton)
+		m_mouse.left = false;
+	else if (e->button() == Qt::RightButton)
+		m_mouse.right = false;
 }
 
-void OglViewerWidget::timerEvent(QTimerEvent *)
+void OglViewerWidget::mouseMoveEvent(QMouseEvent *e)
 {
-	// Decrease angular speed (friction)
-	angularSpeed *= 0.99;
+	if (m_mouse.left)
+	{
+		// get the difference between last press and now
+		QVector2D diff = QVector2D(e->localPos()) - m_mouse.position;
 
-	// Stop rotation when speed goes below threshold
-	if (angularSpeed < 0.01) {
-		angularSpeed = 0.0;
-	} else {
-		// Update rotation
-		rotation = QQuaternion::fromAxisAndAngle(rotationAxis, angularSpeed) * rotation;
+		// update the new position
+		m_mouse.position = QVector2D(e->localPos());
 
-		// Request an update
+		// calculate the rotation axis and rotate
+		m_rotation = QQuaternion::fromAxisAndAngle(QVector3D(diff.y(), diff.x(), 0.0).normalized(), diff.length() * 0.5) * m_rotation;
+
+		// request an update
 		update();
 	}
 }
 
+void OglViewerWidget::keyPressEvent(QKeyEvent *e)
+{
+	if (e->key() == Qt::Key_Space)
+		m_rotation = QQuaternion();
+
+	update();
+}
+
 void OglViewerWidget::initializeGL()
 {
 	initializeOpenGLFunctions();
@@ -80,8 +85,6 @@ void OglViewerWidget::initializeGL()
 
 	geometries = new GeometryEngine;
 
-	// Use QBasicTimer because its faster than QTimer
-	timer.start(12, this);
 }
 
 void OglViewerWidget::initShaders()
@@ -128,10 +131,10 @@ void OglViewerWidget::resizeGL(int w, int h)
 	const qreal zNear = 3.0, zFar = 7.0, fov = 45.0;
 
 	// Reset projection
-	projection.setToIdentity();
+	m_projection.setToIdentity();
 
 	// Set perspective projection
-	projection.perspective(fov, aspect, zNear, zFar);
+	m_projection.perspective(fov, aspect, zNear, zFar);
 }
 
 void OglViewerWidget::paintGL()
@@ -144,10 +147,10 @@ void OglViewerWidget::paintGL()
 	// Calculate model view transformation
 	QMatrix4x4 matrix;
 	matrix.translate(0.0, 0.0, -5.0);
-	matrix.rotate(rotation);
+	matrix.rotate(m_rotation);
 
 	// Set modelview-projection matrix
-	program.setUniformValue("mvp_matrix", projection * matrix);
+	program.setUniformValue("mvp_matrix", m_projection * matrix);
 
 	// Use texture unit 0 which contains cube.png
 	program.setUniformValue("texture", 0);