fertig bis trackball

helloqube/mainwindow.cpp

@@ -95,6 +95,12 @@ MainWindow::MainWindow(QWidget *parent)
     tesselationSlider->setValue(1);
     connect(tesselationSlider,SIGNAL(valueChanged(int)),myGLWidget,SLOT(setTessellation(int)));
     toolBar->addWidget(tesselationSlider);
+
+    //reset Camera button
+    resetCameraAction = new QAction("Reset Camera",toolBar);
+    connect(resetCameraAction,SIGNAL(triggered(bool)),myGLWidget,SLOT(resetCamera()));
+    toolBar->addAction(resetCameraAction);
+
 }
 
 MainWindow::~MainWindow()

helloqube/mainwindow.h

@@ -47,6 +47,8 @@ private:
     QAction *shadePhongAction;
     QActionGroup *shaderGroup;
 
+    QAction *resetCameraAction;
+
     //Widgets
     MyGLWidget *myGLWidget;
 

helloqube/myglwidget.cpp

@@ -4,9 +4,10 @@ MyGLWidget::MyGLWidget(QWidget *parent)
     : QGLWidget(QGLFormat(QGL::SampleBuffers), parent)
 {
     tesselation = 1;
-    cameraZoom = -5;
-    translationX = 0;
-    translationY = 0;
+    qubeRotationQuaternion = QQuaternion();
+    tx = 0;
+    ty = 0;
+    cameraZoom = cameraZoomDefault;
     clickStartPosition = QPoint(0,0);
      rightButtonPressed = false;
 }
@@ -97,11 +98,18 @@ void MyGLWidget::paintGL(){
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
     glLoadIdentity();
 
-    glTranslatef(translationX,translationY,cameraZoom);//Kamera sitzt sonst in (0,0,0) und man sieht nichts (duh)
+    //zoom camera
+    glTranslatef(0,0,cameraZoom);//Kamera sitzt sonst in (0,0,0) und man sieht nichts (duh)
 
+    //for translation
     double qubeWidth = 1.0;
     double dist = qubeWidth/(double)tesselation;
 
+    //for cube rotation
+    QMatrix4x4 m = QMatrix4x4();
+    m.rotate(qubeRotationQuaternion);
+    glMultMatrixf(m.data());
+
     //4.1.1 Unit Qube + Tesselation + Diffuse Material
     {
     glBegin(GL_QUADS);
@@ -116,14 +124,16 @@ void MyGLWidget::paintGL(){
 //    glColor3f(0,0,1);//blau
     GLfloat blue[] = {0,0,1};
     glMaterialfv(GL_FRONT,GL_DIFFUSE,blue);
+    glNormal3f(0,0,1);
     for (int i = 0; i < tesselation; i++){
         for (int j = 0; j < tesselation; j++){
-            glVertex3f(0.5-dist*i,0.5-dist*j,0.5);
-            glVertex3f(0.5-dist*(i+1),0.5-dist*j,0.5);
-            glVertex3f(0.5-dist*(i+1),0.5-dist*(j+1),0.5);
-            glVertex3f(0.5-dist*i,0.5-dist*(j+1),0.5);
+            glVertex3f(tx+0.5-dist*i,ty+0.5-dist*j,0.5);
+            glVertex3f(tx+0.5-dist*(i+1),ty+0.5-dist*j,0.5);
+            glVertex3f(tx+0.5-dist*(i+1),ty+0.5-dist*(j+1),0.5);
+            glVertex3f(tx+0.5-dist*i,ty+0.5-dist*(j+1),0.5);
         }
     }
+    //reference for previous front
 //    glVertex3f(0.5, 0.5, 0.5);//4
 //    glVertex3f(-0.5, 0.5, 0.5);//3
 //    glVertex3f(-0.5, -0.5, 0.5);//2
@@ -132,12 +142,13 @@ void MyGLWidget::paintGL(){
     //oben // y-Achse
     GLfloat green[] = {0,1,0};
     glMaterialfv(GL_FRONT,GL_DIFFUSE,green);
+    glNormal3f(0,1,0);
     for (int i = 0; i < tesselation; i++){
         for (int j = 0; j < tesselation; j++){
-            glVertex3f(0.5-dist*(i+1), 0.5, 0.5-dist*(j+1));
-            glVertex3f(0.5-dist*(i+1), 0.5, 0.5-dist*j);
-            glVertex3f(0.5-dist*i, 0.5, 0.5-dist*j);
-            glVertex3f(0.5-dist*i, 0.5, 0.5-dist*(j+1));
+            glVertex3f(tx+0.5-dist*(i+1), ty+0.5, 0.5-dist*(j+1));
+            glVertex3f(tx+0.5-dist*(i+1), ty+0.5, 0.5-dist*j);
+            glVertex3f(tx+0.5-dist*i, ty+0.5, 0.5-dist*j);
+            glVertex3f(tx+0.5-dist*i, ty+0.5, 0.5-dist*(j+1));
         }
     }
 
@@ -145,12 +156,13 @@ void MyGLWidget::paintGL(){
     //rechts //x-Achse
     GLfloat red[] = {1,0,0};
     glMaterialfv(GL_FRONT,GL_DIFFUSE,red);
+    glNormal3f(1,0,0);
     for (int i = 0; i < tesselation; i++){
         for (int j = 0; j < tesselation; j++){
-            glVertex3f(0.5, 0.5-dist*i, 0.5-dist*j);
-            glVertex3f(0.5, 0.5-dist*(i+1), 0.5-dist*j);
-            glVertex3f(0.5, 0.5-dist*(i+1), 0.5-dist*(j+1));
-            glVertex3f(0.5, 0.5-dist*i, 0.5-dist*(j+1));
+            glVertex3f(tx+0.5, ty+0.5-dist*i, 0.5-dist*j);
+            glVertex3f(tx+0.5, ty+0.5-dist*(i+1), 0.5-dist*j);
+            glVertex3f(tx+0.5, ty+0.5-dist*(i+1), 0.5-dist*(j+1));
+            glVertex3f(tx+0.5, ty+0.5-dist*i, 0.5-dist*(j+1));
         }
     }
 
@@ -158,36 +170,39 @@ void MyGLWidget::paintGL(){
     //hinten // z-Achse
     GLfloat yellow[] = {1,0.9,0};
     glMaterialfv(GL_FRONT,GL_DIFFUSE,yellow);
+    glNormal3f(0,0,-1);
     for (int i = 0; i < tesselation; i++){
         for (int j = 0; j < tesselation; j++){
-            glVertex3f(0.5-dist*i, 0.5-dist*(j+1), -0.5);//4
-            glVertex3f(0.5-dist*(i+1), 0.5-dist*(j+1), -0.5);//3
-            glVertex3f(0.5-dist*(i+1), 0.5-dist*j, -0.5);//2
-            glVertex3f(0.5-dist*i, 0.5-dist*j, -0.5);//1
+            glVertex3f(tx+0.5-dist*i, ty+0.5-dist*(j+1), -0.5);//4
+            glVertex3f(tx+0.5-dist*(i+1), ty+0.5-dist*(j+1), -0.5);//3
+            glVertex3f(tx+0.5-dist*(i+1), ty+0.5-dist*j, -0.5);//2
+            glVertex3f(tx+0.5-dist*i,ty+ 0.5-dist*j, -0.5);//1
         }
     }
 
     //links
     GLfloat cyan[] = {0,1,1};
     glMaterialfv(GL_FRONT,GL_DIFFUSE,cyan);
+    glNormal3f(-1,0,0);
     for (int i = 0; i < tesselation; i++){
         for (int j = 0; j < tesselation; j++){
-            glVertex3f(-0.5, 0.5-dist*i, 0.5-dist*(j+1));
-            glVertex3f(-0.5, 0.5-dist*(i+1), 0.5-dist*(j+1));
-            glVertex3f(-0.5, 0.5-dist*(i+1), 0.5-dist*j);
-            glVertex3f(-0.5, 0.5-dist*i, 0.5-dist*j);
+            glVertex3f(tx-0.5, ty+0.5-dist*i, 0.5-dist*(j+1));
+            glVertex3f(tx-0.5, ty+0.5-dist*(i+1), 0.5-dist*(j+1));
+            glVertex3f(tx-0.5, ty+0.5-dist*(i+1), 0.5-dist*j);
+            glVertex3f(tx-0.5, ty+0.5-dist*i, 0.5-dist*j);
         }
     }
 
     //unten //-y
     GLfloat magenta[] = {1,0,1};
     glMaterialfv(GL_FRONT,GL_DIFFUSE,magenta);
+    glNormal3f(0,-1,0);
     for (int i = 0; i < tesselation; i++){
         for (int j = 0; j < tesselation; j++){
-            glVertex3f(0.5-dist*i, -0.5, 0.5-dist*(j+1));
-            glVertex3f(0.5-dist*i, -0.5, 0.5-dist*j);
-            glVertex3f(0.5-dist*(i+1), -0.5, 0.5-dist*j);
-            glVertex3f(0.5-dist*(i+1), -0.5, 0.5-dist*(j+1));
+            glVertex3f(tx+0.5-dist*i, ty-0.5, 0.5-dist*(j+1));
+            glVertex3f(tx+0.5-dist*i, ty-0.5, 0.5-dist*j);
+            glVertex3f(tx+0.5-dist*(i+1), ty-0.5, 0.5-dist*j);
+            glVertex3f(tx+0.5-dist*(i+1), ty-0.5, 0.5-dist*(j+1));
         }
     }
 
@@ -199,28 +214,31 @@ void MyGLWidget::paintGL(){
 void MyGLWidget::resizeGL(int width, int height){
     double p = (double)width / (double)height;
         qDebug() << "Resize to " << width << "," << height << ", Perspective: " << p;
-//old:
-//    GLInt x = 0;//The lower-left corner of the viewport rectangle, in pixels. The default is (0,0).
-//    GLInt y = 0;//The lower-left corner of the viewport rectangle, in pixels. The default is (0,0).
-//    glViewport(x,y,width,height);//The width of the viewport. When an OpenGL context is first attached to a window, width and height are set to the dimensions of that window.
     glViewport(0,0,width,height);
 
-    glMatrixMode(GL_PROJECTION);
+    glMatrixMode(GL_PROJECTION);//from HelloGL example
     glLoadIdentity();
 
-    gluPerspective(45.0,p,0.1,1000);//TODO komisch: wenn schmaler als hoch auf einmal grau.
+    gluPerspective(45.0,p,0.1,1000);
 
     glMatrixMode(GL_MODELVIEW);
 
+    screenCenter = QPoint((double)width/2.0,(double)height/2.0);//lieber zu oft casten bevors nicht tut...
+
 }
 
 void MyGLWidget::mousePressEvent(QMouseEvent *event){
     rightButtonPressed = false;
+    leftButtonPressed = false;
     if (event->button() == Qt::RightButton){
         rightButtonPressed = true;
         clickStartPosition = event->pos();
         qDebug() << "mouse press at " << clickStartPosition;
+    } else if (event->button() == Qt::LeftButton){
+        leftButtonPressed = true;
+        clickStartPosition = event->pos();
     }
+
 }
 
 void MyGLWidget:: mouseMoveEvent(QMouseEvent *event){
@@ -229,11 +247,73 @@ void MyGLWidget:: mouseMoveEvent(QMouseEvent *event){
         QPoint currentPosition = event->pos();
         QPoint diff = currentPosition - clickStartPosition;
         clickStartPosition = currentPosition;
-        translationX -= 0.01*diff.x();
-        translationY += 0.01*diff.y();
+        tx += 0.01*diff.x();
+        ty -= 0.01*diff.y();
+        updateGL();
+    }else if (leftButtonPressed){
+
+        //according to https://www.opengl.org/wiki/Object_Mouse_Trackball
+
+        double radius = std::min(screenCenter.x(),screenCenter.y());
+
+        //translate touches around screen center
+        double xOld = ((double)(clickStartPosition.x() - screenCenter.x()));
+        double yOld = ((double)(clickStartPosition.y() - screenCenter.y()));
+
+        QPoint newPosition = event->pos();
+        double xNew = ((double)(newPosition.x() - screenCenter.x()));
+        double yNew = ((double)(newPosition.y() - screenCenter.y()));
+
+            clickStartPosition = newPosition;
+
+            //https://www.opengl.org/wiki/Object_Mouse_Trackball#Sit_and_spin
+
+            //compute z coordinates ether on sphere or on hyperbolic sheet
+            double zOld, zNew;
+            double rsquareover2 = radius*radius/2.0;
+            double xyOld = xOld*xOld + yOld*yOld;
+            double xyNew = xNew*xNew + yNew*yNew;
+            if (xyOld < rsquareover2){
+                zOld = sqrt(radius*radius - xyOld);
+            }else{
+                zOld = rsquareover2/(sqrt(xyOld));
+            }
+            if(xyNew < rsquareover2){
+                zNew = sqrt(radius*radius - xyNew);
+            }else{
+                zNew = rsquareover2/sqrt(xyNew);
+            }
+
+            // set V_1 and V_2 (Vectors on Sphere around screen center, corresponding to input
+            QVector3D v1 = QVector3D(xOld,yOld,zOld);
+            v1.normalize();
+
+            QVector3D v2 = QVector3D(xNew,yNew,zNew);
+            v2.normalize();
+
+            //Compute normal of plane through v1 and v2 -> rotation axis
+            QVector3D n = QVector3D::crossProduct(v1,v2);
+            n.normalize();
+
+            //and theta (angle between v1 and v2)
+            double theta = acos(QVector3D::dotProduct(v1,v2));
+
+            //Accumulate Rotation
+            QQuaternion q = QQuaternion(cos(theta/2.0),sin(theta/2)*n);
+            q.normalize();
+            /*
+             * Wikipedia: Two rotation quaternions can be combined into
+             * one equivalent quaternionby the relation:
+             * q' = q_2*q_1'
+             * in which q′ corresponds to the rotation q1 followed by the rotation q2.
+             *  (Note that quaternion multiplication is not commutative.)
+             */
+            qubeRotationQuaternion = q*qubeRotationQuaternion;
+            qubeRotationQuaternion.normalize();
+
             updateGL();
+
     }
-    qDebug() << "mouse move button " << event->button();
 }
 
 //4.1.2 User Input: Zooming
@@ -278,3 +358,11 @@ void MyGLWidget::setTessellation(int t){
     tesselation = t;
     updateGL();
 }
+
+void MyGLWidget::resetCamera(){
+    qubeRotationQuaternion = QQuaternion();
+    tx = 0;
+    ty = 0;
+    cameraZoom = cameraZoomDefault;
+    updateGL();
+}

helloqube/myglwidget.h

@@ -5,6 +5,10 @@
 #include <gl/GLU.h>
 #include <QDebug>
 #include <QWheelEvent>
+#include <QQuaternion>
+#include <QMatrix4x4>
+#include <math.h>
+#include <QVector3D>
 
 class MyGLWidget : public QGLWidget
 {
@@ -28,11 +32,22 @@ protected:
     void wheelEvent(QWheelEvent *event);
 
 private:
+    //tesselation slider
     int tesselation;
+
+    //zoom camera
+    const double cameraZoomDefault = -5;
     double cameraZoom;
+
+    //translate camera
     QPoint clickStartPosition;
     bool rightButtonPressed;
-    double translationX, translationY;
+    double tx, ty;
+
+    //rotate cube
+    bool leftButtonPressed;
+    QQuaternion qubeRotationQuaternion;
+    QPoint screenCenter;//Center of screen in pixel coordinates
 
 
 public slots:
@@ -42,6 +57,7 @@ public slots:
     void shadeGouraudSlot();
     void shadePhongSlot();
     void setTessellation(int t);
+    void resetCamera();
 };
 
 #endif // GLWIDGET_H