Qt and OpenGL: gluPerspective

[giorgik]

Hello to all. I created this simple program with Qt 4.8.2 and OpenGL. It comes to drawing a 3D grid and display it in perspective using gluPerspective. In addition, I use the mouse to move around the scene. The problem I have is to better manage the movement of the mouse. I put my project in attachment. Can you help me make better use of the mouse? The movement of the grid is chaotic, and I wanted with the right mouse button the zoom or removal and the left mouse button the grid rotation axis x and y.piano_griglia3D.zip

I'm going crazy to solve

[giorgik]

The code with glOrtho():

#include "glwidget.h"
#include <GL/gl.h>
#include "GL/glut.h"
#include "GL/freeglut.h"
#include "GL/freeglut_ext.h"
 
GLWidget::GLWidget(QWidget *parent) :
    QGLWidget(parent)
{
    //
}
 
void GLWidget::resizeGL(int w, int h)
{
    int side = qMin(w, h);
    glViewport((w - side) / 2, (h - side) / 2, side, side);
 
    // setta la matrice corrente a quella della proiezione e cancellala
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
 
    // definisci il volume di clipping (frustum) del mondo (left, right, bottom, top, near, far)
    // in base alla massima ampiezza
    glOrtho(-12.0f, 12.0f, -12.0f, 12.0f, 0.0f, 10.0f);
    //gluPerspective(45.0f, (GLfloat)w/(GLfloat)h, -10.0f, 10.0f);
 
    // setta la matrice corrente a quella di modello-vista e cancellala
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}
 
void GLWidget::initializeGL()
{
    // specifica il colore lilla come colore di background
    // usato da glClear()
    glClearColor(0.7, 0.7, 0.8, 1);
}
 
void GLWidget::paintGL()
{
    // cancella lo sfondo con il colore scelto da glClearColor
    // clear buffer
    glClear(GL_COLOR_BUFFER_BIT);
 
    //----------- 20x20 grid: draw XY-grid with default size -----------
    glBegin(GL_LINES);
 
    glColor3f(0.5f, 0.5f, 0.5f);
    for(float i = 1.0f; i <= 10.0f; i+= 1.0f)
    {
        glVertex3f(-10.0f,  i, 0);   // lines parallel to X-axis
        glVertex3f( 10.0f,  i, 0);
        glVertex3f(-10.0f, -i, 0);   // lines parallel to X-axis
        glVertex3f( 10.0f, -i, 0);
 
        glVertex3f( i, -10.0f, 0);   // lines parallel to Y-axis
        glVertex3f( i,  10.0f, 0);
        glVertex3f(-i, -10.0f, 0);   // lines parallel to Y-axis
        glVertex3f(-i,  10.0f, 0);
    }
 
    // x-axis
    glColor3f(1, 0, 0);
    glVertex3f(-10.0f, 0, 0);
    glVertex3f( 10.0f, 0, 0);
 
    // y-axis
    glColor3f(0, 0, 1);
    glVertex3f(0, -10.0f, 0);
    glVertex3f(0,  10.0f, 0);
 
    glEnd();
    //-----------------------------------------------------------------
}

#include "glwidget.h"
#include <GL/gl.h>
#include "GL/glut.h"
#include "GL/freeglut.h"
#include "GL/freeglut_ext.h"

GLWidget::GLWidget(QWidget *parent) :
    QGLWidget(parent)
{
    //
}

void GLWidget::resizeGL(int w, int h)
{
    int side = qMin(w, h);
    glViewport((w - side) / 2, (h - side) / 2, side, side);

    // setta la matrice corrente a quella della proiezione e cancellala
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    // definisci il volume di clipping (frustum) del mondo (left, right, bottom, top, near, far)
    // in base alla massima ampiezza
    glOrtho(-12.0f, 12.0f, -12.0f, 12.0f, 0.0f, 10.0f);
    //gluPerspective(45.0f, (GLfloat)w/(GLfloat)h, -10.0f, 10.0f);
    
    // setta la matrice corrente a quella di modello-vista e cancellala
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

void GLWidget::initializeGL()
{
    // specifica il colore lilla come colore di background
    // usato da glClear()
    glClearColor(0.7, 0.7, 0.8, 1);
}

void GLWidget::paintGL()
{
    // cancella lo sfondo con il colore scelto da glClearColor
    // clear buffer
    glClear(GL_COLOR_BUFFER_BIT);

    //----------- 20x20 grid: draw XY-grid with default size -----------
    glBegin(GL_LINES);

    glColor3f(0.5f, 0.5f, 0.5f);
    for(float i = 1.0f; i <= 10.0f; i+= 1.0f)
    {
        glVertex3f(-10.0f,  i, 0);   // lines parallel to X-axis
        glVertex3f( 10.0f,  i, 0);
        glVertex3f(-10.0f, -i, 0);   // lines parallel to X-axis
        glVertex3f( 10.0f, -i, 0);

        glVertex3f( i, -10.0f, 0);   // lines parallel to Y-axis
        glVertex3f( i,  10.0f, 0);
        glVertex3f(-i, -10.0f, 0);   // lines parallel to Y-axis
        glVertex3f(-i,  10.0f, 0);
    }

    // x-axis
    glColor3f(1, 0, 0);
    glVertex3f(-10.0f, 0, 0);
    glVertex3f( 10.0f, 0, 0);

    // y-axis
    glColor3f(0, 0, 1);
    glVertex3f(0, -10.0f, 0);
    glVertex3f(0,  10.0f, 0);

    glEnd();
    //-----------------------------------------------------------------
}

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how to get the perspective gluPerspective () so you can see my perspective grid ?
I would use GLWidget::mouseMoveEvent (QMouseEvent * event) to rotate the grid and for zooming and moving away. How should I write the code ?