Mouse event handling source code in OpenGL

This source code is written in C++ with OpenGL.It is just a demo for mouse event handling you can use this code for your project. In this example void motionPassive(int x, int y) to find out the cursor position in the window. By finding the difference between the previous and initial position the direction of the camera is changed.

#include <windows.h>

#include <cmath>

#include <cstdlib>

#include <GL/glut.h>

#include <iostream>

using namespace std;

float lastx, lasty;

float angle=0.0,ratio;

float x=0.0f,y=0.0f,z=0.5f;

float lx=0.0f,ly=0.0f,lz=-1.0f;

float _angle = 30.0f;

float _cameraAngle = 0.0f;

void RotY(float ang) {

lx = sin(ang);

lz = -cos(ang);

glLoadIdentity();

gluLookAt(x, y, z,

x + lx,y + ly,z + lz,

0.0f,1.0f,0.0f);

}

void moveFB(int direction) {

x = x + direction*(lx)*0.1;

z = z + direction*(lz)*0.1;

glLoadIdentity();

gluLookAt(x, y, z,

x + lx,y + ly,z + lz,

0.0f,1.0f,0.0f);

}

void LookUpDown(float ang) {

ly = sin(ang);

lz = -cos(ang);

glLoadIdentity();

gluLookAt(x, y, z,

x + lx,y + ly,z + lz,

0,1,0);

if (angle > 360) {

angle -= 360;

}

}

void initRendering() {

glEnable(GL_DEPTH_TEST);

}

void handleKeypress(unsigned char key,

int x, int y) {

switch (key) {

case 27:

exit(0);

}

}

void handleSpecialKey(int key, int x, int y) {

switch (key) {

case GLUT_KEY_LEFT :

angle -= 0.1f;

RotY(angle);

break;

case GLUT_KEY_RIGHT :

angle +=0.1f;

RotY(angle);

break;

case GLUT_KEY_UP :

moveFB(1);

break;

case GLUT_KEY_DOWN :

moveFB(-1);

break;

case GLUT_KEY_PAGE_UP :

angle +=0.01f;

LookUpDown(angle);

break;

case GLUT_KEY_PAGE_DOWN :

angle -=0.01f;

LookUpDown(angle);

break;

}

}

void motionPassive(int x, int y)

{

glutSetCursor(GLUT_CURSOR_FULL_CROSSHAIR);

cout << "Mouse moved at "

<< "(" << x << "," << y << ")" << endl;

int diffx=x-lastx; //check the difference between the current x and the last x position

int diffy=y-lasty; //check the difference between the current y and the last y position

lastx=x; //set lastx to the current x position

lasty=y; //set lasty to the current y position

angle += (float) diffy;

RotY(angle/20); //set the xrot to xrot with the addition of the difference in the y position

angle += (float) diffx;

RotY(angle/20);    //set the xrot to yrot with the addition of the difference in the x position

}

void handleResize(int w, int h) {

glViewport(0, 0, w, h);

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

gluPerspective(45.0,

(double)w / (double)h,

0.25,

200.0);

}

void drawScene() {

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

glEnable(GL_BLEND);

glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

glEnable(GL_COLOR_MATERIAL);

glMatrixMode(GL_MODELVIEW);

glLoadIdentity();

gluLookAt(x, y, z,

x + lx,y + ly,z + lz,

0.0f,1.0f,0.0f);

//glRotatef(LookUpDown,1.0,0,0);

glPushMatrix();

glTranslatef(0.0f, 0.0f, 0.0f);

glRotatef(_angle, 0.0f, 1.0f, 0.0f);

glScalef(0.01f, 0.01f, 0.01f);

glBegin(GL_QUADS);

//Cross back

glColor4f(1.0f,1.0f, 0.0f, 0.9f);

glVertex3f(-0.5, 2.5, -0.5);

glVertex3f(-0.5, -3.0, -0.5);

glVertex3f(0.5, -3.0, -0.5);

glVertex3f(0.5, 2.5, -0.5);

glVertex3f(-2.0, 1.0, -0.5);

glVertex3f(-2.0, 0.0, -0.5);

glVertex3f(2.0, 0.0, -0.5);

glVertex3f(2.0, 1.0, -0.5);

//Cross front

glColor4f(1.0f, 1.0f, 0.0f, 0.5f);

glVertex3f(-0.5, 2.5, 0.5);

glVertex3f(-0.5, -3.0, 0.5);

glVertex3f(0.5, -3.0, 0.5);

glVertex3f(0.5, 2.5, 0.5);

glVertex3f(-2.0, 1.0, 0.5);

glVertex3f(-2.0, 0.0, 0.5);

glVertex3f(2.0, 0.0, 0.5);

glVertex3f(2.0, 1.0, 0.5);

//Cross top

glVertex3f(0.5, 2.5, 0.5);

glVertex3f(-0.5, 2.5, 0.5);

glVertex3f(-0.5, 2.5, -0.5);

glVertex3f(0.5, 2.5, -0.5);

//Cross left top side

glVertex3f(-0.5, 2.5, 0.5);

glVertex3f(-0.5, 2.5, -0.5);

glVertex3f(-0.5, 1.0, -0.5);

glVertex3f(-0.5, 1.0, 0.5);

//Cross left side  top

glVertex3f(-0.5, 1.0, 0.5);

glVertex3f(-0.5, 1.0, -0.5);

glVertex3f(-2.0, 1.0, -0.5);

glVertex3f(-2.0, 1.0, 0.5);

//Cross left side  end

glVertex3f(-2.0, 1.0, 0.5);

glVertex3f(-2.0, 1.0, -0.5);

glVertex3f(-2.0, 0.0, -0.5);

glVertex3f(-2.0, 0.0, 0.5);

//Cross left side bottom

glVertex3f(-2.0, 0.0, 0.5);

glVertex3f(-0.5, 0.0, 0.5);

glVertex3f(-0.5, 0.0, -0.5);

glVertex3f(-2.0, 0.0, -0.5);

//Cross left bottom side

glVertex3f(-0.5, 0.0, 0.5);

glVertex3f(-0.5, 0.0, -0.5);

glVertex3f(-0.5, -3.0, -0.5);

glVertex3f(-0.5, -3.0, 0.5);

//Cross  bottom

glVertex3f(0.5, -3.0, 0.5);

glVertex3f(0.5, -3.0, -0.5);

glVertex3f(-0.5, -3.0, -0.5);

glVertex3f(-0.5, -3.0, 0.5);

//Cross right bottom side

glVertex3f(0.5, 0.0, 0.5);

glVertex3f(0.5, -3.0, 0.5);

glVertex3f(0.5, -3.0, -0.5);

glVertex3f(0.5, 0.0, -0.5);

//Cross right side bottom

glVertex3f(0.5, 0.0, 0.5);

glVertex3f(0.5, 0.0, -0.5);

glVertex3f(2.0, 0.0, -0.5);

glVertex3f(2.0, 0.0, 0.5);

//Cross right side end

glVertex3f(2.0, 1.0, 0.5);

glVertex3f(2.0, 0.0, 0.5);

glVertex3f(2.0, 0.0, -0.5);

glVertex3f(2.0, 1.0, -0.5);

//Cross right side top

glVertex3f(0.5, 1.0, 0.5);

glVertex3f(2.0, 1.0, 0.5);

glVertex3f(2.0, 1.0, -0.5);

glVertex3f(0.5, 1.0, -0.5);

//Cross right side top

glVertex3f(0.5, 1.0, 0.5);

glVertex3f(0.5, 1.0, -0.5);

glVertex3f(0.5, 2.5, -0.5);

glVertex3f(0.5, 2.5, 0.5);

glEnd();

glPopMatrix();

glPushMatrix();

glBegin(GL_QUADS);

glTranslatef(0.0f, -1.5f, 0.0f);

glRotatef(_angle,0.0,0.0,0.0);

//floor

glColor3f(0.5, 1.0, 0.0);

glVertex3f(-10.0,-0.5,10);

glVertex3f(-10.0,-0.5,-10);

glVertex3f(10.0,-0.5,-10);

glVertex3f(10.0,-0.5,10);

glEnd();

glPopMatrix();

glutSwapBuffers();

}

void update(int value) {

_angle += 4.0f;

if (_angle > 360) {

_angle -= 360;

}

glutPostRedisplay();

glutTimerFunc(25, update, 0);

}

int main(int argc, char** argv) {

glutInit(&argc,argv);

glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);

glutInitWindowSize(500,500);

glutCreateWindow("Rotaion Test");

initRendering();

//glutFullScreen();

glutDisplayFunc(drawScene);

glutKeyboardFunc(handleKeypress);

glutSpecialFunc(handleSpecialKey);

glutReshapeFunc(handleResize);

glutTimerFunc(25,update,0);

glutPassiveMotionFunc(motionPassive);

glutMainLoop();

return 0;

}