to have the box move not having to hold the mouse button down

OpenGL OpenGL: Basic Coding
1

// This is my program.
// when I click and hold the middle button down. I want to box to rotate itself with out having to hold it down. I m trying to use idle fucntion.
Please give me pointers on how I should make it work? below is my program.
thx

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>

GLfloat xAngle = 0.0, yAngle = 0.0, zAngle = 0.0;
GLfloat eyeX=0.0, eyeY=0.0, eyeZ=10.0;
GLfloat dx=0.0, dy=0.0, dz=0.0;
GLfloat ty, tx, tz;
int angle;
int spinning=0;
void myInit(int *, char **);
void mouseManager(int, int, int, int);
void displayFunc(void);
void idle(void);

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

myInit(&argc, argv);

glutDisplayFunc(displayFunc);
glutMouseFunc(mouseManager);
glutIdleFunc(idle);
glutMainLoop(); //infinite loop
}

void displayFunc(void){
int i;
static done=0;

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(40.0, // field of view
640.0/480.0, // Aspect ratio
1.0, // Near Z
16.0 // Far Z
);
/*
glMatrixMode(GL_PROJECTION); // virtual camera
glLoadIdentity();
glOrtho(-2.0, 2.0, -2.0, 2.0, -2.0, 2);
*/

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();

gluLookAt(eyeX, eyeY, eyeZ, // Eye is at (0, 0, 10)
0.0, 0.0, 0.0, // center is at (0,0,0)
0.0, 1.0, 0.0); // up is Y direction

glTranslatef( tx, -ty, tz);
glRotatef(xAngle, 1.0, 0.0, 0.0);
glRotatef(yAngle, 0.0, 1.0, 0.0);
glRotatef(zAngle, 0.0, 0.0, 1.0);

if(done)
glCallList(1);
else{
done=1;
glNewList(1, GL_COMPILE_AND_EXECUTE);
glBegin(GL_QUADS);

glColor3f(0.75, 0.75, 0.5);


//left

 glVertex3f(1.0, -1.0, 1.0);
glVertex3f(1.0, -1.0, -1.0);
glVertex3f(1.0, 1.0, -1.0);
glVertex3f(1.0, 1.0, 1.0);

glColor3f(1.0, 0.9, 0.0);

//right side
glVertex3f(-1.0, -1.0, 1.0);
glVertex3f(-1.0, -1.0, -1.0);
glVertex3f(-1.0, 1.0, -1.0);
glVertex3f(-1.0, 1.0, 1.0);

//front
glColor3f(1.0, 0.0, 0.0);
glVertex3f(-1.0, 1.0, 1.0);
glVertex3f(1.0, 1.0, 1.0);
glVertex3f(1.0, -1.0, 1.0);
glVertex3f(-1.0, -1.0, 1.0);



//back 
glColor3f(0.0, 1.0, 0.0);
//    glTranslatef( tx, 0.0, 0.0);
glVertex3f(-1.0, 1.0, -1.0);
glVertex3f(1.0, 1.0, -1.0);
glVertex3f(1.0, -1.0, -1.0);
glVertex3f(-1.0, -1.0, -1.0);


//top
glColor3f(0.0, 0.0, 1.0);

glVertex3f(-1.0, 1.0, 1.0);
glVertex3f(1.0, 1.0, 1.0);
glVertex3f(1.0, 1.0, -1.0);
glVertex3f(-1.0, 1.0, -1.0);


//bottom
glColor3f(0.5, 0.5, 0.5);

glVertex3f(-1.0, -1.0, 1.0);
glVertex3f(1.0, -1.0, 1.0);
glVertex3f(1.0, -1.0, -1.0);
glVertex3f(-1.0, -1.0, -1.0);



glEnd();
glEndList();

}
/*
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(-1.0, -1.0, -12);
glRotatef(2xAngle, 1.0, 0.0, 0.0);
glRotatef(2yAngle, 0.0, 1.0, 0.0);
glRotatef(2*zAngle, 0.0, 0.0, 1.0);
*/
glCallList(1);

glutSwapBuffers();
}

void mouseManager(int button, int state, int x, int y){
float alpha;
alpha=-(angle*3.1415926)/180;
switch(button){
case GLUT_LEFT_BUTTON:

if(state==GLUT_DOWN){
  // xAngle+=2.0;  
  //    dx=0.4;
  // spinning=1;
 // moveX+=10.0;

  angle=0; tx=0; ty=0; tz=0; eyeY=0, eyeZ=10;

}
else{
  dx=0.0;
  spinning=0;
}
break;

case GLUT_RIGHT_BUTTON:
if(state==GLUT_DOWN)
{ //dy=0.4;
// yAngle+=2.0;
spinning=1;
// moveX-=10.0;

}
else{
dy=0.0;
spinning=0;
}
break;

case GLUT_MIDDLE_BUTTON:
if(state==GLUT_DOWN){
dz=0.4;

  //  zAngle+=2.0;
  spinning=1;
}  
else{
  dz=0.0;
  
  spinning=0;
}

break;

defaut:
;
}

displayFunc();
}

void myInit(int *argc, char **argv){
glutInit(argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(640,480);
glutInitWindowPosition(100, 150);
glutCreateWindow(argv[0]);

glClearColor(1.0,1.0,1.0,0.0); // Set clear color to white
angle=0;
ty=0;
tx=0;
tz=0;

glEnable(GL_DEPTH_TEST);
}
void idle(void){
float alpha;
alpha=-(angle*1.1)/180;
if(spinning==1){
xAngle+=dx;
yAngle+=dy;
zAngle+=dz;
// tx=tx + cos(alpha);
// tz=tz + sin(alpha);

/*
light0_position[0]-=dl;
light0_position[1]-=dl;
if(light0_position[0] &lt;-10){
  light0_position[0]=10;
  light0_position[1]=10;
}
*/

};
glutPostRedisplay();
}

2

I prefer to use the glutTimerFunc over the glutIdleFunc. One reason is that you have better control on the rate of updating the animation. You can set the glutimerfunc every X milliseconds.

I think your problem is in your mouse function and you change the state of your object. You have to remember that the mouse function is called every time the state of the mouse changes. In your code from the way it looks, as soon as you release the mouse button your turns the rotation off.
You may want to add a flip-flop type state, this will change the state each time the button is pressed. first press start’s rotation, second press stops rotation.

Example code to add:

if ((spinning = 1) && (state == GLUT_DOWN)
{
spinning = 0; Stop rotation
break;
}

if ((spinning = 0) && (state == GLUT_DOWN)
{
spinning = 1;
break;
}

Your code with error pointed out:

case GLUT_MIDDLE_BUTTON:
if(state==GLUT_DOWN){
dz=0.4;

  //  zAngle+=2.0;
  spinning=1;
}  
else{
  dz=0.0;
  
  spinning=0; // turns off spinning when button is released.
}

break;

[QUOTE]Originally posted by OpenGL_Student:
[b]// This is my program.
// when I click and hold the middle button down. I want to box to rotate itself with out having to hold it down. I m trying to use idle fucntion.
Please give me pointers on how I should make it work? below is my program.
thx

[This message has been edited by nexusone (edited 03-08-2002).]

3

Oh I see I will work on it and see how it goes. Thank you very much! I will get back to you on how I am with it!