opengl model transformations

I am attempting to move all my game objects independantly but it isn't working.

Code:

---

void moveAstroids(void)
{
 
  for_each(astroids.begin(),astroids.end(),mem_fun(&Astroid::translate));
  glutPostRedisplay();
 
}

---

Code:

---

void Astroid::translate(){
  glPushMatrix();
  glTranslatef(velocity,velocity,0);
  Astroid::draw();
  glPopMatrix();
}

---

when I comment out the Push and Pop statements all the game objects move in tandem according to one translation. I am trying to get each object to move independantly. I tried using glLoadIdentity(); but this had the same effect.

What is happening right now? Are the objects not being translated at all?

Also, make sure you are performing the translation on the ModelView matrix, and not the Projection matrix.

The gameobjects are currently not translated at all. As far as I can tell the translations are performed on the ModelView matrix it is the last thing set in the reshape function.

Here is my current code It is a long way from complete and is basicly an adaptation of the double.c program from the redbook.

Code:

---

#include <iostream>
#include <GL/glut.h>
#include <stdlib.h>
#include <list>
#include <functional>
#include <algorithm>
#include <time.h>

#include "gobject.h"
#include "ship.h"
#include "astroid.h"

using namespace std;
extern const int SCREENWIDTH = 450;
extern const int SCREENHEIGHT = 450;

static GLfloat spin = 0.0;
list<GObject*> gameObjects;
list<Astroid*> astroids;
Ship* spaceShip = new Ship();

void display()
{
 
  glClear(GL_COLOR_BUFFER_BIT);
  glColor3f(1.0, 1.0, 1.0);
  for_each(gameObjects.begin(),gameObjects.end(),mem_fun(&GObject::translate));
  glutSwapBuffers();
 
}

void moveAstroids(void)
{
 
  // for_each(astroids.begin(),astroids.end(),mem_fun(&Astroid::translate));
  glutPostRedisplay();
 
}


void idleGameLoop(void)
{
 
  moveAstroids();
  glutPostRedisplay();
}


void init(void)
{
  srand(time(NULL));
  glClearColor (0.0, 0.0, 0.0, 0.0);
  glShadeModel (GL_FLAT);
  gameObjects.push_front(spaceShip);
  for (int i = 0; i<10; i++){
  Astroid* sharedTempAstroid = new Astroid();
    gameObjects.push_back(sharedTempAstroid);
    astroids.push_back(sharedTempAstroid);

  }
}

void reshape(int w, int h)
{
  glViewport (0, 0, (GLsizei) w, (GLsizei) h);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluOrtho2D(-SCREENWIDTH/2,SCREENWIDTH/2,-SCREENHEIGHT/2,SCREENHEIGHT/2);
 
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

/* ARGSUSED2 */
void mouse(int button, int state, int x, int y)
{
  switch (button) {
      case GLUT_RIGHT_BUTTON:
        if (state == GLUT_DOWN)
            glutIdleFunc(idleGameLoop);
        break;
      case GLUT_MIDDLE_BUTTON:
        if (state == GLUT_DOWN)
            glutIdleFunc(NULL);
        break;
      default:
        break;
  }
}

                   

static void
key(unsigned char k, int x, int y)
{
  switch (k) {
  case 27:  /* Escape */
    exit(0);
    break;
  case 65:
  case 97:
    spin = (int)spin % 360 + 2.0;
    glutIdleFunc(idleGameLoop);
    break;
  case 68:
  case 100:
    spin = (int)spin % 360 - 2.0;
    glutIdleFunc(idleGameLoop);
    break;
  default:
    return;
  }
  glutPostRedisplay();
}

/*
 *  Request double buffer display mode.
 *  Register mouse input callback functions
 */
int main(int argc, char** argv)
{
 
  glutInit(&argc, argv);
  glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB);
  glutInitWindowSize (SCREENWIDTH, SCREENHEIGHT);
  glutInitWindowPosition (10, 10);
  glutCreateWindow (argv[0]);
  init ();
 
  glutDisplayFunc(display);
  glutReshapeFunc(reshape);
  glutMouseFunc(mouse);
  glutKeyboardFunc(key);
  glutMainLoop();
  return 0;  /* ANSI C requires main to return int. */
}

---

Code:

---

#include "astroid.h"

extern const int SCREENWIDTH;
extern const int SCREENHEIGHT;

Astroid::Astroid()
{
 
  xcoord=rand()%(SCREENWIDTH/2)+1;
  ycoord=rand()%(SCREENHEIGHT/2)+1;
  velocity = 1*(rand()%4);
 
}

void Astroid::draw(){
  glColor3f(256.0, 0.0 , 0.0);
 
  glRectf(xcoord, ycoord,xcoord+10,ycoord+10);
 
}

void Astroid::rotate(){}
void Astroid::translate(){
  glPushMatrix();
  glTranslatef(velocity,velocity,0);
  Astroid::draw();
  glPopMatrix();
}

Astroid::~Astroid(){}

---