my program display nothing !

[airseb]

a window appears but there is nothing in, even not a black color.
can you help me please !

this is the code :

#include <stdio.h>
#include <iostream.h>
#include <string.h>
#include <GL/glut.h>

#define nb_vertices 697

char tmp [100] ;
int temp [nb_vertices] ;
char chaine [100] ;
float tab_vertices [nb_vertices][3] ;
int i, j ;
char nom_fichier[] = "cool.ase" ;



void lecture ()
{

FILE *cool ; //pointeur sur le fichier cool

if ((cool = fopen(nom_fichier, "r")) == NULL)
return ;

strcpy (chaine , "*MESH_VERTEX") ;

do
{

fscanf(cool, "%s", tmp) ;
}
while (strcmp (chaine, tmp) != 0) ;


for (i = 0; i < nb_vertices ;i++)//rempli le tableau avec des coordonnées de vertices
{
fscanf (cool, "%d%f%f%f%s", &(temp[0]) , &(tab_vertices[i][0]), &(tab_vertices[i][1]), &(tab_vertices[i][2]), tmp) ;
//cout << tab_vertices[i][0]<<" "<< tab_vertices[i][1]<<" "<< tab_vertices[i][2]<<endl ;

}

fclose (cool) ;

}
void reshape (int w, int h)
{
glViewport (0, 0, w, h) ;
glMatrixMode (GL_PROJECTION) ;
glLoadIdentity () ;
glFrustum(-1.0 , 1.0, -1.0, 1.0, 5.0, 500.0); //perspective conique
glMatrixMode(GL_MODELVIEW); //la matrice active de modelisation/visualisation sera affectée
glLoadIdentity(); //charge la matrice identité

gluLookAt (0.0, 0.0, 50.0, 0.0,0.0,0.0, 0.0, 1.0, 0.0) ; //caméra placée sur l'axe des Z et regardant vers l'origine
}
void display ()
{
glEnableClientState (GL_VERTEX_ARRAY);
glVertexPointer (3, GL_FLOAT, 0, &tab_vertices[0][0]);

glPolygonMode (GL_FRONT, GL_LINE) ;

for (j = 0 ; j <nb_vertices; j++)
{
glBegin (GL_TRIANGLES);
glArrayElement (j);
glEnd () ;
}
}

void main (int argc, char** argv)

{

lecture () ;
glutInit (&argc, argv) ;
glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH) ;
glutInitWindowSize (640, 480) ;
glutInitWindowPosition (250,250) ;
glutCreateWindow (argv [0]) ;

glClearColor (0.0, 0.0, 0.0, 0.0) ;
glClear (GL_COLOR_BUFFER_BIT| GL_DEPTH_BUFFER_BIT ) ;
glEnable( GL_DEPTH_TEST );

glutReshapeFunc (reshape) ;
glutDisplayFunc (display) ;
glutMainLoop () ;

}


[This message has been edited by airseb (edited 12-31-2002).]

[Stack Overflow]

Try enabling Depth_Test and glClear in your Display Function.

Ex: Take these functions and put them in your Display Function:
glClearColor (0.0, 0.0, 0.0, 0.0) ;
glClear (GL_COLOR_BUFFER_BIT| GL_DEPTH_BUFFER_BIT ) ;
glEnable( GL_DEPTH_TEST );

Edit:
Change your glutInitDisplayMode Function to this.
glutInitDisplayMode( GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH );

- VC6-OGL

[This message has been edited by VC6-OGL (edited 12-31-2002).]

[airseb]

thanks !
but now i have a black windows without the object that i want to display.

i think that the error come from the values of glFrustum but i'm not sure and i don't know the values which i have to put. can you help me ?

[mdog1234]

well we dont have this file you are loading. so i dont think anybody is going to get anything but a black screen

[mdog1234]

when i tried your code i got a clear screen too. glClear and depth testing are fine. what you forgot is a glFlush(); in your display function. Now i get a black screen but i need that file or something to provide anymore help

[Stack Overflow]

Are you sure you are loading the *.ase file in your program correctly? Have you seen the program work before? What is the program supposed to do or look like?

- VC6-OGL

[This message has been edited by VC6-OGL (edited 12-31-2002).]

[Stack Overflow]

If you want to enable Double Buffering, do the following,

Change your glutInitDisplayMode to:
· glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH );

And at the end of your Display Function, add:
· glFlush();
· glutSwapBuffers();

- VC6-OGL

[airseb]

Originally posted by VC6-OGL:
Are you sure you are loading the *.ase file in your program correctly? Have you seen the program work before? What is the program supposed to do or look like?

- VC6-OGL

[This message has been edited by VC6-OGL (edited 12-31-2002).]

the program with the ase file work, i have tested it before by displaying the datas about meshes.

[airseb]

don't you think that there is an error with glFrustum ?i have put the values a little randomly. Or is it glVertexPointer that just allow an array of one dimension instead of two ?

[his message has been edited by airseb (edited 12-31-2002).]

[This message has been edited by airseb (edited 12-31-2002).]

[Stack Overflow]

It might be your glFrustum, a needed gluPerspective or gluLookAt isn't set in the right coordinates.

- VC6-OGL