a big problem with radial blur

OpenGL OpenGL: Advanced Coding
1

Hi,
i have read the lesson 36 of nehe and i have decided of making my own program about radial blur. But i have a problem :
the big texture that we create and render and witch has like size 640x480 don’t want to be displayed. i don’t understand why !
can you help me ? i really don’t know how to do…
the glutWireCube of the display function is displayed.
this is the code (where i show in commentary what part of the program don’t want to be displayed (at the end)) :
this is first, the main function :

include “main.h”

unsigned int textureNumber ;
Texture *CreateTexture ;

void reshape (int w, int h)
{
glViewport (0, 0, w, h) ;

glMatrixMode (GL_PROJECTION) ;
glLoadIdentity () ;

glFrustum(-5.0 , 5.0, -5.0, 5.0, 5.0, 500.0); //perspective conique
glPushMatrix () ; //permet de revenir à la perspective conique de glFrustum avec glPopMatrix

glMatrixMode(GL_MODELVIEW); //la matrice active de modelisation/visualisation sera affectée
glLoadIdentity(); //charge la matrice identité

gluLookAt (0, 5, 70, 0, 0, 0, 0, 1, 0) ;
//les 3 premières données sont les coordonnées de la caméra,
//les 3 suivantes désignent la cible, et les 3 suivantes, le haut de la caméra suivant un axe(ici y)

}

void display ()
{
glClear (GL_COLOR_BUFFER_BIT| GL_DEPTH_BUFFER_BIT ) ;
glPolygonMode (GL_FRONT_AND_BACK, GL_FILL) ;

CreateTexture->RadialBlur() ; //rend dans la texture et la blur

/*AUX_RGBImageRec *texture1;
texture1 = auxDIBImageLoad(“tex.bmp”);
unsigned int texname ;
glGenTextures (1, &texname) ;
glBindTexture (GL_TEXTURE_2D, texname) ;

glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_LINEAR);

glTexImage2D(GL_TEXTURE_2D, 0, 3, (texture1)->sizeX, (texture1)->sizeY,
0, GL_RGB, GL_UNSIGNED_BYTE, (texture1)->data);

glBindTexture(GL_TEXTURE_2D, texname);
glBegin(GL_QUADS);
glColor3f(1.0,1.0,1.0);
glTexCoord2f(0,0);glVertex2f(-1,-1);
glTexCoord2f(1,0);glVertex2f(1,-1);
glTexCoord2f(1,1);glVertex2f(1,1);
glTexCoord2f(0,1);glVertex2f(-1,1);
glEnd();*/

glutWireCube (20) ;

glutSwapBuffers() ;

}

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

//cout<<“hello”<<endl ;

glutInit (&argc, argv) ;
glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH) ;
glutInitWindowSize (screenWidth, screenHeight) ;
glutInitWindowPosition (250,250) ;
glutCreateWindow (argv [0]) ;
glClearColor (0.0, 0.5, 0.0, 1.0) ;

//glViewport (0, 0, screenWidth, screenHeight) ;

glEnable(GL_TEXTURE_2D);
glEnable( GL_DEPTH_TEST );

CreateTexture=new Texture(128) ;//la 1ère variable contient le n°
//de la texture et la 2ème est sa résolution en largeur et hauteur

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

and then the code witch contains the part that seems to be not executed :

#include “main.h”

void Texture::BlendingOrthoOn ()
{
glDisable(GL_DEPTH_TEST);
glBlendFunc(GL_SRC_ALPHA,GL_ONE);
glEnable(GL_BLEND);

glMatrixMode (GL_PROJECTION) ;
//glLoadIdentity();
glOrtho ( 0, screenWidth , screenHeight , 0, -1, 1) ; //spécifie un repère dont l’origine
//est en haut a gauche

glMatrixMode(GL_MODELVIEW);
//glLoadIdentity();

}

void Texture::BlendingOrthoOff ()
{
glMatrixMode (GL_PROJECTION) ;
glPopMatrix () ; //pour revenir aux valeurs de glFrustum qui est dans reshape (fonction main)
glMatrixMode(GL_MODELVIEW);
//glLoadIdentity(); //le remettre pour test

glDisable(GL_BLEND);
glEnable(GL_DEPTH_TEST);
}

Texture::Texture(int size)
{
unsigned int *pTexture = NULL;

pTexture = new unsigned int [size * size * 4]; // 4= 1 pour chaque composant RGBA
memset(pTexture, 0, size * size * 4 * sizeof(unsigned int));

glGenTextures(1, &textureNumber);
glBindTexture(GL_TEXTURE_2D, textureNumber);

// Cré la texture et la stocke en mémoire vidéo
glTexImage2D(GL_TEXTURE_2D, 0, 4, size, size, 0, GL_RGBA, GL_UNSIGNED_INT, pTexture);

// défini la qualité des textures
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);

// Since we stored the texture space with OpenGL, we can delete the image data
delete pTexture;
}

void Texture::RadialBlur ()
{
float textureReduction = 0.0 ;
//glPolygonMode (GL_FRONT, GL_LINE) ;
glViewport (0,0,128,128); //réduit a la taille du viewport pour que la texture
//de l’objet fasse 128x128 sinon l’objet serait rendu dans un espace
//plus grand et on prend avec glCopyTexImage2D les 128 premiers
//pixels.

glDisable(GL_TEXTURE_2D);

//glutSolidCube (20) ;
glBegin(GL_QUADS);
glColor3f(0.0, 1.0, 1.0) ;
glVertex2f(-10,-10);
glVertex2f(10,-10);
glVertex2f(10,10);
glVertex2f(-10,10);
glEnd();

glEnable(GL_TEXTURE_2D);

glBindTexture(GL_TEXTURE_2D,textureNumber);

glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, 0, 0, 128, 128, 0); //copie l’objet
//dans la texture spécifiée en mémoire vidéo
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glViewport(0 , 0,screenWidth ,screenHeight);

glBindTexture(GL_TEXTURE_2D,textureNumber); //indique que la texture noire va etre utilisée

CreateTexture->BlendingOrthoOn() ;

//glDisable (GL_BLEND) ;
// it’s here the part that don’t display the square
glBegin(GL_QUADS) ;
for (int num = 0;num <25 ; num++)
{
glColor4f(1.0, 1.0, 1.0, 0.2);
glTexCoord2f(0+textureReduction,1-textureReduction);
glVertex2f(0,0);

  	glTexCoord2f(0+textureReduction,0+textureReduction);			
  	glVertex2f(0,480);				

  	glTexCoord2f(1-textureReduction,0+textureReduction);			
  	glVertex2f(640,480);				

  	glTexCoord2f(1-textureReduction,1-textureReduction);			
  	glVertex2f(640,0);				

  	textureReduction = textureReduction + 0.02;	
  }

glEnd();
CreateTexture->BlendingOrthoOff() ;
}

[This message has been edited by airseb (edited 06-23-2003).]

2

Had you asked on the “beginners” board you might have gotten the answer that texture sizes must be a power of two along each side.

If you ask here, you’ll get the answer to ALWAYS CHECK glGetError() AFTER EACH OPERATION. Assert that it’s 0. If it isn’t, you made an error, and the GL helpfully tells you about it.

3

thanks but the texture size is ever a power of 2 (128x128).