Re: Texture Fit to Window

On Aug 22, 4:00=A0pm, Wolfgang Draxinger <wdraxin...@[EMAIL PROTECTED]
>
wrote:
> Knockr wrote:
> > Dear All,
>
> > I've created an OpenGL program to load and draw a texture.
> > Texture is having 800x600 size. but the window has 1440x900
> > pixels size.
>
> > the projection is of type orthogonal - glOrtho(0, win_w, 0,
> > win_h, -1.0, 1.0);
>
> > the texture is loaded as follows
> > glTexImage2D( GL_TEXTURE_RECTANGLE_NV, 0, GL_RGB,
> > =A0 =A0 =A0 TextureImage[i]-> sizeX, TextureImage[i]->sizeY,
> > =A0 =A0 =A0 0, GL_RGB, GL_UNSIGNED_BYTE,
> > =A0 =A0 =A0 TextureImage[i]->data );
>
> > the textures are mapped as follows
>
> > glTexParameteri(GL_TEXTURE_RECTANGLE_NV, GL_TEXTURE_WRAP_S,
> > GL_CLAMP_TO_BORDER);
> > glTexParameteri(GL_TEXTURE_RECTANGLE_NV, GL_TEXTURE_WRAP_T,
> > GL_CLAMP_TO_BORDER);
> > glTexParameteri(GL_TEXTURE_RECTANGLE_NV, GL_TEXTURE_MAG_FILTER,
> > GL_LINEAR);
> > glTexParameteri(GL_TEXTURE_RECTANGLE_NV, GL_TEXTURE_MIN_FILTER,
> > GL_LINEAR);
>
> > glBegin(GL_QUADS);
> > glTexCoord2f(0.0, 0.0); =A0 =A0 =A0 glVertex2f(0.0, 0.0);
> > glTexCoord2f(1, 0.0); glVertex2f(win_w, 0.0);
> > glTexCoord2f(1, 1); =A0 =A0 =A0 =A0 =A0 glVertex2f(win_w, win_h);
> > glTexCoord2f(0.0, 1); glVertex2f(0.0, win_h);
> > glEnd();
>
> > How can make the texture fit to window?
>
> Unh, your code already strechtes the texture to fit the window.
> And thanks to the use of GL_TEXTURE_RECTANGLE (which has become
> an ARB extension for years, so replace all occurences of
> GL_TEXTURE_RECTANGLE_NV with GL_TEXTURE_RECTANGLE_ARB) you also
> don't trip into the pitfall, that normal OpenGL textures are
> addressed by the texel centers: Texture Rectangle textures are
> addressed by texel indices.
>
> So your code looks good so far. So the only thing that you might
> have missed, you didn't write it in your post, is the size of
> your View****t:
>
> glView****t(0, 0, win_w, win_h);
>
> Ideally put that right before setting the projection matrix.
> Actually it would be sufficient if it came right before the
> rendering calls, but some buggy OpenGL drivers apply the
> view****t only, when the projection matrix is manipulated. I
> don't know of any current driver that exposes that behaviour, a
> few years ago it was a problem though.
>
> Wolfgang Draxinger
> --
> E-Mail address works, Jabber: hexar...@[EMAIL PROTECTED]
 ICQ: 134682867

Thanks for your reply.

my code for the same would look as follows

void ChangeSize(int w, int h)
{
       // Set View****t to window dimensions
       glView****t(0, 0, w, h);

	win_h =3D w;
	win_w =3D h;

       // Reset coordinate system
       glMatrixMode(GL_PROJECTION);
       glLoadIdentity();
       glOrtho(0, win_w, 0, win_h, -1.0, 1.0);

       glMatrixMode(GL_MODELVIEW);
       glLoadIdentity();
       glutPostRedisplay();
}

the extra ****tion of the displaying window look as black when
CLAMP_TO_EDGE parameter. Otherwise the something like repeat effect.
but the texture never rendered full view****t