Re: Texture Fit to Window

Knockr wrote:

> 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 = w;
>       win_w = h;
> 
>        // Reset coordinate system
>        glMatrixMode(GL_PROJECTION);
>        glLoadIdentity();
>        glOrtho(0, win_w, 0, win_h, -1.0, 1.0);
> 
>        glMatrixMode(GL_MODELVIEW);
>        glLoadIdentity();
>        glutPostRedisplay();
> }

Here's some advice: Don't do it that way. glView****t and setting
the matrices are very cheap calls. The best practice to do the
whole setup just right before the rendering. So your display()
function would look like

void display()
{
        glView****t(0, 0, win_w, win_h);

        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        glOrtho(0, win_w, 0, win_h, -1.0, 1.0);

        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();
        
        /* render that stuff */
}

the reshape function would simplify to something like

void ChangeSize(int w, int h)
{
        win_w = w;
        win_h = h;
        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

Well, did you try GL_GLAMP (just CLAMP, nothing more)? Normally,
if there's no border supplied, GL_CLAMP_TO_BORDER should exhibit
the same behavior as GL_CLAMP, but some drivers might break
that.

Oh, and something I totally missed before: You actually _made_
some mistake: TEXTURE_RECTANGLE textures are addressed in
absolute pixels, not in relative [0, 1]^n coordinates, so you've
to write:

glEnable(GL_TEXTURE_RECTANGLE_ARB);
glBindTexture(GL_TEXTURE_RECTANGLE_ARB, TextureImage[i]->texID);

GLint tex_w = TextureImage[i]->sizeX;
GLint tex_w = TextureImage[i]->sizeY;

glBegin(GL_QUADS);
glTexCoord2i(0, 0);
glVertex2f(0.0, 0.0);

glTexCoord2i(tex_w, 0);
glVertex2f(win_w, 0.0);

glTexCoord2i(tex_w, tex_h);
glVertex2f(win_w, win_h);

glTexCoord2i(0, tex_h);
glVertex2f(0.0, win_h);
glEnd();


Wolfgang Draxinger
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