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tileing textures

Started by daniel_i_l Apr 2, 2006 at 3:13 AM 4 replies 450+ views

Original Post

Apr 2, 2006 at 3:13 AM

I want to draw a sky with a cloud texture tiled a few time, to do that I tried multiplying the texture coords like this:


void CreateSkyReflection(float x, float y, float z, float width, float height, float length)
{
    glEnable(GL_TEXTURE_2D);
    glEnable(GL_BLEND);
    //glDisable(GL_DEPTH_TEST);
    float tex=2;
    x = x - width  / 2;
    y = y - height / 2;
    z = z - length / 2;
    
    glBindTexture(GL_TEXTURE_2D, g_Texture[BOTTOM_ID]);
    //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
    //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);

    // Start drawing the side as a QUAD
    glBegin(GL_QUADS);      
    
        // Assign the texture coordinates and vertices for the BOTTOM Side
        glTexCoord2f(tex, 0.0f);     glVertex3f(x,         y,          z);
        glTexCoord2f(tex, tex);      glVertex3f(x,         y,          z + length);
        glTexCoord2f(0.0f, tex);     glVertex3f(x + width, y,          z + length); 
        glTexCoord2f(0.0f, 0.0f);    glVertex3f(x + width, y,          z);
    glEnd();
    //glEnable(GL_DEPTH_TEST);
    glDisable(GL_BLEND);
}

But the texture didn't tile, it just smeared out? What did I do wrong? Thanks.

Daaark

Apr 2, 2006 at 3:16 AM

Use x.0f where x is the number of times you want to tile. So if you want to tile twice, use 2.0f.

daniel_i_l

Apr 2, 2006 at 3:27 AM

I did tex=2.0f but it still didn't work?
What happenes if I set tex to 2 is that the BL corner is textered with the whole texture, the BR corner is smeared to the right, the TL is smeared to the top, and the TR corner iis totally smeared!?
Thanks.

Daaark

Apr 2, 2006 at 3:41 AM

On the x coordinate it should look like this:

0.0-----2.0
|
|
|
0.0-----2.0

y will be the same 0.0 on the starting edge, 2.0 on the end edge/point.

2.0-----2.0
|
|
|
0.0-----0.0

Nitrogen

Apr 2, 2006 at 4:15 AM

Your program has been set to clamp the texture instead of tiling it.

Uncomment these lines:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);

And set GL_CLAMP to GL_REPEAT.

But it's best to move them out of your main rendering loop, rather put them straight after loading the picture into opengl.

daniel_i_l

Apr 2, 2006 at 4:53 AM

Thanks, it worked!

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