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Odd texture filtering issue

Started by Blips Sep 24, 2011 at 7:00 PM 4 replies 1.3k views

Original Post

Sep 24, 2011 at 7:00 PM

I'm approaching completion on my first OpenGL ES game (yay!) but just recently ran into an odd issue with texture filtering. I was trying to improve the game's performance when linear filtering suddenly broke. Code when creating textures was this:


 glGenTextures(1, &textureID);
 glBindTexture(GL_TEXTURE_2D, textureID);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); 
 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, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);

But now, I'm having to set the texture parameters when binding textures and rendering geometry. Is this normal and was it just a fluke that it was working before?

dpadam450

Sep 24, 2011 at 11:51 PM

You only need to set it once for each texture.

Blips

Sep 25, 2011 at 6:40 AM

You only need to set it once for each texture.

So why is it not working unless I re-set it during rendering?

L. Spiro

Sep 25, 2011 at 7:49 AM

Unbind the texture after you are done creating it to make sure you are not accidentally changing its properties later.

glBindTexture( GL_TEXTURE_2D, 0 );

L. Spiro

Blips

Sep 25, 2011 at 6:20 PM

Unbind the texture after you are done creating it to make sure you are not accidentally changing its properties later.

glBindTexture( GL_TEXTURE_2D, 0 );

L. Spiro

Sorry, I forgot to include that line. I already was / am doing that.

L. Spiro

Sep 26, 2011 at 1:26 AM

Search your project for GL_TEXTURE_MIN_FILTER and check every location where you are calling that.

After you have set the GL_TEXTURE_MIN_FILTER property on your texture, you do not need to change it. Therefore you need to focus your search on where you are re-binding that texture (unintentionally) and changing its GL_TEXTURE_MIN_FILTER.
Check every location where you use GL_TEXTURE_MIN_FILTER, and be sure of exactly which texture is bound. It may not be the one you think.

L. Spiro

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