Better filters?!

Well, I believe that tri-linear filtering is mip-mapping. Normal OpenGL textures are defined using glTexImage2D(). You can then set up GL_NEAREST or GL_LINEAR in the minification and magnification filters. Mip-mapping uses the function call gluBuild2DMipmaps(), and provides two new filters: GL_NEAREST_MIPMAP_NEAREST and GL_LINEAR_MIPMAP_LINEAR. This is trilinear filering, and gives your polygons better texturing whether you're close up or far away...

---

Coding Stuff ->  [ iNsAn1tY Games | DarkVertex | How To Do CSG | Direct3D Vs. OpenGL | Google ]
Fun Stuff    ->  [ Evil T-Shirts | Stick-Based Comedy | You're Already Here | The Best Film Reviews ]

[edited by - iNsAn1tY on June 1, 2003 12:02:49 PM]

Also, if you want to do anisotropic filtering:

float gl_anisotropy_value;
qglGetFloatv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, ≷_anisotropy_value);

...

qglTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT,
gl_anisotropy_value);

That'll set it to the maximum anisotropic value the card supports.

[edited by - jitspoe on June 2, 2003 3:15:36 AM]

quote:

---

Original post by iNsAn1tY
Well, I believe that tri-linear filtering is mip-mapping. Normal OpenGL textures are defined using glTexImage2D(). You can then set up GL_NEAREST or GL_LINEAR in the minification and magnification filters. Mip-mapping uses the function call gluBuild2DMipmaps(), and provides two new filters: GL_NEAREST_MIPMAP_NEAREST and GL_LINEAR_MIPMAP_LINEAR. This is trilinear filering, and gives your polygons better texturing whether you''re close up or far away...

---

There are actually 4 filters available for mipmaps:

GL_NEAREST_MIPMAP_NEAREST, GL_LINEAR_MIPMAP_NEAREST, GL_NEAREST_MIPMAP_LINEAR, GL_LINEAR_MIPMAP_LINEAR

The 2 you are probably most interested in are GL_LINEAR_MIPMAP_NEAREST (bilinear filtering) and GL_LINEAR_MIPMAP_LINEAR (trilinear filtering).

Thx.. however, for the thing with qglTexParameteri... isn''t that only for the Quake II engine?

qglTexParameteri is a function pointer. It points to glTexParameteri. The quake 2 engine loads the OpenGL dll dynamically and assigns the gl functions to pointers prefixed by qgl, so they are effectively the same thing. Just use glTexparameteri in your code.