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Mipmapping

Started by AIRmichael Jul 20, 2002 at 5:40 AM 3 replies 500+ views

Original Post

Jul 20, 2002 at 5:40 AM

Hey, I know I can do mipmapping by rendering instead of 1 quad, several quads, and load them up with a lower res texture. But isnt there a way to do mipmapping, on 1 surface?

TangentZ

Jul 20, 2002 at 9:42 AM

gluBuild2DMipmaps(...) comes to the rescue!

  
// First bind the texture...

glBindTexture(GL_TEXTURE_2D, TextureID);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
gluBuild2DMipmaps(GL_TEXTURE_2D, 3, Width, Height, GL_RGB, GL_UNSIGNED_BYTE, pImageData);

// Then later draw the textured quad...

glBindTexture(GL_TEXTURE_2D, TextureID);
glBegin(GL_QUAD);
// Draw the quad with texture coordinates...

glEnd();

Nice and easy! Or you can supply your own set of images
at varying resolution and call glTexImage2D to set the
different levels. In practice though, I find gluBuild2DMipmaps(...)
quite sufficient.

~~~~
Kami no Itte ga ore ni zettai naru!

AIRmichael

Jul 21, 2002 at 4:42 AM

Thx alot

AIRmichael

Jul 22, 2002 at 9:43 AM

Geforce 2mx and matrox doesnt display some of the textures anymore

. It''s only at surfaces which are being blended.

kindfluffysteve

Jul 22, 2002 at 6:29 PM

your code which i modify to suit:

I prepared the texture using DevIL

ilImage image("Road.bmp");
ilOgl::Init();
Texture=ilOgl::BindTex(image);
Width = image.Width();
Height = image.Height();

gluBuild2DMipmaps(GL_TEXTURE_2D, 3, Width, Height, format, GL_UNSIGNED_BYTE, image.GetData());

this seems to do something at least. It makes everything kind of red.

somebody else suggested using gluBuild.. and the adaption from his code was this:

gluBuild2DMipmaps(GL_TEXTURE_2D, format, Width, Height, format, GL_UNSIGNED_BYTE, image.GetData());

which resulted in a blue scale image.

what am i missing out?

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