I have the following proglem: Until now i created mipmaps using gluBuild2DMipmaps which worked like a charm. But now i wanted to use s3tc compressed textures using this [http://www.opengl.org/registry/specs/EXT/texture_compression_s3tc.txt] extension. I have all the Mipmaps precalculated in DDS files, and when i open those in ATI's compressionator it reads the mipmaps correctly, so obviously no problem here.
I am loading the mipmaps using DevIL, which seems to work - it tells me the right number of mipmaps, and if i load any of the mipmap levels as a single texture (without mipmaps), it works - i can see the texture correctly in the gDebugger which also reports the size correctly for the compressed texture.
Now the problem is: i can't get mipmaps to work.
The code i use to create them:
int mipmaps = ilGetInteger(IL_NUM_MIPMAPS);
for(int i=0; i<mipmaps; i++)
{
// reset mipmap level to main image, otherwise the counter (i) is relative from the last mipmap level.
ilBindImage(imageName);
ilActiveMipmap(i);
int width = ilGetInteger(IL_IMAGE_WIDTH);
int height = ilGetInteger(IL_IMAGE_HEIGHT);
int size = ilGetDXTCData(NULL,0,dxtcMode);
ILubyte* buffer = new ILubyte[size];
ilGetDXTCData(buffer,size,dxtcMode);
glCompressedTexImage2D(GL_TEXTURE_2D, i, dxtcILtoGL[dxtcMode], width, height, 0, size, buffer);
delete[] buffer;
}
dxtcMode is one of the supported DevIL compression modes (also read from DevIL, so it's the correct one for each image):
* IL_DXT1
* IL_DXT1a
* IL_DXT3
* IL_DXT5
and dxtcILtoGL is a map mapping from the DevIL modes to the GL modes:
* GL_COMPRESSED_RGB_S3TC_DXT1_EXT
* GL_COMPRESSED_RGBA_S3TC_DXT1_EXT
* GL_COMPRESSED_RGBA_S3TC_DXT3_EXT
* GL_COMPRESSED_RGBA_S3TC_DXT5_EXT
When i debug this code in gDebugger, it seems to work correctly, also the texture is created and its size grows with each mipmap. But ingame i can't see any textures as long as mipmapping is enabled. if i disable mipmaps (
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
instead of
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
) everything works.
I think i can exclude DevIL as an error source, because as said, if i do something like
ilActiveMipmap(3);
int width = ilGetInteger(IL_IMAGE_WIDTH);
int height = ilGetInteger(IL_IMAGE_HEIGHT);
int size = ilGetDXTCData(NULL,0,dxtcMode);
ILubyte* buffer = new ILubyte[size];
ilGetDXTCData(buffer,size,dxtcMode);
glCompressedTexImage2D(GL_TEXTURE_2D, 0, dxtcILtoGL[dxtcMode], width, height, 0, size, buffer);
delete[] buffer;
without the for loop, it works (without mipmaps of course).
The *exact* same thing happens by the way when i do the texture uploading without the compression (again everything seems to be ok in gDebugger, but ingame i only see textures if i disable mipmapping):
int mipmaps = ilGetInteger(IL_NUM_MIPMAPS);
for(int i=0; i<mipmaps; i++)
{
ilBindImage(imageName);
ilActiveMipmap(i);
glTexImage2D(GL_TEXTURE_2D, i, ilGetInteger(IL_IMAGE_BPP), ilGetInteger(IL_IMAGE_WIDTH), ilGetInteger(IL_IMAGE_HEIGHT), 0, ilGetInteger(IL_IMAGE_FORMAT),GL_UNSIGNED_BYTE,ilGetData());
}
The posted code snippet is at exactly the same location in my code where gluBuild2DMipmaps was before. in fact there's only an if switching between compressed and uncompressed textures, uncompressed ones are still generated with gluBuild2DMipmaps (and mipmapping still works with those).
At last, the gluBuild2DMipmaps code i use to create mipmaps (which works):
gluBuild2DMipmaps(GL_TEXTURE_2D, ilGetInteger(IL_IMAGE_BPP), ilGetInteger(IL_IMAGE_WIDTH), ilGetInteger(IL_IMAGE_HEIGHT), ilGetInteger(IL_IMAGE_FORMAT), GL_UNSIGNED_BYTE, ilGetData());
pontomedon
[Edited by - pontomedon on June 22, 2009 4:32:20 AM]
