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Re: Seamless Tiling

>Hi,
>
>> Is it possible to, say, render a 256x256 texture as 4 64x64 textures without
>> visible seams?
>
>Did you set the textures to repeat at the edges?
>glBindTexture(GL_TEXTURE_2D, the_texture);
>glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
>glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);

I don't think this works. I tried it and I still get a dark bevel
at the edge of each tile. I am using an iMac 350 with Rage 128. Right
now I am forced to use GL_CLAMP with either a shared pixel on each
texture or a blurred line on each edge (you can read my message, "Re:
Border support on rage pro & 128?" from 12/5/00). From what I have tried
so far, it seems difficult to me to make a game like quake 3, since they
have tiny subdivided triangles from the BSP, yet you never see a blurred
texture or edge.
I also tried the textile example from advanced.5 in SDK/OpenGL
SDK/Source/Examples/glut/advanced/. You need to copy some of the .rgb
files from SDK/OpenGL SDK/Source/Examples/glut/data/ into the /advanced
folder, and then type their name in the command line dialog as glut runs.
In that project, the only thing that remotely works is just clamping
with no borders. I found one piece of encouragement though. If you use
mandrill.rgb in the textile example, you can't see the clamping anymore
since it is so high res. But if you use tree.rgb, you see it immediately.
It seems that GL_CLAMP works well for textures that are shrunk, but
not for ones that are enlarged. If you keep each texel less than 2x2
pixels when it gets drawn on screen, perhaps your eye can't see the
clamping. I guess quake 3 must use such high res textures that you don't
really see the clamping, but I still think I am missing something huge.
If anyone knows the secret, please let us know! Thanx for your time,

Zack Morris
Z Sculpt Entertainment
email@hidden
http://www.zsculpt.com



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