twitchy texture matrices

[ClayOgre]

The attached zip file contains the start of a map and four textures. I have one texture as GroundMaterial and another that covers a single very large mesh that covers the entire map, with a moving texture matrix. If I used fixedscale to make the texture on this mesh larger so the tiling isn't as obvious and then use a texture matrix to move it, it moves, but it "twitches" periodically. I am trying to make it look like there is windblown dust going across the surface of the ground. If I don't used fixedscale, no twitch, but the tiling is quite obvious and intrusive.

[DJ Atomica]

I was trying to get the same thing for my map too!

[ClayOgre]

Did you run into the same problem?

[optic delusion]

I was able to solve it with one simple change, not sure if this is exactly what you want, but it works for me. I changed shift to spin.

textureMatrix
name windSand
fixedscale 3 3
spin .004
end

you could extend the object out past the world extent. Or if you want, i can show you how to spin the floor. I'll dig that up.

Edit:
textureMatrix
name floor
fixedscale 20 20
center 0 0
spin 0.003
#color 1 1 1 1
end
material
name GroundMaterial
addtexture http://images.bzflag.org/pmatous/earthlights4.png
#texsize 20 20 20 20
specular .4 .4 .4 .4
texmat floor
end

If using spin, add the "center" line. The "color" line isn't needed, and specular might make it look a bit better.

Edit again:
Now that i think about it, using texsize in the material (not the matrix)might fix it too.

Third edit:
I can fix twitchy textures on meshboxes, with texsize but not on a mesh face.

[TD-Linux]

Instead of fixedscale, couldn't you use UV coordinates? They are easy to do by hand for a single-faced mesh.

[optic delusion]

I've got the same problem that lamer and spazzy have had. I've seen this before, but i can't replicate the twitch anywhere but in your example map. It only shows up when you don't want it to. It seems to me like some kind of ratio thing.
So I decide to make everything power of 2. the texture is 256 by 256. I make the face vertices 512 on all corners. Next I try the fixedscale at 2 4 8 16 32 64 and 128, none of them work. The twitch remains. I try different shift numbers, nothing works.
Well, i did my best to track it down. No Dice.

[ClayOgre]

I am not sure using texture coords would do what I want. UV map, say, a 512 size texture to a whole map? Wouldn't that be kinda jaggy looking...or am I not understanding what you mean.

I will probably give the spin idea a try, I think that might do the job.

I have seen this "twitch" problem a couple of times before, but both times I was also using scale (not fixedscale).

[optic delusion]

spin solved it for me, instantly. You can move the center to something like 2000 2000 too.

[ClayOgre]

Tried spin, worked like a champ. Thank you.