lines between textures/planes in tiled terrain

Hello everyone,

I'm trying to build a terrain with map tiles. I wrote a shader which can take 10 textures and apply to the mesh (like attached image 3 )which can take like 10 materials and tried to place these planes next to each other.

Problem - I can see some lines like in the attachment 1 and 2
lines like in 1 are caused by each row in the mesh & adjacent planes
lines like in 2 are caused by 2 textures of the same material

This happened with with both unity mesh and a blender exported mesh.

I read here that if I use CLAMP in the wrapmode, I can get rid of these lines.
I tried with quads with CLAMP, and the lines are no more there....but I cannot apply the height map for the terrain in this approach.

Is there something I can do to get rid of the lines and apply the height map is my question.

Thanks in advance
Srikanth

 

Yeah, this one's been driving me crazy. I know it's an old question, but I had several problems that were causing issues like this for me and it took me ages to sort them all out.

I think there's a slight strangeness in the way Unity samples texture colours, in that if you try and draw a sample from exactly x:0 or y:0, it will interpolate between the target pixel and the colour white. I don't know if that's really the case or why, but it would explain the results I was seeing. This happens even with the texture set to clamp and point filtering (I'm doing a faux-8-bit-style game).

To get around the issue, instead of using the exact UV coordinates from the input structure, I did this:

Code (CSharp):

1. float x1 = max(0.000001f, IN.uv_MainTex.x);
2. float y1 = max(0.000001f, IN.uv_MainTex.y);
3. tex2D(_MainTex, float2(x1, y1));

This fixed the issue for me, but it really shouldn't happen in the first place.