Overlapping Line Transparency

Unity Engine
1

Hello, I’m hoping that someone here would be kind enough to provide some assistance with a shader.

I’m using Vectrocity to draw a textured 3D line (free AA edging with bilinear texture filtering) to create a hex grid pattern. However, in order to draw the grid, some of my lines have to overlap with each other. The problem is that it is desired to have this hex grid be semi-transparent and obviously with standard shading I’m going to get an overlay effect on the line parts where they overlap. This will cause the overlapped lines to look less transparent than the rest of the grid where there is no overlap. Is there a shader way that is cheap that I could use to render the line a a contiguous color but still take advantage of the alpha blended edges? Obviously, the fewer passes the better as this is for a mobile game.

The only thoughts so far is to do something like a soft-edge transparency or to write into the stencil buffer. Any suggestions?

2

How about not rendering lines at all, but instead just a single textured plane?

3

That is a good suggestion. I originally started with that, but I don’t want to spend the fill rate or the texture space on a grid that is mostly alpha and 1 color. Alpha testing is slow on some mobile hardware still. The grid takes up the entire board so I’d need a 2048 texture to overlay. It is also less dynamic in regards to being able to create new maps by resizing the grid procedurally. I would instead need to bake all of the textures beforehand for all of the different level sizes.

If I were to make a single grid element texture and repeat it, it could work, but again I’d be wasting a lot of alpha fill rate as well as having difficulty trying to repeat it without overlap.