Track Texturing

Over the iterations of Rush Rally, I've slowly increased the quality of the track textures. Up until now they were simply a main texture which spans the width of the road, and then a detail overlay on top, to give it a bit of detail. They also had no real "edges" where they joined the terrain so this was something I really wanted to address in Rush Rally 4. The issue with this approach is that the track always feels a bit the same and you can see the tiling effect as you drive along it.

I decided that I would instead use a similar approach to that of the terrain for the track, utilising a "mask" texture which blends in multiple different detail textures. This would break up the tiling effect and give us quite a nicely detailed looking track.

Where the edges joined the terrain, I decided that I would use a set of "plaster" verts which simply overlay a texture on top with an alpha blend such that it looks like the track has a proper edge. I'll let the textures do the talking but it did require quite a bit of work to get this working correctly in the procedural generator.

For the road, we have 3 detail textures defined, and then we generate a mask texture such that the red channel defines where details 1 and 2 blend in, and the blue defines where the 3rd detail blends in. We also use the green channel to apply some generic shading to the track to make it less uniform in colour (darker patches etc).

The edge is a single texture which is placed over the top between the terrain and the road, the absolute centre line of this has to be covered to avoid showing the join of the track and road in the game. Other than that we can create some cool masks which blend the track and road together.