Week 19 progress update
Added 2023-03-31 17:51:20 +0000 UTCThis week I focused on improving the visual appearance of the “train in a tunnel paradox” demo. My objective was to replace the remaining placeholder art in the demo with something less rough.
First, I replaced the train rail with a simple repeated texture. The new asset is very simple, but still better than the flat rectangle I had before. The rail was also the first repeated texture in the scene and thus posed an additional challenge.
Next, I added some headlights to the train. These extra lights give some opportunities of improving the illumination and visual appearance of the scene. I added an extra “zone texture” to the train to specify which pixels are associated with the headlights. Hopefully, this approach can be reused in the future for other assets.
I also debugged some rendering problems that affected the demo and realised that I should really pre-multiply the textures in my game. Not only the albedo/diffuse texture, but also normal, depth and zone maps. Basically, whenever a texture has transparency, it also needs to be pre-multiplied. This is a well known thing, but… well, it wasn't to me. I’ll write a blog post about this, in particular to make it clear that pre-multiplication is not much of a color blending issue, but affects any texture with transparency. I think this detail is interesting on its own. I found a post in StackOverflow that was claiming premultiplication is not for normal maps, which is simply not correct. Well, after premultiplying normal maps and other textures I could get rid of the infamous dark border between areas of full transparency and full opacity.
Finally, I created a “train station” asset and also lamps for the lights in the tunnel. I attach a couple of pictures. This was a productive week, but it is clear it will take longer than I expected to improve the visual appearance of the demo.
