Texels vs Units vs Pixels in Lightmaps?

Question

So in the configurations of the Lightmapping I have a lot of strange settings and can't quite understand how they work together:

• First off texels = pixels, right? So texel is just a fancy name for a pixel?
• Lightmap Resolution in texels per unit. What is unit in this context? And how does it fit that stuff in the constant Lightmap Size (let's say 256 texels=pixels)?
• What is the difference between Indirect Resolution and Lightmap Resolution? And why I can't adjust Indirect Resolution in Progressive CPU?

Answer 1

Indirect resolution is the fidelity of indirect lighting, light that comes from stuff like a bright surface being lit by the sun. Lightmap resolution is the fidelity of general lighting (basically direct lights)

I'm fairly sure You can't set it in progressive CPU because it'll eventually reach your lightmap resolution anyway. Progressive CPU does a low quality lighting pass as you edit your scene, and over time improves the quality, so you can get a rough idea of your lighting as you edit, but eventually (particularly in areas you aren't playing around in) the lighting will reach your max resolution. It's purely to improve your workflow, so you can edit your scene without waiting for a slow light pass.

I recommend reading the relevant pages:

https://docs.unity3d.com/Manual/ProgressiveLightmapper.html

https://docs.unity3d.com/Manual/Lightmapping.html

Unity's lighting system is powerful, but also quite complex, take your time and read up on the documentation, when I first started working with it I spent a few days just absorbing all the information, there's a lot to take in.