Posted By: Machinery_Frank
Lightmap Experiments - 02/17/11 13:09
Hi Friends,
I am trying to find a good setup for the light-mapping system called dual lightmapping. Let me explain shortly what that means. This technique uses 2 lightmaps, one when you are far away including all shadows and lights. So there is no dynamic light needed. The other lightmap contains only indirect lighting. Thus it works with realtime lights and shadows when you are close to the camera. The engine blends smoothly between both lighting situations in a given distance.
Here are 2 images of some of my experiments.
The first image is very simple. You see one light and the results of lightmap, dynamic and dual map (right click on image to zoom in):
The advantage is that it works fine in a distance. The lightmap is almost exactly the same as the dual map result. Thus the blending is perfect even when I set shadow distance to only 10 meters.
The disadvantage is that it makes bright spots too bright and washes textures a bit out. And specularity is rarely visible.
Here is another approach. I use only very subtle lightmapping to get more specularity from real-time lights. So I light the lightmap only from emission textures. There is no single light that affects it:
Spec and bumps are better visible but in a distance it gets very dark when the lightmap takes over.
Actually the dualmap system has advantages when I want to animate lights and shadows. But the disadvantage is that it works not very good with normal and spec maps especially when I compare it do directional lightmapping as an alternative.
Can you give me an advise how to proceed? What setup do you prefer?
I am trying to find a good setup for the light-mapping system called dual lightmapping. Let me explain shortly what that means. This technique uses 2 lightmaps, one when you are far away including all shadows and lights. So there is no dynamic light needed. The other lightmap contains only indirect lighting. Thus it works with realtime lights and shadows when you are close to the camera. The engine blends smoothly between both lighting situations in a given distance.
Here are 2 images of some of my experiments.
The first image is very simple. You see one light and the results of lightmap, dynamic and dual map (right click on image to zoom in):
The advantage is that it works fine in a distance. The lightmap is almost exactly the same as the dual map result. Thus the blending is perfect even when I set shadow distance to only 10 meters.
The disadvantage is that it makes bright spots too bright and washes textures a bit out. And specularity is rarely visible.
Here is another approach. I use only very subtle lightmapping to get more specularity from real-time lights. So I light the lightmap only from emission textures. There is no single light that affects it:
Spec and bumps are better visible but in a distance it gets very dark when the lightmap takes over.
Actually the dualmap system has advantages when I want to animate lights and shadows. But the disadvantage is that it works not very good with normal and spec maps especially when I compare it do directional lightmapping as an alternative.
Can you give me an advise how to proceed? What setup do you prefer?
