This post shows a quick comparison of my latest 2D radiosity renderer and my original 3D renderer.

Both implementations are GLSL implementations of Global Line Radiosity (more or less).

Now, it doesn’t make a lot of sense to compare 2D-GI to 3D-GI. A lot of lightpaths are just not possible in 2D so some differences must be expected. Nevertheless, I think this is very interesting.

At this point I am just doing a simple visual comparison. The scene is basically an extruded floor-plan, since (obviously) any difference in the z-dimension is impossible to render in the 2D version.



2D vs. 3D

The overall light distribution seems reasonably similar.

It is quite interesting that, even though the majority of paths is not existent in 2D, the results are very close. There is an overall difference in brightness, and also the intensities seem to falloff a bit faster in 3D.

2D Radiosity

3D Radiosity, Ortho, Top-view



ScreenShots Series

3D Renderer, Perspective, Sunlight enabled

3D Renderer, Top, Emitter enabled

3D Renderer, Top, Sunlight enabled

3D Renderer, Top, Emitter enabled

2D Renderer, Emitter enabled

2D Renderer, Emitter enabled, direct light only (no GI)





Part 1 – Algorithm Overview, Technique

Realtime 2D Radiosity – Global Illumination for 2D Scenes

Part 2 – Tests

Realtime 2D Radiosity – Tests, Part 2