Monday, April 11, 2011

Regular Deferred Shading (Partially) Complete

I have the deferred shading implementation mostly complete for the non-tiled approach. The thing that I lacking is calculating screen space quads ("scissor rectangles") that determine the maximum bounds of effect for a given light. I spent a few hours trying to get it working for spot lights last night, but didn't have any luck with the math when the light originates behind the view plane. I am changing the point lights in my project so that they have a limited sphere of influence.

The forward and deferred paths lead to completely identical images, but the deferred path is currently slower due to the fact that a full-screen quad is being rendered for each spot and point light. That requires too many texture reads for deferred shading to surpass forward shading without significantly increasing the complexity of the scene geometry.

Below is a screen of the deferred shading output for the "sponza" scene available from Crytek:

I also need to give an in-class presentation today on the status of my project. To that end I have made a powerpoint, which is available at: Dropbox link.

The next thing that I need to work on is calculating the scissor rectangles for point lights. I found several sources on how to do this for point lights, so I am going to focus on getting point lights working first, then come back to spot lights at the end of the project if I still have time. Next, I will work on the tile-based shading calculations. Finally, I will add the post-processing effects and create a tile-based solution for them as well.

1 comment:

  1. Excellent progress. Great plan. You are right on track.