Game Development Reference
Figure 5.7. (a) A scene with a large depth variance that the original Forward+ could
not process eciently. (b) Visualization of the number of lights per tile using frustum
culled with maximum and minimum depth values in a tile.
(c) Visualization of the
number of lights per tile using the proposed 2.5D culling.
than 200 lights overlapping. However, by using the 2.5D culling, a tile has at most
120 overlapping lights. The benefit we can get from final shading depends on the
implementation of shader, but culling eliminates a lot of unnecessary memory
reads and computation for the final shader.
have as much depth variance as the scene in Figure 5.7(a). Because the depth
difference is not large in these scenes, the number of lights overlapping a tile,
including an edge of an object, is less than in the previous scene. However, color
temperature is low when the 2.5D culling is used.
A quantitative comparison
Although the improvement is not as large as the