Light Scattering

When we introduced Programmable Pipeline support to Vortex Engine, we claimed that better visual effects could now be introduced into the renderer. With the introduction of Render-to-Texture functionality into Vortex 2.0, coupled with the power of Shaders, we can now make good on our promise.

Light Scattering (also known as “God Rays”) is a prime example of what can be achieved with Shaders and Render-to-Texture capabilities.

In the following image, a room consisting of an art gallery with tall pillars is depicted. We want to convey the effect of sun light coming from outside, illuminating the inner nave. Enter Light Scattering:

It can be seen in the picture above how the the effect, although subtle, brings more life to the rendered scene. There is still much room to improve the visual results, though, particularily with the results of Kenny Mitchel’s article on GPU Gems 3.

There is also room for optimization. Currently, the scene is rendered in realtime at an average of 187 frames per second, producing 1024×1024 images on a NVIDIA GeForce GTX465. Moving the algorithm to mobile devices, although easy from a coding perspective, might require extra work to achieve a high frame rate on the embedded GPU.

Here are three more captures from different angles.