GPU Pro 4 – Practical planar reflections using cubemaps and image proxies (with Video)

I have written with my co-worker Antoine Zanuttini an article in the GPU Pro 4 book:
I am particularly proud of the cover as this is extracted from the project I worked on “Rememer Me” from Dontnod entertainment edited by Capcom. There is a short sum up available on the GPU Pro blog : that I will duplicate here.

Rendering scenes with glossy and specular planar reflections is a challenge in video game, particularly when targeting old hardware like current console (PS3, XBOX360). Real time planar reflection is often implemented by re-rendering the scene from the point of view of a reflected camera, an expensive process. At the opposite, several game developers use a simple generic 2D environment texture which lack realism but is really cheap. Others use screen-space local reflection which has edge cases and still has a not negligible cost. 

For the game “Remember Me”,we have developed a really fast planar reflection solution usable on every ground. In our GPU Pro 4 chapter we discuss how we render an approximation of the reflected scene with the help of parallax corrected offline-generated elements: Environment map and image proxies. The planar reflection has enough quality for game and take into account the roughness of the surface.The chapter discusses about the algorithm details and follows the work we have presented at Siggraph 2012 “Local Image-based Lighting With Parallax-correctedCubemap“.

Our goal was not only to discuss implementation of our algorithm but also its usage in a context of a game development. We describe the tools we develop for our artists and the best practices they discover. Artists are creative peoples and they have pushed the boundary of our tools where we not expected them. Want to look at the result in action? See this video which accompanying the article