Game Development Reference
Practical Planar Reflections Using
Cubemaps and Image Proxies
Sebastien Lagarde and Antoine Zanuttini
Rendering scenes with glossy and specular reflections has always been a challenge
in the field of real-time rendering. Due to their importance in assessing image
quality, many techniques have been developed to simulate reflections.
techniques can be classified in four categories:
1. Real-time techniques, such as dynamic environment mapping, with all kinds
of parameterization: cubemaps, 2D mirror planes, dual paraboloid. Dy-
namic reflections of this type are accurate but costly because they require
resending the whole scene to the graphics pipeline. Many optimizations
have been devised to speed up the process, such as mesh or shader simpli-
fications, but it still induces a significant overhead.
2. Precomputed techniques, such as static environment mapping with all kinds
of parameterization: cube maps, sphere maps, dual paraboloid, etc. Static
reflections lack the accuracy of dynamic reflection but are far cheaper to
3. Screen-space techniques, such as screen-space local reflection [Tiago et al. 12],
often come at a manageable cost for pleasant localized results, but fail where
on-screen information is missing.
4. Real-time ray-tracing techniques such as the image-based reflections found
in Epic's Samaritan demo [Mittring and Dudash 11] are promising tech-
niques, but they require support for features not available on older graphics