* http://blog.selfshadow.com/2012/11/12/counting-quads/
* Quad Overdraw based on ScenePS4 from the revised implementation. The
colours are new, up to 20 levels. Picking pixels shows the overdraw level
* Available per-pass and per-drawcall, a pass defined the same way as in
the mesh view, drawcalls since last clear or RT change.
* List of events now passed through to RenderOverlay the same as RenderMesh
* The explanation is in the FAQ but the short explanation is that most
data e.g. normal maps are conventionally displayed as if they contained
SRGB data, so RenderDoc does the same so things look as expected.