Enabling default rendering pipeline causes minor flickering when in VR

[TrevorDev]

http://www.html5gamedevs.com/topic/35667-enabling-fxaa-in-default-pipeline-is-causing-a-bit-of-flickering-in-vr-headset/

See: https://www.babylonjs-playground.com/#DNUPI2#2

[TrevorDev]

Investigation:
By default webgl native anti-aliasing is turned on for rendering. When a post process is added, this anti aliasing will not be applied as post process uses textures and anti-aliasing is only supported on render buffers in webGL 1.0. In WebGL 2.0 anti-aliasing can be turned on by setting the the following on the first post process. PostProcess.samples = 4; which I will add to the default pipeline.

Edge currently does not fully support WebGL 2.0 so this is why enabling default pipeline will result in a lack of anti-aliasing causing the flickers, The fxaa post process will improve the quality but not to the same level of webgl's anti aliasing. I noticed there currently is a resize being done in textures for each eye so I will try to avoid this which add another minor perf/quality improvement.

Work items:

• Add postprocess.samples = 4 in default pipeline
• Avoid texture resize when rendering each eye with post processes
• Update cache of webVR camera prior to calculating viewMatrix of each eye camera