Improve shaders and renderering "pipeline"

[cyberarm]

Resources

• https://lettier.github.io/3d-game-shaders-for-beginners/index.html
• https://docs.unrealengine.com/5.2/en-US/physically-based-materials-in-unreal-engine/

[cyberarm]

Support PBR materials - with static values or sampled from textures

• Base Color
• Roughness
• Metallic
• Specular

[cyberarm]

Possible Post Processing Order
(https://help.sketchfab.com/hc/en-us/articles/115000728943#order)

• SSR
• SSAO
• Depth of Field (DoF)
• Bloom
• Chromatic Aberrations
• Color Balance
• Tone Mapping
• Vignette (if there is background or ...)
• TAA*
• Sharpen
• FXAA*
• Vignette (if there is no background and no ...)
• Supersampling*
• Grain