Rendering/PBR

These principles only apply to Hedgehog Engine 2 games (Mario & Sonic at the Rio 2016 Olympic Games and onward)

PBR (Physically Based Rendering) refers to the current approach to 3D graphics material rendering used in most modern games. Its goal is to enhance the realism of surfaces by reflecting and refracting light more accurately than previous techniques. This is most noticeable in any kind of metallic surface:

PBR rendering tends to not make use of Diffuse maps and Specular Color Maps that were very common in non-PBR rendering. Instead, the primary texture maps it uses in their place are: Albedo Maps, Metallic Maps, Roughness Maps and Ambient Occlusion Maps.

Albedo Maps differ from Diffuse Maps by generally not containing any kind of depth or lighting information.

Diffuse texture example
Albedo texture example

Metallic Maps contain values ranging from 0-1(black-white). 0 determines a non-metallic surface while 1 determines a metallic surface. Values in between can and are used for stylistic and/or artistic purposes.

Roughness Maps change how the surface reflects light by making the reflection sharper using a value of 0 (smoother surface) or blurrier/more diffuse using a value of 1 (rough surface). This more or less equals the inverse of typical Gloss Maps used in non-PBR rendering.

Ambient Occlusion maps determine what areas of the surface should occlude more light when not directly illuminated. 0 represents the most light occlusion and 1 represents no light occlusion.

non-PBR vs PBR rendering (same lighting conditions):

Grass from Sonic The Hedgehog (2006) rendered in Blender
Grass from Shadow Generations rendered in Blender

(To be continued)