Variable MESH_DEFAULTSConst

Mesh material defaults.

ambient / shadeExponent parameterize the §6.2 wrapped diffuse term, while specular / shininess parameterize its additive Blinn–Phong highlight:

• ambient is the shade floor. It is what a surface facing away from the key light keeps, so it is what makes a silhouette readable rather than black. 1.0 collapses the diffuse gradient; set specular = 0.0 as well for a fully emissive look.
• shadeExponent shapes the falloff between the head-on and edge-on extremes. 1.0 is the plain linear wrap.
• specular is the highlight strength. 0.0 disables it.
• shininess controls highlight width; larger values make it tighter.

alphaCutoff is the opaque-mode cutout threshold (§6.2). 0.5 is the conventional alpha-test midpoint, and — because node opacity folds INTO the coverage that is compared against it — it also fixes where a plain RGB mesh (whose vAlpha is identically 1) dissolves as opacity sweeps down: at 0.5.