Vertex attribute slot the optional per-vertex colour stream is bound to
(§53, §60a; R-19). Four floats — straight RGBA — at layout(location = 3),
for the same reasons as the three slots above.
A geometry without colors reads GL's constant default (0, 0, 0, 1), so a
vertexColors material drawn over one renders black; that is the documented
behaviour on UnlitMaterial.vertexColors, chosen because a visible mistake
beats a silently ignored flag.
Vertex attribute slot the optional per-vertex colour stream is bound to (§53, §60a; R-19). Four floats — straight RGBA — at
layout(location = 3), for the same reasons as the three slots above.A geometry without colors reads GL's constant default
(0, 0, 0, 1), so avertexColorsmaterial drawn over one renders black; that is the documented behaviour onUnlitMaterial.vertexColors, chosen because a visible mistake beats a silently ignored flag.