Face3 constructor
Implementation
Face3(this.a, this.b, this.c, normal, color, {this.materialIndex = 0}) {
this.normal = (normal != null && normal.runtimeType == three.Vector3) ? normal : three.Vector3.init();
vertexNormals = normal ?? [];
this.color = (color != null && color.runtimeType == three.Color) ? color : three.Color(0, 0, 0);
vertexColors = color ?? [];
}