func mix(a, b geometry.Vec3, factor geometry.Float) geometry.Vec3 {
a.X = (1-factor)*a.X + factor*b.X
a.Y = (1-factor)*a.Y + factor*b.Y
a.Z = (1-factor)*a.Z + factor*b.Z
return a
}
func CorrectColours(v geometry.Vec3) geometry.Vec3 {
v.X = CorrectColour(v.X)
v.Y = CorrectColour(v.Y)
v.Z = CorrectColour(v.Z)
return v
}