Optimization for intersections on Triangle

[yarbelk]

There is an optimization you can make for you Triangle type, though it sort of prevents using Triangle literals.

type Triangle struct {
    V1, V2, V3 Vector
    Box        Box
    intersection func(Ray) HIt
}

func NewTriangle(....) Triangle {
    t.intersection = t.generateInsersectionFunction()
    return t
}

func (t *Triangle) generateInsersectionFunction() {
    // Precalculate things like determinants etc here, return the function with these pre-computed
}

func (t *Triangle) Intersection(r Ray)  {
    if t.intersection == nil { t.generateIntersectionFunction()}
    return t.intersection(r)
}

a useful optimization if you are doing a lots of intersections.

[fogleman]

The Compile function would be appropriate for this.

Care to submit a pull request? Would like to see performance numbers before/after.