Checks for full fledged collision between the line segment formed between startPos and endPos and the
triangle and returns the intersection point (or null if no collision occurs)
Checks for full fledged collision between the line segment formed between startPos and endPos and the
triangle and returns the intersection point (or null if no collision occurs)
Checks for a collision between this and another triangle by checking to see if any of vertices when moved along a line segment
of length endPos - startPos collide with the collideeTriangle.