ray.go

package math

type Ray struct {
	Origin    Vector3
	Direction Vector3
}

func NewRay(origin, direction Vector3) *Ray {
	ray := &Ray{Origin: Vec3(0, 0, 0), Direction: Vec3(0, 0, 0)}
	ray.Origin.SetVec3(origin)
	ray.Direction.SetVec3(direction)
	return ray
}

func (r *Ray) Cpy() *Ray {
	return &Ray{Origin: r.Origin, Direction: r.Direction}
}

func (r *Ray) Set(origin, direction Vector3) *Ray {
	r.Origin.SetVec3(origin)
	r.Direction.SetVec3(direction)
	return r
}

func (r *Ray) GetEndPoint(distance float32) Vector3 {
	return r.Origin.Add(r.Direction.Scale(distance))
}

// Multiplies the ray by the given matrix. Use this to transform a ray into another coordinate system.
func (r *Ray) Mul(matrix Matrix4) *Ray {
	tmp := r.Origin.Add(r.Direction)
	tmp = matrix.MulVec3(tmp)
	r.Origin = matrix.MulVec3(r.Origin)
	tmp = tmp.Sub(r.Origin)
	r.Direction.Set(tmp.X, tmp.Y, tmp.Z)
	return r
}