ray_line Function

public function ray_line(origin, dir, point, axis, s, line_point) result(hit)

The point of the line through point along axis closest to the ray (origin, unit dir): its parameter s (the point is point + s * axis, axis normalized) and the point. False if the ray and the line are parallel (within 1e-6 of it, as a sine squared), or the closest point of the ray is behind its origin.

Arguments

Type IntentOptional Attributes Name
real(kind=wp), intent(in) :: origin(3)

the ray (dir: a unit vector)
real(kind=wp), intent(in) :: dir(3)

the ray (dir: a unit vector)
real(kind=wp), intent(in) :: point(3)

the line (axis: any length but 0)
real(kind=wp), intent(in) :: axis(3)

the line (axis: any length but 0)
real(kind=wp), intent(out) :: s

along the line (scene units, from point)
real(kind=wp), intent(out) :: line_point(3)

the point of the line

Return Value logical


Called by

proc~~ray_line~~CalledByGraph proc~ray_line ray_line proc~constrained constrained proc~constrained->proc~ray_line proc~drag DragHandle%drag proc~drag->proc~constrained proc~grab DragHandle%grab proc~grab->proc~constrained proc~drag_handle drag_handle proc~drag_handle->proc~drag proc~grab_handle grab_handle proc~grab_handle->proc~grab proc~dispatch_event dispatch_event proc~dispatch_event->proc~drag_handle proc~dispatch_event->proc~grab_handle proc~dispatch_events dispatch_events proc~dispatch_events->proc~dispatch_event proc~frame WindowProxy%frame proc~frame->proc~dispatch_events proc~resize WindowProxy%resize proc~resize->proc~frame proc~run WindowProxy%run proc~run->proc~frame

Source Code

    logical function ray_line(origin, dir, point, axis, s, line_point) result(hit)
        real(wp), intent(in) :: origin(3), dir(3)           !! the ray (dir: a unit vector)
        real(wp), intent(in) :: point(3), axis(3)           !! the line (axis: any length but 0)
        real(wp), intent(out) :: s                          !! along the line (scene units, from `point`)
        real(wp), intent(out) :: line_point(3)              !! the point of the line
        real(wp) :: u(3), w(3), b, d, e, denom
        hit = .false.
        s = 0.0_wp
        line_point = point
        if (norm2(axis) <= 0.0_wp) return
        u = axis / norm2(axis)
        w = point - origin
        b = dot_product(u, dir)
        d = dot_product(u, w)
        e = dot_product(dir, w)
        denom = 1.0_wp - b * b
        if (denom < 1.0e-6_wp) return
        s = (b * e - d) / denom
        if ((e + b * s) < 0.0_wp) return                    ! (the ray's closest point: origin + (e + b s) dir)
        line_point = point + s * u
        hit = .true.
    end function ray_line