camera_orientation Subroutine

private pure subroutine camera_orientation(cam, q, d)

A camera's orientation (columns: right, up, back, as a quaternion) and its distance from eye to center (at least a tiny one).

Arguments

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

(columns: eye, center, up)
real(kind=wp), intent(out) :: q(4)

orientation quaternion [x, y, z, w]
real(kind=wp), intent(out) :: d

distance from eye to center

Calls

proc~~camera_orientation~~CallsGraph proc~camera_orientation camera_orientation proc~cross cross proc~camera_orientation->proc~cross proc~quat_from_matrix quat_from_matrix proc~camera_orientation->proc~quat_from_matrix

Called by

proc~~camera_orientation~~CalledByGraph proc~camera_orientation camera_orientation proc~camera_between camera_between proc~camera_between->proc~camera_orientation proc~fly fly proc~fly->proc~camera_between proc~place_camera place_camera proc~place_camera->proc~fly proc~frame WindowProxy%frame proc~frame->proc~place_camera proc~resize WindowProxy%resize proc~resize->proc~frame proc~run WindowProxy%run proc~run->proc~frame

Source Code

    pure subroutine camera_orientation(cam, q, d)
        real(wp), intent(in) :: cam(3,3)    !! (columns: eye, center, up)
        real(wp), intent(out) :: q(4)       !! orientation quaternion [x, y, z, w]
        real(wp), intent(out) :: d          !! distance from eye to center
        real(wp) :: f(3), r(3), m(3,3)
        f = cam(:, 2) - cam(:, 1)
        d = norm2(f)
        if (d > 0.0_wp) then
            f = f / d
        else
            f = [0.0_wp, 1.0_wp, 0.0_wp]
        end if
        d = max(d, tiny(1.0_wp) * 1.0e10_wp)
        r = cross(f, cam(:, 3))
        if (norm2(r) < 1.0e-12_wp) r = cross(f, [0.0_wp, 0.0_wp, 1.0_wp])     ! (up along the view: any)
        if (norm2(r) < 1.0e-12_wp) r = cross(f, [1.0_wp, 0.0_wp, 0.0_wp])
        r = r / norm2(r)
        m(:, 1) = r
        m(:, 2) = cross(r, f)
        m(:, 3) = -f
        q = quat_from_matrix(m)
    end subroutine camera_orientation