handy function for getting the 2d camera coords for a worldspace location.

bpy_extras.object_utils.world_to_camera(scene, obj, coord)

release/scripts/modules/bpy_extras/object_utils.py

@@ -25,6 +25,7 @@ __all__ = (
     "object_add_grid_scale",
     "object_add_grid_scale_apply_operator",
     "object_image_guess",
+    "world_to_camera",
     )
 
 
@@ -265,3 +266,40 @@ def object_image_guess(obj, bm=None):
                         if image is not None:
                             return image
     return None
+
+
+def world_to_camera(scene, obj, coord):
+    """
+    Returns the 2d camera space coords for a 3d point.
+
+    Where (0, 0) is the bottom left and (1, 1) is the top right of the camera frame.
+    values outside 0-1 are also supported.
+
+    Takes shift-x/y, lens angle and sensor size into account
+    as well as perspective/ortho projections.
+
+    :arg scene: Scene to use for frame size.
+    :type scene: :class:`bpy.types.Scene`
+    :arg obj: Camera object.
+    :type obj: :class:`bpy.types.Object`
+    :arg coord: World space location.
+    :type coord: :class:`mathutils.Vector`
+    :return: normalized 2d vector.
+    :rtype: :class:`mathutils.Vector`
+    """
+
+    co_local = obj.matrix_world.normalized().inverted() * coord
+
+    camera = obj.data
+    frame = [-v for v in camera.view_frame(scene=scene)[:3]]
+    if camera.type != 'ORTHO':
+        frame = [(v / -v.z) * co_local.z for v in frame]
+
+    min_x, max_x = frame[1].x, frame[2].x
+    min_y, max_y = frame[0].y, frame[1].y
+
+    x = (co_local.x - min_x) / (max_x - min_x)
+    y = (co_local.y - min_y) / (max_y - min_y)
+
+    from mathutils import Vector
+    return Vector((x, y))