[Bf-committers] [Bf-blender-cvs] SVN commit: /data/svn/bf-blender [57433] trunk/blender/release/scripts/ modules/bpy_extras/object_utils.py: handy function for getting the 2d camera coords for a worldspace location.

Campbell Barton ideasman42 at gmail.com
Thu Jun 13 17:24:41 CEST 2013


Fair point, not really a fan of `ndc space`, though I can't think of
one I'm especially happy with either...

other possibilities ...
world_to_view2d (except it returns z component)
world_to_camera_frame (since it uses camera framing functions, though
this is more of a detail)
world_to_view_uvw
world_to_render ?

On Fri, Jun 14, 2013 at 12:06 AM, Brecht Van Lommel
<brechtvanlommel at pandora.be> wrote:
> Nitpick about the terminology used here. "Camera space" usually refers
> to the coordinates when transformed by the camera matrix but without
> any perspective transformation applied, so I would say "2D camera
> space coords" here. OpenGL and Renderman would call the result of this
> function Normalized Device Coordinates, though I'm not sure if there
> is a common name for the space, maybe "NDC space".
>
> On Thu, Jun 13, 2013 at 3:51 PM, Campbell Barton <ideasman42 at gmail.com> wrote:
>> Revision: 57433
>>           http://projects.blender.org/scm/viewvc.php?view=rev&root=bf-blender&revision=57433
>> Author:   campbellbarton
>> Date:     2013-06-13 13:51:01 +0000 (Thu, 13 Jun 2013)
>> Log Message:
>> -----------
>> handy function for getting the 2d camera coords for a worldspace location.
>>
>>  bpy_extras.object_utils.world_to_camera(scene, obj, coord)
>>
>> Modified Paths:
>> --------------
>>     trunk/blender/release/scripts/modules/bpy_extras/object_utils.py
>>
>> Modified: trunk/blender/release/scripts/modules/bpy_extras/object_utils.py
>> ===================================================================
>> --- trunk/blender/release/scripts/modules/bpy_extras/object_utils.py    2013-06-13 13:09:32 UTC (rev 57432)
>> +++ trunk/blender/release/scripts/modules/bpy_extras/object_utils.py    2013-06-13 13:51:01 UTC (rev 57433)
>> @@ -25,6 +25,7 @@
>>      "object_add_grid_scale",
>>      "object_add_grid_scale_apply_operator",
>>      "object_image_guess",
>> +    "world_to_camera",
>>      )
>>
>>
>> @@ -265,3 +266,40 @@
>>                          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))
>>
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-- 
- Campbell


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