Conversion function for screen coords to local Canvas coords

[Razzlegames]

• Useful if you need to Convert screen coords to the coordinate space of a CanvasItem, but don't have an
  associated InputEvent to use in #make_event_local.

For example, if you have a particular point on the screen you'd like to project into World Space, for various reasons, you would use this function on the root of the scene. This is analogous to ray casting from screen space in 3D.

[Razzlegames]

Use as so:

var local_coord = make_screen_coord_local(screen_coord)

func useCoord(screen_coord):
   var local_coord = make_canvas_pos_local(screen_coord)
   # Do whatever you want with coord that is now local to
   #      the CanvasItem you called this in!

[reduz]

there is get_global_transform_with_canvas().affine_inverse() * pos

but i guess this is probably a little easier to use, maybe you could rename it to make_canvas_pos_local()

[Razzlegames]

Yes I can rename however you'd like for the SDK. Yes, I think users new to
Linear Algebra don't really know what the meaning of that math is.

On Mon, Jun 6, 2016 at 4:42 PM, Juan Linietsky notifications@github.com
wrote:

there is get_global_transform_with_canvas().affine_inverse() * pos

but i guess this is probably a little easier to use, maybe you could
rename it to make_canvas_pos_local()

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[reduz]

yeah agreed, forcing them to use linear algebra may be too much

[reduz]

if you manage to rename it, let me know and I will merge

[EdwardAngeles]

Thanks for get_global_transform_with_canvas().affine_inverse() * pos to get the ScreenToWorld coords.

I have to ask: What would be a way to get the WorldToScreen coords?

[Razzlegames]

Sorry for the delay in editing this.

@EdwardAngeles You'd just make, the root of your Scene, a Canvas2D node and call the inverse of this. It would be:

var screen_pos = (get_canvas_transform() * get_global_transform())* world_pos

@reduz Does it make sense to make a function for this? It could be make_local_pos_canvas_pos or something similar.

[Razzlegames]

@EdwardAngeles if you'd like a convenience function make_local_pos_canvas_pos I'll add it in another commit.

[EdwardAngeles]

@Razzlegames That sounds like a good idea. Thanks!

[bojidar-bg]

Breaks the XML, @akien-mga (found by @vnen )

[vnen]

Fixed by 98eec17.