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pick_items(3)			 Arcan Lua API			 pick_items(3)

NAME
       pick_items  -  Pick a number of objects based on	a screen-space coordi-
       nate.

SYNOPSIS
       vidtbl:results
       pick_items( number:x, number:y )
       pick_items( number:x, number:y, number:limit=8 )
       pick_items( number:x, number:y, number:limit=8 )
       pick_items( number:x, number:y, number:limit=8<=64,  bool:reverse=false
       )
       pick_items( number:x, number:y, number:limit=8<=64, bool:reverse=false,
       vid:rtgt=WORLDID	)

DESCRIPTION
       pick_items  is a	low level function for building	user-interface related
       picking tools. It takes a screen- or rendertarget- space	coordinate and
       sweeps through the pipeline based on their render order (see  order_im-
       age  ).	If reverse  is provided	it will	sweep from high	to low,	other-
       wise from low to	high. It will early out	once limit  objects have  been
       found. It will always return an integer indexed table of	zero to	limit
       number of VID s.	Limit is not allowed to	exceed 64.

NOTES
       1      All  VID	s  start out as	eligible for picking. This can be con-
	      trolled by setting the MASK_UNPICKABLE  mask, see	image_mask_set
	      .	This mask value	is not inherited by default  through  linking.
	      This  means it needs to be set for each new object regardless of
	      how link_image  is being used.

       2      Clipping and alpha channel is ignored and	will need to  be  con-
	      sidered  manually	 by testing against any	possible clipping par-
	      ents.

       3      This function can	be very	costly based on	the complexity of  the
	      scene and	some caching mechanism should be used if a high	number
	      of  calls	 is  expected,	for  instance  when tied to a touch or
	      mouse- input device event	handler.

       4      The cost progression is roughly (low to high)  normal,  rotated,
	      linked, 3d object, rotated-linked, rotated-linked-3d object.

       5      If  an  object  is  shader  displayed or manually	manipulated by
	      skewing vertices through image_tesselation  or  a	 vertex	 stage
	      shader, the picking operation result is undefined.

SEE ALSO:
       image_hit(3)

image				  April	2025			 pick_items(3)

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