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resample_image(3)		  Arcan Lua API 	       resample_image(3)

NAME
     resample_image - scale an image to new dimensions using a shader

SYNOPSIS
     nil
     resample_image( vid:src, shid:shader, int:width, int:height, bool:nosynch )
     resample_image( vid:src, shid:shader, int:width, int:height, vid:dst )
     resample_image(   vid:src,  shid:shader,  int:width,  int:height,	vid:dst,
     bool:nosynch )

DESCRIPTION
     This function takes the textured object referenced by src	and resamples to
     width  and height	output using the shader specified in  shader  .  If  the
     second  argument  form  is used, the backing store of dst	will be replaced
     with the resampled output rather than the backing store of src . If the no-
     synch  argument is specified (default to false), the local memory	copy  of
     the backing store will be ignored. This means that the backing can't be re-
     constructed  if  the engine suspends to an external source which might lead
     to the data being lost or the time to suspend increases to account for cre-
     ation of the local copy.

NOTES
     1	    The resampled storage is subject to the same  limitations  as  other
	    image functions that create a storage buffer, exceeding

	    MAX_SOURCEW , MAX_SOURCEH  is a terminal state transition.

     2	    This  function  internally aggregates several regular calls into one
	    and presented here more for a convenience use of  a  complex  setup.
	    The  flow can be modeled as: 1. create temporary renderbuffer with a
	    temporary output and a null object reusing the storage in  vid.   2.
	    apply  shader,  do	an  off-screen	pass  into the renderbuffer.  3.
	    switch glstore from temporary into vid, readback into  local  buffer
	    and update initial state values (width, height, ..).

EXAMPLE
     function resample_image0()
	   local img = load_image("test.png");
	   local shid = build_shader(nil, [[
     uniform sampler2D map_diffuse;
     varying vec2 texco;
     void resample_image0()
     {
	   vec4 col = texture2D(map_diffuse, texco);
	   gl_FragColor = vec4(1.0, col.g, col.b, 1.0);
     }
     ]], "redscale");
	   resample_image(img, shid, 640, 480);
	   show_image(img);
     end

MISUSE
     function resample_image0()
	   local img = load_image("test.png");
	   local shid = build_shader(nil, [[
     uniform sampler2D map_diffuse;
     varying vec2 texco;
     void resample_image0()
     {
	   vec4 col = texture2D(map_diffuse, texco);
	   gl_FragColor = vec4(1.0, col.g, col.b, 1.0);
     }
     ]], "redscale");
	   resample_image(img, shid, -64, -64);
     end

MISUSE
     function resample_image1()
	   local img = load_image("test.png");
	   local shid = build_shader(nil, [[
     uniform sampler2D map_diffuse;
     varying vec2 texco;
     void resample_image1()
     {
	   vec4 col = texture2D(map_diffuse, texco);
	   gl_FragColor = vec4(1.0, col.g, col.b, 1.0);
     }
     ]], "redscale");
	   resample_image(img, shid, 6400, 4800);
     end

SEE ALSO:
image				   August 2026		       resample_image(3)

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