NAME

image_shader - Set the active shader for an object.

SYNOPSIS

oldshid
image_shader( vid:image, string:identifier )
image_shader( vid:image, integer:identifier )
image_shader( vid:image, string:identifier, integer:attributes )
image_shader( vid:image, integer:identifier, integer:attributes )

DESCRIPTION

Processing programs can be created using the build_shader call. These programs can then be assigned to an image through this function. if attributes are provided, the value is expected to be one of these constants:

SHADER_DOMAIN_RENDERTARGET : find a rendertarget bound to image and assign the shader as the default program for objects using this rendertarget. if image does not contain a rendertarget, it is a terminal state transition.

SHADER_DOMAIN_RENDERTARGET_HARD : same as for SHADER_DOMAIN_RENDERTARGET , except all shaders on objects attached to the rendertarget will be ignored. This is useful for a temporary suspension of all shaders, as well as for rendertargets created using define_linktarget .

NOTES

1

if only the vid is provided, the active program won't be changed and the function is then used to query the active program of a video object.

2

if a string argument is supplied as the second argument, the routine will first resolve it by looking for a previously compiled shader with a name that matches the argument.

3

the shader state of all video objects are set to ' DEFAULT ' which is some platform default safe sate that follows obj_opacity and normal texturing.

EXAMPLE

function image_shader0()


      shid = build_shader(nil, [[


            void image_shader0(){


                  gl_FragColor = vec4(0.5, 1.0, 0.5, 1.0);


            }


      ]], "demoshader");


      a = fill_surface(64, 64, 0, 0, 0);


      show_image(a);


      image_shader(a, shid);
end

SEE ALSO:

build_shader(3) shader_ugroup(3) shader_uniform(3)