NAME

image_clip_on - Control clipping for a video object.

SYNOPSIS

nil
image_clip_on( vid:image )
image_clip_on( vid:image, int:mode )
image_clip_on( vid:image, int:mode=CLIP_SHALLOW, vid:cliptgt )

DESCRIPTION

This changes the clipping mode for the video object referenced by image . By default the mode is CLIP_ON , which is the more expensive one. It uses a stencil buffer to draw the entire hierarchy built using link_image . It is thus useful for complex hierarchies with possibly rotated objects. Another option is CLIP_SHALLOW . This only uses the immediate parent, and will get a fast-path assuming that both objects are rotated as that can be solved by adjusting object size and texture coordinates alone. If a cliptgt is provided with the CLIP_SHALLOW clipping mode, a specific object will be used for calculating the clipping bounds rather than using the link_image specified one. This is useful when a transform hierarchy is needed, but with specific clipping anchors.

NOTES

1: If a clip target is set to a non-existing or otherwise bad object or becomes invalid through deletion, clipping will revert to the image parent as if no clip target had been specified.

EXAMPLE

function image_clip_on0()
      a = fill_surface(64, 64, 255, 0, 0);
      b = fill_surface(64, 64, 0, 255, 0);
      link_image(b, a);
      move_image(b, 32, 32);
      show_image({a,b});
      image_clip_on(b, CLIP_SHALLOW);
end

MISUSE