= Distort or convolve an image =

== General convolutions ==

    To apply general convolution kernels, use the [Convolve
    operator|Node:cop2/convolve]. You can specify up to a 9x9 kernel in
    the node's parameters, or connect an image to use as a kernel.


    TIP:
        Convolving images is a slow operation, so try to keep the the
        kernel image smaller than 50x50.

== Image displacement maps ==

    Use the [Deform operator|Node:cop2/deform] to move pixels based on a
    displacement map.

== Waves and ripples ==

    [Image:images/water_reflect.jpg]

    You can use slowly animated, smooth noise as the basis for
    concentric ripples. Use a cycling [Ramp node|Node:cop2/ramp] with a
    range from 0 to 1 and an interpolation of "Ease in Ease Out" to
    create ripples (concentric ramp) or waves (rotated horizontal map).

    Create a [Deform node|Node:cop2/deform] and use the noise to
    displace the image.

    [Image:images/water_ripple.jpg]

    [Image:images/ripple.jpg]

    TIP:
        You should use  [floating point
        images|comp_terms#comp_datatypes]  for distortion maps whenever
        possible. Otherwise, quantization errors can cause unwanted
        noise in the image.