Ripple Transition Timing

  • I am trying to use Apple's documentation for using CoreImage effects,
    but it doesn't work well. The transition is too fast and choppy, and
    it stops and starts.

    One thing that seems strange about Apple's code is this:
      [transition setValue: [NSNumber numberWithFloat:
                                0.5*(1-cos(fmodf(t, 1.0f) * M_PI))]
                        forKey: @"inputTime"];

    0.5*(1-cos(fmodf(t, 1.0f) * M_PI)) Always produces zero, which seems
    inherent to it. If so, why should that equation be used to constantly
    set the time for the filter?

    Apple's documentation seems to be specifically for the scanner
    effect, but the documentation for the ripple effect doesn't provide
    any information  for this.
  • On 10/29/06, Henry Skelton <dimensiondude.oss...> wrote:
    > I am trying to use Apple's documentation for using CoreImage effects,
    > but it doesn't work well. The transition is too fast and choppy, and
    > it stops and starts.
    >
    > One thing that seems strange about Apple's code is this:
    > [transition setValue: [NSNumber numberWithFloat:
    > 0.5*(1-cos(fmodf(t, 1.0f) * M_PI))]
    > forKey: @"inputTime"];
    >
    > 0.5*(1-cos(fmodf(t, 1.0f) * M_PI)) Always produces zero, which seems
    > inherent to it. If so, why should that equation be used to constantly
    > set the time for the filter?

    Won't it only produce zero when t is an integer multiple of 1.0?

    --
    Clark S. Cox III
    <clarkcox3...>
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