Filter error

Question

Hi, I´m just learning and developing my first filter for After Effects I found something really weird.
I´m just making an easy zoom in and zoom out effect using 2 imput images, it seems to work OK in Pixel Bender.
this is my code:
<languageVersion : 1.0;>
kernel TwoImagesZooming
<   namespace : "blablabla";
    vendor : "Meh";
    version : 1;
    description : "zoom in zoom out with 2 images";
    displayname : "Pixel Displacement Complex";
    category : "AE filter category";
>
    input image4 src;
    input image4 src2;
    output pixel4 dst;
    parameter float ZoomA
    <
    minValue:0.0;
    maxValue:1.0;
    defaultValue:1.0;
    >;
    parameter float ZoomB
    <
    minValue:0.0;
    maxValue:1.0;
    defaultValue:0.0;
    >;
    void
    evaluatePixel()
        pixel4 dst2 = sampleNearest(src,outCoord()/float2(DisplacementA, DisplacementA));
        pixel4 dst3 = sampleNearest(src2,outCoord()/float2(DisplacementB, DisplacementB));
        dst=dst2+dst3;
but when I taste it in AE (CS4 by the way), it shows me these error:
Can Somebody help me to find whats going on....Please

Answer 1

Hi,
The error gives a hint what might be going on.
In below two calls you are diving outCoord() with DisplacementA & DisplacementB. If any of them is zero, you will get "division by zero" error.
pixel4 dst2 = sampleNearest(src,outCoord()/float2(DisplacementA, DisplacementA));
pixel4 dst3 = sampleNearest(src2,outCoord()/float2(DisplacementB, DisplacementB));
To fix it, you should make sure values of DisplacementA & DisplacementB are never zero. There are several ways of doing that: either you can set minValue of those parameters to be greater than zero or you can do things differently if their value is zero.
Hope that helps.