how to make value persistent

pirelouit · **Joined:** Mon Jan 16, 2006 12:08 pm **Posts:** 18

Hi! I made an expression (applied on timeRemap of a sequence) that displays a specific frame of a sequence based on the position of a guide layer. If the guide layer (called "temoin" in the following code) is over a certain reference layer (in "targetComp" in the code), it then displays a specific frame based on the reference layer index. The problem is that by default it always resets to 1. I would like it to keep the last valid value. Is there a a way to achieve this?

Thanks,
Louis

Code:

targetComp = comp("as_claydog");
temoin = thisComp.layer("temoin");
curClosestIndex = null;
previousFrame = timeRemap;

for (var i = 1; i <= targetComp.numLayers; i++)
{
   layerPos   = targetComp.layer(i).position;
   layerWidth   = targetComp.layer(i).width/2*(targetComp.layer(i).scale[0]/100);
   layerHeight= targetComp.layer(i).height/2*(targetComp.layer(i).scale[1]/100);
   minX      = layerPos[0] - (layerWidth);
   maxX      = layerPos[0] + (layerWidth);
   minY      = layerPos[1] - (layerHeight);
   maxY      = layerPos[1] + (layerHeight);
   curPos   = temoin.position;
   if ( curPos[0] > minX && curPos[0] < maxX)
   {
      if ( curPos[1] > minY && curPos[1] < maxY)
      {
         curClosestIndex = i;
      }
   }
}

if (curClosestIndex != null)
{
   frames = curClosestIndex -1;
   fps = 1.0 / thisComp.frameDuration;
   timeRemap = framesToTime(frames, fps );
} else {
   timeRemap = previousFrame;
}

Mylenium · **Joined:** Wed Jul 20, 2005 12:07 am **Posts:** 139

You need to create another loop that forces the expression to evaluate for every frame while(x < thisComp.duration){}.

Mylenium

pirelouit · **Joined:** Mon Jan 16, 2006 12:08 pm **Posts:** 18

Thank you, it worked perfectly. Here is the final script.

Code:

targetComp      = comp("as_claydog");
temoin            = thisComp.layer("temoin");
curClosestIndex   = null;
timeIndex         = time;
fps               = 1.0 / thisComp.frameDuration;

while (curClosestIndex == null && timeIndex > temoin.startTime)
{
   curClosestIndex = evalPos(targetComp, temoin, timeIndex);
   timeIndex = timeIndex - framesToTime(1, fps );
}

frames      = curClosestIndex -1;
timeRemap   = framesToTime(frames, fps );


function evalPos(targetComp, temoin, timeIndex)
{
   for (var i = 1; i <= targetComp.numLayers; i++)
   {
      layerPos      = targetComp.layer(i).position.valueAtTime(timeIndex);
      layerWidth   = targetComp.layer(i).width/2*(targetComp.layer(i).scale.valueAtTime(timeIndex)[0]/100);
      layerHeight   = targetComp.layer(i).height/2*(targetComp.layer(i).scale.valueAtTime(timeIndex)[1]/100);
      minX         = layerPos[0] - (layerWidth);
      maxX         = layerPos[0] + (layerWidth);
      minY         = layerPos[1] - (layerHeight);
      maxY         = layerPos[1] + (layerHeight);
      curPos         = temoin.position.valueAtTime(timeIndex);
      if ( curPos[0] > minX && curPos[0] < maxX)
      {
         if ( curPos[1] > minY && curPos[1] < maxY)
         {
            return(i);
         }
      }
   }
   return(null);
}

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