/*
This is a very basic ufh script to "prep" some finite difference model data
consisting of a split spread, 481 traces/rec, and a trace at 0-range. Group
interval is 27.5
*/

func Begin() {                /* initialize variable */
	TotalTraces = 1;
	RelativeTraces = 1;
	RNum = 1;
	DepthIndex = -241;
}

func OnLineHeader()           /* done nothing to line header - output it */
{
	output(LH);
}

func OnTrace() {              /* for each input trace - prep */

	RecordRollAlong = ((RelativeTraces - 1)%481) + 1;
	Tr.DstSgn = 27.5 * (RecordRollAlong - 241);
	Tr.DphInd = DepthIndex + RelativeTraces;
        Tr.RecNum = RNum;
        Tr.SrcLoc = RNum;

	output(Tr);           /* output "prepped" trace */

/*  we could print out info to stderr to monitor our prep

	 print( "TotalTraces = ", TotalTraces,
                 " RelativeTraces = ", RelativeTraces,
	 	" Tr.DstSgn = ", Tr.DstSgn,
	 	" Tr.DphInd = ", Tr.DphInd,
	 	"\n");
*/

	if((TotalTraces%481) == 0){      /* update rolling index variables */
		++RNum;
		DepthIndex = DepthIndex + 40;
		RelativeTraces = 1;
	} else {
		++RelativeTraces;
	}
	TotalTraces++;
}