use strict;
use warnings;
use PDL;

# user params
my $floor = 100;
my $component = 0;
my $delta = 6;
my $elevation = 2;
my $camerapos = -1;
$| = 1;

my $alpha = 0;
my $srcdata = rpic($ARGV[0]);
my $destdata = $srcdata->zeroes; # "filled" with black
$destdata->slice(3) .= 255 if $alpha;
my $destmv = $destdata->mv(0,-1); # x y rgb
my (undef, $width, $height) = $srcdata->dims;
my $relord = $width / 255;
$delta = 1 if $delta < 1;

my $quant = ($srcdata->slice("($component)")->max / $delta)->floor->sclr;
return if $quant <= 0;
for my $x (0..$width-1) {
  my $col = $srcdata->slice("($component),($x)");
  my $exceed_floor = ($col > $floor);
  my $r = $col->where($exceed_floor); # nvals
  my $destx = ($width - $r * $relord + ($x / $elevation))->long; # nvals
  #Apply elevation following the x offset in original picture
  my $remain_s = zeroes(long, 3, $quant, $r->dim(0)); # xyr quant nvals
  my $yslice = $remain_s->slice("(1)") .= $exceed_floor->which->dummy(0); # quant nvals
  my $xslice = $remain_s->slice("(0)") .= $yslice->xvals + $destx->dummy(0); # quant nvals
  my $rslice = $remain_s->slice("(2)") .= $yslice->xlinvals(0,-1) * $quant*$delta + $r->dummy(0); # quant nvals
  $rslice->whereND($xslice >= $width) .= -1;
  my $gt150_ind = whichND($rslice > 150);
  my $btwn_ind = whichND(($rslice <= 150) & ($rslice >= 50));
  my $lt50_ind = whichND(($rslice < 50) & ($rslice > 0));
  $destmv->slice(',,1:2')->indexND(cat(map $_->indexND($gt150_ind), $xslice, $yslice)->mv(-1,0)) .= $rslice->indexND($gt150_ind) if $gt150_ind->nelem;
  $destmv->slice(',,1')->indexND(cat(map $_->indexND($btwn_ind), $xslice, $yslice)->mv(-1,0)) .= $rslice->indexND($btwn_ind) + 55 if $btwn_ind->nelem;
  $destmv->slice(',,2')->indexND(cat(map $_->indexND($lt50_ind), $xslice, $yslice)->mv(-1,0)) .= $rslice->indexND($lt50_ind) + 200 if $lt50_ind->nelem;
#  Gimp::Progress->update($x / $height);
}

$destdata->wpic("OUT$ARGV[0]");