Morning all,

I have a working SDLx application implementing a 2D water drop effect (application start and initialize the display with a colored chessboard, then compute random water drops on it). This application is working fine (see the full code below) until I try to resize it (by clicking & dragging the bottom right of the window for example). As soon as I release the mouse button, the application ends without any message (window is closing, and I get back to the terminal prompt).

I have Strawberry Perl (5.14.4) installed (running on a Win10 laptop), and I wonder if my Perl/libraries installation is knowing issues, or if there is something wrong in my code.

Could someone test it and revert? Or provide a little help if something seems wrong? Thanks!

Here is the code:

#!/bin/perl
use SDL;
use SDL::Event;
use SDL::GFX::Rotozoom;
use SDL::Rect;
use SDL::Video;
use SDLx::App;
use SDLx::Surface;
use Math::Trig;
use strict;
use warnings;

my $imgfile='';
my $scale=4;

#########################
# Global initialization

# Initialize buffers
my $surface=load_surface();
my $surf_m=SDLx::Surface::pixel_array($surface);
my $image=load_surface();
my $imge_m=SDLx::Surface::pixel_array($image);

# Initialize application
my $app=SDLx::App->new(t=>'Example',w=>$image->w*$scale,h=>$image->h*$
+scale,d=>32,resizeable=>'on');

# Initialize wavemaps
my %wavemap=(wave=>0);
foreach(0..(($image->h+1)*($image->w+1))){$wavemap{$wavemap{wave}}[$_]
+=$wavemap{1-$wavemap{wave}}[$_]=0};

# Precompute maths
my @displut;
foreach(-256..256){$displut[$_+256]=int(tan(asin(sin(atan(int($_/4)))/
+4))*int($_/4)*15)};

# Add events
$app->add_event_handler(\&on_event);
$app->add_move_handler(\&on_move);
$app->add_show_handler(\&on_show);

# Start main loop
$app->run;

#########################
# Functions

sub on_event{
  my($event,$app)=@_;
  $app->stop if $event->type==SDL_QUIT;
  $app->resize($event->resize_w,$event->resize_h) if $event->type==SDL
+_VIDEORESIZE;
}

sub on_move{
  my($x,$y,$nx,$ny,$xdiff,$ydiff,$xdisp,$ydisp,$idx);
  my($w,$h)=($image->w,$image->h);

  # Set random drops
  (!int(rand(2)))&&($wavemap{$wavemap{wave}}[((int(rand($w-10))+5)*$w)
++int(rand($w-10))+5]=-100);

  # Update the wave map
  updatewavemaps();

  # Draw screen
  SDL::Video::lock_surface($surface);
  for($x=0;$x<$w;$x++){
    for($y=0;$y<$h;$y++){
      $idx=($y*$w)+$x;
      $xdiff=int($wavemap{$wavemap{wave}}[$idx+1]-$wavemap{$wavemap{wa
+ve}}[$idx]);
      $ydiff=int($wavemap{$wavemap{wave}}[$idx+$w]-$wavemap{$wavemap{w
+ave}}[$idx]);
      $xdisp=$displut[$xdiff+256];
      $ydisp=$displut[$ydiff+256];
      $nx=$xdiff<0?$x-$xdisp:$x+$xdisp;
      $ny=$ydiff<0?$y-$ydisp:$y+$ydisp;
      $nx=$nx<0?0:$nx>=$w?$w-1:$nx;
      $ny=$ny<0?0:$ny>=$h?$h-1:$ny;
      vec(${$surf_m->[$x][$y]},0,32)=vec(${$imge_m->[$nx][$ny]},0,32);
    }
  }
  SDL::Video::unlock_surface($surface);
}

sub on_show{
  my $buffer=SDL::GFX::Rotozoom::surface_xy($surface,0,($app->w/$surfa
+ce->w),($app->h/$surface->h),1);
  SDL::Video::blit_surface($buffer,SDL::Rect->new(0,0,$buffer->w,$buff
+er->h),$app,SDL::Rect->new(0,0,$app->w,$app->h));
  $app->sync;
}

sub load_surface{
  my $surface;
  if($imgfile ne ''){
    my $tmp=SDL::Image::load($imgfile);
    $surface=SDLx::Surface->new(w=>$tmp->w,h=>$tmp->h,d=>32,color=>0xF
+FFFFFFF);
    $surface->blit_by($tmp);
  }else{
    $surface=SDLx::Surface->new(w=>100,h=>100,d=>32,color=>0xFFFFFFFF)
+;
    for(my $x=0;$x<($surface->w)-5;$x+=20){
      for(my $y=0;$y<($surface->h)-5;$y+=20){
        my $c=SDL::Video::map_RGBA($surface->format(),255-int(($x*$y)/
+40),0,int(($x*$y)/40),255);
        SDL::Video::fill_rect($surface,SDL::Rect->new($x+2,$y+2,15,15)
+,$c);
      }
    }
  }
  return $surface;
}

sub updatewavemaps{
  my($x,$y,$n,$idx);
  my($w,$h,$da)=($image->w,$image->h,24);

  for($y=1;$y<$h;$y++){
    for($x=1;$x<$w;$x++){
      $idx=($y*$w)+$x;
      $n=($wavemap{$wavemap{wave}}[$idx-1]+
          $wavemap{$wavemap{wave}}[$idx+1]+
          $wavemap{$wavemap{wave}}[$idx-$w]+
          $wavemap{$wavemap{wave}}[$idx+$w])/2-
          $wavemap{1-$wavemap{wave}}[$idx];
      $wavemap{1-$wavemap{wave}}[$idx]=$n-($n/$da);
    }
  }
  $wavemap{wave}=1-$wavemap{wave};
}

[download]

Update:

I have optimized the code above (issue still not fixed), and I have around 40 FPS for an image of 100x100 pixels (it is stretched to 400x400 for display, but performances on pixels manipulation is what matters here). Not too bad, but not enough to process a larger screen (e.g. 640x480 is 1 FPS).

In reply to SDL/SDLx issue with application resizing by Garden Dwarf

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