#! /usr/bin/perl -w

use strict;
use OpenGL qw(:all);
use OpenGL::Image;
use Time::HiRes qw( gettimeofday );

use constant ESCAPE => 27;
use constant FRAME_RATE_SAMPLES => 60;


my ($width, $height) = (640,480);
my ($FrameCount, $FrameRate, $last) = (0, 0, 0);
my ($now, $window) = (gettimeofday(), );
my ($Depth,$Top,$Bot,$Width) = (3.0,0.0,0.0,0.0);
DepthCalc();

my @hours = (13..24);
my @channels = (1..25);

sub InitGL {
  glClearColor(0.0, 0.0, 0.0, 1.0);
  glClearDepth(1.0);
  glEnable(GL_DEPTH_TEST);
  glDepthFunc(GL_LESS);
  glEnable (GL_BLEND); 
  glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  glShadeModel(GL_SMOOTH);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity;
  gluPerspective(90.0, $width/$height, 0.1, 100.0);
  glMatrixMode(GL_MODELVIEW);
}

sub ReSizeGLScene {
    ($width, $height) = @_;
    if ($width < 640) {$width = 640;}
    if ($height < 480) {$height = 480;}
    glViewport(0, 0, $width, $height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity;
    gluPerspective(90.0, $width/$height, 0.1, 100.0);
    glMatrixMode(GL_MODELVIEW);
  DepthCalc();
}

sub DepthCalc {
$Top = $Depth-($Depth / 7.5);
$Bot = $Depth-($Depth / 7.5);
$Width = (($width/$height)*$Depth)-($Depth / 100);
return 1;
}

sub keyPressed {
  my ($key, $x, $y) = @_;
  if ($key == ord('q')) {glutDestroyWindow($window);exit(0);}
  elsif ($key == ESCAPE) {glutDestroyWindow($window);exit(0);}
  else {}
}



sub DrawGLScene {
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  $FrameCount++;
  if ($FrameCount == FRAME_RATE_SAMPLES / 2) {FPS_calc();}
  elsif ($FrameCount == 0) {FPS_calc();}
  elsif ($FrameCount == FRAME_RATE_SAMPLES) {$FrameCount = 0;}

  glLoadIdentity();
  glTranslatef(0.0, 0.0,-2.075);
  glColor4f(1.0,1.0,1.0,0.7);
  my $buf = sprintf("FPS: %f D: %2d F: %2d",$FrameRate,$Depth,$FrameCo
+unt);
  glRasterPos2i(-1.8,-2.5); ourPrintString(GLUT_BITMAP_TIMES_ROMAN_24,
+$buf);

  glLoadIdentity();
  glTranslatef(0.0, 0.0,-($Depth+0.1));
  glBegin(GL_QUADS);
  glColor4f(0.0,0.0,0.0,0.7);
      glVertex3f( $Width, $Depth, 0.0);
      glVertex3f( $Width, $Depth-($Depth/7.5), 0.0);
      glVertex3f(-$Width, $Depth-($Depth/7.5), 0.0);
      glVertex3f(-$Width, $Depth, 0.0);
  glEnd;

  my ($left_width, $right_width) = (-($Width-0.05), -($Width-5.95));

  glLoadIdentity();
  glTranslatef(0.0, 0.0,-($Depth));
  glBegin(GL_QUADS);
  glColor4f(1.0,1.0,1.0,0.7);
  foreach my $hour (@hours) {
    my ($top_half, $bot_half) = ($Top-0.05, ($Top-4.0));
    my $width_repl = $right_width;
    if ($right_width >= $Width) {$width_repl = ($Width-0.05);}
    foreach my $channel (@channels) {
    my $bot_repl = $bot_half;
      if ($bot_half <= -$Bot) {$bot_repl = -($Bot-0.05);}
      glVertex3f($left_width , $top_half  , 0.0);
      glVertex3f($left_width , $bot_repl, 0.0);
      glVertex3f($width_repl, $bot_repl, 0.0);
      glVertex3f($width_repl, $top_half  , 0.0);
      last if ($bot_half <= -$Bot);
      $top_half -= 4.0;
      $bot_half -= 4.0;
    }
    last if ($right_width >= $Width);
    $right_width += 5.95;
    $left_width += 5.95;
  }
  glEnd;

  glColor4f(1.0,1.0,0.8,1.0);
  glBegin(GL_QUADS);
  glVertex3f( $Width, $Top, 0.0);
  glVertex3f( $Width,-$Bot, 0.0);
  glVertex3f(-$Width,-$Bot, 0.0);
  glVertex3f(-$Width, $Top, 0.0);
  glEnd;

  glutSwapBuffers;
}

sub ourPrintString {
  my ($font, $str) = @_;
  my @c = split '', $str;
  for(@c) {
    glutBitmapCharacter($font, ord $_);
  }
}

sub FPS_calc {
  $now =  gettimeofday();
  my $delta = ($now - $last);
  $last = $now;
  $FrameRate = FRAME_RATE_SAMPLES / ($delta or 1);
  $FrameRate = substr($FrameRate, 0, 11);
}

sub MousePressed {
  my ($button, $state, $x, $y) = @_;
  return if ($state == 1);
  $Depth-- and DepthCalc() and return if ($button == 3 and $state == 0
+ and !($Depth <= 2));
  $Depth++ and DepthCalc() and return if ($button == 4 and $state == 0
+ and !($Depth >= 27));
  print (join(" ",@_)."\n");

 #print $width." ".$height."  ".$Width."/".$Depth.
 #"=".$Width / $Depth."\n" if $state == 0;
}


glutInit;
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
glutInitWindowSize($width, $height);
$window = glutCreateWindow("OpenGL Project");
glutReshapeFunc(\&ReSizeGLScene);
glutDisplayFunc(\&DrawGLScene);
glutIdleFunc(\&DrawGLScene);
glutKeyboardFunc(\&keyPressed);
glutMouseFunc(\&MousePressed);
InitGL();
glutMainLoop();

return 1;
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