2009-07-10 - Just another pong!

To control the pads use 'q', 'a', 'p' and 'l' keys. 

[http://1.bp.blogspot.com/_FDA3N96YFtA/SSylsKA2p4I/AAAAAAAAAAw/I62t0ZWgncg/s400/tkpong-screenshoot.png]
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Copyright (c) 2008, 2009 Héctor Francisco Hernández <hectorfh@gmail.com>

Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

package require Tk

canvas .canvas -width 520 -height 390 -bg green4
label .lblbtm -textvariable lblbtm
pack .canvas
pack .lblbtm -fill x

.canvas create rectangle 10 156 25 234 -tag pad1 -fill gray -outline gray
.canvas create rectangle 495 156 510 234 -tag pad2 -fill gray -outline gray
.canvas create oval 255 190 265 200 -tag ball -fill white -outline white

wm title . "tkpong"
wm protocol . WM_DELETE_WINDOW exit

bind . <Escape> exit
bind . <KeyPress-q> {set pad1ay -0.001}
bind . <KeyPress-a> {set pad1ay 0.001}
bind . <KeyRelease-q> {set pad1ay 0}
bind . <KeyRelease-a> {set pad1ay 0}
bind . <KeyPress-p> {set pad2ay -0.001}
bind . <KeyPress-l> {set pad2ay 0.001}
bind . <KeyRelease-p> {set pad2ay 0}
bind . <KeyRelease-l> {set pad2ay 0}

while 1 {
  set pad1y 195
  set pad1ay 0
  set pad1vy 0
  set pad2y 195
  set pad2ay 0
  set pad2vy 0
  set plyr1pts 0
  set plyr2pts 0

  set lblbtm "Press \"Return\" to start or \"Esc\" to exit."
  bind . <Return> {set sleep {}}
  tkwait variable sleep
  bind . <Return> {}

  while {10 > $plyr1pts && 10 > $plyr2pts} {
    set n 0
    set ballx 260
    set bally 195
    set ballvx [expr {rand () < 0.5 ? -0.2 : 0.2}]
    set ballvy [expr {rand () * 0.1 - 0.05}]

    set lblbtm "$plyr1pts - $plyr2pts"

    while {-5 < $ballx && 525 > $ballx} {
      set pad1vy [expr {0 < $pad1y && 390 > $pad1y \
          || 0 >= $pad1y && 0 <= $pad1vy && 0 < $pad1ay \
          || 390 <= $pad1y && 0 >= $pad1vy && 0 > $pad1ay \
          ? $pad1vy + $pad1ay : 0}]
      set pad1y [expr {$pad1y + $pad1vy}]

      set pad2vy [expr {0 < $pad2y && 390 > $pad2y \
          || 0 >= $pad2y && 0 <= $pad2vy && 0 < $pad2ay \
          || 390 <= $pad2y && 0 >= $pad2vy && 0 > $pad2ay \
          ? $pad2vy + $pad2ay : 0}]
      set pad2y [expr {$pad2y + $pad2vy}]

      set ballx [expr {$ballx + $ballvx}]
      set bally [expr {$bally + $ballvy}]

      set ballvy [expr {5 > $bally && 0 > $ballvy
        || 385 < $bally && 0 < $ballvy ? -$ballvy : $ballvy}]

      if {25 > $ballx && 20 < $ballx && 0 > $ballvx} {
        if {$pad1y - 45 < $bally && $pad1y + 45 > $bally} {
          set ballvx [expr {-$ballvx + 0.01}]
          set ballvy [expr {$ballvy + ($bally - $pad1y) / 45.0 * 0.15 + \
              $pad1vy * 0.4}]
        }
      } elseif {500 > $ballx && 495 < $ballx && 0 < $ballvx} {
        if {$pad2y - 45 < $bally && $pad2y + 45 > $bally} {
          set ballvx [expr {-$ballvx - 0.01}]
          set ballvy [expr {$ballvy + ($bally - $pad2y) / 45.0 * 0.15 + \
              $pad2vy * 0.4}]
        }
      }

      if {0 == $n % 20} {
        .canvas coords pad1 10 [expr {$pad1y - 39}] 25 [expr {$pad1y + 39}]
        .canvas coords pad2 495 [expr {$pad2y - 39}] 510 [expr {$pad2y + 39}]
        .canvas coords ball [expr {$ballx - 5}] [expr {$bally - 5}] \
            [expr {$ballx + 5}] [expr {$bally + 5}]

        after 20 {set sleep {}}
        tkwait variable sleep
      }

      incr n
    }

    set plyr1pts [expr {525 < $ballx ? $plyr1pts + 1 : $plyr1pts}]
    set plyr2pts [expr {-5 > $ballx ? $plyr2pts + 1 : $plyr2pts}]

  }

  tk_messageBox -parent . -title "Congratulations!" \
      -message "Player [expr {10 == $plyr1pts ? "one" : "two"}] wins."
}
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!!!!!!
%| [Category Games] | [Category Application] | [Category Graphics] |%
!!!!!!