lisp/play/pong.el

   1 ;;; pong.el - classical implementation of pong
   2
   3 ;; Copyright 1999, 2000 by Free Software Foundation, Inc.
   4
   5 ;; Author: Benjamin Drieu <drieu@bocal.cs.univ-paris8.fr>
   6 ;; Keywords: games
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  22 ;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23 ;; Boston, MA 02111-1307, USA.
  24
  25 ;;; Commentary:
  26
  27 ;; This is an implementation of the classical game pong.
  28
  29 ;;; Code:
  30
  31 (eval-when-compile (require 'cl))
  32
  33 (require 'gamegrid)
  34
  35 ;;; Customization
  36
  37 (defgroup pong nil
  38   "Emacs-Lisp implementation of the classical game pong."
  39   :tag "Pong"
  40   :group 'games)
  41
  42 (defcustom pong-buffer-name "*Pong*"
  43   "*Name of the buffer used to play."
  44   :group 'pong
  45   :type '(string))
  46
  47 (defcustom pong-width 50
  48   "*Width of the playfield."
  49   :group 'pong
  50   :type '(integer))
  51
  52 (defcustom pong-height 30
  53   "*Height of the playfield."
  54   :group 'pong
  55   :type '(integer))
  56
  57 (defcustom pong-bat-width 3
  58   "*Width of the bats for pong."
  59   :group 'pong
  60   :type '(integer))
  61
  62 (defcustom pong-blank-color "black"
  63   "*Color used for background."
  64   :group 'pong
  65   :type 'color)
  66
  67 (defcustom pong-bat-color "yellow"
  68   "*Color used for bats."
  69   :group 'pong
  70   :type 'color)
  71
  72 (defcustom pong-ball-color "red"
  73   "*Color used for the ball."
  74   :group 'pong
  75   :type 'color)
  76
  77 (defcustom pong-border-color "white"
  78   "*Color used for pong balls."
  79   :group 'pong
  80   :type 'color)
  81
  82 (defcustom pong-left-key "4"
  83   "*Alternate key to press for bat 1 to go up (primary one is [left])."
  84   :group 'pong
  85   :type '(restricted-sexp :match-alternatives (stringp vectorp)))
  86
  87 (defcustom pong-right-key "6"
  88   "*Alternate key to press for bat 1 to go down (primary one is [right])."
  89   :group 'pong
  90   :type '(restricted-sexp :match-alternatives (stringp vectorp)))
  91
  92 (defcustom pong-up-key "8"
  93   "*Alternate key to press for bat 2 to go up (primary one is [up])."
  94   :group 'pong
  95   :type '(restricted-sexp :match-alternatives (stringp vectorp)))
  96
  97 (defcustom pong-down-key "2"
  98   "*Alternate key to press for bat 2 to go down (primary one is [down])."
  99   :group 'pong
 100   :type '(restricted-sexp :match-alternatives (stringp vectorp)))
 101
 102 (defcustom pong-quit-key "q"
 103   "*Key to press to quit pong."
 104   :group 'pong
 105   :type '(restricted-sexp :match-alternatives (stringp vectorp)))
 106
 107 (defcustom pong-pause-key "p"
 108   "Key to press to pause pong."
 109   :group 'pong
 110   :type '(restricted-sexp :match-alternatives (stringp vectorp)))
 111
 112 (defcustom pong-resume-key "p"
 113   "*Key to press to resume pong."
 114   :group 'pong
 115   :type '(restricted-sexp :match-alternatives (stringp vectorp)))
 116
 117 (defcustom pong-timer-delay 0.1
 118   "*Time to wait between every cycle."
 119   :group 'pong
 120   :type 'number)
 121
 122
 123 ;;; This is black magic.  Define colors used
 124
 125 (defvar pong-blank-options
 126   '(((glyph colorize)
 127      (t ?\040))
 128     ((color-x color-x)
 129      (mono-x grid-x)
 130      (color-tty color-tty))
 131     (((glyph color-x) [0 0 0])
 132      (color-tty pong-blank-color))))
 133
 134 (defvar pong-bat-options
 135   '(((glyph colorize)
 136      (emacs-tty ?O)
 137      (t ?\040))
 138     ((color-x color-x)
 139      (mono-x mono-x)
 140      (color-tty color-tty)
 141      (mono-tty mono-tty))
 142     (((glyph color-x) [1 1 0])
 143      (color-tty pong-bat-color))))
 144
 145 (defvar pong-ball-options
 146   '(((glyph colorize)
 147      (t ?\*))
 148     ((color-x color-x)
 149      (mono-x grid-x)
 150      (color-tty color-tty))
 151     (((glyph color-x) [1 0 0])
 152      (color-tty pong-ball-color))))
 153
 154 (defvar pong-border-options
 155   '(((glyph colorize)
 156      (t ?\+))
 157     ((color-x color-x)
 158      (mono-x grid-x))
 159     (((glyph color-x) [0.5 0.5 0.5])
 160      (color-tty pong-border-color))))
 161
 162 (defconst pong-blank    0)
 163 (defconst pong-bat      1)
 164 (defconst pong-ball     2)
 165 (defconst pong-border   3)
 166
 167
 168 ;;; Determine initial positions for bats and ball
 169
 170 (defvar pong-xx nil
 171   "Horizontal speed of the ball.")
 172
 173 (defvar pong-yy nil
 174   "Vertical speed of the ball.")
 175
 176 (defvar pong-x nil
 177   "Horizontal position of the ball.")
 178
 179 (defvar pong-y nil
 180   "Vertical position of the ball.")
 181
 182 (defvar pong-bat-player1 nil
 183   "Vertical position of bat 1.")
 184
 185 (defvar pong-bat-player2 nil
 186   "Vertical position of bat 2.")
 187
 188 (defvar pong-score-player1 nil)
 189 (defvar pong-score-player2 nil)
 190
 191 ;;; Initialize maps
 192
 193 (defvar pong-mode-map
 194   (make-sparse-keymap 'pong-mode-map) "Modemap for pong-mode.")
 195
 196 (defvar pong-null-map
 197   (make-sparse-keymap 'pong-null-map) "Null map for pong-mode.")
 198
 199 (define-key pong-mode-map [left]         'pong-move-left)
 200 (define-key pong-mode-map [right]        'pong-move-right)
 201 (define-key pong-mode-map [up]           'pong-move-up)
 202 (define-key pong-mode-map [down]         'pong-move-down)
 203 (define-key pong-mode-map pong-left-key  'pong-move-left)
 204 (define-key pong-mode-map pong-right-key 'pong-move-right)
 205 (define-key pong-mode-map pong-up-key    'pong-move-up)
 206 (define-key pong-mode-map pong-down-key  'pong-move-down)
 207 (define-key pong-mode-map pong-quit-key  'pong-quit)
 208 (define-key pong-mode-map pong-pause-key 'pong-pause)
 209
 210
 211 ;;; Fun stuff -- The code
 212
 213 (defun pong-display-options ()
 214   "Computes display options (required by gamegrid for colors)."
 215   (let ((options (make-vector 256 nil)))
 216     (loop for c from 0 to 255 do
 217       (aset options c
 218             (cond ((= c pong-blank)
 219                    pong-blank-options)
 220                   ((= c pong-bat)
 221                    pong-bat-options)
 222                   ((= c pong-ball)
 223                    pong-ball-options)
 224                   ((= c pong-border)
 225                    pong-border-options)
 226                   (t
 227                    '(nil nil nil)))))
 228     options))
 229
 230
 231
 232 (defun pong-init-buffer ()
 233   "Initialize pong buffer and draw stuff thanks to gamegrid library."
 234   (interactive)
 235   (get-buffer-create pong-buffer-name)
 236   (switch-to-buffer pong-buffer-name)
 237   (use-local-map pong-mode-map)
 238
 239   (setq gamegrid-use-glyphs t)
 240   (setq gamegrid-use-color t)
 241   (gamegrid-init (pong-display-options))
 242
 243   (gamegrid-init-buffer pong-width
 244                         (+ 2 pong-height)
 245                         1)
 246
 247   (let ((buffer-read-only nil))
 248     (loop for y from 0 to (1- pong-height) do
 249           (loop for x from 0 to (1- pong-width) do
 250                 (gamegrid-set-cell x y pong-border)))
 251     (loop for y from 1 to (- pong-height 2) do
 252           (loop for x from 1 to (- pong-width 2) do
 253                 (gamegrid-set-cell x y pong-blank))))
 254
 255   (loop for y from pong-bat-player1 to (1- (+ pong-bat-player1 pong-bat-width)) do
 256         (gamegrid-set-cell 2 y pong-bat))
 257   (loop for y from pong-bat-player2 to (1- (+ pong-bat-player2 pong-bat-width)) do
 258         (gamegrid-set-cell (- pong-width 3) y pong-bat)))
 259
 260
 261
 262 (defun pong-move-left ()
 263   "Move bat 2 up.
 264 This is called left for historical reasons, since in some pong
 265 implementations you move with left/right paddle."
 266   (interactive)
 267   (if (> pong-bat-player1 1)
 268       (and
 269        (setq pong-bat-player1 (1- pong-bat-player1))
 270        (pong-update-bat 2 pong-bat-player1))))
 271
 272
 273
 274 (defun pong-move-right ()
 275   "Move bat 2 up."
 276   (interactive)
 277   (if (< (+ pong-bat-player1 pong-bat-width) (1- pong-height))
 278       (and
 279        (setq pong-bat-player1 (1+ pong-bat-player1))
 280        (pong-update-bat 2 pong-bat-player1))))
 281
 282
 283
 284 (defun pong-move-up ()
 285   "Move bat 2 up."
 286   (interactive)
 287   (if (> pong-bat-player2 1)
 288       (and
 289        (setq pong-bat-player2 (1- pong-bat-player2))
 290        (pong-update-bat (- pong-width 3) pong-bat-player2))))
 291
 292
 293
 294 (defun pong-move-down ()
 295   "Move bat 2 down."
 296   (interactive)
 297   (if (< (+ pong-bat-player2 pong-bat-width) (1- pong-height))
 298       (and
 299        (setq pong-bat-player2 (1+ pong-bat-player2))
 300        (pong-update-bat (- pong-width 3) pong-bat-player2))))
 301
 302
 303
 304 (defun pong-update-bat (x y)
 305   "Move a bat (suppress a cell and draw another one on the other side)."
 306
 307   (cond
 308    ((string-equal (buffer-name (current-buffer)) pong-buffer-name)
 309     (gamegrid-set-cell x y pong-bat)
 310     (gamegrid-set-cell x (1- (+ y pong-bat-width)) pong-bat)
 311     (if (> y 1)
 312         (gamegrid-set-cell x (1- y) pong-blank))
 313     (if (< (+ y pong-bat-width) (1- pong-height))
 314         (gamegrid-set-cell x (+ y pong-bat-width) pong-blank)))))
 315
 316
 317
 318 (defun pong-init ()
 319   "Initialize a game."
 320
 321   (define-key pong-mode-map pong-pause-key 'pong-pause)
 322
 323   (make-local-hook 'kill-buffer-hook)
 324   (add-hook 'kill-buffer-hook 'pong-quit nil t)
 325
 326   ;; Initialization of some variables
 327   (setq pong-bat-player1 (1+ (/ (- pong-height pong-bat-width) 2)))
 328   (setq pong-bat-player2 pong-bat-player1)
 329   (setq pong-xx -1)
 330   (setq pong-yy 0)
 331   (setq pong-x (/ pong-width 2))
 332   (setq pong-y (/ pong-height 2))
 333
 334   (pong-init-buffer)
 335   (gamegrid-kill-timer)
 336   (gamegrid-start-timer pong-timer-delay 'pong-update-game)
 337   (pong-update-score))
 338
 339
 340
 341 (defun pong-update-game (pong-buffer)
 342   "\"Main\" function for pong.
 343 It is called every pong-cycle-delay seconds and
 344 updates ball and bats positions.  It is responsible of collision
 345 detection and checks if a player scores."
 346   (if (not (eq (current-buffer) pong-buffer))
 347       (pong-pause)
 348
 349     (let ((old-x pong-x)
 350           (old-y pong-y))
 351
 352       (setq pong-x (+ pong-x pong-xx))
 353       (setq pong-y (+ pong-y pong-yy))
 354
 355       (if (and (> old-y 0)
 356                (< old-y (- pong-height 1)))
 357           (gamegrid-set-cell old-x old-y pong-blank))
 358
 359       (if (and (> pong-y 0)
 360                (< pong-y (- pong-height 1)))
 361           (gamegrid-set-cell pong-x pong-y pong-ball))
 362
 363       (cond
 364        ((or (= pong-x 3) (= pong-x 2))
 365         (if (and (>= pong-y pong-bat-player1)
 366                  (< pong-y (+ pong-bat-player1 pong-bat-width)))
 367             (and
 368              (setq pong-yy (+ pong-yy
 369                               (cond
 370                                ((= pong-y pong-bat-player1) -1)
 371                                ((= pong-y (1+ pong-bat-player1)) 0)
 372                                (t 1))))
 373              (setq pong-xx (- pong-xx)))))
 374
 375        ((or (= pong-x (- pong-width 4)) (= pong-x (- pong-width 3)))
 376         (if (and (>= pong-y pong-bat-player2)
 377                  (< pong-y (+ pong-bat-player2 pong-bat-width)))
 378             (and
 379              (setq pong-yy (+ pong-yy
 380                               (cond
 381                                ((= pong-y pong-bat-player2) -1)
 382                                ((= pong-y (1+ pong-bat-player2)) 0)
 383                                (t 1))))
 384              (setq pong-xx (- pong-xx)))))
 385
 386        ((<= pong-y 1)
 387         (setq pong-yy (- pong-yy)))
 388
 389        ((>= pong-y (- pong-height 2))
 390         (setq pong-yy (- pong-yy)))
 391
 392        ((< pong-x 1)
 393         (setq pong-score-player2 (1+ pong-score-player2))
 394         (pong-init))
 395
 396        ((>= pong-x (- pong-width 1))
 397         (setq pong-score-player1 (1+ pong-score-player1))
 398         (pong-init))))))
 399
 400
 401
 402 (defun pong-update-score ()
 403   "Update score and print it on bottom of the game grid."
 404   (let* ((string (format "Score:  %d / %d" pong-score-player1 pong-score-player2))
 405          (len (length string)))
 406     (loop for x from 0 to (1- len) do
 407           (if (string-equal (buffer-name (current-buffer)) pong-buffer-name)
 408               (gamegrid-set-cell x
 409                                  pong-height
 410                                  (aref string x))))))
 411
 412
 413
 414 (defun pong-pause ()
 415   "Pause the game."
 416   (interactive)
 417   (gamegrid-kill-timer)
 418   ;; Oooohhh ugly.  I don't know why, gamegrid-kill-timer don't do the
 419   ;; jobs it is made for.  So I have to do it "by hand".  Anyway, next
 420   ;; line is harmless.
 421   (cancel-function-timers 'pong-update-game)
 422   (define-key pong-mode-map pong-resume-key 'pong-resume))
 423
 424
 425
 426 (defun pong-resume ()
 427   "Resume a paused game."
 428   (interactive)
 429   (define-key pong-mode-map pong-pause-key 'pong-pause)
 430   (gamegrid-start-timer pong-timer-delay 'pong-update-game))
 431
 432
 433
 434 (defun pong-quit ()
 435   "Quit the game and kill the pong buffer."
 436   (interactive)
 437   (gamegrid-kill-timer)
 438   ;; Be sure not to draw things in another buffer and wait for some
 439   ;; time.
 440   (run-with-timer pong-timer-delay nil 'kill-buffer pong-buffer-name))
 441
 442
 443
 444 ;;;###autoload
 445 (defun pong ()
 446   "Play pong and waste time.
 447 This is an implementation of the classical game pong.
 448 Move left and right bats and try to bounce the ball to your opponent.
 449
 450 pong-mode keybindings:\\<pong-mode-map>
 451
 452 \\{pong-mode-map}"
 453   (interactive)
 454   (setq pong-score-player1 0)
 455   (setq pong-score-player2 0)
 456   (pong-init))
 457
 458
 459
 460 (provide 'pong)