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6e44da43 | 1 | ;;; snake.el --- implementation of Snake for Emacs |
0bbf74a8 RS |
2 | |
3 | ;; Copyright (C) 1997 Free Software Foundation, Inc. | |
4 | ||
5 | ;; Author: Glynn Clements <glynn@sensei.co.uk> | |
6 | ;; Created: 1997-09-10 | |
7 | ;; Keywords: games | |
8 | ||
9 | ;; This file is part of GNU Emacs. | |
10 | ||
11 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
12 | ;; it under the terms of the GNU General Public License as published by | |
13 | ;; the Free Software Foundation; either version 2, or (at your option) | |
14 | ;; any later version. | |
15 | ||
16 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
17 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | ;; GNU General Public License for more details. | |
20 | ||
21 | ;; You should have received a copy of the GNU General Public License | |
22 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
23 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
24 | ;; Boston, MA 02111-1307, USA. | |
25 | ||
26 | ;;; Commentary: | |
27 | ||
6e44da43 PJ |
28 | ;;; Code: |
29 | ||
0bbf74a8 RS |
30 | (eval-when-compile |
31 | (require 'cl)) | |
32 | ||
33 | (require 'gamegrid) | |
34 | ||
35 | ;; ;;;;;;;;;;;;; customization variables ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
36 | ||
5bcfaa07 | 37 | (defvar snake-use-glyphs-flag t |
0bbf74a8 RS |
38 | "Non-nil means use glyphs when available.") |
39 | ||
5bcfaa07 | 40 | (defvar snake-use-color-flag t |
0bbf74a8 RS |
41 | "Non-nil means use color when available.") |
42 | ||
43 | (defvar snake-buffer-name "*Snake*" | |
44 | "Name used for Snake buffer.") | |
45 | ||
46 | (defvar snake-buffer-width 30 | |
47 | "Width of used portion of buffer.") | |
48 | ||
49 | (defvar snake-buffer-height 22 | |
50 | "Height of used portion of buffer.") | |
51 | ||
52 | (defvar snake-width 30 | |
53 | "Width of playing area.") | |
54 | ||
55 | (defvar snake-height 20 | |
56 | "Height of playing area.") | |
57 | ||
58 | (defvar snake-initial-length 5 | |
59 | "Initial length of snake.") | |
60 | ||
61 | (defvar snake-initial-x 10 | |
62 | "Initial X position of snake.") | |
63 | ||
64 | (defvar snake-initial-y 10 | |
65 | "Initial Y position of snake.") | |
66 | ||
67 | (defvar snake-initial-velocity-x 1 | |
68 | "Initial X velocity of snake.") | |
69 | ||
70 | (defvar snake-initial-velocity-y 0 | |
71 | "Initial Y velocity of snake.") | |
72 | ||
73 | (defvar snake-tick-period 0.2 | |
74 | "The default time taken for the snake to advance one square.") | |
75 | ||
76 | (defvar snake-mode-hook nil | |
77 | "Hook run upon starting Snake.") | |
78 | ||
79 | (defvar snake-score-x 0 | |
80 | "X position of score.") | |
81 | ||
82 | (defvar snake-score-y snake-height | |
83 | "Y position of score.") | |
84 | ||
35ce93eb | 85 | ;; It is not safe to put this in /tmp. |
adcce7d5 | 86 | ;; Someone could make a symlink in /tmp |
35ce93eb | 87 | ;; pointing to a file you don't want to clobber. |
e6eb4750 | 88 | (defvar snake-score-file "snake-scores" |
0bbf74a8 RS |
89 | "File for holding high scores.") |
90 | ||
91 | ;; ;;;;;;;;;;;;; display options ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
92 | ||
93 | (defvar snake-blank-options | |
94 | '(((glyph colorize) | |
95 | (t ?\040)) | |
96 | ((color-x color-x) | |
97 | (mono-x grid-x) | |
98 | (color-tty color-tty)) | |
99 | (((glyph color-x) [0 0 0]) | |
100 | (color-tty "black")))) | |
101 | ||
102 | (defvar snake-snake-options | |
103 | '(((glyph colorize) | |
104 | (emacs-tty ?O) | |
105 | (t ?\040)) | |
106 | ((color-x color-x) | |
107 | (mono-x mono-x) | |
108 | (color-tty color-tty) | |
109 | (mono-tty mono-tty)) | |
110 | (((glyph color-x) [1 1 0]) | |
111 | (color-tty "yellow")))) | |
112 | ||
113 | (defvar snake-dot-options | |
114 | '(((glyph colorize) | |
115 | (t ?\*)) | |
116 | ((color-x color-x) | |
117 | (mono-x grid-x) | |
118 | (color-tty color-tty)) | |
119 | (((glyph color-x) [1 0 0]) | |
120 | (color-tty "red")))) | |
121 | ||
122 | (defvar snake-border-options | |
123 | '(((glyph colorize) | |
124 | (t ?\+)) | |
125 | ((color-x color-x) | |
c2f8b57c FP |
126 | (mono-x grid-x) |
127 | (color-tty color-tty)) | |
0bbf74a8 RS |
128 | (((glyph color-x) [0.5 0.5 0.5]) |
129 | (color-tty "white")))) | |
130 | ||
131 | (defvar snake-space-options | |
132 | '(((t ?\040)) | |
133 | nil | |
134 | nil)) | |
135 | ||
136 | ;; ;;;;;;;;;;;;; constants ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
137 | ||
138 | (defconst snake-blank 0) | |
139 | (defconst snake-snake 1) | |
140 | (defconst snake-dot 2) | |
141 | (defconst snake-border 3) | |
142 | (defconst snake-space 4) | |
143 | ||
144 | ;; ;;;;;;;;;;;;; variables ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
145 | ||
146 | (defvar snake-length 0) | |
147 | (defvar snake-velocity-x 1) | |
148 | (defvar snake-velocity-y 0) | |
149 | (defvar snake-positions nil) | |
150 | (defvar snake-cycle 0) | |
151 | (defvar snake-score 0) | |
152 | (defvar snake-paused nil) | |
5bcfaa07 RS |
153 | (defvar snake-moved-p nil) |
154 | (defvar snake-velocity-queue nil | |
155 | "This queue stores the velocities requested too quickly by user. | |
156 | They will take effect one at a time at each clock-interval. | |
157 | This is necessary for proper behavior. | |
158 | ||
159 | For instance, if you are moving right, you press up and then left, you | |
160 | want the snake to move up just once before starting to move left. If | |
161 | we implemented all your keystrokes immediately, the snake would | |
162 | effectively never move up. Thus, we need to move it up for one turn | |
163 | and then start moving it leftwards.") | |
164 | ||
0bbf74a8 RS |
165 | |
166 | (make-variable-buffer-local 'snake-length) | |
167 | (make-variable-buffer-local 'snake-velocity-x) | |
168 | (make-variable-buffer-local 'snake-velocity-y) | |
169 | (make-variable-buffer-local 'snake-positions) | |
170 | (make-variable-buffer-local 'snake-cycle) | |
171 | (make-variable-buffer-local 'snake-score) | |
172 | (make-variable-buffer-local 'snake-paused) | |
5bcfaa07 RS |
173 | (make-variable-buffer-local 'snake-moved-p) |
174 | (make-variable-buffer-local 'snake-velocity-queue) | |
0bbf74a8 RS |
175 | |
176 | ;; ;;;;;;;;;;;;; keymaps ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
177 | ||
178 | (defvar snake-mode-map | |
179 | (make-sparse-keymap 'snake-mode-map)) | |
180 | ||
181 | (define-key snake-mode-map "n" 'snake-start-game) | |
182 | (define-key snake-mode-map "q" 'snake-end-game) | |
183 | (define-key snake-mode-map "p" 'snake-pause-game) | |
184 | ||
185 | (define-key snake-mode-map [left] 'snake-move-left) | |
186 | (define-key snake-mode-map [right] 'snake-move-right) | |
187 | (define-key snake-mode-map [up] 'snake-move-up) | |
188 | (define-key snake-mode-map [down] 'snake-move-down) | |
189 | ||
190 | (defvar snake-null-map | |
191 | (make-sparse-keymap 'snake-null-map)) | |
192 | ||
193 | (define-key snake-null-map "n" 'snake-start-game) | |
194 | ||
195 | ;; ;;;;;;;;;;;;;;;; game functions ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
196 | ||
197 | (defun snake-display-options () | |
198 | (let ((options (make-vector 256 nil))) | |
199 | (loop for c from 0 to 255 do | |
200 | (aset options c | |
201 | (cond ((= c snake-blank) | |
202 | snake-blank-options) | |
203 | ((= c snake-snake) | |
204 | snake-snake-options) | |
205 | ((= c snake-dot) | |
206 | snake-dot-options) | |
207 | ((= c snake-border) | |
208 | snake-border-options) | |
209 | ((= c snake-space) | |
210 | snake-space-options) | |
211 | (t | |
212 | '(nil nil nil))))) | |
213 | options)) | |
214 | ||
215 | (defun snake-update-score () | |
216 | (let* ((string (format "Score: %05d" snake-score)) | |
217 | (len (length string))) | |
218 | (loop for x from 0 to (1- len) do | |
219 | (gamegrid-set-cell (+ snake-score-x x) | |
220 | snake-score-y | |
221 | (aref string x))))) | |
222 | ||
223 | (defun snake-init-buffer () | |
224 | (gamegrid-init-buffer snake-buffer-width | |
225 | snake-buffer-height | |
226 | snake-space) | |
227 | (let ((buffer-read-only nil)) | |
228 | (loop for y from 0 to (1- snake-height) do | |
229 | (loop for x from 0 to (1- snake-width) do | |
230 | (gamegrid-set-cell x y snake-border))) | |
231 | (loop for y from 1 to (- snake-height 2) do | |
232 | (loop for x from 1 to (- snake-width 2) do | |
233 | (gamegrid-set-cell x y snake-blank))))) | |
234 | ||
235 | (defun snake-reset-game () | |
236 | (gamegrid-kill-timer) | |
237 | (snake-init-buffer) | |
238 | (setq snake-length snake-initial-length | |
239 | snake-velocity-x snake-initial-velocity-x | |
240 | snake-velocity-y snake-initial-velocity-y | |
241 | snake-positions nil | |
242 | snake-cycle 1 | |
243 | snake-score 0 | |
5bcfaa07 RS |
244 | snake-paused nil |
245 | snake-moved-p nil | |
246 | snake-velocity-queue nil) | |
0bbf74a8 RS |
247 | (let ((x snake-initial-x) |
248 | (y snake-initial-y)) | |
249 | (dotimes (i snake-length) | |
250 | (gamegrid-set-cell x y snake-snake) | |
251 | (setq snake-positions (cons (vector x y) snake-positions)) | |
252 | (incf x snake-velocity-x) | |
253 | (incf y snake-velocity-y))) | |
254 | (snake-update-score)) | |
255 | ||
256 | (defun snake-update-game (snake-buffer) | |
257 | "Called on each clock tick. | |
5bcfaa07 RS |
258 | Advances the snake one square, testing for collision. |
259 | Argument SNAKE-BUFFER is the name of the buffer." | |
260 | (when (and (not snake-paused) | |
261 | (eq (current-buffer) snake-buffer)) | |
262 | (snake-update-velocity) | |
263 | (let* ((pos (car snake-positions)) | |
264 | (x (+ (aref pos 0) snake-velocity-x)) | |
265 | (y (+ (aref pos 1) snake-velocity-y)) | |
266 | (c (gamegrid-get-cell x y))) | |
267 | (if (or (= c snake-border) | |
268 | (= c snake-snake)) | |
269 | (snake-end-game) | |
270 | (cond ((= c snake-dot) | |
271 | (incf snake-length) | |
272 | (incf snake-score) | |
273 | (snake-update-score)) | |
274 | (t | |
275 | (let* ((last-cons (nthcdr (- snake-length 2) | |
276 | snake-positions)) | |
277 | (tail-pos (cadr last-cons)) | |
278 | (x0 (aref tail-pos 0)) | |
279 | (y0 (aref tail-pos 1))) | |
280 | (gamegrid-set-cell x0 y0 | |
281 | (if (= (% snake-cycle 5) 0) | |
282 | snake-dot | |
283 | snake-blank)) | |
284 | (incf snake-cycle) | |
285 | (setcdr last-cons nil)))) | |
286 | (gamegrid-set-cell x y snake-snake) | |
287 | (setq snake-positions | |
288 | (cons (vector x y) snake-positions)) | |
289 | (setq snake-moved-p nil))))) | |
290 | ||
291 | (defun snake-update-velocity () | |
292 | (unless snake-moved-p | |
293 | (if snake-velocity-queue | |
294 | (let ((new-vel (car (last snake-velocity-queue)))) | |
295 | (setq snake-velocity-x (car new-vel) | |
296 | snake-velocity-y (cadr new-vel)) | |
297 | (setq snake-velocity-queue | |
298 | (nreverse (cdr (nreverse snake-velocity-queue)))))) | |
299 | (setq snake-moved-p t))) | |
300 | ||
301 | (defun snake-final-x-velocity () | |
302 | (or (caar snake-velocity-queue) | |
303 | snake-velocity-x)) | |
304 | ||
305 | (defun snake-final-y-velocity () | |
306 | (or (cadr (car snake-velocity-queue)) | |
307 | snake-velocity-y)) | |
0bbf74a8 RS |
308 | |
309 | (defun snake-move-left () | |
5bcfaa07 | 310 | "Make the snake move left." |
0bbf74a8 | 311 | (interactive) |
5bcfaa07 RS |
312 | (when (zerop (snake-final-x-velocity)) |
313 | (push '(-1 0) snake-velocity-queue))) | |
0bbf74a8 RS |
314 | |
315 | (defun snake-move-right () | |
5bcfaa07 | 316 | "Make the snake move right." |
0bbf74a8 | 317 | (interactive) |
5bcfaa07 RS |
318 | (when (zerop (snake-final-x-velocity)) |
319 | (push '(1 0) snake-velocity-queue))) | |
0bbf74a8 RS |
320 | |
321 | (defun snake-move-up () | |
5bcfaa07 | 322 | "Make the snake move up." |
0bbf74a8 | 323 | (interactive) |
5bcfaa07 RS |
324 | (when (zerop (snake-final-y-velocity)) |
325 | (push '(0 -1) snake-velocity-queue))) | |
0bbf74a8 RS |
326 | |
327 | (defun snake-move-down () | |
5bcfaa07 | 328 | "Make the snake move down." |
0bbf74a8 | 329 | (interactive) |
5bcfaa07 RS |
330 | (when (zerop (snake-final-y-velocity)) |
331 | (push '(0 1) snake-velocity-queue))) | |
0bbf74a8 RS |
332 | |
333 | (defun snake-end-game () | |
5bcfaa07 | 334 | "Terminate the current game." |
0bbf74a8 RS |
335 | (interactive) |
336 | (gamegrid-kill-timer) | |
337 | (use-local-map snake-null-map) | |
338 | (gamegrid-add-score snake-score-file snake-score)) | |
339 | ||
340 | (defun snake-start-game () | |
5bcfaa07 | 341 | "Start a new game of Snake." |
0bbf74a8 RS |
342 | (interactive) |
343 | (snake-reset-game) | |
344 | (use-local-map snake-mode-map) | |
345 | (gamegrid-start-timer snake-tick-period 'snake-update-game)) | |
346 | ||
347 | (defun snake-pause-game () | |
5bcfaa07 | 348 | "Pause (or resume) the current game." |
0bbf74a8 RS |
349 | (interactive) |
350 | (setq snake-paused (not snake-paused)) | |
351 | (message (and snake-paused "Game paused (press p to resume)"))) | |
352 | ||
353 | (defun snake-active-p () | |
354 | (eq (current-local-map) snake-mode-map)) | |
355 | ||
356 | (put 'snake-mode 'mode-class 'special) | |
357 | ||
358 | (defun snake-mode () | |
359 | "A mode for playing Snake. | |
360 | ||
5bcfaa07 | 361 | Snake mode keybindings: |
0bbf74a8 RS |
362 | \\{snake-mode-map} |
363 | " | |
364 | (kill-all-local-variables) | |
365 | ||
0bbf74a8 RS |
366 | (add-hook 'kill-buffer-hook 'gamegrid-kill-timer nil t) |
367 | ||
368 | (use-local-map snake-null-map) | |
369 | ||
370 | (setq major-mode 'snake-mode) | |
371 | (setq mode-name "Snake") | |
372 | ||
373 | (setq mode-popup-menu | |
374 | '("Snake Commands" | |
375 | ["Start new game" snake-start-game] | |
376 | ["End game" snake-end-game | |
377 | (snake-active-p)] | |
378 | ["Pause" snake-pause-game | |
379 | (and (snake-active-p) (not snake-paused))] | |
380 | ["Resume" snake-pause-game | |
381 | (and (snake-active-p) snake-paused)])) | |
382 | ||
5bcfaa07 RS |
383 | (setq gamegrid-use-glyphs snake-use-glyphs-flag) |
384 | (setq gamegrid-use-color snake-use-color-flag) | |
0bbf74a8 RS |
385 | |
386 | (gamegrid-init (snake-display-options)) | |
387 | ||
388 | (run-hooks 'snake-mode-hook)) | |
389 | ||
390 | ;;;###autoload | |
391 | (defun snake () | |
392 | "Play the Snake game. | |
393 | Move the snake around without colliding with its tail or with the border. | |
394 | ||
395 | Eating dots causes the snake to get longer. | |
396 | ||
5bcfaa07 | 397 | Snake mode keybindings: |
0bbf74a8 RS |
398 | \\<snake-mode-map> |
399 | \\[snake-start-game] Starts a new game of Snake | |
400 | \\[snake-end-game] Terminates the current game | |
401 | \\[snake-pause-game] Pauses (or resumes) the current game | |
402 | \\[snake-move-left] Makes the snake move left | |
403 | \\[snake-move-right] Makes the snake move right | |
404 | \\[snake-move-up] Makes the snake move up | |
5bcfaa07 | 405 | \\[snake-move-down] Makes the snake move down" |
0bbf74a8 RS |
406 | (interactive) |
407 | ||
408 | (switch-to-buffer snake-buffer-name) | |
409 | (gamegrid-kill-timer) | |
410 | (snake-mode) | |
411 | (snake-start-game)) | |
412 | ||
413 | (provide 'snake) | |
414 | ||
6b61353c | 415 | ;;; arch-tag: 512ffc92-cfac-4287-9a4e-92890701a5c8 |
0bbf74a8 | 416 | ;;; snake.el ends here |