1 ;;; Gacela, a GNU Common Lisp extension for fast games development
2 ;;; Copyright (C) 2009 by Javier Sancho Fernandez <jsf at jsancho dot org>
4 ;;; This program is free software: you can redistribute it and/or modify
5 ;;; it under the terms of the GNU General Public License as published by
6 ;;; the Free Software Foundation, either version 3 of the License, or
7 ;;; (at your option) any later version.
9 ;;; This program is distributed in the hope that it will be useful,
10 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
11 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 ;;; GNU General Public License for more details.
14 ;;; You should have received a copy of the GNU General Public License
15 ;;; along with this program. If not, see <http://www.gnu.org/licenses/>.
18 (eval-when (compile load eval)
19 (when (not (find-package 'gacela)) (make-package 'gacela :nicknames '(gg) :use '(lisp)))
20 (in-package 'gacela :nicknames '(gg) :use '(lisp)))
23 (defconstant INFINITY MOST-POSITIVE-LONG-FLOAT)
25 (defun append-if (new test tree &key (key #'first) (test-if #'equal))
26 (cond ((atom tree) tree)
30 (mapcar (lambda (x) (append-if new test x :key key :test-if test-if)) tree)
34 (defun append-if-1 (new test tree &key (key #'first) (test-if #'equal))
35 (cond ((funcall test-if (funcall key tree) test) (append tree new))
39 (if (listp var) (car var) var))
41 (defun avg (&rest numbers)
43 (dolist (n numbers) (incf total n))
44 (/ total (length numbers))))
50 (let ((sig (signum num)))
54 (defmacro destructure (destructuring-list &body body)
55 (let ((lambda-list nil) (exp-list nil))
56 (dolist (pair destructuring-list)
57 (setq exp-list (cons (car pair) exp-list))
58 (setq lambda-list (cons (cadr pair) lambda-list)))
59 `(destructuring-bind ,lambda-list ,(cons 'list exp-list) ,@body)))
61 (defun match-pattern (list pattern)
62 (cond ((and (null list) (null pattern)) t)
63 ((and (consp list) (consp pattern))
64 (and (match-pattern (car list) (car pattern)) (match-pattern (cdr list) (cdr pattern))))
65 ((and (atom list) (atom pattern))
66 (cond ((or (numberp list) (numberp pattern)) (and (numberp list) (numberp pattern)))
69 (defun nearest-power-of-two (n)
71 (cond ((> (* p 2) n) p)
72 (t (power (* p 2) n)))))
75 (defmacro secure-block (output-stream &rest forms)
76 (let ((error-handler #'si::universal-error-handler))
78 (defun si::universal-error-handler (error-name correctable function-name continue-format-string error-format-string &rest args)
81 (cond ((eq error-name :WRONG-TYPE-ARGUMENT) (string error-name))
82 (t error-format-string))
84 (setf (symbol-function 'si::universal-error-handler) ,error-handler)
87 (setq result-eval (progn ,@forms))
88 (setf (symbol-function 'si::universal-error-handler) ,error-handler)
91 (defmacro persistent-let (name vars &rest forms)
92 (labels ((get-vars (vars)
93 (cond ((null vars) nil)
94 (t (cons (if (consp (car vars)) (caar vars) (car vars))
95 (get-vars (cdr vars)))))))
97 `(let ,(cond ((functionp name)
98 (let ((old-vars (funcall name)))
99 (cond ((equal (get-vars vars) (get-vars old-vars)) old-vars)
103 ,(let ((lvars (get-vars vars)))
104 `(mapcar (lambda (x y) (list x y)) ',lvars ,(cons 'list lvars))))
109 (match-pattern dot '(0 0)))
111 (defun vectorp (vector)
112 (match-pattern vector '(0 0)))
114 (defun circlep (circle)
115 (match-pattern circle '((0 0) 0)))
117 (defun polygonp (polygon)
118 (cond ((consp polygon)
119 (and (dotp (car polygon))
120 (if (null (cdr polygon)) t (polygonp (cdr polygon)))))))
122 (defun make-dot (x y)
125 (defun make-vector (x y)
128 (defun make-line (dot1 dot2)
131 (defun make-rectangle (x1 y1 x2 y2)
132 `((,x1 ,y1) (,x2 ,y1) (,x2 ,y2) (,x1 ,y2)))
134 (defun polygon-center (polygon)
135 (apply #'mapcar #'avg polygon))
137 (defun dots-distance (dot1 dot2)
138 (destructure ((dot1 (x1 y1))
140 (sqrt (+ (expt (- x2 x1) 2)
141 (expt (- y2 y1) 2)))))
143 (defun dot-line-distance (dot line)
144 (destructure ((line ((ax ay) (bx by)))
146 (let* ((r-numerator (+ (* (- cx ax) (- bx ax)) (* (- cy ay) (- by ay))))
147 (r-denomenator (+ (expt (- bx ax) 2) (expt (- by ay) 2)))
148 (r (/ r-numerator r-denomenator)))
150 (* (abs (/ (- (* (- ay cy) (- bx ax)) (* (- ax cx) (- by ay)))
152 (sqrt r-denomenator))
155 (defun dot-segment-distance (dot segment)
157 (dist r) (dot-line-distance dot segment)
158 (cond ((and (>= r 0) (<= r 1)) dist)
159 (t (let ((dist1 (dots-distance dot (car segment)))
160 (dist2 (dots-distance dot (cadr segment))))
161 (if (< dist1 dist2) dist1 dist2))))))
163 (defun perpendicular-line (dot line)
164 (destructure ((line ((ax ay) (bx by))))
166 (dist r) (dot-line-distance dot line)
168 (make-dot (+ ax (* r (- bx ax)))
169 (+ ay (* r (- by ay))))))))
171 (defun line-angle (line)
172 (destructure ((line ((ax ay) (bx by))))
173 (let ((x (- bx ax)) (y (- by ay)))
174 (if (and (= x 0) (= y 0)) 0 (atan y x)))))
176 (defun inverse-angle (angle)
177 (cond ((< angle pi) (+ angle pi))
180 (defun translate-dot (dot dx dy)
181 (destructure ((dot (x y)))
182 (list (+ x dx) (+ y dy))))
184 (defun translate-circle (circle dx dy)
185 (destructure ((circle (center radius)))
186 (list (translate-dot center dx dy) radius)))
188 (defun translate-polygon (pol dx dy)
189 (mapcar (lambda (dot)
190 (translate-dot dot dx dy))
193 (defun polygon-edges (pol)
194 (mapcar (lambda (v1 v2) (list v1 v2))
196 (union (cdr pol) (list (car pol)))))
198 (defun polygon-dot-intersection (polygon dot)
199 ;Eric Haines algorithm
200 (let ((edges (polygon-edges
201 (translate-polygon polygon (neg (car dot)) (neg (cadr dot)))))
204 (destructure ((edge ((x1 y1) (x2 y2))))
205 (cond ((/= (signum+ y1) (signum+ y2))
206 (cond ((and (> x1 0) (> x2 0)) (incf counter))
207 ((and (or (> x1 0) (> x2 0))
208 (> (- x1 (* y1 (/ (- x2 x1) (- y2 y1)))) 0))
210 (not (evenp counter))))
212 (defun circle-segment-intersection (circle segment)
213 (destructure ((circle (center radius)))
214 (<= (dot-segment-distance center segment) radius)))
216 (defun circle-edges-intersection (circle polygon)
217 (let ((edges (polygon-edges polygon))
220 (cond ((circle-segment-intersection circle edge) (setq edges-i (cons edge edges-i)))))
223 (defun circle-polygon-intersection (circle polygon)
224 (or (polygon-dot-intersection polygon (car circle))
225 (circle-edges-intersection circle polygon)))
227 (defun circle-circle-intersection (circle1 circle2)
228 (destructure ((circle1 (center1 radius1))
229 (circle2 (center2 radius2)))
230 (<= (dots-distance center1 center2) (+ r1 r2))))