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/>.
19 (defconstant INFINITY MOST-POSITIVE-LONG-FLOAT)
21 (defun append-if (new test tree &key (key #'first) (test-if #'equal))
22 (cond ((atom tree) tree)
26 (mapcar (lambda (x) (append-if new test x :key key :test-if test-if)) tree)
30 (defun append-if-1 (new test tree &key (key #'first) (test-if #'equal))
31 (cond ((funcall test-if (funcall key tree) test) (append tree new))
35 (if (listp var) (car var) var))
37 (defun avg (&rest numbers)
39 (dolist (n numbers) (incf total n))
40 (/ total (length numbers))))
46 (let ((sig (signum num)))
50 (defmacro destructure (destructuring-list &body body)
51 (let ((lambda-list nil) (exp-list nil))
52 (dolist (pair destructuring-list)
53 (setq exp-list (cons (car pair) exp-list))
54 (setq lambda-list (cons (cadr pair) lambda-list)))
55 `(destructuring-bind ,lambda-list ,(cons 'list exp-list) ,@body)))
57 (defun match-pattern (list pattern)
58 (cond ((and (null list) (null pattern)) t)
59 ((and (consp list) (consp pattern))
60 (and (match-pattern (car list) (car pattern)) (match-pattern (cdr list) (cdr pattern))))
61 ((and (atom list) (atom pattern))
62 (cond ((or (numberp list) (numberp pattern)) (and (numberp list) (numberp pattern)))
65 (defun nearest-power-of-two (n)
67 (cond ((> (* p 2) n) p)
68 (t (power (* p 2) n)))))
71 (defmacro secure-block (output-stream &rest forms)
72 (let ((error-handler #'si::universal-error-handler))
74 (defun si::universal-error-handler (error-name correctable function-name continue-format-string error-format-string &rest args)
76 `(format ,output-stream
77 (cond ((eq error-name :WRONG-TYPE-ARGUMENT) (string error-name))
78 (t error-format-string))))
79 (setf (symbol-function 'si::universal-error-handler) ,error-handler)
82 (setq result-eval (progn ,@forms))
83 (setf (symbol-function 'si::universal-error-handler) ,error-handler)
88 (match-pattern dot '(0 0)))
90 (defun vectorp (vector)
91 (match-pattern vector '(0 0)))
93 (defun circlep (circle)
94 (match-pattern circle '((0 0) 0)))
96 (defun polygonp (polygon)
97 (cond ((consp polygon)
98 (and (dotp (car polygon))
99 (if (null (cdr polygon)) t (polygonp (cdr polygon)))))))
101 (defun make-dot (x y)
104 (defun make-vector (x y)
107 (defun make-line (dot1 dot2)
110 (defun make-rectangle (x1 y1 x2 y2)
111 `((,x1 ,y1) (,x2 ,y1) (,x2 ,y2) (,x1 ,y2)))
113 (defun polygon-center (polygon)
114 (apply #'mapcar #'avg polygon))
116 (defun dots-distance (dot1 dot2)
117 (destructure ((dot1 (x1 y1))
119 (sqrt (+ (expt (- x2 x1) 2)
120 (expt (- y2 y1) 2)))))
122 (defun dot-line-distance (dot line)
123 (destructure ((line ((ax ay) (bx by)))
125 (let* ((r-numerator (+ (* (- cx ax) (- bx ax)) (* (- cy ay) (- by ay))))
126 (r-denomenator (+ (expt (- bx ax) 2) (expt (- by ay) 2)))
127 (r (/ r-numerator r-denomenator)))
129 (* (abs (/ (- (* (- ay cy) (- bx ax)) (* (- ax cx) (- by ay)))
131 (sqrt r-denomenator))
134 (defun dot-segment-distance (dot segment)
136 (dist r) (dot-line-distance dot segment)
137 (cond ((and (>= r 0) (<= r 1)) dist)
138 (t (let ((dist1 (dots-distance dot (car segment)))
139 (dist2 (dots-distance dot (cadr segment))))
140 (if (< dist1 dist2) dist1 dist2))))))
142 (defun perpendicular-line (dot line)
143 (destructure ((line ((ax ay) (bx by))))
145 (dist r) (dot-line-distance dot line)
147 (make-dot (+ ax (* r (- bx ax)))
148 (+ ay (* r (- by ay))))))))
150 (defun line-angle (line)
151 (destructure ((line ((ax ay) (bx by))))
152 (let ((x (- bx ax)) (y (- by ay)))
153 (if (and (= x 0) (= y 0)) 0 (atan y x)))))
155 (defun inverse-angle (angle)
156 (cond ((< angle pi) (+ angle pi))
159 (defun translate-dot (dot dx dy)
160 (destructure ((dot (x y)))
161 (list (+ x dx) (+ y dy))))
163 (defun translate-circle (circle dx dy)
164 (destructure ((circle (center radius)))
165 (list (translate-dot center dx dy) radius)))
167 (defun translate-polygon (pol dx dy)
168 (mapcar (lambda (dot)
169 (translate-dot dot dx dy))
172 (defun polygon-edges (pol)
173 (mapcar (lambda (v1 v2) (list v1 v2))
175 (union (cdr pol) (list (car pol)))))
177 (defun polygon-dot-intersection (polygon dot)
178 ;Eric Haines algorithm
179 (let ((edges (polygon-edges
180 (translate-polygon polygon (neg (car dot)) (neg (cadr dot)))))
183 (destructure ((edge ((x1 y1) (x2 y2))))
184 (cond ((/= (signum+ y1) (signum+ y2))
185 (cond ((and (> x1 0) (> x2 0)) (incf counter))
186 ((and (or (> x1 0) (> x2 0))
187 (> (- x1 (* y1 (/ (- x2 x1) (- y2 y1)))) 0))
189 (not (evenp counter))))
191 (defun circle-segment-intersection (circle segment)
192 (destructure ((circle (center radius)))
193 (<= (dot-segment-distance center segment) radius)))
195 (defun circle-edges-intersection (circle polygon)
196 (let ((edges (polygon-edges polygon))
199 (cond ((circle-segment-intersection circle edge) (setq edges-i (cons edge edges-i)))))
202 (defun circle-polygon-intersection (circle polygon)
203 (or (polygon-dot-intersection polygon (car circle))
204 (circle-edges-intersection circle polygon)))
206 (defun circle-circle-intersection (circle1 circle2)
207 (destructure ((circle1 (center1 radius1))
208 (circle2 (center2 radius2)))
209 (<= (dots-distance center1 center2) (+ r1 r2))))