1 ;;; Gacela, a GNU Guile extension for fast games development
2 ;;; Copyright (C) 2013 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 (define-module (gacela system)
19 #:use-module (ice-9 receive)
20 #:use-module (srfi srfi-1)
21 #:use-module (srfi srfi-9))
24 ;;; Component definitions
26 (define (symbol-concatenate . args)
29 (map (lambda (a) (if (symbol? a) (symbol->string a) a)) args))))
31 (define-macro (define-component name . args)
33 (use-modules (srfi srfi-9) (srfi srfi-9 gnu))
34 (define-record-type ,name
35 (,(symbol-concatenate "make-" name) ,@args)
36 ,(symbol-concatenate name "?")
37 ,@(map (lambda (a) (list a (symbol-concatenate name "-" a) (symbol-concatenate "set-" name "-" a "!"))) args))
38 (set-record-type-printer! ,name
40 (format port "#<[~a]" ',name)
41 ,@(map (lambda (a) `(format port " ~a: ~a" ',a (,(symbol-concatenate name "-" a) record))) args)
45 (define (export-component component)
46 (let ((name (record-type-name component))
48 (module-export! m (list
49 (symbol-concatenate "make-" name)
50 (symbol-concatenate name "?")))
53 (module-export! (current-module)
55 (symbol-concatenate name "-" a)
56 (symbol-concatenate "set-" name "-" a "!"))))
57 (record-type-fields component))))
59 (define (get-component-type component)
60 (record-type-name (record-type-descriptor component)))
62 (export define-component
67 ;;; Entities and components
69 (define (register-components entity components clist)
70 (cond ((null? components) clist)
72 (let* ((type (car components))
73 (elist (assoc-ref clist type)))
74 (register-components entity (cdr components)
75 (assoc-set! clist type
77 (lset-adjoin eq? elist entity))
81 (define (unregister-components entity components clist)
82 (cond ((null? components) clist)
84 (let* ((type (car components))
85 (elist (lset-difference eq? (assoc-ref clist type) (list entity))))
86 (unregister-components entity (cdr components)
88 (assoc-remove! clist type))
90 (assoc-set! clist type elist))))))))
92 (define (new-entity new-components entities components)
95 (acons key new-components entities)
96 (register-components key
97 (map (lambda (c) (car c)) new-components)
101 (define (remove-entity key entities components)
102 (let ((clist (map (lambda (c) (car c)) (assoc-ref entities key))))
104 (assoc-remove! entities key)
105 (unregister-components key clist components))))
107 (define (set-entity key new-components entities components)
108 (let ((clist (map (lambda (c) (car c)) (assoc-ref entities key)))
109 (nclist (map (lambda (c) (car c)) new-components)))
111 (assoc-set! entities key new-components)
112 (register-components key (lset-difference eq? nclist clist)
113 (unregister-components key (lset-difference eq? clist nclist) components)))))
115 (define (set-entity-components key new-components entities components)
116 (define (set-components clist new-components)
117 (cond ((null? new-components)
121 (if (cdar new-components)
122 (assoc-set! clist (caar new-components) (cdar new-components))
123 (assoc-remove! clist (caar new-components)))
124 (cdr new-components)))))
125 (set-entity key (set-components (alist-copy (assoc-ref entities key)) new-components) entities components))
127 (define (set-entities new-entities entities components)
128 (cond ((null? new-entities)
129 (values entities components))
131 (cond ((not (caar new-entities))
132 (receive (e c k) (new-entity (cdar new-entities) entities components)
133 (set-entities (cdr new-entities) e c)))
134 ((not (cdar new-entities))
135 (receive (e c) (remove-entity (caar new-entities) entities components)
136 (set-entities (cdr new-entities) e c)))
138 (receive (e c) (set-entity-components (caar new-entities) (cdar new-entities) entities components)
139 (set-entities (cdr new-entities) e c)))))))
145 set-entity-components
151 (define* (find-entities-by-components c t)
152 (cond ((null? t) '())
154 (let* ((e (assoc-ref c (car t)))
156 (cond ((null? (cdr t)) e*)
158 (lset-intersection eq? e* (find-entities-by-components c (cdr t)))))))))
161 (define (make-system component-types system-fun)
162 (lambda (entities components)
163 (let* ((e (find-entities-by-components components component-types))
164 (e* (map (lambda (x) (assoc x entities)) e))
165 (e** (map (lambda (x) (cons (car x) (filter (lambda (x) (memq (car x) component-types)) (cdr x)))) e*))
166 (res (system-fun e**)))
167 (lambda* (#:optional (entities2 #f) (components2 #f))
168 (let ((e (if (and entities2 components2) entities2 entities))
169 (c (if (and entities2 components2) components2 components)))
170 (set-entities res e c))))))
173 (export find-entities-by-components