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 (srfi srfi-1)
20 #:use-module (srfi srfi-9))
23 ;;; Component definitions
25 (define (symbol-concatenate . args)
28 (map (lambda (a) (if (symbol? a) (symbol->string a) a)) args))))
30 (define-macro (define-component name . args)
32 (use-modules (srfi srfi-9) (srfi srfi-9 gnu))
33 (define-record-type ,name
34 (,(symbol-concatenate "make-" name) ,@args)
35 ,(symbol-concatenate name "?")
36 ,@(map (lambda (a) (list a (symbol-concatenate name "-" a) (symbol-concatenate "set-" name "-" a "!"))) args))
37 (set-record-type-printer! ,name
39 (format port "#<[~a]" ',name)
40 ,@(map (lambda (a) `(format port " ~a: ~a" ',a (,(symbol-concatenate name "-" a) record))) args)
44 (define (export-component component)
45 (let ((name (record-type-name component))
47 (module-export! m (list
48 (symbol-concatenate "make-" name)
49 (symbol-concatenate name "?")))
52 (module-export! (current-module)
54 (symbol-concatenate name "-" a)
55 (symbol-concatenate "set-" name "-" a "!"))))
56 (record-type-fields component))))
58 (define (get-component-type component)
59 (record-type-name (record-type-descriptor component)))
61 (export define-component
66 ;;; Entities and components
68 (define (register-components entity components clist)
69 (cond ((null? components) clist)
71 (let* ((type (car components))
72 (elist (assoc-ref clist type)))
73 (register-components entity (cdr components)
74 (assoc-set! clist type
76 (lset-adjoin eq? elist entity))
80 (define (unregister-components entity components clist)
81 (cond ((null? components) clist)
83 (let* ((type (car components))
84 (elist (lset-difference eq? (assoc-ref clist type) (list entity))))
85 (unregister-components entity (cdr components)
87 (assoc-remove! clist type))
89 (assoc-set! clist type elist))))))))
91 (define (new-entity new-components entities components)
94 (acons key new-components entities)
95 (register-components key
96 (map (lambda (c) (car c)) new-components)
100 (define (remove-entity key entities components)
101 (let ((clist (map (lambda (c) (car c)) (assoc-ref entities key))))
103 (assoc-remove! entities key)
104 (unregister-components key clist components))))
106 (define (set-entity key new-components entities components)
107 (let ((clist (map (lambda (c) (car c)) (assoc-ref entities key)))
108 (nclist (map (lambda (c) (car c)) new-components)))
110 (assoc-set! entities key new-components)
111 (register-components key (lset-difference eq? nclist clist)
112 (unregister-components key (lset-difference eq? clist nclist) components)))))
114 (define (set-entity-components key new-components entities components)
115 (define (set-components clist new-components)
116 (cond ((null? new-components)
120 (if (cdar new-components)
121 (assoc-set! clist (caar new-components) (cdar new-components))
122 (assoc-remove! clist (caar new-components)))
123 (cdr new-components)))))
124 (set-entity key (set-components (alist-copy (assoc-ref entities key)) new-components) entities components))
130 set-entity-components)
135 (define* (find-entities-by-components c t)
136 (cond ((null? t) '())
138 (let* ((e (assoc-ref c (car t)))
140 (cond ((null? (cdr t)) e*)
142 (lset-intersection eq? e* (find-entities-by-components c (cdr t)))))))))
145 (define (make-system component-types system-fun)
146 (lambda (entities components)
147 (let* ((e (find-entities-by-components components component-types))
148 (e* (map (lambda (x) (assoc x entities)) e))
149 (e** (map (lambda (x) (cons (car x) (filter (lambda (x) (memq (get-component-type x) component-types)) (cdr x)))) e*))
150 (res (system-fun e**)))
151 (lambda* (#:optional (entities2 #f) (components2 #f))
152 (let* ((e2 (if (and entities2 components2)
153 (find-entities-by-components components2 component-types)
155 (e2* (if (and entities2 components2)
156 (map (lambda (x) (assoc x entities2)) e2)
158 (e2** (if (and entities2 components2)
159 (map (lambda (x) (cons (car x) (filter (lambda (x) (memq (get-component-type x) component-types)) (cdr x)))) e2*)
163 ; ((1 a b) (2 a b c) (3 c))
166 ; ((1 a) (3 c) (4 a b))
168 (export find-entities-by-components