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 (map (lambda (c) `(,(get-component-type c) . ,c)) new-components) entities)
97 (map (lambda (c) (get-component-type 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))))
113 (define* (find-entities-by-components c t)
114 (cond ((null? t) '())
116 (let* ((e (assoc-ref c (car t)))
118 (cond ((null? (cdr t)) e*)
120 (lset-intersection eq? e* (find-entities-by-components c (cdr t)))))))))
123 (define (make-system component-types system-fun)
124 (lambda (entities components)
125 (let* ((e (find-entities-by-components components component-types))
126 (e* (map (lambda (x) (assoc x entities)) e))
127 (e** (map (lambda (x) (cons (car x) (filter (lambda (x) (memq (get-component-type x) component-types)) (cdr x)))) e*))
128 (res (system-fun e**)))
129 (lambda* (#:optional (entities2 #f) (components2 #f))
130 (let* ((e2 (if (and entities2 components2)
131 (find-entities-by-components components2 component-types)
133 (e2* (if (and entities2 components2)
134 (map (lambda (x) (assoc x entities2)) e2)
136 (e2** (if (and entities2 components2)
137 (map (lambda (x) (cons (car x) (filter (lambda (x) (memq (get-component-type x) component-types)) (cdr x)))) e2*)
141 ; ((1 a b) (2 a b c) (3 c))
144 ; ((1 a) (3 c) (4 a b))
146 (export find-entities-by-components