blob: 199cb80b46eb96614be0d102609473800eaa7a39 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
|
;;; guile-2d
;;; Copyright (C) 2013 David Thompson <dthompson2@worcester.edu>
;;;
;;; Guile-2d is free software: you can redistribute it and/or modify it
;;; under the terms of the GNU Lesser General Public License as
;;; published by the Free Software Foundation, either version 3 of the
;;; License, or (at your option) any later version.
;;;
;;; Guile-2d is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;;; Lesser General Public License for more details.
;;;
;;; You should have received a copy of the GNU Lesser General Public
;;; License along with this program. If not, see
;;; <http://www.gnu.org/licenses/>.
;;; Commentary:
;;
;; Game loop.
;;
;;; Code:
(define-module (2d game-loop)
#:use-module ((sdl sdl) #:prefix SDL:)
#:use-module (figl gl)
#:use-module (2d agenda)
#:use-module (2d coroutine)
#:use-module (2d repl server)
#:export (on-active-hook
on-resize-hook
on-quit-hook
on-render-hook
on-update-hook
on-key-up-hook
on-key-down-hook
on-mouse-motion-hook
on-mouse-button-down-hook
on-mouse-button-up-hook
run-game-loop
current-fps))
;;;
;;; Constants
;;;
(define target-fps 60)
(define tick-interval (floor (/ 1000 target-fps)))
;;;
;;; Globals
;;;
(define *fps* 0)
;;;
;;; Hooks
;;;
(define on-active-hook (make-hook))
(define on-resize-hook (make-hook 2))
(define on-quit-hook (make-hook))
(define on-render-hook (make-hook))
(define on-update-hook (make-hook))
(define on-key-up-hook (make-hook 3))
(define on-key-down-hook (make-hook 3))
(define on-mouse-motion-hook (make-hook 5))
(define on-mouse-button-down-hook (make-hook 3))
(define on-mouse-button-up-hook (make-hook 3))
;;;
;;; Event Handling
;;;
(define handle-events
(let ((e (SDL:make-event)))
(lambda ()
"Handles all events in the SDL event queue."
(while (SDL:poll-event e)
(handle-event e)))))
(define (handle-event e)
"Calls the relevant callback for the event."
(case (SDL:event:type e)
((active)
(run-hook on-active-hook))
((video-resize)
(run-hook on-resize-hook (SDL:event:resize:w e)
(SDL:event:resize:h e)))
((quit)
(run-hook on-quit-hook))
((key-down)
(run-hook on-key-down-hook
(SDL:event:key:keysym:sym e)
(SDL:event:key:keysym:mod e)
(SDL:event:key:keysym:unicode e)))
((key-up)
(run-hook on-key-up-hook
(SDL:event:key:keysym:sym e)
(SDL:event:key:keysym:mod e)
(SDL:event:key:keysym:unicode e)))
((mouse-motion)
(run-hook on-mouse-motion-hook
(SDL:event:motion:state e)
(SDL:event:motion:x e)
(SDL:event:motion:y e)
(SDL:event:motion:xrel e)
(SDL:event:motion:yrel e)))
((mouse-button-down)
(run-hook on-mouse-button-down-hook
(SDL:event:button:button e)
(SDL:event:button:x e)
(SDL:event:button:y e)))
((mouse-button-up)
(run-hook on-mouse-button-up-hook
(SDL:event:button:button e)
(SDL:event:button:x e)
(SDL:event:button:y e)))))
;;;
;;; Frames Per Second
;;;
(define accumulate-fps!
(let* ((frame-time 0)
(alpha 1/5)
(inverse-alpha (- 1 alpha)))
(lambda (dt)
"Computes a weighted average FPS."
(set! frame-time (+ (* alpha dt) (* inverse-alpha frame-time)))
(unless (zero? frame-time)
(set! *fps* (/ 1000 frame-time))))))
(define (current-fps)
"Returns the current FPS value."
*fps*)
(codefine (show-fps)
"Display the current FPS every second."
(wait 60)
(pk 'FPS (floor *fps*))
(show-fps))
;;;
;;; Update and Render
;;;
(define (render)
"Renders a frame."
(set-gl-matrix-mode (matrix-mode modelview))
(gl-load-identity)
(gl-clear (clear-buffer-mask color-buffer depth-buffer))
(run-hook on-render-hook)
(SDL:gl-swap-buffers))
(define (update accumulator)
"Call the update callback. The update callback will be called as
many times as tick-interval can divide accumulator. The return value
is the unused accumulator time."
(if (>= accumulator tick-interval)
(begin
(run-hook on-update-hook)
(update-agenda)
(update (- accumulator tick-interval)))
accumulator))
(define (time-left current-time next-time)
(max (floor (- next-time current-time)) 0))
;;;
;;; Game Loop
;;;
(define (game-loop last-time next-time accumulator)
"Runs input, render, and update hooks."
(handle-events)
(let* ((time (SDL:get-ticks))
(dt (- time last-time))
(accumulator (+ accumulator dt))
(remainder (update accumulator)))
(render)
(accumulate-fps! dt)
;; Sleep for a bit if there's time in between frames
(SDL:delay (time-left (SDL:get-ticks) next-time))
(game-loop time
(+ next-time tick-interval)
remainder)))
(define (run-game-loop)
"Spawns a REPL server and starts the main game loop."
(spawn-server)
(agenda-schedule show-fps)
(let ((time (SDL:get-ticks)))
(game-loop time (+ time tick-interval) 0)))
|
