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;;; Chickadee Game Toolkit
;;; Copyright © 2018 David Thompson <davet@gnu.org>
;;;
;;; Chickadee is free software: you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License as published
;;; by the Free Software Foundation, either version 3 of the License,
;;; or (at your option) any later version.
;;;
;;; Chickadee 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
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with this program. If not, see
;;; <http://www.gnu.org/licenses/>.
;;; Commentary:
;;
;; Simple SDL + OpenGL game loop implementation.
;;
;;; Code:
(define-module (chickadee)
#:use-module (sdl2)
#:use-module (sdl2 events)
#:use-module (sdl2 input game-controller)
#:use-module (sdl2 input joystick)
#:use-module ((sdl2 input keyboard) #:prefix sdl2:)
#:use-module ((sdl2 input mouse) #:prefix sdl2:)
#:use-module (sdl2 input text)
#:use-module (sdl2 mixer)
#:use-module (sdl2 video)
#:use-module (chickadee game-loop)
#:use-module (chickadee math matrix)
#:use-module (chickadee render)
#:use-module (chickadee render color)
#:use-module (chickadee render gl)
#:use-module (chickadee render gpu)
#:use-module (chickadee render viewport)
#:export (mouse-x
mouse-y
mouse-button-pressed?
mouse-button-released?
key-pressed?
key-released?
current-window
run-game)
#:re-export (abort-game))
(define (key-pressed? key)
"Return #t if KEY is currently being pressed."
(sdl2:key-pressed? key))
(define (key-released? key)
"Return #t if KEY is not currently being pressed."
(sdl2:key-released? key))
(define (mouse-x)
"Return the current X coordinate of the mouse cursor."
(sdl2:mouse-x))
(define (mouse-y)
"Return the current Y coordinate of the mouse cursor."
(sdl2:mouse-y))
(define (mouse-button-pressed? button)
"Return #t if BUTTON is currently being pressed."
(sdl2:mouse-button-pressed? button))
(define (mouse-button-released? button)
"Return #t if BUTTON is not currently being pressed."
(sdl2:mouse-button-released? button))
(define *controllers* (make-hash-table))
(define (lookup-controller joystick-id)
(hashv-ref *controllers* joystick-id))
(define (add-controller joystick-index)
(let ((controller (open-game-controller joystick-index)))
(hashv-set! *controllers*
(joystick-instance-id
(game-controller-joystick controller))
controller)
controller))
(define (remove-controller joystick-id)
(hashv-remove! *controllers* joystick-id))
(define (open-all-controllers)
(let loop ((i 0))
(when (< i (num-joysticks))
(when (game-controller-index? i)
(add-controller i))
(loop (+ i 1)))))
(define current-window (make-parameter #f))
(define* (run-game #:key
(window-title "Chickadee!")
(window-width 640)
(window-height 480)
window-fullscreen?
(update-hz 60)
(load (const #t))
(update (const #t))
(draw (const #t))
(quit abort-game)
(key-press (const #t))
(key-release (const #t))
(text-input (const #t))
(mouse-press (const #t))
(mouse-release (const #t))
(mouse-move (const #t))
(controller-add (const #t))
(controller-remove (const #t))
(controller-press (const #t))
(controller-release (const #t))
(controller-move (const #t))
error)
(sdl-init)
(false-if-exception (mixer-init))
(open-audio)
(start-text-input)
(open-all-controllers)
(let* ((window (make-window #:opengl? #t
#:title window-title
#:size (list window-width window-height)
#:fullscreen? window-fullscreen?))
(gl-context (make-gl-context window))
(default-viewport (make-viewport 0 0 window-width window-height))
(default-projection (orthographic-projection 0 window-width
window-height 0
0 1)))
(define (invert-y y)
;; SDL's origin is the top-left, but our origin is the bottom
;; left so we need to invert Y coordinates that SDL gives us.
(- window-height y))
(define (input-sdl)
(define (process-event event)
(cond
((quit-event? event)
(quit))
((keyboard-down-event? event)
(key-press (keyboard-event-key event)
(keyboard-event-scancode event)
(keyboard-event-modifiers event)
(keyboard-event-repeat? event)))
((keyboard-up-event? event)
(key-release (keyboard-event-key event)
(keyboard-event-scancode event)
(keyboard-event-modifiers event)))
((text-input-event? event)
(text-input (text-input-event-text event)))
((mouse-button-down-event? event)
(mouse-press (mouse-button-event-button event)
(mouse-button-event-clicks event)
(mouse-button-event-x event)
(invert-y (mouse-button-event-y event))))
((mouse-button-up-event? event)
(mouse-release (mouse-button-event-button event)
(mouse-button-event-x event)
(invert-y (mouse-button-event-y event))))
((mouse-motion-event? event)
(mouse-move (mouse-motion-event-x event)
(invert-y (mouse-motion-event-y event))
(mouse-motion-event-x-rel event)
(- (mouse-motion-event-y-rel event))
(mouse-motion-event-buttons event)))
((and (controller-device-event? event)
(eq? (controller-device-event-action event) 'added))
(controller-add (add-controller
(controller-device-event-which event))))
((and (controller-device-event? event)
(eq? (controller-device-event-action event) 'removed))
(let ((controller (lookup-controller
(controller-device-event-which event))))
(controller-remove controller)
(remove-controller (controller-device-event-which event))
(close-game-controller controller)))
((controller-button-down-event? event)
(controller-press (lookup-controller
(controller-button-event-which event))
(controller-button-event-button event)))
((controller-button-up-event? event)
(controller-release (lookup-controller
(controller-button-event-which event))
(controller-button-event-button event)))
((controller-axis-event? event)
(controller-move (lookup-controller
(controller-axis-event-which event))
(controller-axis-event-axis event)
(/ (controller-axis-event-value event) 32768.0)))))
;; Process all pending events.
(let loop ((event (poll-event)))
(when event
(process-event event)
(loop (poll-event)))))
(define (update-sdl dt)
(input-sdl)
(update dt)
;; Free any GPU resources that have been GC'd.
(gpu-reap!))
(define (render-sdl-opengl alpha)
;; Switch to the null viewport to ensure that
;; the default viewport will be re-applied and
;; clear the screen.
(gpu-state-set! *viewport-state* null-viewport)
(with-viewport default-viewport
(with-projection default-projection
(draw alpha)))
(swap-gl-window window))
(dynamic-wind
(const #t)
(lambda ()
(parameterize ((current-window window))
;; Attempt to activate vsync, if possible. Some systems do
;; not support setting the OpenGL swap interval.
(catch #t
(lambda ()
(set-gl-swap-interval! 'vsync))
(lambda args
(display "warning: could not enable vsync\n"
(current-error-port))))
(load)
;; Notify about all controllers that were already connected
;; when the game was launched because SDL will not create
;; events for them.
(hash-for-each (lambda (key controller)
(controller-add controller))
*controllers*)
(run-game* #:update update-sdl
#:render render-sdl-opengl
#:error error
#:time sdl-ticks
#:update-hz update-hz)))
(lambda ()
(delete-gl-context! gl-context)
(close-window! window)))))
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