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(module input
*
(import scheme
(chicken base)
(chicken format)
(only srfi-1 any filter fold alist-delete)
(only srfi-13 string-join)
(only srfi-197 chain)
(prefix sdl2 sdl2:)
simple-logger
entity
defstruct)
;; Input configuration record
(defstruct input-config
actions ; list of action symbols
keyboard-map ; alist: (sdl2-key-sym . action)
joy-button-map ; alist: (button-id . action)
controller-button-map ; alist: (button-sym . action)
joy-axis-bindings ; list of (axis-id positive-action negative-action)
controller-axis-bindings ; list of (axis-sym positive-action negative-action)
deadzone) ; integer threshold for analog sticks
;; Default input configuration (capture current hardcoded values)
(define *default-input-config*
(make-input-config
actions: '(up down left right a b start select quit)
keyboard-map: '((w . up) (up . up)
(s . down) (down . down)
(a . left) (left . left)
(d . right) (right . right)
(j . a) (z . a)
(k . b) (x . b)
(return . start)
(escape . quit))
joy-button-map: '((0 . a) (1 . b) (7 . start) (6 . select))
controller-button-map: '((a . a) (b . b) (start . start) (back . select)
(dpad-up . up) (dpad-down . down)
(dpad-left . left) (dpad-right . right))
joy-axis-bindings: '((0 right left) (1 down up))
controller-axis-bindings: '((left-x right left) (left-y down up))
deadzone: 8000))
(define-record input-state
current ; Alist: (action . bool)
previous) ; Alist: (action . bool)
;; Create empty input state from config
(define (create-input-state config)
(let ((initial (map (lambda (a) (cons a #f)) (input-config-actions config))))
(make-input-state initial initial)))
;; Helper to update the Alist
(define (set-action state action value)
(let* ((curr (input-state-current state))
(new-curr (cons (cons action value) (alist-delete action curr eq?))))
(make-input-state new-curr (input-state-previous state))))
(define (input-state-diff state)
"Retrieve the difference between current and previous input state maps"
(fold (lambda (item agg)
(unless (eq? (alist-ref item (input-state-previous state)) item)
(cons item agg)))
'()
(input-state-current state)))
(define (handle-noop state event type config)
state)
(define (handle-keyboard state event type config)
(let* ((pressed? (eq? type 'key-down))
(sym (sdl2:keyboard-event-sym event))
(action (alist-ref sym (input-config-keyboard-map config) eq? #f)))
(if action (set-action state action pressed?) state)))
(define (apply-axis-to-state state val positive-action negative-action deadzone)
(chain state
(set-action _ positive-action (> val deadzone))
(set-action _ negative-action (< val (- deadzone)))))
(define (handle-joy-button state event type config)
(let* ((pressed? (eq? type 'joy-button-down))
(btn (sdl2:joy-button-event-button event))
(action (alist-ref btn (input-config-joy-button-map config) eqv? #f)))
(if action (set-action state action pressed?) state)))
(define (handle-joy-axis state event type config)
(let ((axis (sdl2:joy-axis-event-axis event))
(val (sdl2:joy-axis-event-value event))
(dz (input-config-deadzone config)))
(let ((binding (assv axis (input-config-joy-axis-bindings config))))
(if binding
(apply-axis-to-state state val (cadr binding) (caddr binding) dz)
state))))
(define (handle-controller-button state event type config)
(let* ((pressed? (eq? type 'controller-button-down))
(btn (sdl2:controller-button-event-button event))
(action (alist-ref btn (input-config-controller-button-map config) eq? #f)))
(if action (set-action state action pressed?) state)))
(define (handle-controller-axis state event type config)
(let ((axis (sdl2:controller-axis-event-axis event))
(val (sdl2:controller-axis-event-value event))
(dz (input-config-deadzone config)))
(let ((binding (assv axis (input-config-controller-axis-bindings config))))
(if binding
(apply-axis-to-state state val (cadr binding) (caddr binding) dz)
state))))
(define (handle-controller-device state event type config)
(when (eq? type 'controller-device-added)
(sdl2:game-controller-open! (sdl2:controller-device-event-which event)))
state)
(define (handle-event state event config)
(let* ((type (sdl2:event-type event))
(handler (case type
((key-down key-up) handle-keyboard)
((joy-button-down joy-button-up) handle-joy-button)
((joy-axis-motion) handle-joy-axis)
((controller-button-down
controller-button-up) handle-controller-button)
((controller-axis-motion) handle-controller-axis)
((controller-device-added
controller-device-removed) handle-controller-device)
(else handle-noop))))
(handler state event type config)))
(define (input-state-update state events config)
(let ((rolled (make-input-state (input-state-current state)
(input-state-current state))))
(let* ((new-state (fold (lambda (ev st) (handle-event st ev config)) rolled events))
(state-diff (input-state-diff new-state)))
(unless (eq? state-diff '())
(log-debug "input-state change: ~a" state-diff))
new-state)))
;; 5. Simple Getters
(define (input-held? state action)
(alist-ref action (input-state-current state) eq? #f))
(define (input-pressed? state action)
(and (input-held? state action)
(not (alist-ref action (input-state-previous state) eq? #f))))
(define (input-released? state action)
(and (not (input-held? state action))
(alist-ref action (input-state-previous state) eq? #f)))
(define (input-any-pressed? state config)
(any (lambda (a) (input-pressed? state a)) (input-config-actions config)))
(define (input-state->string state config)
(let ((active (filter (lambda (a) (input-held? state a)) (input-config-actions config))))
(format #f "[Input: ~a]" (string-join (map symbol->string active) " "))))
(define (set-facing-from-vx entity vx)
(cond
((> vx 0) (entity-set entity #:facing 1))
((< vx 0) (entity-set entity #:facing -1))
(else entity)))
(define (apply-input-to-entity entity held?)
(let ((input-map (entity-ref entity #:input-map #f)))
(if (not input-map)
entity
(let* ((delta (fold (lambda (entry acc)
(let* ((action (car entry))
(d (cdr entry))
(dvx (car d))
(dvy (cdr d)))
(if (held? action)
(cons (+ (car acc) dvx)
(+ (cdr acc) dvy))
acc)))
'(0 . 0)
input-map))
(speed (entity-ref entity #:move-speed 1))
(vx (* speed (car delta))))
(set-facing-from-vx (entity-set entity #:vx vx) vx)))))
) ;; end module
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