Add bindings for game controller input.

* sdl2.scm (%default-init-flags): Add 'joystick' to default flags.
(sdl-init): Translate to 'joystick' to SDL2 init bit flag.
* sdl2/bindings.scm (SDL_INIT_JOYSTICK, SDL_JOYSTICK_POWER_UNKNOWN,
SDL_JOYSTICK_POWER_EMPTY, SDL_JOYSTICK_POWER_LOW,
SDL_JOYSTICK_POWER_MEDIUM, SDL_JOYSTICK_POWER_FULL,
SDL_JOYSTICK_POWER_WIRED, SDL_JOYSTICK_POWER_MAX,
SDL_CONTROLLER_AXIS_INVALID, SDL_CONTROLLER_AXIS_LEFTX,
SDL_CONTROLLER_AXIS_LEFTY, SDL_CONTROLLER_AXIS_RIGHTX,
SDL_CONTROLLER_AXIS_RIGHTY, SDL_CONTROLLER_AXIS_TRIGGERLEFT,
SDL_CONTROLLER_AXIS_TRIGGERRIGHT, SDL_CONTROLLER_AXIS_MAX,
SDL_CONTROLLER_BUTTON_INVALID, SDL_CONTROLLER_BUTTON_A,
SDL_CONTROLLER_BUTTON_B, SDL_CONTROLLER_BUTTON_X,
SDL_CONTROLLER_BUTTON_Y, SDL_CONTROLLER_BUTTON_BACK,
SDL_CONTROLLER_BUTTON_GUIDE, SDL_CONTROLLER_BUTTON_START,
SDL_CONTROLLER_BUTTON_LEFTSTICK, SDL_CONTROLLER_BUTTON_RIGHTSTICK,
SDL_CONTROLLER_BUTTON_LEFTSHOULDER, SDL_CONTROLLER_BUTTON_RIGHTSHOULDER,
SDL_CONTROLLER_BUTTON_DPAD_UP, SDL_CONTROLLER_BUTTON_DPAD_DOWN,
SDL_CONTROLLER_BUTTON_DPAD_LEFT, SDL_CONTROLLER_BUTTON_DPAD_RIGHT,
SDL_CONTROLLER_BUTTON_MAX): New variables.
(sdl-joystick-open, sdl-joystick-close,
sdl-joystick-current-power-level, sdl-joystick-event-state,
sdl-joystick-from-instance-id, sdl-joystick-get-attached,
sdl-joystick-get-axis, sdl-joystick-get-ball, sdl-joystick-get-button,
sdl-joystick-get-device-guid, sdl-joystick-get-guide,
sdl-joystick-get-guid-from-string, sdl-joystick-get-guid-string,
sdl-joystick-get-hat, sdl-joystick-instance-id, sdl-joystick-name,
sdl-joystick-name-for-index, sdl-joystick-num-axes,
sdl-joystick-num-balls, sdl-joystick-num-buttons, sdl-joystick-num-hats,
sdl-num-joysticks, sdl-joystick-update, sdl-game-controller-add-mapping,
sdl-game-controller-open, sdl-game-controller-close,
sdl-game-controller-event-state, sdl-game-controller-from-instance-id,
sdl-game-controller-get-attached, sdl-game-controller-get-axis,
sdl-game-controller-get-axis-from-string,
sdl-game-controller-get-string-from-axis,
sdl-game-controller-get-string-for-axis, sdl-game-controller-get-button,
sdl-game-controller-get-button-from-string,
sdl-game-controller-get-string-from-button,
sdl-game-controller-get-joystick, sdl-game-controller-mapping,
sdl-game-controller-mapping-for-guid, sdl-game-controller-name,
sdl-game-controller-name-for-index, sdl-game-controller-update,
sdl-is-game-controller): New procedures.
* sdl2/events.scm (make-joystick-ball-event, joystick-ball-event?,
joystick-ball-event-timestamp, joystick-ball-event-which,
joystick-ball-event-ball, joystick-ball-event-x-rel,
joystick-ball-event-y-rel, make-joystick-hat-event, joystick-hat-event?,
joystick-hat-event-timestamp, joystick-hat-event-which,
joystick-hat-event-hat, joystick-hat-event-value,
make-joystick-device-event, joystick-device-event?,
joystick-device-event-timestamp, joystick-device-event-which,
joystick-device-event-action, make-controller-axis-event,
controller-axis-event?, controller-axis-event-timestamp,
controller-axis-event-which, controller-axis-event-axis,
controller-axis-event-value, make-controller-button-event,
controller-button-event?, controller-button-down-event?,
controller-button-up-event?, controller-button-event-timestamp,
controller-button-event-which, controller-button-event-button,
controller-button-event-pressed?, make-controller-device-event,
controller-device-event?, controller-device-event-timestamp,
controller-device-event-which, controller-device-event-action,
parse-joystick-ball-event, parse-joystick-hat-event,
parse-joystick-device-event, parse-controller-axis-event,
parse-controller-button-event, parse-controller-device-event): New
procedures.
(poll-event): Parse joystick/controller events.
* sdl2/input/joystick.scm: New file.
* sdl2/input/game-controller.scm: New file.
* Makefile.am (SOURCES): Add them

4 files changed, 680 insertions, 0 deletions

diff --git a/sdl2/bindings.scm b/sdl2/bindings.scm
index e48ce64..1eb4813 100644
--- a/sdl2/bindings.scm
+++ b/sdl2/bindings.scm
@@ -71,6 +71,7 @@ RETURN-TYPE and accept arguments of ARG-TYPES."
 (define-public SDL_INIT_TIMER          #x00000001)
 (define-public SDL_INIT_AUDIO          #x00000010)
 (define-public SDL_INIT_VIDEO          #x00000020)
+(define-public SDL_INIT_JOYSTICK       #x00000200)
 (define-public SDL_INIT_HAPTIC         #x00001000)
 (define-public SDL_INIT_GAMECONTROLLER #x00002000)
 (define-public SDL_INIT_EVENTS         #x00004000)
@@ -949,3 +950,174 @@ RETURN-TYPE and accept arguments of ARG-TYPES."
 (define-public AUDIO_F32LSB #x8120)
 (define-public AUDIO_F32MSB #x9120)
 (define-public AUDIO_F32    AUDIO_F32LSB)
+
+
+;;;
+;;; Joystick
+;;;
+
+(define-public SDL_JOYSTICK_POWER_UNKNOWN -1)
+(define-public SDL_JOYSTICK_POWER_EMPTY 0)
+(define-public SDL_JOYSTICK_POWER_LOW 1)
+(define-public SDL_JOYSTICK_POWER_MEDIUM 2)
+(define-public SDL_JOYSTICK_POWER_FULL 3)
+(define-public SDL_JOYSTICK_POWER_WIRED 4)
+(define-public SDL_JOYSTICK_POWER_MAX 5)
+
+(define-foreign sdl-joystick-open
+  '* "SDL_JoystickOpen" (list int))
+
+(define-foreign sdl-joystick-close
+  void "SDL_JoystickClose" '(*))
+
+(define-foreign sdl-joystick-current-power-level
+  int "SDL_JoystickCurrentPowerLevel" '(*))
+
+(define-foreign sdl-joystick-event-state
+  int "SDL_JoystickEventState" (list int))
+
+(define-foreign sdl-joystick-from-instance-id
+  '* "SDL_JoystickFromInstanceID" (list int32))
+
+(define-foreign sdl-joystick-get-attached
+  sdl-bool "SDL_JoystickGetAttached" '(*))
+
+(define-foreign sdl-joystick-get-axis
+  int16 "SDL_JoystickGetAxis" (list '* int))
+
+(define-foreign sdl-joystick-get-ball
+  int "SDL_JoystickGetBall" (list '* int '* '*))
+
+(define-foreign sdl-joystick-get-button
+  uint8 "SDL_JoystickGetButton" (list '* int))
+
+(define-foreign sdl-joystick-get-device-guid
+  '* "SDL_JoystickGetDeviceGUID" (list int))
+
+(define-foreign sdl-joystick-get-guid
+  '* "SDL_JoystickGetGUID" (list int))
+
+(define-foreign sdl-joystick-get-guid-from-string
+  '* "SDL_JoystickGetGUIDFromString" '(*))
+
+(define-foreign sdl-joystick-get-guid-string
+  void "SDL_JoystickGetGUIDString" (list '* '* int))
+
+(define-foreign sdl-joystick-get-hat
+  uint8 "SDL_JoystickGetHat" (list '* int))
+
+(define-foreign sdl-joystick-instance-id
+  int32 "SDL_JoystickInstanceID" '(*))
+
+(define-foreign sdl-joystick-name
+  '* "SDL_JoystickName" '(*))
+
+(define-foreign sdl-joystick-name-for-index
+  '* "SDL_JoystickNameForIndex" (list int))
+
+(define-foreign sdl-joystick-num-axes
+  int "SDL_JoystickNumAxes" '(*))
+
+(define-foreign sdl-joystick-num-balls
+  int "SDL_JoystickNumBalls" '(*))
+
+(define-foreign sdl-joystick-num-buttons
+  int "SDL_JoystickNumButtons" '(*))
+
+(define-foreign sdl-joystick-num-hats
+  int "SDL_JoystickNumHats" '(*))
+
+(define-foreign sdl-num-joysticks
+  int "SDL_NumJoysticks" '())
+
+(define-foreign sdl-joystick-update
+  void "SDL_JoystickUpdate" '())
+
+
+;;;
+;;; Game Controllers
+;;;
+
+(define-public SDL_CONTROLLER_AXIS_INVALID -1)
+(define-public SDL_CONTROLLER_AXIS_LEFTX 0)
+(define-public SDL_CONTROLLER_AXIS_LEFTY 1)
+(define-public SDL_CONTROLLER_AXIS_RIGHTX 2)
+(define-public SDL_CONTROLLER_AXIS_RIGHTY 3)
+(define-public SDL_CONTROLLER_AXIS_TRIGGERLEFT 4)
+(define-public SDL_CONTROLLER_AXIS_TRIGGERRIGHT 5)
+(define-public SDL_CONTROLLER_AXIS_MAX 6)
+
+(define-public SDL_CONTROLLER_BUTTON_INVALID -1)
+(define-public SDL_CONTROLLER_BUTTON_A 0)
+(define-public SDL_CONTROLLER_BUTTON_B 1)
+(define-public SDL_CONTROLLER_BUTTON_X 2)
+(define-public SDL_CONTROLLER_BUTTON_Y 3)
+(define-public SDL_CONTROLLER_BUTTON_BACK 4)
+(define-public SDL_CONTROLLER_BUTTON_GUIDE 5)
+(define-public SDL_CONTROLLER_BUTTON_START 6)
+(define-public SDL_CONTROLLER_BUTTON_LEFTSTICK 7)
+(define-public SDL_CONTROLLER_BUTTON_RIGHTSTICK 8)
+(define-public SDL_CONTROLLER_BUTTON_LEFTSHOULDER 9)
+(define-public SDL_CONTROLLER_BUTTON_RIGHTSHOULDER 10)
+(define-public SDL_CONTROLLER_BUTTON_DPAD_UP 11)
+(define-public SDL_CONTROLLER_BUTTON_DPAD_DOWN 12)
+(define-public SDL_CONTROLLER_BUTTON_DPAD_LEFT 13)
+(define-public SDL_CONTROLLER_BUTTON_DPAD_RIGHT 14)
+(define-public SDL_CONTROLLER_BUTTON_MAX 15)
+
+(define-foreign sdl-game-controller-add-mapping
+  int "SDL_GameControllerAddMapping" '(*))
+
+(define-foreign sdl-game-controller-open
+  '* "SDL_GameControllerOpen" (list int))
+
+(define-foreign sdl-game-controller-close
+  void "SDL_GameControllerClose" '(*))
+
+(define-foreign sdl-game-controller-event-state
+  int "SDL_GameControllerEventState" (list int))
+
+(define-foreign sdl-game-controller-from-instance-id
+  '* "SDL_GameControllerFromInstanceID" (list int32))
+
+(define-foreign sdl-game-controller-get-attached
+  sdl-bool "SDL_GameControllerGetAttached" '(*))
+
+(define-foreign sdl-game-controller-get-axis
+  int16 "SDL_GameControllerGetAxis" (list '* int))
+
+(define-foreign sdl-game-controller-get-axis-from-string
+  int "SDL_GameControllerGetAxisFromString" '(*))
+
+(define-foreign sdl-game-controller-get-string-for-axis
+  '* "SDL_GameControllerGetStringForAxis" (list int))
+
+(define-foreign sdl-game-controller-get-button
+  uint8 "SDL_GameControllerGetButton" (list '* int))
+
+(define-foreign sdl-game-controller-get-button-from-string
+  int "SDL_GameControllerGetButtonFromString" '(*))
+
+(define-foreign sdl-game-controller-get-string-for-button
+  '* "SDL_GameControllerGetStringForButton" (list int))
+
+(define-foreign sdl-game-controller-get-joystick
+  '* "SDL_GameControllerGetJoystick" '(*))
+
+(define-foreign sdl-game-controller-mapping
+  '* "SDL_GameControllerMapping" '(*))
+
+(define-foreign sdl-game-controller-mapping-for-guid
+  '* "SDL_GameControllerMappingForGUID" '(*))
+
+(define-foreign sdl-game-controller-name
+  '* "SDL_GameControllerName" '(*))
+
+(define-foreign sdl-game-controller-name-for-index
+  '* "SDL_GameControllerNameForIndex" (list int))
+
+(define-foreign sdl-game-controller-update
+  void "SDL_GameControllerUpdate" '())
+
+(define-foreign sdl-is-game-controller
+  sdl-bool "SDL_IsGameController" (list int))
diff --git a/sdl2/events.scm b/sdl2/events.scm
index c9e391b..f207348 100644
--- a/sdl2/events.scm
+++ b/sdl2/events.scm
@@ -116,6 +116,49 @@
             joystick-button-event-button
             joystick-button-event-pressed?
 
+            make-joystick-ball-event
+            joystick-ball-event?
+            joystick-ball-event-timestamp
+            joystick-ball-event-which
+            joystick-ball-event-ball
+            joystick-ball-event-x-rel
+            joystick-ball-event-y-rel
+
+            make-joystick-hat-event
+            joystick-hat-event?
+            joystick-hat-event-timestamp
+            joystick-hat-event-which
+            joystick-hat-event-hat
+            joystick-hat-event-value
+
+            make-joystick-device-event
+            joystick-device-event?
+            joystick-device-event-timestamp
+            joystick-device-event-which
+            joystick-device-event-action
+
+            make-controller-axis-event
+            controller-axis-event?
+            controller-axis-event-timestamp
+            controller-axis-event-which
+            controller-axis-event-axis
+            controller-axis-event-value
+
+            make-controller-button-event
+            controller-button-event?
+            controller-button-down-event?
+            controller-button-up-event?
+            controller-button-event-timestamp
+            controller-button-event-which
+            controller-button-event-button
+            controller-button-event-pressed?
+
+            make-controller-device-event
+            controller-device-event?
+            controller-device-event-timestamp
+            controller-device-event-which
+            controller-device-event-action
+
             poll-event))
 
 (define (make-sdl-event)
@@ -1000,6 +1043,186 @@
      (make-joystick-button-event timestamp which button
                                  (= state ffi:SDL_PRESSED)))))
 
+(define-record-type <joystick-ball-event>
+  (make-joystick-ball-event timestamp which ball x-rel y-rel)
+  joystick-ball-event?
+  (timestamp joystick-ball-event-timestamp)
+  (which joystick-ball-event-which)
+  (ball joystick-ball-event-ball)
+  (x-rel joystick-ball-event-x-rel)
+  (y-rel joystick-ball-event-y-rel))
+
+(define (parse-joystick-ball-event ptr)
+  (define types
+    (list uint32  ; type
+          uint32  ; timestamp
+          int32   ; which
+          uint8   ; ball
+          uint8   ; padding1
+          uint8   ; padding2
+          uint8   ; padding3
+          int16   ; xrel
+          int16)) ; yrel
+
+  (match (parse-c-struct ptr types)
+    ((_ timestamp which ball xrel yrel)
+     (make-joystick-ball-event timestamp which ball xrel yrel))))
+
+(define-record-type <joystick-hat-event>
+  (make-joystick-hat-event timestamp which hat value)
+  joystick-hat-event?
+  (timestamp joystick-hat-event-timestamp)
+  (which joystick-hat-event-which)
+  (hat joystick-hat-event-hat)
+  (value joystick-hat-event-value))
+
+(define (parse-joystick-hat-event ptr)
+  (define types
+    (list uint32  ; type
+          uint32  ; timestamp
+          int32   ; which
+          uint8   ; hat
+          uint8)) ; value
+
+  (match (parse-c-struct ptr types)
+    ((_ timestamp which hat value)
+     ;; TODO: Parse 'value' and convert to symbol.
+     (make-joystick-hat-event timestamp which hat value))))
+
+(define-record-type <joystick-device-event>
+  (make-joystick-device-event timestamp which action)
+  joystick-device-event?
+  (timestamp joystick-device-event-timestamp)
+  (which joystick-device-event-which)
+  (action joystick-device-event-action)) ; added or removed
+
+(define (parse-joystick-device-event ptr)
+  (define types
+    (list uint32  ; type
+          uint32  ; timestamp
+          int32)) ; which
+
+  (match (parse-c-struct ptr types)
+    ((type timestamp which)
+     (make-joystick-device-event timestamp which
+                                 (if (= type ffi:SDL_JOYDEVICEADDED)
+                                     'added
+                                     'removed)))))
+
+
+;;;
+;;; Game Controller
+;;;
+
+(define-record-type <controller-axis-event>
+  (make-controller-axis-event timestamp which axis value)
+  controller-axis-event?
+  (timestamp controller-axis-event-timestamp)
+  (which controller-axis-event-which)
+  (axis controller-axis-event-axis)
+  (value controller-axis-event-value))
+
+(define (parse-controller-axis-event ptr)
+  (define types
+    (list uint32  ; type
+          uint32  ; timestamp
+          int32   ; which
+          uint8   ; axis
+          uint8   ; padding1
+          uint8   ; padding2
+          uint8   ; padding3
+          int16)) ; value
+
+  (define (int->axis-symbol axis)
+    (cond
+      ((= axis ffi:SDL_CONTROLLER_AXIS_LEFTX) 'left-x)
+      ((= axis ffi:SDL_CONTROLLER_AXIS_LEFTY) 'left-y)
+      ((= axis ffi:SDL_CONTROLLER_AXIS_RIGHTX) 'right-x)
+      ((= axis ffi:SDL_CONTROLLER_AXIS_RIGHTY) 'right-y)
+      ((= axis ffi:SDL_CONTROLLER_AXIS_TRIGGERLEFT) 'trigger-left)
+      ((= axis ffi:SDL_CONTROLLER_AXIS_TRIGGERRIGHT) 'trigger-right)))
+
+  (match (parse-c-struct ptr types)
+    ((_ timestamp which axis _ _ _ value)
+     (make-controller-axis-event timestamp
+                                 which
+                                 (int->axis-symbol axis)
+                                 value))))
+
+(define-record-type <controller-button-event>
+  (make-controller-button-event timestamp which button pressed?)
+  controller-button-event?
+  (timestamp controller-button-event-timestamp)
+  (which controller-button-event-which)
+  (button controller-button-event-button)
+  (pressed? controller-button-event-pressed?))
+
+(define (controller-button-down-event? event)
+  (and (controller-button-event? event)
+       (controller-button-event-pressed? event)))
+
+(define (controller-button-up-event? event)
+  (and (controller-button-event? event)
+       (not (controller-button-event-pressed? event))))
+
+(define (parse-controller-button-event ptr)
+  (define types
+    (list uint32  ; type
+          uint32  ; timestamp
+          int32   ; which
+          uint8   ; button
+          uint8)) ; state
+
+  (define (int->button-symbol button)
+    (cond
+      ((= button ffi:SDL_CONTROLLER_BUTTON_A) 'a)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_B) 'b)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_X) 'x)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_Y) 'y)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_BACK) 'back)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_GUIDE) 'guide)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_START) 'start)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_LEFTSTICK) 'left-stick)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_RIGHTSTICK) 'right-stick)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_LEFTSHOULDER) 'left-shoulder)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_RIGHTSHOULDER) 'right-shoulder)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_DPAD_UP) 'dpad-up)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_DPAD_DOWN) 'dpad-down)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_DPAD_LEFT) 'dpad-left)
+      ((= button ffi:SDL_CONTROLLER_BUTTON_DPAD_RIGHT) 'dpad-right)))
+
+  (match (parse-c-struct ptr types)
+    ((_ timestamp which button state)
+     (make-controller-button-event timestamp
+                                   which
+                                   (int->button-symbol button)
+                                   (= state ffi:SDL_PRESSED)))))
+
+(define-record-type <controller-device-event>
+  (make-controller-device-event timestamp which action)
+  controller-device-event?
+  (timestamp controller-device-event-timestamp)
+  (which controller-device-event-which)
+  (action controller-device-event-action))
+
+(define (parse-controller-device-event ptr)
+  (define types
+    (list uint32  ; type
+          uint32  ; timestamp
+          int32)) ; which
+
+  (match (parse-c-struct ptr types)
+    ((type timestamp which)
+     (make-controller-device-event timestamp
+                                   which
+                                   (cond
+                                    ((= type ffi:SDL_CONTROLLERDEVICEADDED)
+                                     'added)
+                                    ((= type ffi:SDL_CONTROLLERDEVICEREMOVED)
+                                     'removed)
+                                    ((= type ffi:SDL_CONTROLLERDEVICEREMAPPED)
+                                     'remapped))))))
+
 
 ;;;
 ;;; Event management
@@ -1028,7 +1251,23 @@
              (parse-mouse-motion-event ptr))
             ((= type ffi:SDL_JOYAXISMOTION)
              (parse-joystick-axis-event ptr))
+            ((= type ffi:SDL_JOYBALLMOTION)
+             (parse-joystick-ball-event ptr))
+            ((= type ffi:SDL_JOYHATMOTION)
+             (parse-joystick-hat-event ptr))
             ((or (= type ffi:SDL_JOYBUTTONDOWN)
                  (= type ffi:SDL_JOYBUTTONUP))
              (parse-joystick-button-event ptr))
+            ((or (= type ffi:SDL_JOYDEVICEADDED)
+                 (= type ffi:SDL_JOYDEVICEREMOVED))
+             (parse-joystick-device-event ptr))
+            ((= type ffi:SDL_CONTROLLERAXISMOTION)
+             (parse-controller-axis-event ptr))
+            ((or (= type ffi:SDL_CONTROLLERBUTTONDOWN)
+                 (= type ffi:SDL_CONTROLLERBUTTONUP))
+             (parse-controller-button-event ptr))
+            ((or (= type ffi:SDL_CONTROLLERDEVICEADDED)
+                 (= type ffi:SDL_CONTROLLERDEVICEREMOVED)
+                 (= type ffi:SDL_CONTROLLERDEVICEREMAPPED))
+             (parse-controller-device-event ptr))
             (else 'fixme:unsupported-event))))))
diff --git a/sdl2/input/game-controller.scm b/sdl2/input/game-controller.scm
new file mode 100644
index 0000000..66441a9
--- /dev/null
+++ b/sdl2/input/game-controller.scm
@@ -0,0 +1,155 @@
+;;; guile-sdl2 --- FFI bindings for SDL2
+;;; Copyright © 2016 David Thompson <davet@gnu.org>
+;;;
+;;; This file is part of guile-sdl2.
+;;;
+;;; Guile-sdl2 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-sdl2 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 Lesser General Public
+;;; License along with guile-sdl2.  If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; Joystick input.
+;;
+;;; Code:
+
+(define-module (sdl2 input game-controller)
+  #:use-module (ice-9 match)
+  #:use-module (srfi srfi-9)
+  #:use-module (srfi srfi-9 gnu)
+  #:use-module (system foreign)
+  #:use-module ((sdl2 bindings) #:prefix ffi:)
+  #:use-module (sdl2)
+  #:export (open-game-controller
+            close-game-controller
+            game-controller?
+            game-controller-attached?
+            game-controller-joystick
+            game-controller-name
+            game-controller-axis
+            game-controller-button-pressed?
+            game-controller-index?))
+
+(define-wrapped-pointer-type <game-controller>
+  game-controller?
+  wrap-game-controller unwrap-game-controller
+  (lambda (game-controller port)
+    (format port "#<game-controller ~a>"
+            (game-controller-name game-controller))))
+
+(define-record-type <game-controller>
+  (make-game-controller pointer joystick)
+  game-controller?
+  (pointer unwrap-game-controller)
+  (joystick %game-controller-joystick))
+
+(set-record-type-printer! <game-controller>
+                          (lambda (game-controller port)
+                            (format port "#<game-controller ~s>"
+                                    (game-controller-name game-controller))))
+
+(define wrap-joystick (@@ (sdl2 input joystick) wrap-joystick))
+
+(define (open-game-controller joystick-index)
+  "Return a game controller object for the physical joystick device
+associated with ."
+  (let ((ptr (ffi:sdl-game-controller-open joystick-index)))
+    (if (null-pointer? ptr)
+        (sdl-error "open-game-controller" "failed to open game controller")
+        (let ((joystick (wrap-joystick
+                         (ffi:sdl-game-controller-get-joystick ptr))))
+         (make-game-controller ptr joystick)))))
+
+(define (close-game-controller controller)
+  "Close CONTROLLER."
+  (ffi:sdl-game-controller-close (unwrap-game-controller controller)))
+
+(define (game-controller-joystick controller)
+  "Return the underlying joystick object associated with CONTROLLER."
+  (%game-controller-joystick controller))
+
+(define (game-controller-attached? controller)
+  "Return #t if CONTROLLER is currently in use."
+  (= (ffi:sdl-game-controller-get-attached (unwrap-game-controller controller)) 1))
+
+(define (game-controller-name controller)
+  "Return the human readable name for CONTROLLER."
+  (pointer->string (ffi:sdl-game-controller-name (unwrap-game-controller controller))))
+
+(define (axis-symbol->int axis)
+  (match axis
+    ('left-x ffi:SDL_CONTROLLER_AXIS_LEFTX)
+    ('left-y ffi:SDL_CONTROLLER_AXIS_LEFTY)
+    ('right-x ffi:SDL_CONTROLLER_AXIS_RIGHTX)
+    ('right-x ffi:SDL_CONTROLLER_AXIS_RIGHTY)
+    ('trigger-left ffi:SDL_CONTROLLER_AXIS_TRIGGERLEFT)
+    ('trigger-right ffi:SDL_CONTROLLER_AXIS_TRIGGERRIGHT)))
+
+(define (game-controller-axis controller axis)
+  "Return a number in the range [-32768, 32767] representing the
+current state of AXIS on CONTROLLER.
+
+AXIS may be one of the following symbols:
+- left-x
+- left-y
+- right-x
+- right-y
+- trigger-left
+- trigger-right"
+  (ffi:sdl-game-controller-get-axis (unwrap-game-controller controller)
+                                    (axis-symbol->int axis)))
+
+(define (button-symbol->int button)
+  (match button
+    ('a ffi:SDL_CONTROLLER_BUTTON_A)
+    ('b ffi:SDL_CONTROLLER_BUTTON_B)
+    ('x ffi:SDL_CONTROLLER_BUTTON_X)
+    ('y ffi:SDL_CONTROLLER_BUTTON_Y)
+    ('back ffi:SDL_CONTROLLER_BUTTON_BACK)
+    ('guide ffi:SDL_CONTROLLER_BUTTON_GUIDE)
+    ('start ffi:SDL_CONTROLLER_BUTTON_START)
+    ('left-stick ffi:SDL_CONTROLLER_BUTTON_LEFTSTICK)
+    ('right-stick ffi:SDL_CONTROLLER_BUTTON_RIGHTSTICK)
+    ('left-shoulder ffi:SDL_CONTROLLER_BUTTON_LEFTSHOULDER)
+    ('right-shoulder ffi:SDL_CONTROLLER_BUTTON_RIGHTSHOULDER)
+    ('dpad-up ffi:SDL_CONTROLLER_BUTTON_DPAD_UP)
+    ('dpad-down ffi:SDL_CONTROLLER_BUTTON_DPAD_DOWN)
+    ('dpad-left ffi:SDL_CONTROLLER_BUTTON_DPAD_LEFT)
+    ('dpad-right ffi:SDL_CONTROLLER_BUTTON_DPAD_RIGHT)))
+
+(define (game-controller-button-pressed? controller button)
+  "Return #t if BUTTON is pressed on CONTROLLER.
+
+BUTTON may be one of the following symbols:
+- a
+- b
+- x
+- y
+- back
+- guide
+- start
+- left-stick
+- right-stick
+- left-shoulder
+- right-shoulder
+- dpad-up
+- dpad-down
+- dpad-left
+- dpad-right"
+  (= (ffi:sdl-game-controller-get-button (unwrap-game-controller controller)
+                                         (button-symbol->int button))
+     1))
+
+(define (game-controller-index? joystick-index)
+  "Return #t if JOYSTICK-INDEX is a valid game controller index."
+  (= (ffi:sdl-is-game-controller joystick-index) 1))
diff --git a/sdl2/input/joystick.scm b/sdl2/input/joystick.scm
new file mode 100644
index 0000000..ecab8ec
--- /dev/null
+++ b/sdl2/input/joystick.scm
@@ -0,0 +1,114 @@
+;;; guile-sdl2 --- FFI bindings for SDL2
+;;; Copyright © 2016 David Thompson <davet@gnu.org>
+;;;
+;;; This file is part of guile-sdl2.
+;;;
+;;; Guile-sdl2 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-sdl2 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 Lesser General Public
+;;; License along with guile-sdl2.  If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; Joystick input.
+;;
+;;; Code:
+
+(define-module (sdl2 input joystick)
+  #:use-module (ice-9 format)
+  #:use-module (ice-9 match)
+  #:use-module (system foreign)
+  #:use-module ((sdl2 bindings) #:prefix ffi:)
+  #:use-module (sdl2)
+  #:export (num-joysticks
+            open-joystick
+            close-joystick
+            joystick?
+            joystick-instance-id
+            joystick-power-level
+            joystick-num-axes
+            joystick-num-balls
+            joystick-num-buttons
+            joystick-num-hats))
+
+(define (num-joysticks)
+  "Return the current number of connected joystick devices."
+  (ffi:sdl-num-joysticks))
+
+(define-wrapped-pointer-type <joystick>
+  joystick?
+  wrap-joystick unwrap-joystick
+  (lambda (joystick port)
+    (format port "#<joystick id: ~d>"
+            (joystick-instance-id joystick))))
+
+(define (open-joystick device-index)
+  "Return a joystick object for the physical joystick device
+associated with DEVICE-INDEX."
+  (let ((ptr (ffi:sdl-joystick-open device-index)))
+    (if (null-pointer? ptr)
+        (sdl-error "open-joystick" "failed to open joystick")
+        (wrap-joystick ptr))))
+
+(define (close-joystick joystick)
+  "Close JOYSTICK."
+  (ffi:sdl-joystick-close (unwrap-joystick joystick)))
+
+(define (joystick-instance-id joystick)
+  "Return the instance id of JOYSTICK."
+  (ffi:sdl-joystick-instance-id (unwrap-joystick joystick)))
+
+(define (joystick-attached? joystick)
+  "Return #t if JOYSTICK has been opened."
+  (= (ffi:sdl-joystick-get-attached (unwrap-joystick joystick)) 1))
+
+(define (joystick-power-level joystick)
+  "Return the symbolic battery power level for JOYSTICK, either
+'unknown', 'empty', 'low', 'medium', 'full', or 'wired'."
+  (let ((level (ffi:sdl-joystick-current-power-level
+                (unwrap-joystick joystick))))
+    (cond
+     ((= level ffi:SDL_JOYSTICK_POWER_UNKNOWN) 'unknown)
+     ((= level ffi:SDL_JOYSTICK_POWER_EMPTY) 'empty)
+     ((= level ffi:SDL_JOYSTICK_POWER_LOW) 'low)
+     ((= level ffi:SDL_JOYSTICK_POWER_MEDIUM) 'medium)
+     ((= level ffi:SDL_JOYSTICK_POWER_FULL) 'full)
+     ((= level ffi:SDL_JOYSTICK_POWER_WIRED) 'wired))))
+
+(define (joystick-num-axes joystick)
+  "Return the number of axes for JOYSTICK."
+  (ffi:sdl-joystick-num-axes (unwrap-joystick joystick)))
+
+(define (joystick-num-balls joystick)
+  "Return the number of balls for JOYSTICK."
+  (ffi:sdl-joystick-num-balls (unwrap-joystick joystick)))
+
+(define (joystick-num-buttons joystick)
+  "Return the number of buttons for JOYSTICK."
+  (ffi:sdl-joystick-num-buttons (unwrap-joystick joystick)))
+
+(define (joystick-num-hats joystick)
+  "Return the number of hats for JOYSTICK."
+  (ffi:sdl-joystick-num-hats (unwrap-joystick joystick)))
+
+(define (joystick-axis joystick axis-index)
+  "Return a number in the range [-32768, 32767] representing the
+current state of AXIS-INDEX on JOYSTICK.  On most joysticks, use 0 to
+query the X axis and 1 to query the Y axis."
+  (ffi:sdl-joystick-get-axis (unwrap-joystick joystick) axis-index))
+
+(define (joystick-button-pressed? joystick button-index)
+  "Return #t if BUTTON-INDEX is pressed on JOYSTICK.  Button indices
+start from 0."
+  (= (ffi:sdl-joystick-get-button (unwrap-joystick joystick) button-index) 1))
+
+;; TODO: joystick-hat and joystick-ball