;;; guile-sdl2 --- FFI bindings for SDL2
;;; Copyright © 2017 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:
;;
;; Mouse input.
;;
;;; Code:

(define-module (sdl2 input mouse)
  #:use-module (ice-9 match)
  #:use-module (rnrs bytevectors)
  #:use-module (sdl2)
  #:use-module ((sdl2 bindings) #:prefix ffi:)
  #:use-module (system foreign)
  #:export (mouse-x
            mouse-y
            mouse-button-pressed?
            mouse-button-released?))

(define (make-int)
  (make-bytevector (sizeof int)))

(define (get-int bv)
  (bytevector-sint-ref bv 0 (native-endianness) (sizeof int)))

(define mouse-x
  (let* ((bv (make-int))
         (ptr (bytevector->pointer bv)))
    (lambda ()
      "Return the x coordinate of the mouse cursor."
      (ffi:sdl-get-mouse-state ptr %null-pointer)
      (get-int bv))))

(define mouse-y
  (let* ((bv (make-int))
         (ptr (bytevector->pointer bv)))
    (lambda ()
      "Return the y coordinate of the mouse cursor."
      (ffi:sdl-get-mouse-state %null-pointer ptr)
      (get-int bv))))

(define (mouse-button-pressed? button)
  "Return #t if BUTTON is currently being pressed."
  (let ((mask (match button
                ('left ffi:SDL_BUTTON_LMASK)
                ('middle ffi:SDL_BUTTON_MMASK)
                ('right ffi:SDL_BUTTON_RMASK)
                ('x1 ffi:SDL_BUTTON_X1MASK)
                ('x2 ffi:SDL_BUTTON_X2MASK)))
        (buttons (ffi:sdl-get-mouse-state %null-pointer %null-pointer)))
    (> (logand mask buttons) 0)))

(define (mouse-button-released? button)
  "Return #t if BUTTON is not currently being pressed."
  (not (mouse-button-pressed? button)))