src/ballistics.lisp @ 53c65c1a0121

(in-package #:coding-math.ballistics)

;;;; Config
(defparameter *width* 600)
(defparameter *height* 400)

(defparameter *center-x* (/ *width* 2))
(defparameter *center-y* (/ *height* 2))


;;;; Drawing
(defparameter *gun-pen* (make-pen :stroke (gray 0.0) :fill (gray 0.0)))
(defparameter *ball-pen* (make-pen :stroke (gray 0.1) :fill (gray 0.6)))
(defparameter *force-bg-pen* (make-pen :fill (gray 0.6)))
(defparameter *force-fg-pen* (make-pen :fill (rgb 1.000 0.478 0.749)))

(defun draw-gun (gun)
  (in-context
    (translate (getf gun 'x) (getf gun 'y))
    (with-pen *gun-pen*
      (circle 0 0 25)
      (rotate (degrees (getf gun 'angle)))
      (rect 0 -8 40 16))))

(defun draw-ball (ball)
  (with-pen *ball-pen*
     (circle (particle-x ball) (particle-y ball) (particle-radius ball))))

(defun draw-force (force)
  (with-pen *force-bg-pen*
    (circle 20 (- *height* 50) 15))
  (with-pen *force-fg-pen*
    (circle 20
            (- *height* 50)
            (map-range -1.0 1.0 0 15 force))))


;;;; Game
(defun aim (gun x y)
  (setf (getf gun 'angle)
        (clamp (- (/ tau 4))
               -0.3
               (atan (- y (getf gun 'y))
                     (- x (getf gun 'x))))))

(defun shoot (game)
  (force-output)
  (with-slots (gun cannonball firedp raw-force) game
    (let ((angle (getf gun 'angle)))
      (setf
        firedp t
        (particle-x cannonball) (+ (getf gun 'x) (* 40 (cos angle)))
        (particle-y cannonball) (+ (getf gun 'y) (* 40 (sin angle)))
        (particle-speed cannonball) (map-range -1.0 1.0 2 20.0 raw-force)
        (particle-direction cannonball) angle))))

(defun update-ball (game)
  (with-slots (cannonball firedp) game
    (particle-update! cannonball)
    (when (> (- (particle-y cannonball)
                (particle-radius cannonball))
             *height*)
      (setf firedp nil))))

(defsketch game (:width *width*
                 :height *height*
                 :debug :scancode-d)
    ((aiming)
     (gun)
     (cannonball)
     (can-shoot-p)
     (firedp)
     (force-speed 0.05)
     (force-angle 0.0)
     (raw-force)
     )
  (with-fps
    (background (gray 1))
    ;;
    (when (not firedp)
      (incf force-angle force-speed)
      (setf raw-force (sin force-angle)))

    (draw-ball cannonball)
    (draw-gun gun)
    (draw-force raw-force)
    (when firedp
      (update-ball sketch::sketch-window))

    ;;
    ))


(defun make-game ()
  (make-sketch 'game
    (aiming nil)
    (firedp nil)
    (gun `(x 40
           y ,*height*
           angle ,(- (/ tau 8))))
    (cannonball (make-particle (getf gun 'x)
                               (getf gun 'y)
                               :speed 15
                               :direction (getf gun 'angle)
                               :radius 7
                               :gravity 0.2))))


;;;; Mouse
(defmethod kit.sdl2:mousebutton-event
    ((game game) state timestamp button x y)
  (declare (ignore timestamp x y))
  (when (= 1 button)
    (case state
      (:mousebuttondown (setf (slot-value game 'aiming) t))
      (:mousebuttonup (setf (slot-value game 'aiming) nil)))))

(defmethod kit.sdl2:mousemotion-event
    ((game game) timestamp button-mask x y xrel yrel)
  (declare (ignore timestamp button-mask xrel yrel))
  (when (slot-value game 'aiming)
    (aim (slot-value game 'gun) x y)))


;;;; Keyboard
(defun keydown (game scancode)
  (declare (ignore game))
  (scancode-case scancode
    (:scancode-space
     nil)))

(defun keyup (game scancode)
  (scancode-case scancode
    (:scancode-space
     (when (not (firedp game))
       (shoot game)))))


(defmethod kit.sdl2:keyboard-event ((instance game) state timestamp repeatp keysym)
  (declare (ignore timestamp repeatp))
  (cond
    ((eql state :keyup) (keyup instance (sdl2:scancode-value keysym)))
    ((eql state :keydown) (keydown instance (sdl2:scancode-value keysym)))
    (t nil)))



;;;; Run
; (defparameter *demo* (make-game))