;;;; examples/11-canvas-geometry.lisp

(defpackage #:ww.examples/11
  (:use #:cl)
  (:export #:start))

(in-package :ww.examples/11)

(defclass geo-demo (ww:application) ())

(ww:defhandler quit
    (ww::on-keydown (app scancode)
      (when (eql :scancode-q scancode)
        (ww::stop))))

(ww:defhandler clear-and-draw
    (ww::on-perframe (canvas time)
      (ww::clear-canvas canvas)
      (draw-stuff canvas time)
      (ww::blit canvas)))

(defun draw-stuff (canvas &optional time)
  ;; draw a circle
  (ww::with-grid-circle (x y) (350 100 90 :interiorp t)
    (ww::with-pixel (r g b a) (ww::pixel canvas x y)
      (setf r (mod (* 3 x y time) 256)
            g (mod x 256)
            b (mod y 256))))
  
  ;; draw a bunch of circles
  (loop
    for cx from 0 to 50  
    for cy from 0 to 50 do
      (ww::with-grid-circle (x y) ((+ 300 cx) (+ 300 cy) 80)
        (ww::with-pixel (r g b a) (ww::pixel canvas x y)
          (setf r (mod (* x y) 256)
                g (mod time 256)
                b (mod (* y x) 256)))))
  
  ;; draw a random thing
  (let ((path
          (loop repeat 7
                collect (list (+ 10 (random 240))
                              (+ 10 (random 240))))))
    (ww::with-grid-path (x y) (path :autoclosep t :interiorp t)
      (ww::with-pixel (r g b a) (ww::pixel canvas x y)
        (setf r (mod (* 2 y) 256)
              g (mod (* 3 x) 256)
              b (mod (* x y) 256)))))
  
  (let ((control-points
          `((100 250)
            (,(+ (mod time 20) -10 -100) 490)
            (,(+ (mod time 20) -10 300) 490)
            (100 250)))
        (path nil))
    ;; collect the points along the curve
    (ww::with-grid-bezier (x y) (control-points :count 16)
      (push (list x y) path))

    ;; and then treat them as a closed path, which is filled.
    (ww::with-grid-path (x y) (path :interiorp t)
      (ww::with-pixel (r g b a) (ww::pixel canvas x y)
        (setf r 200 b 120 g 30)))))

(defmethod ww:boot ((app geo-demo))
  (let ((canvas
          (make-instance 'ww:canvas
                         :pixel-width 500
                         :pixel-height 500)))
    ;; stretch canvas over the whole app
    (setf (ww:width canvas) (ww::application-width app)
          (ww:height canvas) (ww::application-height app))

    ;; add it to the display tree
    (ww:add-unit app canvas)

    ;; handlers
    (ww::add-handler canvas #'clear-and-draw)
    (ww:add-handler app #'quit)
    (ww:add-handler canvas #'quit)))

(defun start (&optional (side 500))
  (ww::start
   (make-instance
    'geo-demo
    :fps 10
    :width side
    :height side
    :title "Pixels Geometry")))