draw-order.clj

(ns draw-order (:use [penumbra.opengl] [penumbra.window]))

(defn- init [state]
  (enable :depth-test)
  (ortho-view 0 0 640 480 -1 1)
  (scale 1 1 -1)
  state)

(defn draw-square [x y w h]
  (draw-quads
   (vertex x y 0)
   (vertex x (+ y h) 0)
   (vertex (+ x w) (+ y h) 0)
   (vertex (+ x w) y 0)))

(defn- display [[delta time] state]
  (let [[x y] [100 100]
        [w h] [32 32]
        [r g b] [1 0 0]]
    (color r g b)
    (draw-square x y w h))
  (push-matrix
   (translate 100 100 -0.5)
   (let [[x y] [16 16]
         [w h] [32 32]
         [r g b] [0 1 0]]
     (color r g b)
     (draw-square x y w h)))
  (push-matrix
   (translate 100 100 0.5)
   (let [[x y] [-16 -16]
         [w h] [32 32]
         [r g b] [0 0 1]]
     (color r g b)
     (draw-square x y w h)))
  (write-to-screen (format "%d fps" (int (/ 1 delta))) 0 1)
  (repaint))

(def engine {:init init :display display})

(start engine nil)