;;;; render.lisp
(in-package :break)

(defstruct-g pos-col
  (posiiton :vec3 :accessor pos)
  (color    :vec4 :accessor col))

(defun-g vert ((vert pos-col) &uniform (to-view :mat4) (to-world :mat4))
  (values (* to-view
	     (* to-world
		(v! (pos vert) 1.0)))
	  (col vert)))

(defun-g frag ((color :vec4))
  color)

(defpipeline-g render ()
  (vert pos-col)
  (frag :vec4))

(defun make-square-e-stream (x y color)
  (let* ((verts (make-gpu-array `((,(v! x y 0) ,color)
				  (,(v! 0 y 0) ,color) 
				  (,(v! 0 0 0) ,color)
				  (,(v! x 0 0) ,color))
				:element-type 'pos-col :dimensions 4))
	 (indices (make-gpu-array '(0 1 2  0 2 3)
				  :dimensions 6 :element-type :unsigned-short)))
    (make-buffer-stream verts :index-array indices)))

(defun viewport-internal-size (viewport)
  (let* ((viewport-width (viewport-resolution-x viewport))
	 (viewport-height (viewport-resolution-y viewport))
	 (internal-width (aref *internal-size* 0))
	 (internal-height (aref *internal-size* 1))
	 (viewport-aspect-ratio (/ viewport-width viewport-height)))
    (if (> viewport-aspect-ratio (/ internal-width internal-height))
	(v! (* internal-height viewport-aspect-ratio)
	    internal-height)
	(v! internal-width
	    (/ internal-width viewport-aspect-ratio)))))

(defun update-matrix (window-size)
  (let* ((window-width (aref window-size 0))
	 (window-height (aref window-size 1))
	 (internal-width (aref *internal-size* 0))
	 (internal-height (aref *internal-size* 1))
	 (window-aspect-ratio (reduce #'/ window-size))
	 (new-size (if (> window-aspect-ratio (/ internal-width internal-height))
		       (v! (* internal-height window-aspect-ratio)
			   internal-height) ; wider, preserve height
		       (v! internal-width
			   (/ internal-width window-aspect-ratio)))))
;;   (format t "Matrix arguments: ~a ~a.~%" (aref new-size 0) (aref new-size 1))
    
    (rtg-math.projection:orthographic
     (aref new-size 0) (aref new-size 1)
     1.0 100.0)))