#|
  This file is a part of stoe project.
  Copyright (c) 2015 Renaud Casenave-Péré (renaud@casenave-pere.fr)
|#

(uiop:define-package :stoe/engine/gl-utils
    (:use :cl)
  (:export #:gl-assert
           #:gl-restart
           #:size-of))
(in-package :stoe/engine/gl-utils)

(defmacro gl-assert (&body body)
  `(progn
     ,@(loop for form in body
          collect `(prog1
                       ,form
                     (let ((err-sym (%gl:get-error)))
                       (unless (eq err-sym :zero)
                         (error "The OpenGL command `~a'~%~2iresulted in an error: ~s~%"
                                ',form err-sym)))))))

(defmacro gl-restart (form)
  `(restart-case
       (gl-assert ,form)
     (continue () :report "Continue")))

(defun size-of (type)
  (ecase type
    (:byte 1)
    (:unsigned-short 2)
    (:float 4)))