lib/opengl-extensions.lisp

   1 (defpackage #:opengl-extensions
   2   (:nicknames #:gl-ext)
   3   (:use #:cl)
   4   (:export #:scan-available-extensions #:available-extensions #:extension-available-p #:load-extension))
   5
   6 (in-package #:gl-ext)
   7
   8 (defparameter *available* nil)
   9
  10 (defun scan-available-extensions ()
  11   (setf *available*
  12         (mapcar #'(lambda (ext-name) (subseq (symbol-name ext-name) 3))
  13                 (let ((*readtable* (copy-readtable nil)))
  14                   (setf (readtable-case *readtable*) :preserve)
  15                   (read-from-string (format nil "(~a)" (gl:get-string gl:+extensions+)))))))
  16
  17 (defun available-extensions ()
  18   (if (and *available* (not (equal *available* '(""))) (not (eql *available* '(nil))))
  19       *available*
  20       (scan-available-extensions)))
  21
  22 (defun extension-available-p (extension)
  23   (declare (type string extension))
  24   (find extension (available-extensions) :test 'equalp))
  25
  26 (defun load-extension (extension)
  27   "Try to load an opengl extension where the extension name is a string of the form
  28      \"ARB_vertex_buffer_object\". Returns t if the extension is available and loads,
  29      otherwise, nil."
  30   (let ((extension (extension-available-p extension)))
  31     (when extension
  32       (handler-case
  33         (asdf:oos 'asdf:load-op (string-downcase (format nil "cl-glfw-opengl-~a" extension)))
  34         (asdf:missing-component () (warn "Extension ~a has nothing to load~%" extension)))
  35       t)))