Fiddle を使って OpenGL の DLL (libGL.dylib) から関数をいくつかインポート

gl.rb

# -*- coding: utf-8 -*-
require 'fiddle'

module GL
  GL_COLOR_BUFFER_BIT = 0x00004000
  GL_PROJECTION = 0x1701
  GL_MODELVIEW = 0x1700
  GL_TRIANGLES = 0x0004

  GL_FUNCTIONS_MAP = {}
  @@gl_dll = nil

  def self.load_dll(lib = 'libGL.dylib', path = '/System/Library/Frameworks/OpenGL.framework/Libraries')
    @@gl_dll = Fiddle.dlopen( path + '/' + lib )

    # void glViewport (GLint x, GLint y, GLsizei width, GLsizei height)
    GL_FUNCTIONS_MAP[:glViewport] = Fiddle::Function.new( @@gl_dll["glViewport"], 
                                                          [Fiddle::TYPE_INT, Fiddle::TYPE_INT, Fiddle::TYPE_INT, Fiddle::TYPE_INT],
                                                          Fiddle::TYPE_VOID )

    # void glClear (GLbitfield mask)
    GL_FUNCTIONS_MAP[:glClear] = Fiddle::Function.new( @@gl_dll["glClear"],
                                                       [Fiddle::TYPE_INT],
                                                       Fiddle::TYPE_VOID )

    # void glMatrixMode (GLenum mode)
    GL_FUNCTIONS_MAP[:glMatrixMode] = Fiddle::Function.new( @@gl_dll["glMatrixMode"],
                                                            [Fiddle::TYPE_INT],
                                                            Fiddle::TYPE_VOID )
    # void glLoadIdentity (void)
    GL_FUNCTIONS_MAP[:glLoadIdentity] = Fiddle::Function.new( @@gl_dll["glLoadIdentity"],
                                                              [],
                                                              Fiddle::TYPE_VOID )

    # void glOrtho (GLdouble left, GLdouble right, GLdouble bottom, GLdouble top, GLdouble zNear, GLdouble zFar)
    GL_FUNCTIONS_MAP[:glOrtho] = Fiddle::Function.new( @@gl_dll["glOrtho"],
                                                       [Fiddle::TYPE_DOUBLE, Fiddle::TYPE_DOUBLE, Fiddle::TYPE_DOUBLE, Fiddle::TYPE_DOUBLE, Fiddle::TYPE_DOUBLE, Fiddle::TYPE_DOUBLE],
                                                       Fiddle::TYPE_VOID )

    # void glRotatef (GLfloat angle, GLfloat x, GLfloat y, GLfloat z)
    GL_FUNCTIONS_MAP[:glRotatef] = Fiddle::Function.new( @@gl_dll["glRotatef"],
                                                         [Fiddle::TYPE_FLOAT, Fiddle::TYPE_FLOAT, Fiddle::TYPE_FLOAT, Fiddle::TYPE_FLOAT],
                                                         Fiddle::TYPE_VOID )

    # void glBegin (GLenum mode)
    GL_FUNCTIONS_MAP[:glBegin] = Fiddle::Function.new( @@gl_dll["glBegin"],
                                                       [Fiddle::TYPE_INT],
                                                       Fiddle::TYPE_VOID )

    # void glColor3f (GLfloat red, GLfloat green, GLfloat blue)
    GL_FUNCTIONS_MAP[:glColor3f] = Fiddle::Function.new( @@gl_dll["glColor3f"],
                                                         [Fiddle::TYPE_FLOAT, Fiddle::TYPE_FLOAT, Fiddle::TYPE_FLOAT],
                                                         Fiddle::TYPE_VOID )

    # void glVertex3f (GLfloat x, GLfloat y, GLfloat z)
    GL_FUNCTIONS_MAP[:glVertex3f] = Fiddle::Function.new( @@gl_dll["glVertex3f"],
                                                         [Fiddle::TYPE_FLOAT, Fiddle::TYPE_FLOAT, Fiddle::TYPE_FLOAT],
                                                          Fiddle::TYPE_VOID )

    # void glEnd (void)
    GL_FUNCTIONS_MAP[:glEnd] = Fiddle::Function.new( @@gl_dll["glEnd"],
                                                     [],
                                                     Fiddle::TYPE_VOID )

  end

  def self.glViewport(x, y, width, height)
    GL_FUNCTIONS_MAP[:glViewport].call(x, y, width, height)
  end

  def self.glClear(mask)
    GL_FUNCTIONS_MAP[:glClear].call(mask)
  end

  def self.glMatrixMode(mode)
    GL_FUNCTIONS_MAP[:glMatrixMode].call(mode)
  end

  def self.glLoadIdentity()
    GL_FUNCTIONS_MAP[:glLoadIdentity].call()
  end

  def self.glOrtho(left, right, bottom, top, zNear, zFar)
    GL_FUNCTIONS_MAP[:glOrtho].call(left, right, bottom, top, zNear, zFar)
  end

  def self.glRotatef(angle, x, y, z)
    GL_FUNCTIONS_MAP[:glRotatef].call(angle, x, y, z)
  end

  def self.glBegin(mode)
    GL_FUNCTIONS_MAP[:glBegin].call(mode)
  end

  def self.glColor3f(red, green, blue)
    GL_FUNCTIONS_MAP[:glColor3f].call(red, green, blue)
  end

  def self.glVertex3f(x, y, z)
    GL_FUNCTIONS_MAP[:glVertex3f].call(x, y, z)
  end

  def self.glEnd()
    GL_FUNCTIONS_MAP[:glEnd].call()
  end

end