GL_KTX_buffer_region
	GL_KTX_FRONT_REGION 0x0
	GL_KTX_BACK_REGION 0x1
	GL_KTX_Z_REGION 0x2
	GL_KTX_STENCIL_REGION 0x3
	GLuint glBufferRegionEnabledEXT (void)
	GLuint glNewBufferRegionEXT (GLenum region)
	void glDeleteBufferRegionEXT (GLenum region)
	void glReadBufferRegionEXT (GLuint region, GLint x, GLint y, GLsizei width, GLsizei height)
	void glDrawBufferRegionEXT (GLuint region, GLint x, GLint y, GLsizei width, GLsizei height, GLint xDest, GLint yDest)