fastuidraw::gl_binding Namespace Reference

Provides interface for application to use GL where function pointers are auto-resolved transparently and under debug provides error checking. Built as a part of a seperate library; for GL it is libNGL; for GLES it is NGLES. The header defines for each GL/GLES function, glFoo, the macro fastuidraw_glFoo. More...

Classes
class	CallbackGL
	A CallbackGL defines the interface (via its base class) for callbacks before and after each GL call. More...

Functions
void *	get_proc (c_string function)
void	get_proc_function (void *(*get_proc)(c_string), bool fetch_functions=true)
void	get_proc_function (void *datum, void *(*get_proc)(void *, c_string), bool fetch_functions=true)
void	message (c_string message, c_string src_file, int src_line)

Detailed Description

Provides interface for application to use GL where function pointers are auto-resolved transparently and under debug provides error checking. Built as a part of a seperate library; for GL it is libNGL; for GLES it is NGLES. The header defines for each GL/GLES function, glFoo, the macro fastuidraw_glFoo.

Short version:

• application should call fastuidraw::gl_binding::get_proc_function() to set the function which will be used to fetch GL function pointers.
• If an application wishes, it can include <fastuidraw/gl_backend/ngl_header.hpp>. The header will add the GL function-macros and an application can issue GL calls without needing to fetch the GL functions via fastuidraw_glFoo where glFoo is the GL funcion to all. Under release, the macros are defined to function pointers that automatically set themselves up correcty. For debug, the macros preceed and postceed each GL function call with error checking call backs so an application writer can quickly know what line/file triggered an GL error. If an application does not wish to use the macro system (and will also need to fetch function pointers itself) it can just include <fastuidraw/gl_backend/gl_header.hpp> which will include the correct system GL/GLES headers.

Long Version:

The namespace gl_binding provides an interface for an application to specify how to fetch GL function pointers (see fastuidraw::gl_binding::get_proc_function()) and additional functionality of where to write/store GL error messages. An application can also use this functionality by including <fastuidraw/gl_backend/ngl_header.hpp>. The header will create a macro fastuidraw_glFoo for each GL function glFoo. If FASTUIDRAW_DEBUG is defined, each GL call will be preceded by a callback and postceeded by another call back. The preceed callback to the GL call will call the implementation of CallbackGL::pre_call() of each active CallbackGL object. The post-process callback will repeatedly call glGetError (until it returns no error) to build an error-string. If the error string is non-empty, it is printed to stderr. In addition, regardless if the error-string is non-empty, CallbackGL::post_call() of each active CallbackGL is called.

The gl_binding system requires that an application provides a function which the binding system uses to fetch function pointers for the GL API, this is set via gl_binding::get_proc_function().

Lastly, before using a GL (or GLES) function, an application should check the GL implementation supports the named function by examining the GL version and/or extensions itself before using the function.

Function Documentation

get_proc()

void* fastuidraw::gl_binding::get_proc

(

c_string

function

)

Fetches a GL function using the function fetcher passed to get_proc_function().

Parameters

function

name of function to fetch

get_proc_function() [1/2]

void fastuidraw::gl_binding::get_proc_function	(	void *(*)(c_string)	get_proc,
		bool	fetch_functions = true
	)

Sets the function that the system uses to fetch the function pointers for GL or GLES.

Parameters

get_proc	value to use, default is nullptr.
fetch_functions	if true, fetch all GL functions immediately instead of fetching on first call.

get_proc_function() [2/2]

void fastuidraw::gl_binding::get_proc_function	(	void *	datum,
		void *(*)(void *, c_string)	get_proc,
		bool	fetch_functions = true
	)

Sets the function that the system uses to fetch the function pointers for GL or GLES.

Parameters

datum	data pointer passed to get_proc when invoked
get_proc	value to use, default is nullptr.
fetch_functions	if true, fetch all GL functions immediately instead of fetching on first call.

message()

void fastuidraw::gl_binding::message	(	c_string	message,
		c_string	src_file,
		int	src_line
	)

Function that implements FASTUIDRAW_GL_MESSAGE