ogl.h File Reference

#include "lib/config2.h"
#include "lib/sysdep/os.h"
#include <glad/gl.h>

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Macros
#define	ogl_WarnIfError()   ogl_WarnIfErrorLoc(__FILE__, __LINE__)

Functions
bool	ogl_Init (void *(load)(const char *), void *display, int subsystem)
	initialization: import extension function pointers and do feature detect. More...
void	ogl_SetVsyncEnabled (bool enabled)
	Change vsync state. More...
bool	ogl_HaveExtension (const char *ext)
	Check whether the given OpenGL extension is supported. More...
bool	ogl_HaveVersion (int major, int minor)
	make sure the OpenGL implementation version matches or is newer than the given version. More...
const char *	ogl_HaveExtensions (int dummy,...) SENTINEL_ARG
	check if a list of extensions are all supported (as determined by ogl_HaveExtension). More...
const char *	ogl_ExtensionString ()
	get a list of all supported extensions. More...
void	ogl_WarnIfErrorLoc (const char *file, int line)
	raise a warning (break into the debugger) if an OpenGL error is pending. More...
const char *	ogl_GetErrorName (GLenum err)
	get a name of the error. More...
bool	ogl_SquelchError (GLenum err_to_ignore)
	ignore and reset the specified OpenGL error. More...

Macro Definition Documentation

ogl_WarnIfError

#define ogl_WarnIfError

(

)

ogl_WarnIfErrorLoc(__FILE__, __LINE__)

Function Documentation

ogl_ExtensionString()

const char * ogl_ExtensionString

(

)

get a list of all supported extensions.

useful for crash logs / system information.

Returns

read-only C string of unspecified length containing all advertised extension names, separated by space.

ogl_GetErrorName()

const char * ogl_GetErrorName

(

GLenum

err

)

get a name of the error.

useful for debug.

Returns

read-only C string of unspecified length containing the error's name.

ogl_HaveExtension()

bool ogl_HaveExtension

(

const char *

ext

)

Check whether the given OpenGL extension is supported.

NOTE: this does not check whether the extensions is loaded. for that, check whether GLAD_<extension name> is not null.

Parameters

ext	extension string; exact case.

Returns

bool.

ogl_HaveExtensions()

const char * ogl_HaveExtensions	(	int	dummy,
			...
	)

check if a list of extensions are all supported (as determined by ogl_HaveExtension).

Parameters

dummy

value ignored; varargs requires a placeholder. follow it by a list of const char* extension string parameters, terminated by a 0 pointer.

Returns

0 if all are present; otherwise, the first extension in the list that's not supported (useful for reporting errors).

ogl_HaveVersion()

bool ogl_HaveVersion	(	int	major,
		int	minor
	)

make sure the OpenGL implementation version matches or is newer than the given version.

ogl_Init()

bool ogl_Init	(	void *	load)(const char *,
		void *	display,
		int	subsystem
	)

initialization: import extension function pointers and do feature detect.

call before using any other function. fails if OpenGL not ready for use. TODO: move loading functionality to GL backend.

ogl_SetVsyncEnabled()

void ogl_SetVsyncEnabled

(

bool

enabled

)

Change vsync state.

ogl_SquelchError()

bool ogl_SquelchError

(

GLenum

err_to_ignore

)

ignore and reset the specified OpenGL error.

this is useful for suppressing annoying error messages, e.g. "invalid enum" for GL_CLAMP_TO_EDGE even though we've already warned the user that their OpenGL implementation is too old.

call after the fact, i.e. the error has been raised. if another or different error is pending, those are reported immediately.

Parameters

err_to_ignore

one of the glGetError enums.

Returns

true if the requested error was seen and ignored

ogl_WarnIfErrorLoc()

void ogl_WarnIfErrorLoc	(	const char *	file,
		int	line
	)

raise a warning (break into the debugger) if an OpenGL error is pending.

resets the OpenGL error state afterwards.

when an error is reported, insert calls to this in a binary-search scheme to quickly narrow down the actual error location.

reports a bogus invalid_operation error if called before OpenGL is initialized, so don't!

disabled in release mode for efficiency and to avoid annoying errors.