gl.h File Reference

This file defines wrapper functions for OpenGL in FLTK. More...

#include "Enumerations.H"
#include <GL/gl.h>

Go to the source code of this file.

Functions
void	gl_color (Fl_Color i)
	Sets the curent OpenGL color to an FLTK color. More...
void	gl_color (int c)
	back compatibility
int	gl_descent ()
	Returns the current font's descent.
void	gl_draw (const char *)
	Draws a nul-terminated string in the current font at the current position. More...
void	gl_draw (const char *, float x, float y)
	Draws a nul-terminated string in the current font at the given position. More...
void	gl_draw (const char *, int n)
	Draws an array of n characters of the string in the current font at the current position. More...
void	gl_draw (const char *, int n, float x, float y)
	Draws n characters of the string in the current font at the given position. More...
void	gl_draw (const char *, int n, int x, int y)
	Draws n characters of the string in the current font at the given position. More...
void	gl_draw (const char *, int x, int y)
	Draws a nul-terminated string in the current font at the given position. More...
void	gl_draw (const char *, int x, int y, int w, int h, Fl_Align)
	Draws a string formatted into a box, with newlines and tabs expanded, other control characters changed to ^X. More...
void	gl_draw_image (const uchar *, int x, int y, int w, int h, int d=3, int ld=0)
void	gl_finish ()
	Releases an OpenGL context.
void	gl_font (int fontid, int size)
	Sets the current OpenGL font to the same font as calling fl_font(). More...
int	gl_height ()
	Returns the current font's height.
void	gl_measure (const char *, int &x, int &y)
	Measure how wide and tall the string will be when drawn by the gl_draw() function.
void	gl_rect (int x, int y, int w, int h)
	Outlines the given rectangle with the current color. More...
void	gl_rectf (int x, int y, int w, int h)
	Fills the given rectangle with the current color. More...
void	gl_start ()
	Creates an OpenGL context.
int	gl_texture_pile_height ()
	Returns the current maximum height of the pile of pre-computed string textures. More...
void	gl_texture_pile_height (int max)
	Changes the maximum height of the pile of pre-computed string textures. More...
void	gl_texture_reset ()
	To call after GL operations that may invalidate textures used to draw text in GL scenes (e.g., switch between FL_DOUBLE / FL_SINGLE modes).
double	gl_width (const char *)
	Returns the width of the string in the current fnt.
double	gl_width (const char *, int n)
	Returns the width of n characters of the string in the current font.
double	gl_width (uchar)
	Returns the width of the character in the current font.

Detailed Description

This file defines wrapper functions for OpenGL in FLTK.

To use OpenGL from within an FLTK application you MUST use gl_visual() to select the default visual before doing show() on any windows. Mesa will crash if you try to use a visual not returned by glxChooseVisual.

Historically, this did not always work well with Fl_Double_Window's! It can try to draw into the front buffer. Depending on the system this might either crash or do nothing (when pixmaps are being used as back buffer and GL is being done by hardware), work correctly (when GL is done with software, such as Mesa), or draw into the front buffer and be erased when the buffers are swapped (when double buffer hardware is being used)

Function Documentation

gl_color()

void gl_color

(

Fl_Color

i

)

Sets the curent OpenGL color to an FLTK color.

For color-index modes it will use fl_xpixel(c), which is only right if the window uses the default colormap!

gl_draw() [1/7]

void gl_draw

(

const char *

str

)

Draws a nul-terminated string in the current font at the current position.

See also

gl_texture_pile_height(int)

gl_draw() [2/7]

void gl_draw	(	const char *	str,
		float	x,
		float	y
	)

Draws a nul-terminated string in the current font at the given position.

See also

gl_texture_pile_height(int)

gl_draw() [3/7]

void gl_draw	(	const char *	str,
		int	n
	)

Draws an array of n characters of the string in the current font at the current position.

See also

gl_texture_pile_height(int)

gl_draw() [4/7]

void gl_draw	(	const char *	str,
		int	n,
		float	x,
		float	y
	)

Draws n characters of the string in the current font at the given position.

See also

gl_texture_pile_height(int)

gl_draw() [5/7]

void gl_draw	(	const char *	str,
		int	n,
		int	x,
		int	y
	)

Draws n characters of the string in the current font at the given position.

See also

gl_texture_pile_height(int)

gl_draw() [6/7]

void gl_draw	(	const char *	str,
		int	x,
		int	y
	)

Draws a nul-terminated string in the current font at the given position.

See also

gl_texture_pile_height(int)

gl_draw() [7/7]

void gl_draw	(	const char *	str,
		int	x,
		int	y,
		int	w,
		int	h,
		Fl_Align	align
	)

Draws a string formatted into a box, with newlines and tabs expanded, other control characters changed to ^X.

and aligned with the edges or center. Exactly the same output as fl_draw().

gl_font()

void gl_font	(	int	fontid,
		int	size
	)

Sets the current OpenGL font to the same font as calling fl_font().

See also

Fl::draw_GL_text_with_textures(int val)

gl_rect()

void gl_rect	(	int	x,
		int	y,
		int	w,
		int	h
	)

Outlines the given rectangle with the current color.

If Fl_Gl_Window::ortho() has been called, then the rectangle will exactly fill the given pixel rectangle.

gl_rectf()

void gl_rectf	(	int	x,
		int	y,
		int	w,
		int	h
	)

Fills the given rectangle with the current color.

See also

gl_rect(int x, int y, int w, int h)

gl_texture_pile_height() [1/2]

int gl_texture_pile_height

(

void

)

Returns the current maximum height of the pile of pre-computed string textures.

The default value is 100

See also

Fl::draw_GL_text_with_textures(int)

gl_texture_pile_height() [2/2]

void gl_texture_pile_height

(

int

max

)

Changes the maximum height of the pile of pre-computed string textures.

Strings that are often re-displayed can be processed much faster if this pile is set high enough to hold all of them.

Parameters

max	Maximum height of the texture pile

See also

Fl::draw_GL_text_with_textures(int)