To use this, you must subclass it, and implement the draw() method. The draw() method can use any OpenGL functions to draw the window. Flushing the GL stream and swapping buffers is handled automatically by Fl_Gl_Window after draw() returns.
The draw() method can only use OpenGL calls. Do not attempt to call X, any of the functions in <FL/fl_draw.H>, or glX directly. Do not call gl_start() or gl_finish().
Fl_Gl_Window::Fl_Gl_Window(int W, int H, const char *l=0);
Fl_Gl_Window::Fl_Gl_Window(int X, int Y, int W, int H, const char
*l=0)
FL_RGB|FL_DOUBLE|FL_DEPTH
.
const int Fl_Gl_Window::mode() const;
int Fl_Gl_Window::mode(int);
FL_RGB
- Color (not indexed)
FL_RGB8
- Color with at least 8 bits of each color
FL_INDEX
- Indexed mode
FL_SINGLE
- not double buffered
FL_DOUBLE
- double buffered
FL_ACCUM
- accumulation buffer
FL_ALPHA
- alpha channel in color
FL_DEPTH
- depth buffer
FL_STENCIL
- stencil buffer
FL_MULTISAMPLE
- multisample antialiasing
FL_RGB
and FL_SINGLE
have a
value of zero, they are "on" unless you give
FL_INDEX
or FL_DOUBLE
.
If the desired combination cannot be done, fltk will try turning off
the FL_MULTISAMPLE
. If this also fails show() will call
Fl::error() and not show the window.
You can change the mode while the window is displayed. This is most useful for turning double-buffering on and off. Under X this will cause the old X window to be destroyed and a new one created. If this is a top-level window this will unfortunately also cause the window to blink, raise to the top, and be de-iconized, and the xid() will change, possibly breaking other code. It is best to make the GL window a child of another window if you wish to do this!
int Fl_Gl_Window::mode(const int *);
This call only works on systems using glX. This value is
passed unchanged to glXChooseVisual(), superceeding the value
calculated from mode(int). See "man glXChooseVisual" if you wish to
construct your own mode. Fltk assummes that the pointer is to static
const data, and caches the pointer with the found visual.
glXChooseVisual is not called until show() or can_do()
is called. To restore the use of mode(int), call
mode((int*)0)
.
static int Fl_Gl_Window::can_do(int);
static int Fl_Gl_Window::can_do(const int *mode);
int Fl_Gl_Window::can_do() const;
char Fl_Gl_Window::valid() const;
void Fl_Gl_Window::invalidate();
void Fl_Gl_Window::valid(char i);
Fl_Gl_Window::valid()
is turned off when fltk creates a
new context for this window and by the window resizing, and is turned
on after draw() is called. You can use this inside your draw()
method to avoid unneccessarily initializing the OpenGL context. Just
do this:
void mywindow::draw() {
if (!valid()) {
glViewport(0,0,w(),h());
glFrustum(...);
glLight(...);
...other initilization...
}
... draw your geometry here ...
}
You can also turn valid() off yourself (for instance if you know
the current projection has changed). To do this call
invalidate()
.
You can turn valid() on by calling valid(1). You should only do this after fixing the transformation inside a draw() or after make_current(). This is done automatically after draw() returns.
void Fl_Gl_Window::ortho();
void Fl_Gl_Window::make_current();
void Fl_Gl_Window::make_overlay_current();
void Fl_Gl_Window::swap_buffers();
void Fl_Gl_Window::hide();
Fl_Gl_Window::~Fl_Gl_Window();
int Fl_Gl_Window::can_do_overlay();
void Fl_Gl_Window::redraw_overlay();
virtual void Fl_Gl_Window::draw_overlay();
Both this function and Fl_Gl_Window::draw() must check Fl_Gl_Window::valid(), and set the same transformation. If you don't your code may not work on other systems. Depending on the OS, and on whether overlays are real or simulated, the OpenGL context may be the same or different between the overlay and main window.
static uchar Fl_Gl_Window::overlay_color;
void gl_color(uchar);
void gl_rect(int x,int y,int w,int h);
void gl_rectf(int x,int y,int w,int h);
void gl_font(uchar fontid, int size);
int gl_height();
int gl_descent();
float gl_width(const char *);
float gl_width(const char *, int n);
float gl_width(uchar);
void gl_draw(const char *);
void gl_draw(const char *, int n);
void gl_draw(const char *, int x, int y);
void gl_draw(const char *, int n, int x, int y);
void gl_draw(const char *, int x, int y, int w, int h, uchar align);