al_set_new_display_flags
void al_set_new_display_flags(int flags)
Sets various flags to be used when creating new displays on the calling thread. flags is a bitfield containing any reasonable combination of the following:
- ALLEGRO_WINDOWED
- Prefer a windowed mode. - Under multi-head X (not XRandR/TwinView), the use of more than one adapter is impossible due to bugs in X and glX. al_create_display will fail if more than one adapter is attempted to be used. 
- ALLEGRO_FULLSCREEN
- Prefer a fullscreen mode. - Under X the use of more than one FULLSCREEN display when using multi-head X, or true Xinerama is not possible due to bugs in X and glX, display creation will fail if more than one adapter is attempted to be used. 
- ALLEGRO_FULLSCREEN_WINDOW
- Make the window span the entire screen. Unlike ALLEGRO_FULLSCREEN this will never attempt to modify the screen resolution. Instead the pixel dimensions of the created display will be the same as the desktop. - The passed width and height are only used if the window is switched out of fullscreen mode later but will be ignored initially. - Under Windows and X11 a fullscreen display created with this flag will behave differently from one created with the ALLEGRO_FULLSCREEN flag - even if the ALLEGRO_FULLSCREEN display is passed the desktop dimensions. The exact difference is platform dependent, but some things which may be different is how alt-tab works, how fast you can toggle between fullscreen/windowed mode or how additional monitors behave while your display is in fullscreen mode. - Additionally under X, the use of more than one adapter in multi-head mode or with true Xinerama enabled is impossible due to bugs in X/glX, creation will fail if more than one adapter is attempted to be used. 
- ALLEGRO_RESIZABLE
- The display is resizable (only applicable if combined with ALLEGRO_WINDOWED). 
- ALLEGRO_OPENGL
- Require the driver to provide an initialized OpenGL context after returning successfully. 
- ALLEGRO_OPENGL_3_0
- Require the driver to provide an initialized OpenGL context compatible with OpenGL version 3.0. 
- ALLEGRO_OPENGL_FORWARD_COMPATIBLE
- If this flag is set, the OpenGL context created with ALLEGRO_OPENGL_3_0 will be forward compatible only, meaning that all of the OpenGL API declared deprecated in OpenGL 3.0 will not be supported. Currently, a display created with this flag will not be compatible with Allegro drawing routines; the display option ALLEGRO_COMPATIBLE_DISPLAY will be set to false. 
- ALLEGRO_DIRECT3D
- Require the driver to do rendering with Direct3D and provide a Direct3D device. 
- ALLEGRO_NOFRAME
- Try to create a window without a frame (i.e. no border or titlebar). This usualy does nothing for fullscreen modes, and even in windowed moded it depends on the underlying platform whether it is supported or not. 
- ALLEGRO_GENERATE_EXPOSE_EVENTS
- Let the display generate expose events. 
0 can be used for default values.
See also: al_set_new_display_option, al_get_display_option
Examples: ex_audio_props, ex_blend2, ex_color, ex_d3d, ex_disable_screensaver, ex_display_options, ex_dualies, ex_expose, ex_font, ex_font_justify, ex_fs_resize, ex_fs_window, ex_gldepth, ex_glext, ex_mouse_cursor, ex_mouse_events, ex_multiwin, ex_noframe, ex_ogre3d, ex_opengl, ex_opengl_pixel_shader, ex_pixelformat, ex_resize, ex_resize2, ex_subbitmap, ex_synth, ex_threads, ex_vsync, ex_warp_mouse, ex_winfull
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