glutInitDisplayMode - sets the initial display mode.


void glutInitDisplayMode(unsigned int mode);



Display mode, normally the bitwise {\m OR}-ing of GLUT display mode bit masks. See values below:


Bit mask to select an RGBA mode window. This is the default if neither GLUT_RGBA nor GLUT_INDEX are specified.


An alias for GLUT_RGBA.


Bit mask to select a color index mode window. This overrides GLUT_RGBA if it is also specified.


Bit mask to select a single buffered window. This is the default if neither GLUT_DOUBLE or GLUT_SINGLE are specified.


Bit mask to select a double buffered window. This overrides GLUT_SINGLE if it is also specified.


Bit mask to select a window with an accumulation buffer.


Bit mask to select a window with an alpha component to the color buffer(s).


Bit mask to select a window with a depth buffer.


Bit mask to select a window with a stencil buffer.


Bit mask to select a window with multisampling support. If multisampling is not available, a non-multisampling window will automatically be chosen. Note: both the OpenGL client-side and server-side implementations must support the GLX_SAMPLE_SGIS extension for multisampling to be available.


Bit mask to select a stereo window.


Bit mask to select a window with a ‘‘luminance’’ color model. This model provides the functionality of OpenGL’s RGBA color model, but the green and blue components are not maintained in the frame buffer. Instead each pixel’s red component is converted to an index between zero and glutGet(GLUT_WINDOW_COLORMAP_SIZE)-1 and looked up in a per-window color map to determine the color of pixels within the window. The initial colormap of GLUT_LUMINANCE windows is initialized to be a linear gray ramp, but can be modified with GLUT’s colormap routines.


The initial display mode is used when creating top-level windows, subwindows, and overlays to determine the OpenGL display mode for the to-be-created window or overlay.

Note that GLUT_RGBA selects the RGBA color model, but it does not request any bits of alpha (sometimes called an alpha buffer or destination alpha) be allocated. To request alpha, specify GLUT_ALPHA. The same applies to GLUT_LUMINANCE.

The glutInitDisplayString routine provides a more powerful way to select frame buffer capabilities for GLUT windows.


GLUT_LUMINANCE is not supported on most OpenGL platforms.


glutInit, glutCreateWindow, glutInitDisplayString


Mark J. Kilgard (


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