glXChooseFBConfigSGIX(3G)
glXChooseFBConfigSGIX - return a list of GLX frame buffer configurations that match the specified attributes
As shipped in IRIX 6.5.7. Unchanged since IRIX 6.5.
NAME glXChooseFBConfigSGIX - return a list of GLX frame buffer configurations that match the specified attributes C SPECIFICATION GLXFBConfigSGIX * glXChooseFBConfigSGIX( Display *dpy, int screen, int *attrib_list, int *nitems ) PARAMETERS dpy Specifies the connection to the X server. screen Specifies the screen number. attrib_list Specifies a list of attribute/value pairs. The last attribute must be None. nitems Returns the number of elements in the list returned by glXChooseFBConfigSGIX. DESCRIPTION If attrib_list is NULL then glXChooseFBConfigSGIX returns an array of GLX frame buffer configurations that are available on the specified screen; otherwise glXChooseFBConfigSGIX returns an array of GLX frame buffer configurations that match the specified attributes. If an error occurs, no frame buffer configurations exist on the specified screen, or if no frame buffer configurations match the specified attributes, then NULL is returned. Use XFree to free the memory returned by glXChooseFBConfigSGIX. All attributes in attrib_list, including boolean attributes, are immediately followed by the corresponding desired value. The list is terminated with None. If an attribute is not specified in attrib_list then the default value (see below) is used (and the attribute is said to be specified implicitly). For example, if GLX_STEREO is not specified then it is assumed to be False. For some attributes, the default is "don't care" meaning that any value is OK for this attribute, so the attribute will not be checked. Attributes are matched in an attribute-specific manner. Some of the attributes, such as GLX_LEVEL, must match the specified value exactly; others, such as, GLX_RED_SIZE must meet or exceed the specified minimum values. If more than one GLX frame buffer configuration is found, then a list of configurations, sorted according to the "best" match criteria, is returned. The match criteria for each attribute and the exact sorting order is defined below. The interpretations of the various GLX visual attributes are as follows: GLX_BUFFER_SIZE Must be followed by a nonnegative integer that indicates the desired color index buffer size. The smallest index buffer of at least the specified size is preferred. Ignored if GLX_COLOR_INDEX_BIT_SGIX is not set in GLX_RENDER_TYPE_SGIX. The default value is 0. GLX_LEVEL Must be followed by an integer buffer-level specification. This specification is honored exactly. Buffer level zero corresponds to the default frame buffer of the display. Buffer level one is the first overlay frame buffer, level two the second overlay frame buffer, and so on. Negative buffer levels correspond to underlay frame buffers. The default value is 0. GLX_DOUBLEBUFFER Must be followed by True or False. If True is specified then only double-buffered frame buffer configurations are considered; if False is specified then only single-buffered frame buffer configurations are considered. The default value is "don't care". GLX_STEREO Must be followed by True or False. If True is specified then only stereo frame buffer configurations are considered; if False is specified then only monoscopic frame buffer configurations are considered. The default value is False. GLX_AUX_BUFFERS Must be followed by a nonnegative integer that indicates the desired number of auxiliary buffers. Configurations with the smallest number of auxiliary buffers that meet or exceed the specified number are preferred. The default value is 0. GLX_RED_SIZE Must be followed by a nonnegative minimum size specification. If this value is zero, the smallest available red buffer is preferred. Otherwise, the largest available red buffer of at least the minimum size is preferred. The default value is 0. GLX_GREEN_SIZE Must be followed by a nonnegative minimum size specification. If this value is zero, the smallest available green buffer is preferred. Otherwise, the largest available green buffer of at least the minimum size is preferred. The default value is 0. GLX_BLUE_SIZE Must be followed by a nonnegative minimum size specification. If this value is zero, the smallest available blue buffer is preferred. Otherwise, the largest available blue buffer of at least the minimum size is preferred. The default value is 0. GLX_ALPHA_SIZE Must be followed by a nonnegative minimum size specification. If this value is zero, the smallest available alpha buffer is preferred. Otherwise, the largest available alpha buffer of at least the minimum size is preferred. The default value is 0. GLX_DEPTH_SIZE Must be followed by a nonnegative minimum size specification. If this value is zero, frame buffer configurations with no depth buffer are preferred. Otherwise, the largest available depth buffer of at least the minimum size is preferred. The default value is 0. GLX_STENCIL_SIZE Must be followed by a nonnegative integer that indicates the desired number of stencil bitplanes. The smallest stencil buffer of at least the specified size is preferred. If the desired value is zero, frame buffer configurations with no stencil buffer are preferred. The default value is 0. GLX_ACCUM_RED_SIZE Must be followed by a nonnegative minimum size specification. If this value is zero, frame buffer configurations with no red accumulation buffer are preferred. Otherwise, the largest possible red accumulation buffer of at least the minimum size is preferred. The default value is 0. GLX_ACCUM_GREEN_SIZE Must be followed by a nonnegative minimum size specification. If this value is zero, frame buffer configurations with no green accumulation buffer are preferred. Otherwise, the largest possible green accumulation buffer of at least the minimum size is preferred. The default value is 0. GLX_ACCUM_BLUE_SIZE Must be followed by a nonnegative minimum size specification. If this value is zero, frame buffer configurations with no blue accumulation buffer are preferred. Otherwise, the largest possible blue accumulation buffer of at least the minimum size is preferred. The default value is 0. GLX_ACCUM_ALPHA_SIZE Must be followed by a nonnegative minimum size specification. If this value is zero, frame buffer configurations with no alpha accumulation buffer are preferred. Otherwise, the largest possible alpha accumulation buffer of at least the minimum size is preferred. The default value is 0. GLX_SAMPLE_BUFFERS_SGIS Must be followed by the minimum acceptable number of multisample buffers. Configurations with the smallest number of multisample buffers that meet or exceed this minimum number are preferred. Currently operation with more than one multisample buffer is undefined, so only values of zero or one will produce a match. The default value is 0. GLX_SAMPLES_SGIS Must be followed by the minimum number of samples required in multisample buffers. Configurations with the smallest number of samples that meet or exceed the specified minimum number are preferred. Note that it is possible for color samples in the multisample buffer to have fewer bits than colors in the main color buffers. However, multisampled colors maintain at least as much color resolution in aggregate as the main color buffers. The default value is 0. GLX_TRANSPARENT_TYPE_EXT Must be followed by one of GLX_NONE_EXT, GLX_TRANSPARENT_RGB_EXT, GLX_TRANSPARENT_INDEX_EXT. If GLX_NONE_EXT is specified, then only opaque frame buffer configurations will be considered; if GLX_TRANSPARENT_RGB_EXT is specified, then only transparent frame buffer configurations that support RGBA rendering will be considered; if GLX_TRANSPARENT_INDEX_EXT is specified, then only transparent frame buffer configurations that support color index rendering will be considered. The default value is GLX_NONE_EXT. GLX_TRANSPARENT_INDEX_VALUE_EXT Must be followed by an integer value indicating the transparent index value; the value must be between 0 and the maximum framebuffer value for indices. Only frame buffer configurations that use the specified transparent index value will be considered. The default value is "don't care". This attribute is ignored unless GLX_TRANSPARENT_TYPE_EXT is included in attrib_list and specified as GLX_TRANSPARENT_INDEX_EXT. GLX_TRANSPARENT_RED_VALUE_EXT Must be followed by an integer value indicating the transparent red value; the value must be between 0 and the maximum framebuffer value for red. Only frame buffer configurations that use the specified transparent red value will be considered. The default value is "don't care". This attribute is ignored unless GLX_TRANSPARENT_TYPE_EXT is included in attrib_list and specified as GLX_TRANSPARENT_RGB_EXT. GLX_TRANSPARENT_GREEN_VALUE_EXT Must be followed by an integer value indicating the transparent green value; the value must be between 0 and the maximum framebuffer value for green. Only frame buffer configurations that use the specified transparent green value will be considered. The default value is "don't care". This attribute is ignored unless GLX_TRANSPARENT_TYPE_EXT is included in attrib_list and specified as GLX_TRANSPARENT_RGB_EXT. GLX_TRANSPARENT_BLUE_VALUE_EXT Must be followed by an integer value indicating the transparent blue value; the value must be between 0 and the maximum framebuffer value for blue. Only frame buffer configurations that use the specified transparent blue value will be considered. The default value is "don't care". This attribute is ignored unless GLX_TRANSPARENT_TYPE_EXT is included in attrib_list and specified as GLX_TRANSPARENT_RGB_EXT. GLX_TRANSPARENT_ALPHA_VALUE_EXT Must be followed by an integer value. This attribute is always ignored; it is for future use only. GLX_VISUAL_CAVEAT_EXT Must be followed by one of GLX_NONE_EXT, GLX_SLOW_VISUAL_EXT, GLX_NON_CONFORMANT_EXT. If GLX_NONE_EXT is specified, then only frame buffer configurations with no caveats will be considered; if GLX_SLOW_VISUAL_EXT, is specified then only slow frame buffer configurations will be considered; if GLX_NON_CONFORMANT_EXT is specified then only non-conformant frame buffer configurations will be considered. The default value is "don't care". GLX_DRAWABLE_TYPE_SGIX Must be followed by a mask indicating which GLX drawable types the frame buffer configuration must support. Valid bits are GLX_WINDOW_BIT_SGIX, GLX_PIXMAP_BIT_SGIX and GLX_PBUFFER_BIT_SGIX. For example, if mask is set to GLX_WINDOW_BIT_SGIX | GLX_PIXMAP_BIT_SGIX, only frame buffer configurations that support both windows and GLX pixmaps will be considered. The default value is GLX_WINDOW_BIT_SGIX. GLX_RENDER_TYPE_SGIX Must be followed by a mask indicating which OpenGL rendering modes the frame buffer configuration must support. Valid bits are GLX_RGBA_BIT_SGIX and GLX_COLOR_INDEX_BIT_SGIX. If the mask is set to GLX_RGBA_BIT_SGIX | GLX_COLOR_INDEX_BIT_SGIX then only frame buffer configurations that can be bound to both RGBA contexts and color index contexts will be considered. The default value is GLX_RGBA_BIT_SGIX. GLX_X_VISUAL_TYPE_EXT Must be followed by one of GLX_TRUE_COLOR_EXT, GLX_DIRECT_COLOR_EXT, GLX_PSEUDO_COLOR_EXT, GLX_STATIC_COLOR_EXT, GLX_GRAY_SCALE_EXT, GLX_STATIC_GRAY_EXT, indicating the desired X visual type. Not all frame buffer configurations have an associated X visual. If GLX_DRAWABLE_TYPE_SGIX is specified in attrib_list and the mask that follows does not have GLX_WINDOW_BIT_SGIX set, then this value is ignored. It is also ignored if GLX_X_RENDERABLE_SGIX is specified as False. RGBA rendering may be supported for visuals of type GLX_TRUE_COLOR_EXT, GLX_DIRECT_COLOR_EXT, GLX_PSEUDO_COLOR_EXT, or GLX_STATIC_COLOR_EXT, but color index rendering is only supported for visuals of type GLX_PSEUDO_COLOR_EXT or GLX_STATIC_COLOR_EXT (i.e., single-channel visuals). The tokens GLX_GRAY_SCALE_EXT and GLX_STATIC_GRAY_EXT will not match current OpenGL enabled visuals, but are included for future use. The default value for GLX_X_VISUAL_TYPE_EXT is "don't care". GLX_X_RENDERABLE_SGIX Must be followed by True or False. If True is specified, then only frame buffer configurations that have associated X visuals (and can be used to render to Windows and/or GLX pixmaps) will be considered. The default value is "don't care". GLX_FBCONFIG_ID_SGIX Must be followed by an XID for a GLXFBConfig. When GLX_FBCONFIG_ID_SGIX is specified in attrib_list, all other attributes are ignored, and only the frame buffer configuration with the given XID is returned. NULL is returned if the frame buffer configuration does not exist. The default value for GLX_FBCONFIG_ID_SGIX is "don't care". When more than one GLX frame buffer configuration matches the specified attributes, a list of matching configurations is returned. The list is sorted according to the following precedence rules that are applied in ascending order (i.e., configurations that are considered equal by lower numbered rule are sorted by the higher numbered rule): 1. by GLX_VISUAL_RATING_EXT where the precedence is GLX_NONE_EXT, GLX_NON_CONFORMANT, GLX_SLOW_VISUAL. 2. larger total number of RGBA color components (GLX_RED_BITS, GLX_GREEN_BITS, GLX_BLUE_BITS, and GLX_ALPHA_BITS) that have higher number of bits, 3. smaller GLX_INDEX_BITS, 4. single buffered configuration (GLX_DOUBLE_BUFFER being False) precedes a double buffered one, 5. smaller GLX_AUX_BUFFERS, 6. smaller GLX_SAMPLE_BUFFERS_SGIS, 7. smaller GLX_SAMPLES_SGIS, 8. larger GLX_DEPTH_BITS, 9. smaller GLX_STENCIL_BITS, 10. larger total number of accumulation buffer color components (GLX_ACCUM_RED_BITS, GLX_ACCUM_GREEN_BITS, GLX_ACCUM_BLUE_BITS, and GLX_ACCUM_ALPHA_BITS) that have higher number of bits; 11. sort by GLX_VISUAL_TYPE_EXT where the precedence order is GLX_TRUE_COLOR_EXT, GLX_DIRECT_COLOR_EXT, GLX_PSEUDO_COLOR_EXT, GLX_STATIC_COLOR_EXT, GLX_GRAY_SCALE_EXT, GLX_STATIC_GRAY_EXT, EXAMPLES attrib_list = {GLX_RENDER_TYPE_SGIX, GLX_RGBA_BIT_SGIX, GLX_RED_SIZE, 4, GLX_GREEN_SIZE, 4, GLX_BLUE_SIZE, 4, None}; Specifies a frame buffer configuration that supports RGBA rendering and exists in the normal frame buffer, not an overlay or underlay buffer. The returned visual supports at least four bits each of red, green, and blue, and possibly no bits of alpha. It does not support stereo display. It may or may not have one or more auxiliary color buffers, a back buffer, a depth buffer, a stencil buffer, or an accumulation buffer. NOTES glXChooseFBConfigSGIX is part of the GLX_SGIX_fbconfig extension. glXChooseFBConfigSGIX is implemented as a client-side utility; it does not require a round-trip to the X server. glXChooseFBConfigSGIX and glXGetFBConfigAttribSGIX can be used to implement selection algorithms other than the generic one implemented by glXChooseFBConfigSGIX. Call glXChooseFBConfigSGIX to retrieve all the frame buffer configurations on a particular screen or, alternatively, all the frame buffer configurations with a particular set of attributes. Next call glXGetFBConfigAttribSGIX to retrieve additional attributes for the frame buffer configurations and then select between them. GLX implementers are strongly discouraged, but not proscribed, from changing the selection algorithm used by glXChooseFBConfigSGIX. Therefore, selections may change from release to release of the client- side library. GLX_SAMPLE_BUFFERS_SGIS and GLX_SAMPLES_SGIS are not valid attributes unless the SGIS_multisample extension is supported. GLX_X_VISUAL_TYPE_EXT, GLX_TRANSPARENT_TYPE_EXT, GLX_TRANSPARENT_INDEX_VALUE_EXT, GLX_TRANSPARENT_RED_VALUE_EXT, GLX_TRANSPARENT_GREEN_VALUE_EXT, GLX_TRANSPARENT_BLUE_VALUE_EXT, and GLX_TRANSPARENT_ALPHA_VALUE_EXT are not valid attributes unless the EXT_visual_info extension is supported. GLX_VISUAL_CAVEAT_EXT is not a valid attribute unless the EXT_visual_rating extension is supported. ERRORS NULL is returned if an undefined GLX attribute is encountered in attrib_list, if screen is invalid or if dpy does not support the GLX extension. MACHINE DEPENDENCIES The SGIS_multisample extension is supported only on RealityEngine, RealityEngine2, and VTX systems and InfiniteReality systems. SEE ALSO glXGetFBConfigAttribSGIX, glXCreateContextWithConfigSGIX, glXCreateGLXPixmapWithConfigSGIX, glXGetVisualFromFBConfigSGIX.