| XXXmdf - incomplete |
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| Name |
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| SGIX_fbconfig_float |
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| Name Strings |
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| GLX_SGIX_fbconfig_float |
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| Version |
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| $Date: 1999/01/08 19:41:53 $ $Revision: 1.1 $ |
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| Number |
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| XXXmdf |
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| Dependencies |
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| SGIX_fbconfig is required |
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| Overview |
| |
| This extension enhances the fbconfig visual selection and description |
| capabilities by adding support for floating-point attributes. While |
| SGIX_fbconfig only provides for integral attributes, some visual |
| attributes are best described with floating point |
| numbers. Applications which seek to choose visuals based on those |
| attributes may use the facilites described in this extension. |
| |
| Issues |
| |
| * There is an implicit assumption that all attribute tokens can be |
| cast to double and back to int without losing information. There |
| are currently no tokens with more than 16 significant bits so this |
| is almost certainly a safe assumption, however it should be noted |
| as a limitation. |
| |
| New Procedures and Functions |
| |
| int glXGetFBConfigFltAttribSGIX(Display *dpy, |
| GLXFBConfigSGIX config, |
| int attribute, |
| double *value); |
| |
| GLXFBConfigSGIX *glXChooseFBConfigWithFltSGIX( |
| Display *dpy, |
| int screen, |
| const int *int_attrib_list, |
| const double *flt_attrib_list, |
| int *nelements); |
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| New Tokens |
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| None |
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| Additions to the OpenGL 1.0 Specification |
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| None |
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| Additions to the GLX Specification |
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| [Added following the description of glXChooseFBConfigSGIX] |
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| Use glXChooseFBConfigWithFltSGIX in place of |
| glXChooseFBConfigSGIX in order to select GLXFBConfigSGIXs based on |
| floating point attributes. |
| |
| GLXFBConfigSGIX *glXChooseFBConfigWithFltSGIX( |
| Display *dpy, |
| int screen, |
| const int *attrib_list, |
| const double *flt_attrib_list, |
| int *nelements); |
| |
| If <flt_attrib_list> is NULL then glXChooseFBConfigWithFltSGIX behaves |
| identically to glXChooseFBConfigSGIX; otherwise, the attributes |
| listed in <flt_attrib_list> are used in conjunction with |
| the attributes listed in <attrib_list> to select a |
| matching GLXFBConfigSGIX. |
| |
| All attributes have an inherent data type, listed in Table 3, such as |
| integer, boolean, enumerated, bitmask, XID, or floating point. |
| Any of these attributes may appear in <attrib_list>, although |
| in the case of floating point attributes the cast to integer may lose |
| information. Only floating point attributes may appear in |
| <flt_attrib_list>. Since the attribute tokens are integer constants, |
| they must be cast to double to appear in <flt_attrib_list>. Any |
| attribute which appears in both lists will take on the value from |
| <flt_attrib_list>. |
| |
| [Added following the description of glXGetFBConfigAttribSGIX] |
| |
| To get the value of a floating point GLX attribute for a |
| GLXFBConfigSGIX use: |
| |
| int glXGetFBConfigFltAttribSGIX(Display *dpy, |
| GLXFBConfigSGIX config, |
| int attribute, |
| double *value); |
| |
| glXGetFBConfigFltAttribSGIX has the same semantics as |
| glXGetFBConfigAttribSGIX, although it returns a double value |
| rather than an int value. Non-floating-point attributes undergo |
| a cast to double before they are returned. |
| |
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| GLX Protocol |
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| None |
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| Errors |
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| None |
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| New State |
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| None |
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| New Implementation Dependent State |
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| None |