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1XXXmdf - incomplete
2
3Name
4
5    SGIX_fbconfig_float
6
7Name Strings
8
9    GLX_SGIX_fbconfig_float
10
11Version
12
13    $Date: 1999/01/08 19:41:53 $ $Revision: 1.1 $
14
15Number
16
17    XXXmdf
18
19Dependencies
20
21    SGIX_fbconfig is required
22
23Overview
24
25    This extension enhances the fbconfig visual selection and description
26    capabilities by adding support for floating-point attributes. While
27    SGIX_fbconfig only provides for integral attributes, some visual
28    attributes are best described with floating point
29    numbers.  Applications which seek to choose visuals based on those
30    attributes may use the facilites described in this extension.
31
32Issues
33
34    * There is an implicit assumption that all attribute tokens can be
35      cast to double and back to int without losing information.  There
36      are currently no tokens with more than 16 significant bits so this
37      is almost certainly a safe assumption, however it should be noted
38      as a limitation.
39
40New Procedures and Functions
41
42    int glXGetFBConfigFltAttribSGIX(Display *dpy,
43			            GLXFBConfigSGIX config,
44			            int attribute,
45			            double *value);
46
47    GLXFBConfigSGIX *glXChooseFBConfigWithFltSGIX(
48		Display *dpy,
49		int screen,
50		const int *int_attrib_list,
51		const double *flt_attrib_list,
52		int *nelements);
53
54New Tokens
55
56    None
57
58Additions to the OpenGL 1.0 Specification
59
60    None
61
62Additions to the GLX Specification
63
64    [Added following the description of glXChooseFBConfigSGIX]
65
66    Use glXChooseFBConfigWithFltSGIX in place of
67    glXChooseFBConfigSGIX in order to select GLXFBConfigSGIXs based on
68    floating point attributes.
69
70        GLXFBConfigSGIX *glXChooseFBConfigWithFltSGIX(
71		Display *dpy,
72		int screen,
73		const int *attrib_list,
74		const double *flt_attrib_list,
75		int *nelements);
76
77    If <flt_attrib_list> is NULL then glXChooseFBConfigWithFltSGIX behaves
78    identically to glXChooseFBConfigSGIX; otherwise, the attributes
79    listed in <flt_attrib_list> are used in conjunction with
80    the attributes listed in <attrib_list> to select a
81    matching GLXFBConfigSGIX.
82
83    All attributes have an inherent data type, listed in Table 3, such as
84    integer, boolean, enumerated, bitmask, XID, or floating point.
85    Any of these attributes may appear in <attrib_list>, although
86    in the case of floating point attributes the cast to integer may lose
87    information. Only floating point attributes may appear in
88    <flt_attrib_list>.  Since the attribute tokens are integer constants,
89    they must be cast to double to appear in <flt_attrib_list>.  Any
90    attribute which appears in both lists will take on the value from
91    <flt_attrib_list>.
92
93    [Added following the description of glXGetFBConfigAttribSGIX]
94
95    To get the value of a floating point GLX attribute for a
96    GLXFBConfigSGIX use:
97
98        int glXGetFBConfigFltAttribSGIX(Display *dpy,
99			                GLXFBConfigSGIX config,
100			                int attribute,
101			                double *value);
102
103    glXGetFBConfigFltAttribSGIX has the same semantics as
104    glXGetFBConfigAttribSGIX, although it returns a double value
105    rather than an int value.  Non-floating-point attributes undergo
106    a cast to double before they are returned.
107
108
109GLX Protocol
110
111    None
112
113Errors
114
115    None
116
117New State
118
119    None
120
121New Implementation Dependent State
122
123    None
124