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1XXX - Not complete yet!!!
2
3Name
4
5    SGIX_async_histogram
6
7Name Strings
8
9    GL_SGIX_async_histogram
10
11Version
12
13    $Date: 1998/02/11 23:24:25 $ $Revision: 1.3 $
14
15Number
16
17    134
18
19Dependencies
20
21    SGIX_async is required.
22    EXT_histogram is required.
23
24Overview
25
26    This extension introduces a new asynchronous mode for histogram
27    and minmax readbacks.  It allows programs to get the contents of a
28    histogram or minmax table without blocking and to continue issuing
29    graphics commands during the readback.
30
31New Procedures and Functions
32
33    None
34
35New Tokens
36
37    Accepted by the <cap> parameter of Enable, Disable and IsEnabled,
38    and by the <pname> parameter of GetBooleanv, GetIntegerv, GetFloatv,
39    and GetDoublev:
40
41        ASYNC_HISTOGRAM_SGIX		0x832C
42
43    Accepted by the <pname> parameter of GetBooleanv, GetIntegerv,
44    GetFloatv, and GetDoublev:
45
46        MAX_ASYNC_HISTOGRAM_SGIX        0x832D
47
48Additions to Chapter 2 of the 1.1 Specification (OpenGL Operation)
49
50    None
51
52Additions to Chapter 3 of the 1.1 Specification (Rasterization)
53
54    Add the following to the end of the specification of histogram and
55    minmax operators in section 3.6.4 ("Pixel Transfer Operations"):
56
57    Calling Enable with the <cap> parameter set to
58    ASYNC_HISTOGRAM_SGIX causes subsequent GetHistogramEXT and
59    GetMinmaxEXT commands to be asynchronous (similar to the
60    asynchronous DrawPixels command described earlier).  An
61    implementation of these asynchronous commands may be non-blocking:
62    It may return control to the program immediately rather than
63    waiting for an asynchronous query command's results to be written
64    into host memory.  Asynchronous histogram and minmax readback
65    commands sample the OpenGL state vector at the time they are
66    issued, but they may be executed at some undefined point in the
67    future.  In particular, if subsequent commands change the contents
68    of the histogram or minmax table then the result of the query is
69    undefined.
70
71    Calling Disable with the <cap> parameter set to
72    ASYNC_HISTOGRAM_SGIX restores the default synchronous behavior.
73
74Additions to Chapter 4 of the 1.1 Specification (Fragments and the
75Frame Buffer)
76
77    None
78
79Additions to Chapter 5 of the 1.1 Specification (Special Functions)
80
81    None
82
83Additions to Chapter 6 of the 1.1 Specification (State and State Requests)
84
85    None
86
87Additions to the GLX Specification
88
89    None
90
91GLX Protocol
92
93    None
94
95Dependencies on SGIX_async
96
97    This document adds a new category of asynchronous commands to
98    the framework defined by SGIX_async.
99
100Dependencies on EXT_histogram
101
102    This document changes the semantics of the query commands defined
103    by EXT_histogram.
104
105Errors
106
107    INVALID_OPERATION is generated if GetHistogramEXT or GetMinmaxEXT
108    is called and ASYNC_HISTOGRAM_SGIX is enabled and the number of
109    asynchronous histogram or minmax readback commands that have been
110    issued but not queried (using FinishAsyncSGIX or PollAsyncSGIX)
111    exceeds MAX_ASYNC_HISTOGRAM_SGIX.
112
113New State
114
115    Get Value			Get Command	Type	Value	Attrib
116    ---------			-----------	----	-------	------
117    ASYNC_HISTOGRAM_SGIX        IsEnabled       B       False   enable
118
119New Implementation Dependent State
120
121								Minimum
122    Get Value			Get Command	Type		Value
123    ---------			-----------	----		-------
124    MAX_ASYNC_HISTOGRAM_SGIX    GetIntegerv     Z+              1
125