4 Before reporting, please skim through the known issues below.
6 Report any issues on [github](https://github.com/apitrace/apitrace/issues),
7 always including the following information:
9 * operating system name and version
11 * OpenGL/D3D driver name and version
17 These are issues that the developers are already aware of, but for which there
18 is no immediate plan to address them, because either:
20 * they stem from architectural limitations that are difficult to overcome
21 and/or time-consuming;
23 * they are corners cases that are thought to be of very little practical use;
25 * merely lack of time/opportunity.
27 That said, feel free to file an issue and/or send an email to the mailing list
30 * you want discuss the rationale, propose your ideas on how to address it, or
31 volunteer to work on it;
33 * a known issue is important for you and you would like to see it addressed
34 sooner rather than later.
40 * Fake calls may be emitted in the trace, in order to provide complete
41 information for retracing. The typical case is OpenGL vertex arrays in user
42 memory (as opposed to VBOs): where glXxxPointer calls will be deferred,
43 glInterleavedArrays will be decomposed, etc.
45 This should not affect the rendered output, but it may use different paths in
46 the OpenGL driver, exercising different paths and with different performance
49 There is no way to distinguish the fake calls from those actually
50 made by the application yet.
52 * Huge traces will be generated for applications that make extensive use of
53 immediate mode drawing (ie., glBegin/glEnd), use vertex/element arrays in
54 user memory, or generate a lot of dynamic vertex data per frame. This is
55 because large quantities of (often redundant) data will be recorded over and
56 over; and although the traces are compressed, the compression algorithms used
57 aim a good performance/compression balance, hence fail to identify and remove
58 the redundancy at this scale.
60 However, this should not be a problem for modern OpenGL applications that
61 make an efficient use of VBOs and vertex shaders.
63 * On MacOSX, the internal OpenGL calls done by GLU are not traced yet.
69 * Replaying can take substantially more CPU due to the overhead of reading the
72 However, the overhead should not be significant for modern 3D applications
73 that do efficient use of VBOs and vertex shaders. The communication between
74 CPU to GPU can easily be a bottleneck on the powerful discrete GPUs of
75 nowadays, and trace overhead tend to be propotional so it is not a
76 coincidence that applications that are optimized for modern GPUs will also be
77 traced and replayed efficiently.
79 * glretrace needs to infer window sizes from glViewport calls, because calls
80 that create/resize windows happen outside of OpenGL and are not traced.
81 Therefore window will be missing if the application relies on the default
82 viewport instead of explicitly invoking glViewport; or it will to too big if
83 the window is shrunk. Most apps call glViewport before rendering.
85 * OS specific OpenGL APIs (WGL, GLX, CGL, etc), are not retraced literally, but
86 instead partially emulated. This is by design, to allow traces to be
87 retraced on any OS, as the focus is on the OS-independent parts of OpenGL API.
89 * There is no guarantee that the same visual that was used on tracing will be
90 used for retracing OpenGL. Actually currently, glretrace will always choose
91 a standard 32bit RGBA, 24bit depth, 8bit alpha, double buffer visual. Unless
92 overridden on command line.
94 * OpenGL context sharing is not fully respected -- all contexts are assumed to
95 share state. This is by far the most common case though.
101 * Not all types of arguments can be edited.
105 Proprietary/confidential applications
106 =====================================
108 Issues should be preferably filed on github to facilitate collaborative
109 development and for future reference.
111 Access to applications source code is not required -- binaries are sufficient.
113 If the bug happens with a proprietary application, and you don't want to
114 publicly release the application and/or any data collected from it, then
115 alternatively you can provide the necessary application and/or data via e-mail,
116 to *jose dot r dot fonseca at gmail dot com*.
118 If it is not technically/legally feasible for you to provide application and/or
119 data at all, then you must be either:
121 * develop and provide a test application, stripped-down of all
122 proprietary/confidential data, but that can reproduce the issue;
124 * be willing/able to do the investigation of the issue, namely to identify the
125 root cause of the issue (e.g., which OpenGL call is not properly handled and
126 why), using all necessary tools (such as debuggers).
128 Failure to do so will render the apitrace authors powerless to address the
135 github issue tracker doesn't support attachments.
137 Please attach long logs to https://gist.github.com/ and paste the URL into the
140 For big attachments, such as traces, please upload them temporarily to a web
141 server you control, or use a file upload service such as http://dropbox.com/
142 and paste the URL into the issue description.
144 Trace files are only slightly compressed (for performance reasons). You can
145 further reduce their size when attaching/uploading by compressing with
146 [XZ](http://tukaani.org/xz/) or [7-Zip](http://www.7-zip.org/).
152 For bugs that happen while tracing (e.g., crashes while tracing the
153 application, or incorrect traces) please:
155 * provide information on how to obtain the application;
157 * describe how you were using it when the issue happened.
160 Bugs on retracing/GUI
161 =====================
163 For bugs on retracing (e.g. crashes when retracing the application,
164 incorrect inconsistent rendering, or viewing with the GUI) please:
166 * provide the trace file;
168 * describe the results you got, and what results you were expecting.
171 Obtaining stack back-traces
172 ===========================
178 Please rebuild apitrace with debugging information, by passing
179 `-DCMAKE_BUILD_TYPE=Debug` to cmake.
181 To obtain a stack back-trace, run the application with gdb from a terminal:
183 $ gdb --args application arg1 arg2 ...
189 See also more detailed and Distro specific instructions:
191 * http://wiki.debian.org/HowToGetABacktrace
193 * https://wiki.ubuntu.com/Backtrace
195 * http://fedoraproject.org/wiki/StackTraces
197 * http://live.gnome.org/GettingTraces
205 * https://developer.mozilla.org/en/how_to_get_a_stacktrace_with_windbg