c++ - 在多个显示器上使用 GLX RHEL -- OpenGL、XLib 和多个显示器(带线程)

Question

我面临的问题是我有一个基于 glx 的应用程序，它可以在单个线程上很好地渲染基本图元。我可以在两个屏幕之间移动 XWindow，我的渲染循环继续进行。但是，如果我的应用程序的任何部分有线程，即使它没有进行任何 openGL 调用或在任何其他线程上接触 XWindow 但主线程，当我将 XWindow 从一个屏幕移动到另一个屏幕时，我渲染的图形就会丢失。

我进行的第一个函数调用是 XInitThreads，因此我知道 X11 应该是线程安全的。正如我所说，这在一个线程上绘制图元时有效，但当我添加 1 个或多个线程时它不起作用。这些线程位于我无权访问源代码的库中。我只是被要求使用 X11 创建代码的窗口部分。

我应该寻找什么来解决这个问题？

另请注意，我已经保证所有 glcalls 都发生在我从库内部调用它们的线程上。

---

更新

[matt6809@hogganz400 SampleApp]$ cat /etc/X11/xorg.conf && echo "--------" && xrandr --verbose && echo "-------" && glxinfo && echo "-------" && xdpyinfo
# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings:  version 295.20  (buildmeister@swio-display-x86-rhel47-05.nvidia.com)  Mon Feb  6 22:13:16 PST 2012

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 295.20  (buildmeister@swio-display-x86-rhel47-05.nvidia.com)  Mon Feb  6 22:13:40 PST 2012

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
    Screen      1  "Screen1" RightOf "Screen0"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "1"
EndSection

Section "Files"
    FontPath        "/usr/share/fonts/default/Type1"
EndSection

Section "InputDevice"

    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/input/mice"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"

    # generated from data in "/etc/sysconfig/keyboard"
    Identifier     "Keyboard0"
    Driver         "kbd"
    Option         "XkbLayout" "us"
    Option         "XkbModel" "pc105"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "DELL P190S"
    HorizSync       30.0 - 81.0
    VertRefresh     56.0 - 76.0
    Option         "DPMS"
    EndSection

    Section "Monitor"
        Identifier     "Monitor1"
        VendorName     "Unknown"
 ModelName      "DELL P190S"
    HorizSync       30.0 - 81.0
    VertRefresh     56.0 - 76.0
    Option         "DPMS"
EndSection

Section "Monitor"
    Identifier     "Monitor1"
    VendorName     "Unknown"
    ModelName      "DELL 1908FP"
    HorizSync       31.0 - 83.0
    VertRefresh     56.0 - 76.0
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "Quadro 4000"
    BusID          "PCI:15:0:0"
    Screen          0
EndSection

Section "Device"
    Identifier     "Device1"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "Quadro 4000"
    BusID          "PCI:15:0:0"
    Screen          1
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "TwinView" "0"
    Option         "TwinViewXineramaInfoOrder" "DFP-0"
    Option         "metamodes" "DFP-0: nvidia-auto-select +0+0"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Section "Screen"
    Identifier     "Screen1"
    Device         "Device1"
    Monitor        "Monitor1"
    DefaultDepth    24
    Option         "TwinView" "0"
    Option         "metamodes" "DFP-2: nvidia-auto-select +0+0"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

--------
Xlib:  extension "RANDR" missing on display ":0.0".
RandR extension missing
[matt6809@hogganz400 SampleApp]$ 

Answer 1

这只是一种预感，但也可能是 OpenGL 上下文没有在线程之间完全迁移。如果您可以完全控制 OpenGL 和窗口操作，您的问题并不清楚。

涉及 OpenGL 和多线程时，通常的方法是将所有 OpenGL 操作限制在一个特定的线程中。

如果你不能确定这一点，你应该打电话

glXMakeContextCurrent(display, None, None, NULL); // GLX 1.3

或

glXMakeCurrent(display, None, NULL); // GLX 1.2 and earlier

在屈服于另一个线程或完成 tasklet 之前完成 OpenGL 操作之后，以确保上下文与当前线程正确解除绑定(bind)。

在需要时相应地重新绑定(bind)上下文。