OpenGL Discussion and Help Forums - OpenGL on Linux

xdbeBackBuffer glxMakeCurrent GLXBadDrawable

JohnTheSoftware — Fri, 17 May 2013 12:27:49 GMT

Hi

I'm trying to double buffer an animated image being written to an X Window on RHEL 5.0 using xdbe and glDrawPixels

I'm getting a GLXBadDrawable error when I try to make the xdbe back buffer current using glxMakeCurrent. The error occurs in the glxMakeCurrentCall.

Using the back buffer for calls to XDrawString (for example) works fine and using the primary Window/Front buffer in glxMakeCurrent also works fine.

The actual back buffer drawable value is contiguous with the Window value and works with normal X calls so is clearly correct.

Can't find any reference to this on the web. Any ideas?

Thanks

John

glGenVertexArrays returns 0 without glError in worker-thread?

yousry — Thu, 16 May 2013 07:32:19 GMT

To change the scene-graph during runtime I'm using several working threads which disable the render-loop and update the gl-context (load/unload shaders / replace buffers etc.) e.g.

stop render-loop
get context
update
continue render-loop

If I try to generate a vao in a worker thread with:

glGenVertexArrays(1, &vaoId);

vaoId (the vertex array name) is 0 and glGenVertexArrays doesn't cast any error message.

I use a library for the gl-context processing but the code looks like this:

glXMakeCurrent(_glfw.x11.display, window->x11.handle, window->glx.context);

This behaviour isn't described in the SDK documatation about glGenVertexArrays.

I'm using a 3.2 core context (also tested with 4.3). My actual workaround would be to create a name-heap at startup and manage them by myself instead of using the gl-Is and gl-delete functions.

Sharing contexts with GLX for multithreaded app

Vylsain — Wed, 15 May 2013 08:59:18 GMT

Hello everyone.

I'm programming a flight simulator app and I have data for the whole world.
Then, there is a lot of textures and geometry to load so I made a background thread that dynamically load all that data depending on my position on Earth.
Since I'm using SOIL to load my textures, I need to create a 2nd context for that background thread that will share OpenGL data with the main thread's context.

I use GLX to manage my window and I didn't find any example of this. I just know which functions to use but I'm facing some problems.

Here's what I do:

- init XLib thread support
- create the foreground context
- create the background context with the foreground one as shareList
- make the foreground context current for the rendering thread
- create the loader thread passing a structure containing the Display, the Window and the background context
- in the loader thread, make the background context current

It crashes with a segfault on the last step, when I call glXMakeCurrent with the Display, the Window and the thread context...

I'm doing something wrong but I don't know what and can't find solutions on forums.
Do you have any idea ?

Thank you for your help !

Here's my full code :

main

Code :

Display *dpy;
Window win;
GLXContext foregroundCtx, backgroundCtx;
 
int32_t main(int32_t argc, char** argv) 
{       
    //init my own stuff (data paths, ini...)
    initVisualSystem(argc, argv);
 
    //create the window
    initXDisplay();
 
    glewInit();
    //init my openGL stuff and create background thread
    init(dpy, &backgroundCtx, &win, argc, argv);
 
    event_loop(dpy, win);
 
    cleanVisualSystem();
 
    //XClean
    glXDestroyContext(dpy, foregroundCtx);
    glXDestroyContext(dpy, backgroundCtx);
    XDestroyWindow(dpy, win);
    XCloseDisplay(dpy);
 
    return 0;
}

initXDisplay

Code :

void initXDisplay()
{
    XInitThreads();
 
    dpy = XOpenDisplay(NULL);
    if (!dpy) 
    {
        cerr << "Error: couldn't open display" << endl;
        exit(1);
    }
 
    uint32_t width = renderer.getView()->getWidth();
    uint32_t height = renderer.getView()->getHeight();
 
    make_window(dpy, "XN3", 0, 0, width, height, &win, &foregroundCtx, &backgroundCtx);
 
    XMapWindow(dpy, win);
    [b]glXMakeCurrent(dpy, win, foregroundCtx);[/b]
 
    if (FULLSCREEN) 
    {
        makeFullscreen(dpy, win);
    }
    hideCursor(dpy, win);
}
 
 
static void make_window( Display *dpy, const char *name,
             int x, int y, int width, int height,
             Window *winRet, GLXContext *foregroundCtxRet, GLXContext *backgroundCtxRet)
{
    if(VSYNC)
        putenv( (char *) "__GL_SYNC_TO_VBLANK=1" );
    else
        putenv( (char *) "__GL_SYNC_TO_VBLANK=0" );
 
    int attrib[] = { GLX_RGBA,
                     GLX_RED_SIZE, 1,
                     GLX_GREEN_SIZE, 1,
                     GLX_BLUE_SIZE, 1,
                     GLX_DOUBLEBUFFER,
                     GLX_DEPTH_SIZE, 24,
                     GLX_SAMPLE_BUFFERS  , 1*MULTISAMPLING,      // <-- MSAA
                     GLX_SAMPLES         , 4*MULTISAMPLING,      // <-- MSAA
                     None };
    int scrnum;
    XSetWindowAttributes attr;
    unsigned long mask;
    Window root;
    Window win;
    GLXContext foregroundCtx, backgroundCtx;
    XVisualInfo *visinfo;
 
    scrnum = DefaultScreen( dpy );
    root = RootWindow( dpy, scrnum );
 
    visinfo = glXChooseVisual( dpy, scrnum, attrib );
    if (!visinfo) {
       printf("Error: couldn't get an RGB, Double-buffered visual\n");
       exit(1);
    }
 
    /* window attributes */
    attr.background_pixel = 0;
    attr.border_pixel = 0;
    attr.colormap = XCreateColormap( dpy, root, visinfo->visual, AllocNone);
    attr.event_mask = StructureNotifyMask | ExposureMask | KeyPressMask | KeyReleaseMask | ButtonPress | PointerMotionMask;
    mask = CWBackPixel | CWBorderPixel | CWColormap | CWEventMask;
 
    win = XCreateWindow( dpy, root, 0, 0, width, height,
                         0, visinfo->depth, InputOutput,
                         visinfo->visual, mask, &attr );
 
    /* set hints and properties */
    {
       XSizeHints sizehints;
       sizehints.x = x;
       sizehints.y = y;
       sizehints.width  = width;
       sizehints.height = height;
       sizehints.flags = USSize | USPosition;
       XSetNormalHints(dpy, win, &sizehints);
       XSetStandardProperties(dpy, win, name, name,
                               None, (char **)NULL, 0, &sizehints);
    }
 
    foregroundCtx = glXCreateContext( dpy, visinfo, NULL, True );
    if (!foregroundCtx) {
       printf("Error: glXCreateContext for mainCtx failed\n");
       exit(1);
    }  
    backgroundCtx = glXCreateContext( dpy, visinfo, foregroundCtx, True );
    if (!backgroundCtx) {
       printf("Error: glXCreateContext for threadCtx failed\n");
       exit(1);
    }
 
    XFree(visinfo);
 
    *winRet = win;
    *foregroundCtxRet = foregroundCtx;
    *backgroundCtxRet = backgroundCtx;
}

init

Code :

void init(Display *dpy, GLXContext* backgroundCtx, Window* win, int32_t argc, char** argv)
{          
    //init my OpenGL stuff (shaders...)
    ...
 
    SLoaderThread sLoaderThread;
    sLoaderThread.pBV3DManager = renderer.getBV3DManager();
    sLoaderThread.dpy = dpy;
    sLoaderThread.backgroundCtx = backgroundCtx;
    sLoaderThread.win = win;
    pthread_create(&loaderThread, NULL, startLoaderThread, (void*)&sLoaderThread);
}
 
struct SLoaderThread
{
    CBV3DManager* pBV3DManager;    //manages my world geometries and textures
    Display *dpy;
    GLXContext* backgroundCtx;
    Window* win;
};
 
 
void* startLoaderThread(void* data)
{
    SLoaderThread* pSLoaderThread = (SLoaderThread*)data;
 
    glXMakeCurrent(pSLoaderThread->dpy, *pSLoaderThread->win, *pSLoaderThread->backgroundCtx);    //Crashes here with a segfault
    while(1)
    {
        pSLoaderThread->pBV3DManager->updateZones();
    }
    return NULL;
}

RGBA filling in texture is not working using gles

anilec — Fri, 10 May 2013 06:40:17 GMT

I am writing a code using gles. I created a texture and tried to fill that using different colours, But when i swapped the buffer only one color is visible at whole screen.

I am turning off the filtering using glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_MAG_FILTER, GL_NEAREST) and glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_MIN_FILTER, GL_NEAREST).

My texture width and height is 1920*1024.
and i want to draw the complete texture as it is on my Device screen.

Any help would be appreciated.

GLSL version confusion

wimmla — Wed, 08 May 2013 08:58:58 GMT

Hi,
Ubuntu 13.4 64bits
Intel Mobile GM965/GL960 Integrated Graphics Controller
My glxinfo gives:
OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) 965GM
OpenGL version string: 2.1 Mesa 9.1.1
OpenGL shading language version string: 1.20

When opening a WebGL page in FireFox as well as Chromium with "#version 110" (or anything higher than 100), I get an error:
"Error compiling shaderERROR: 0:1: '110' : version number not supported"
How is this possible?
The GLSL version is 1.20.
Thanks.

FBO missing attachment issue

DmitryM — Tue, 30 Apr 2013 02:59:51 GMT

Hello folks,

I'm getting a weird GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT status on an FBO that contains only a depth attachment. This didn't happen on my OSX station, so I suspect Linux drivers to be at fault. Here is what apitrace thinks is going on.
Texture & FBO creation:

Code :

529 glBindTexture(target = GL_TEXTURE_2D, texture = 37)
530 glTexImage2D(target = GL_TEXTURE_2D, level = 0, internalformat = GL_DEPTH_COMPONENT, width = 512, height = 512, border = 0, format = GL_DEPTH_COMPONENT, type = GL_UNSIGNED_BYTE, pixels = NULL)
531 glGenFramebuffers(n = 1, framebuffers = &4)

Framebuffer binding:

Code :

1134 glBindFramebuffer(target = GL_DRAW_FRAMEBUFFER, framebuffer = 4)
1135 glFramebufferTexture(target = GL_DRAW_FRAMEBUFFER, attachment = GL_DEPTH_ATTACHMENT, texture = 37, level = 0)
1136 glDrawBuffer(mode = GL_ZERO)
1137 glCheckFramebufferStatus(target = GL_DRAW_FRAMEBUFFER) = GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT

The description for this FBO status is "No images are attached to the framebuffer". In my case, there is clearly an image (depth texture) attached to it, so the status is at least misleading.

System Info:
Linux mezon 3.8.10-1-ARCH #1 SMP PREEMPT Sat Apr 27 12:36:59 CEST 2013 x86_64 GNU/Linux
OpenGL vendor string: X.Org
OpenGL renderer string: Gallium 0.4 on AMD RV730
OpenGL core profile version string: 3.1 (Core Profile) Mesa 9.1.1

serial reading

tharageorge — Tue, 23 Apr 2013 15:08:39 GMT

is it possible to import data serially into glvertex3f function
i mean inside like glvertext3f(call values )
please help me

Connect Rdp via ubuntu 12.04 to Windows Server 2012 - OpenGL not workin`

Jonfr3 — Tue, 23 Apr 2013 09:42:53 GMT

Hi! i have this problem. I'm connected with remmina remote desktop from ubuntu to a Server who had Windows Server 2012 software..
I work with photoshop and i want to work 3d but Open GL doesn't appear. What I have to do? Please Help. Thank you in advance.

Jon.

glCopyPixels doesn't work on Ubuntu 10.04

hzl2928963 — Mon, 22 Apr 2013 06:46:01 GMT

I use glCopyPixels to implement that a image (filled in a window) shift from left to right, but it doesn't work and generate a error number, the error number doesn't match any error number define in the documentation of glCopyPixels.Does anyone know what is the problem?
PS:The Video card I use is ATI Radeon HD 5670 and the driver support GL 4.2