Results 1 to 6 of 6

Thread: Exception caught: Pixel Buffers Objects are not supported for OpenGL 1.3

  1. #1

    Default Exception caught: Pixel Buffers Objects are not supported for OpenGL 1.3

    Hi.

    If I remember correctly in "ClanLib-2.x" I could run the PixelBuffer example( Bloom too).

    Compile ok. But:
    Code:
    Exception caught: Pixel Buffers Objects are not supported for OpenGL 1.3
        at clan::System::capture_stack_trace(int, int, void**, unsigned int*) (/usr/lib/libclan30Core-3.0.so.1)
        at clan::Exception::Exception(std::string const&) (/usr/lib/libclan30Core-3.0.so.1)
        at clan::GL1GraphicContextProvider::alloc_pixel_buffer() (/usr/lib/libclan30GL-3.0.so.1)
        at clan::TransferTexture::TransferTexture(clan::GraphicContext&, clan::PixelBuffer const&, clan::PixelBufferDirection, clan::BufferUsage) (/usr/lib/libclan30Display-3.0.so.1)
        at  (/home/dani/pack/ClanLib/Examples/Display_Render/PixelBuffer/pixelbuffer)
        at  (/home/dani/pack/ClanLib/Examples/Display_Render/PixelBuffer/pixelbuffer)
        at main (/usr/lib/libclan30App-3.0.so.1)
        at __libc_start_main (/usr/lib/libc.so.6)
        at  (/home/dani/pack/ClanLib/Examples/Display_Render/PixelBuffer/pixelbuffer)
    Info glxinfo say:
    Code:
    server glx version string: 1.4
    server glx extensions:
        GLX_ARB_create_context,
    	...
    client glx vendor string: Mesa Project and SGI
    client glx version string: 1.4
    client glx extensions:
        GLX_ARB_create_context, GLX_ARB_create_context_profile, 
        GLX_ARB_create_context_robustness, GLX_ARB_fbconfig_float, 
        GLX_ARB_framebuffer_sRGB, GLX_ARB_get_proc_address, GLX_ARB_multisample, 
        ...
    GLX version: 1.4
    GLX extensions:
        GLX_ARB_create_context, GLX_ARB_create_context_profile, 
        GLX_ARB_get_proc_address, GLX_ARB_multisample, 
        ...
    OpenGL vendor string: Intel Open Source Technology Center
    OpenGL renderer string: Mesa DRI Intel(R) 965GM 
    OpenGL version string: 2.1 Mesa 9.2.4
    OpenGL shading language version string: 1.20
    Possible problem, debugging.
    Code:
    Breakpoint 1, clan::OpenGLWindowProvider::create_context_glx_1_3 (this=0x665ac0, desc=..., shared_context=0x0) at GLX/opengl_window_provider_glx.cpp:744
    744             if (is_glx_extension_supported("GLX_ARB_create_context"))
    (gdb) n
    746                     if (glx.glXGetProcAddressARB)
    (gdb) n
    747                             glXCreateContextAttribs = (ptr_glXCreateContextAttribs) glx.glXGetProcAddressARB((GLubyte*) "glXCreateContextAttribsARB");
    (gdb) n
    748                     if (glx.glXGetProcAddress)
    (gdb) n
    749                             glXCreateContextAttribs = (ptr_glXCreateContextAttribs) glx.glXGetProcAddress((GLubyte*) "glXCreateContextAttribsARB");
    (gdb) n
    753             if (glXCreateContextAttribs)
    (gdb) n
    760                     int (*oldHandler)(::Display*, XErrorEvent*) = XSetErrorHandler(&cl_ctxErrorHandler);
    .....
    Observe how the variable "glXCreateContextAttribs" is overwritten.
    I do not understand if they are 2 different problems or is the same.

    Regards.

  2. #2
    ClanLib Developer
    Join Date
    May 2007
    Posts
    1,824

    Default

    OpenGL version string: 2.1 Mesa 9.2.4
    ClanLib 2.x branch contained clanGL and clanGL1
    clanGL supported OpenGL 2.0 and above.
    clanGL1 supported OpenGL 1.3 and above.

    In ClanLib 3.x branch, there is only clanGL, that internally contains 2 modules
    GL3 supports OpenGL 3.0 and above
    GL1 supports OpenGL 1.3 and above.

    GL1 does not support shaders and OpenGL pixel buffer objects
    Although, from a technical point of view, they can, if the driver supports them.
    It just means that someone would have to implement it - copy GL3PixelBufferProvider to GL1PixelBufferProvider with "if (!glGenBuffers) throw("Not supported by this driver") everywhere

  3. #3

    Default

    Quote Originally Posted by rombust View Post
    ClanLib 2.x branch contained clanGL and clanGL1
    GL1 does not support shaders and OpenGL pixel buffer objects
    Although, from a technical point of view, they can, if the driver supports them.
    So that's my problem, my driver supports it.
    The good news is that there is another way to use extensions, which is not only to check versions

    Regards.

  4. #4
    ClanLib Developer
    Join Date
    Sep 2006
    Location
    Denmark
    Posts
    554

    Default

    ClanLib checks the OpenGL version rather than the extension string mainly for simplicity. Drivers from the OpenGL dark ages (1.5 to 2.1) tended to be so poorly coded that half of them would crash if you truly tried to use what they advertised anyway, so we drew a line in the sand at version 3.0. Anything older would only get basic legacy support.

    Personally I do not think it is worth it to start adding extensive support for this old hardware by this point. Unless you own a laptop, I can literally buy you a new better supported and faster card for less than what employers pay me to work one single hour. If it is a laptop, I can probably scavenge an old unused laptop from someone with a better card by now as well.

  5. #5
    ClanLib Developer
    Join Date
    May 2007
    Posts
    1,824

    Default

    Yeah, I agree

  6. #6

    Default

    It seems to touch a sensitive issue
    Thanks for the clarification anyway.

Similar Threads

  1. OpenGL don't support Pixel Buffer and Shader Objects
    By Gandhi in forum Official ClanLib SDK Forums
    Replies: 2
    Last Post: 07-21-2013, 09:57 PM
  2. New OpenGL Pixel Buffer Object Example
    By rombust in forum Official ClanLib SDK Forums
    Replies: 3
    Last Post: 06-25-2011, 01:35 PM
  3. Freeing memory after use of sound buffers ??
    By babyvegas in forum Official ClanLib SDK Forums
    Replies: 0
    Last Post: 08-21-2008, 08:25 PM
  4. How to know if it's GL supported
    By code for food in forum Official ClanLib SDK Forums
    Replies: 2
    Last Post: 10-05-2007, 05:42 PM
  5. Input Buffers
    By gmatt in forum Official ClanLib SDK Forums
    Replies: 7
    Last Post: 07-14-2007, 08:18 PM

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •