2 Replies Latest reply: Jan 18, 2011 7:08 AM by Guest RSS

GMA 4500MHD - OpenGL - GL_EXT_packed_depth_stencil - Problems

nnexai Community Member
Currently Being Moderated

Since the new driver release my gma4500mhd now lists support for the ogl extension GL_EXT_packed_depth_stencil. After running a short test OpenGL reports unknown enum if i try to create a renderbuffer using the format GL_DEPTH24_STENCIL8_EXT. It would be nice if someone could explain this to me.

 

I'm trying to use a depth and a stencil buffer for a fbo since i bought this laptop without success.

If someone knows a way to setup a complete fbo with depth and stencil buffer please let me know.

 

If needed I'm going to write an example program for GL_EXT_packed_depth_stencil.

 

I'm running Windows7 Prof. with the current 8.15.10.2086 drivers

  • 1. Re: GMA 4500MHD - OpenGL - GL_EXT_packed_depth_stencil - Problems
    Currently Being Moderated

    Hello, nnexai.

     

    I was having probably the same problem with an application at my office today.

    I'm trying to run the app on a laptop with an intel Core i5 and GMA HD graphics, running Windows XP.

    Not sure about the graphics driver version because I'm currently writing this at home.

     

    Here's a snippet similar to the code I'm having trouble with:

     

        glGenTextures( 1, &tex );
        glBindTexture( GL_TEXTURE_2D, tex );
        glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, tex_w, tex_h, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0 );
        glGenRenderbuffersEXT( 1, &rb );
        glBindRenderbufferEXT( GL_RENDERBUFFER_EXT, rb );
        glRenderbufferStorageEXT( GL_RENDERBUFFER_EXT, GL_DEPTH24_STENCIL8_EXT, rb_w, rb_h );
        glGenFramebuffersEXT( 1, &fb );
        glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, fb );
        glFramebufferTexture2DEXT( GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, tex, 0 );
        glFramebufferRenderbufferEXT( GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, rb );
        glFramebufferRenderbufferEXT( GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, rb );

     

    This code works perfectly on other graphics boards I tested: a GeForce 7950 GT, a Quadro FX 4500, and a Radeon HD 4650.

     

    After wrestling with the code for half a day, I decided that I can find an alternative to the stencil attachment for the application.

    The GMA HD just didn't seem to want to work with the depth-and-stencil extension.

     

    I think there is a possibility that there's either a bug in the general GMA OpenGL driver's framebuffer module or,

    maybe intel's hardware just plain doesn't support it.

  • 2. Re: GMA 4500MHD - OpenGL - GL_EXT_packed_depth_stencil - Problems
    Currently Being Moderated

    For us passing in GL_DEPTH_STENCIL_EXT instead of GL_DEPTH24_STENCIL8_EXT in to glRenderbufferStorageEXT worked but it crashed freeing the buffer.

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