[Xcb] Any xcb glx working examples?

[Jeremy Kolb]

Adam Burton wrote:
> Hi,
> So far the only example I found is this,
> http://lists.freedesktop.org/archives/xcb/2007-July/002948.html
> which doesn't appear to work (although I see no reason why). If you look at 
> the source it attempts to get gl errors (commented out) which crashes the 
> XServer, I can confirm the same happens to me (in 1.0 and 1.1), in fact it 
> also happens when using xcb_glx_finish.
> Using the x.h and x.c of the above example I converted the following ibm glx 
> example to xcb and I run into the same problem (have attached my code).
> http://publib.boulder.ibm.com/infocenter/systems/index.jsp?topic=/com.ibm.aix.opengl/doc/openglrf/HowRenderXdraw.htm
> 
> I realise the glx guy is on vacation so I don't expect a speedy response but 
> any assistance is appreciated.
> 
> Regards,
> Adam
> 
> 
> ------------------------------------------------------------------------
> 
> #include "GL/gl.h"
> #include "x.h"
> 
> static int AttributeList[] = { GLX_RGBA, 0 };
> 
> xcb_glx_context_t glxcontext;
> xcb_colormap_t    xcolormap;
> xcb_window_t      xwindow;
> xcb_glx_window_t  glxwindow;
> xcb_glx_context_tag_t glxcontext_tag;
> int32_t screen_number;
> xcb_connection_t* xconnection;
> xcb_screen_t* xscreen;
> 
> void setup_glx13() {
> 	/* Find a FBConfig that uses RGBA.  Note that no attribute list is */
> 	/* needed since GLX_RGBA_BIT is a default attribute.*/
> 	    uint32_t glxattribs[] = {
>                                 GLX_DOUBLEBUFFER, 1,
>                                 GLX_RED_SIZE, 8,
>                                 GLX_GREEN_SIZE, 8,
>                                 GLX_BLUE_SIZE, 8,
>                                 GLX_ALPHA_SIZE, 8,
>                                 GLX_STENCIL_SIZE, 8,
>                                 GLX_DEPTH_SIZE, 24,
>                                 GLX_BUFFER_SIZE, 32,
>                                 GLX_RENDER_TYPE, GLX_RGBA_BIT,
>                                 GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT | GLX_PIXMAP_BIT | GLX_PBUFFER_BIT,
>                                 GLX_X_RENDERABLE, true
>                             };
> 
> 	xcb_glx_fbconfig_t fbconfig = glx_choose_fbconfig( xconnection, screen_number, glxattribs, sizeof(glxattribs)/2/sizeof(uint32_t));
> 	xcb_visualid_t glxvisual = get_attrib_from_fbconfig( xconnection, screen_number, fbconfig, GLX_VISUAL_ID );
> 
> 	/* Create a GLX context using the first FBConfig in the list. */
> 	xcb_glx_create_new_context( xconnection, glxcontext, fbconfig, screen_number, GLX_RGBA_TYPE, 0, true, 0, 0 );
> 
> 	/* Create a colormap */
> 	xcb_create_colormap( xconnection , XCB_COLORMAP_ALLOC_NONE, xcolormap, xscreen->root, glxvisual );
> 
> 	/* Create a window */
> 	uint32_t value_list[2], value_mask = XCB_CW_BACK_PIXEL | XCB_CW_COLORMAP ;
>     value_list[0] = xscreen->white_pixel;
>     value_list[1] = xcolormap;
> 
>     xcb_create_window( xconnection, xscreen->root_depth, xwindow, xscreen->root, 0, 0, 100, 100, 0,
>                                                             XCB_WINDOW_CLASS_INPUT_OUTPUT,
>                                                             glxvisual,
>                                                             value_mask,
>                                                             value_list );
>     xcb_map_window( xconnection, xwindow );
> 	/* Create a GLX window using the same FBConfig that we used for the */
> 	/* the GLX context.                                                 */
> 	xcb_glx_create_window( xconnection, screen_number, fbconfig, xwindow, glxwindow, 0, 0);
> 	/* Connect the context to the window for read and write */
>     xcb_glx_make_context_current_reply_t* reply_ctx = xcb_glx_make_context_current_reply ( xconnection, xcb_glx_make_context_current( xconnection, 0, glxwindow, glxwindow, glxcontext ), 0);
> 	glxcontext_tag = reply_ctx->context_tag;
> }
> 
> int main(int argc, char **argv) {
> 
>     xconnection = xcb_connect( NULL, &screen_number );
> 
>     // getting the default screen
>     xscreen = xcb_setup_roots_iterator( xcb_get_setup( xconnection )).data;
> 
> 	glxcontext = xcb_generate_id( xconnection );
> 	xcolormap  = xcb_generate_id( xconnection );
> 	xwindow    = xcb_generate_id( xconnection );
> 	glxwindow  = xcb_generate_id( xconnection );
> 
> 	setup_glx13();
> 	xcb_flush(xconnection);
> 	/* clear the buffer */
> 	glClearColor(1,1,0,1);
> 	glClear(GL_COLOR_BUFFER_BIT);
> 	glFlush();
> 
> 	//This kills xserver
> 	//xcb_glx_finish_reply_t* reply = xcb_glx_finish_reply(xconnection, xcb_glx_finish (xconnection, glxcontext_tag), 0);
> 
> 	xcb_glx_swap_buffers( xconnection, glxcontext_tag, glxwindow );
> 
> 	/* wait a while */
> 	sleep(10);
> }
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Xcb mailing list
> Xcb at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/xcb

My guess on the crash is that instead of doing xcb_glx_finish you
probably need to do glFinish as it probably does things that
xcb_glx_finish doesn't do.  Also what are you using for GL
(mesa/nvidia/fglrx)?  You'll have better luck if you stick to mesa
indirect rendering, probably compiled xcb support.

Jeremy