On 12/12/2011 05:37 PM, Jose Fonseca wrote: > ----- Original Message ----- >> On 12/12/2011 02:49 PM, Jose Fonseca wrote: >>> ----- Original Message ----- >>>> From: Marek Olšák <mar...@gmail.com> >>>> >>>> It's like DrawArrays, but the count is taken from a transform >>>> feedback >>>> object. >>>> >>>> This removes DrawTransformFeedback from dd_function_table and adds >>>> the same >>>> function to GLvertexformat (with the function parameters matching >>>> GL). >>>> >>>> The vbo_draw_func callback has a new parameter >>>> "struct gl_transform_feedback_object *tfb_vertcount". >>>> >>>> The rest of the code just validates states and forwards the >>>> transform >>>> feedback object into vbo_draw_func. >>> >>> I ventured reviewing this too, and I have a question: the >>> unfinished code in master had comments saying >>> >>> /* >>> * Get number of vertices in obj's feedback buffer. >>> * Call ctx->Exec.DrawArrays(mode, 0, count); >>> */ >>> >>> which seems simpler than passing the new tfb_vertcount parameter >>> everywhere, just for the sake of obtaining count, so what's the >>> rationale for doing this differently here? >>> >> >> The count is "contained" in the TFB object (through its association >> with >> a pipe_stream_output_target which tracks the amount of vertices >> written >> to it) and is not supposed to be read back by the CPU because that >> would >> mean waiting. >> >> The driver will let the GPU write the count into the command buffer, >> so >> it only needs to sync command processing with TFB. > > I see. Makes sense. > > I have no more objections against the series FWIW. >
Thank you very much for reviewing the changes. If no one comes along with objections/improvements Marek or I will push the series in a few days then. > It would be nice to fix softpipe/llvmpipe though, but IIUC they could not > possibly have worked with Mesa before, and I don't think anybody is relying > on that softpipe/llvmpipe functionality w/ other state trackers at this > point, so I suppose it could wait. > > Jose > _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
