Hi, There are two primitive transformations in gallium draw module. In varray, primitives are "split"ted. When a primitive has more vertices than the middle end can handle, varray splits the primitive and calls the middle end multiple times.
In vcache, primitives are "decompose"d. More advanced primitives are decomposed into one of point, line(_adj), or triangle(_adj). Similarly, vcache may call the middle end multiple times to flush its internal buffer. In some cases, vcache passes the primitves through without decomposing nor splitting, as can be seen in vcache_check_run. The issue with vcache is that it has to decompose a primitive differently depending on the provoking convention, as explained in http://lists.freedesktop.org/archives/mesa-dev/2010-August/001797.html It becomes a problem when GS is active. My proposal is to make vcache split instead of decompose. Because varray only splits and vcache has a pass-through path, the rest of the workflow already has to support all primitive types. Switching from decompose to split does not require a big change to the rest of the workflow. But then vcache will look a lot like varray, only with indexed primitive support. It leads me to a new frontend that replaces both varray and vcache: vsplit http://cgit.freedesktop.org/~olv/mesa/log/?h=draw-vsplit vsplit is based on varray. It uses some code from vcache to support indexed primitives. When vcache decomposes, there are flags being set to indicate that if the stipple counter should be reset or if some edge of a triangle should be omitted in unfilled mode. The segments of a splitted primitive have flags for similar purposes too: DRAW_SPLIT_AFTER More segments to come after this one DRAW_SPLIT_BEFORE There are preceding segments These flags are set by vsplit and the middle ends pass them to the other stages. Therefore, the run methods of middle ends are augmented to take the flags. To summarize, vsplit - fixes GS when (flatshade && flatshade_first) is on - never sends more vertices than the middle end claims to handle - is faster than vcache: split instead of decompose, no get_elt calls - no longer uses the higher bits of draw_elts for stipple/edge flags Suggestions? -- o...@lunarg.com _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
