gallium: beginnings of draw module vertex rework

Trying to put a structure in place that we can actually optimize.
Initially just implementing a passthrough mode, this will fairly soon
replace all the vertex_cache/prim_queue/shader_queue stuff that's so
hard to understand...

Split the vertex processing into a couple of distinct stages:
- Frontend
    - Prepares two lists of elements (fetch and draw) to be processed
      by the next stage.  This stage doesn't fetch or draw vertices, but
      makes the decision which to draw.  Multiple implementations of this
      will implement different strategies, currently just a vcache
      implementation.
- MiddleEnd
    - Takes the list of fetch elements, fetches them, runs the vertex
      shader, cliptest, viewport transform on them to produce a
      linear array of vertex_header vertices.
    - Passes that list of vertices, plus the draw_elements (which index
      into that list) onto the backend
- Backend
    - Either the existing primitive/clipping pipeline, or the vbuf_render
      hardware backend provided by the driver.

Currently, the middle-end is the old passthrough code, and it build hardware
vertices, not vertex_header vertices as above.  It may be that passthrough
is a special case in this respect.

1 files changed, 206 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/draw/draw_pt.c b/src/gallium/auxiliary/draw/draw_pt.c
new file mode 100644
index 0000000000..219b563422
--- /dev/null
+++ b/src/gallium/auxiliary/draw/draw_pt.c
@@ -0,0 +1,206 @@
+/**************************************************************************
+ * 
+ * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
+ * All Rights Reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ * 
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ * 
+ **************************************************************************/
+
+ /*
+  * Authors:
+  *   Keith Whitwell <keith@tungstengraphics.com>
+  */
+
+#include "pipe/p_util.h"
+#include "draw/draw_context.h"
+#include "draw/draw_private.h"
+#include "draw/draw_pt.h"
+
+
+static boolean too_many_verts( struct draw_context *draw,
+                               unsigned verts )
+{
+   return verts < 1024;
+}
+
+static boolean too_many_elts( struct draw_context *draw,
+                              unsigned elts )
+{
+   return elts < (16 * 1024);
+}
+
+
+boolean
+draw_pt_arrays(struct draw_context *draw, 
+               unsigned prim,
+               unsigned start, 
+               unsigned count)
+{
+   const boolean pipeline = draw_need_pipeline(draw);
+   const boolean cliptest = !draw->rasterizer->bypass_clipping;
+   const boolean shading  = !draw->rasterizer->bypass_vs;
+   struct draw_pt_front_end *frontend = NULL;
+   struct draw_pt_middle_end *middle = NULL;
+
+
+   /* Overall we do:
+    *     - frontend -- prepare fetch_elts, draw_elts - eg vcache
+    *     - middle   -- fetch, shade, cliptest, viewport
+    *     - pipeline -- the prim pipeline: clipping, wide lines, etc 
+    *     - backend  -- the vbuf_render provided by the driver.
+    */
+
+
+#if 0
+   if (!cliptest && !pipeline && !shading) {
+      /* This is the 'passthrough' path:
+       */
+      /* Fetch user verts, emit hw verts:
+       */
+      middle = draw->pt.middle.fetch_emit;
+   }
+   else if (!cliptest && !pipeline) {
+      /* Fetch user verts, run vertex shader, emit hw verts:
+       */
+      middle = draw->pt.middle.fetch_shade_emit;
+   }
+   else if (!pipeline) {
+      /* Even though !pipeline, we have to run it to get clipping.  We
+       * do know that the pipeline is just the clipping operation, but
+       * that probably doesn't help much.
+       *
+       * This is going to be the most important path for a lot of
+       * swtnl cards.
+       */
+      /* Fetch user verts, 
+       *    run vertex shader, 
+       *    cliptest and viewport trasform
+       *    if no clipped vertices,
+       *        emit hw verts
+       *    else
+       *        run pipline
+       */
+      middle = draw->pt.middle.fetch_shade_cliptest_pipeline_or_emit;
+   }
+   else if (!cliptest) {
+      /* Fetch user verts, run vertex shader, run pipeline:
+       */
+      middle = draw->pt.middle.fetch_shade_pipeline;
+   }
+   else {
+      /* This is what we're currently always doing:
+       */
+      /* Fetch user verts, run vertex shader, cliptest, run pipeline:
+       */
+      middle = draw->pt.middle.fetch_shade_cliptest_pipeline;
+   }
+#else
+   if (cliptest /*|| pipeline*/ || shading)
+      return FALSE;
+
+   middle = draw->pt.middle.fetch_emit;
+#endif
+
+
+   /* If !pipeline, need to make sure we respect the driver's limited
+    * capabilites to receive blocks of vertex data and elements.
+    */
+#if 0
+   if (!pipeline) {
+      unsigned vertex_mode = passthrough;
+      unsigned nr_verts = count_vertices( draw, start, count );
+      unsigned hw_prim = prim;
+
+      if (is_elts(draw)) {
+         frontend = draw->pt.front.vcache;
+         hw_prim = reduced_prim(prim);
+      }
+      
+      if (too_many_verts(nr_verts)) {
+         /* if (is_verts(draw) && can_split(prim)) {
+            draw = draw_arrays_split;
+         }
+         else */ {
+            frontend = draw->pt.front.vcache;
+            hw_prim = reduced_prim(prim);
+         }
+      }
+
+      if (too_many_elts(count)) {
+
+         /* if (is_elts(draw) && can_split(prim)) {
+            draw = draw_elts_split;
+         }
+         else */ {
+            frontend = draw->pt.front.vcache;
+            hw_prim = reduced_prim(prim);
+         }
+      }
+
+      if (!good_prim(hw_prim)) {
+         draw = draw->pt.front.vcache;
+      }
+   }
+#else
+   frontend = draw->pt.front.vcache;
+#endif   
+
+   frontend->prepare( frontend, middle );
+
+   frontend->run( frontend,
+                  prim,
+                  draw_pt_elt_func( draw ),
+                  draw_pt_elt_ptr( draw, start ),
+                  count );
+
+   frontend->finish( frontend );
+
+   return TRUE;
+}
+
+
+boolean draw_pt_init( struct draw_context *draw )
+{
+   draw->pt.middle.fetch_emit = draw_pt_fetch_emit( draw );
+   if (!draw->pt.middle.fetch_emit)
+      return FALSE;
+
+   draw->pt.front.vcache = draw_pt_vcache();
+   if (!draw->pt.front.vcache)
+      return FALSE;
+
+   return TRUE;
+}
+
+
+void draw_pt_destroy( struct draw_context *draw )
+{
+   if (draw->pt.middle.fetch_emit) {
+      draw->pt.middle.fetch_emit->destroy( draw->pt.middle.fetch_emit );
+      draw->pt.middle.fetch_emit = NULL;
+   }
+
+   if (draw->pt.front.vcache) {
+      draw->pt.front.vcache->destroy( draw->pt.front.vcache );
+      draw->pt.front.vcache = NULL;
+   }
+}