draw: add mesh pipeline middle end.

This sets up the mesh pipeline to call the post vs clipping
and so emit for stats (not for so).

Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23066>

src/gallium/auxiliary/draw/draw_context.h

@@ -366,6 +366,11 @@ void draw_vbo(struct draw_context *draw,
               unsigned num_draws,
               uint8_t patch_vertices);
 
+void
+draw_mesh(struct draw_context *draw,
+          struct draw_vertex_info *vert_info,
+          struct draw_prim_info *prim_info);
+
 
 /*******************************************************************************
  * Driver backend interface

src/gallium/auxiliary/draw/draw_private.h

@@ -177,6 +177,7 @@ struct draw_context
          struct draw_pt_middle_end *fetch_shade_emit;
          struct draw_pt_middle_end *general;
          struct draw_pt_middle_end *llvm;
+         struct draw_pt_middle_end *mesh;
       } middle;
 
       struct {

src/gallium/auxiliary/draw/draw_pt.c

@@ -206,8 +206,10 @@ draw_pt_init(struct draw_context *draw)
       return FALSE;
 
 #ifdef DRAW_LLVM_AVAILABLE
-   if (draw->llvm)
+   if (draw->llvm) {
       draw->pt.middle.llvm = draw_pt_fetch_pipeline_or_emit_llvm(draw);
+      draw->pt.middle.mesh = draw_pt_mesh_pipeline_or_emit(draw);
+   }
 #endif
 
    return TRUE;
@@ -217,6 +219,11 @@ draw_pt_init(struct draw_context *draw)
 void
 draw_pt_destroy(struct draw_context *draw)
 {
+   if (draw->pt.middle.mesh) {
+      draw->pt.middle.mesh->destroy(draw->pt.middle.mesh);
+      draw->pt.middle.mesh = NULL;
+   }
+
    if (draw->pt.middle.llvm) {
       draw->pt.middle.llvm->destroy(draw->pt.middle.llvm);
       draw->pt.middle.llvm = NULL;
@@ -625,3 +632,16 @@ draw_vbo(struct draw_context *draw,
    }
    util_fpstate_set(fpstate);
 }
+
+/* to be called after a mesh shader is run */
+void
+draw_mesh(struct draw_context *draw,
+          struct draw_vertex_info *vert_info,
+          struct draw_prim_info *prim_info)
+{
+   struct draw_pt_middle_end *middle = draw->pt.middle.mesh;
+
+   middle->prepare(middle, 0, 0, NULL);
+
+   draw_mesh_middle_end_run(middle, vert_info, prim_info);
+}

src/gallium/auxiliary/draw/draw_pt.h

@@ -151,7 +151,7 @@ struct draw_pt_front_end *draw_pt_vsplit(struct draw_context *draw);
 struct draw_pt_middle_end *draw_pt_middle_fse(struct draw_context *draw);
 struct draw_pt_middle_end *draw_pt_fetch_pipeline_or_emit(struct draw_context *draw);
 struct draw_pt_middle_end *draw_pt_fetch_pipeline_or_emit_llvm(struct draw_context *draw);
-
+struct draw_pt_middle_end *draw_pt_mesh_pipeline_or_emit(struct draw_context *draw);
 
 
 /*******************************************************************************
@@ -268,5 +268,8 @@ draw_pt_split_prim(enum mesa_prim prim, unsigned *first, unsigned *incr);
 unsigned
 draw_pt_trim_count(unsigned count, unsigned first, unsigned incr);
 
-
+void
+draw_mesh_middle_end_run(struct draw_pt_middle_end *middle,
+                         struct draw_vertex_info *vert_info,
+                         struct draw_prim_info *prim_info);
 #endif

src/gallium/auxiliary/draw/draw_pt_mesh_pipeline.c

@@ -0,0 +1,131 @@
+/**************************************************************************
+ *
+ * Copyright 2023 Red Hat.
+ * 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, sublicense,
+ * 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 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 NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS 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.
+ *
+ **************************************************************************/
+
+#include "draw/draw_context.h"
+#include "draw/draw_private.h"
+#include "draw/draw_pt.h"
+#include "draw/draw_mesh.h"
+
+/*
+ * Mesh shader middle end,
+ * This doesn't need a frontend as mesh shader frontend
+ * is done with compute shaders in llvmpipe.
+ */
+
+struct mesh_pipeline_middle_end {
+   struct draw_pt_middle_end base;
+   struct draw_context *draw;
+
+   struct pt_so_emit *so_emit;
+   struct pt_post_vs *post_vs;
+};
+
+/** cast wrapper */
+static inline struct mesh_pipeline_middle_end *
+mesh_pipeline_middle_end(struct draw_pt_middle_end *middle)
+{
+   return (struct mesh_pipeline_middle_end *) middle;
+}
+
+static void
+mesh_pipeline_destroy(struct draw_pt_middle_end *middle)
+{
+   struct mesh_pipeline_middle_end *mpme = mesh_pipeline_middle_end(middle);
+
+   if (mpme->so_emit)
+      draw_pt_so_emit_destroy(mpme->so_emit);
+   if (mpme->post_vs)
+      draw_pt_post_vs_destroy(mpme->post_vs);
+   FREE(middle);
+}
+
+static void
+mesh_middle_end_prepare(struct draw_pt_middle_end *middle,
+                        enum mesa_prim prim,
+                        unsigned opt,
+                        unsigned *max_vertices)
+{
+   struct mesh_pipeline_middle_end *mpme = mesh_pipeline_middle_end(middle);
+   struct draw_context *draw = mpme->draw;
+   enum mesa_prim out_prim = draw->ms.mesh_shader->output_primitive;
+   unsigned point_clip = draw->rasterizer->fill_front == PIPE_POLYGON_MODE_POINT ||
+                         out_prim == MESA_PRIM_POINTS;
+   draw_pt_post_vs_prepare(mpme->post_vs,
+                           draw->clip_xy,
+                           draw->clip_z,
+                           draw->clip_user,
+                           point_clip ? draw->guard_band_points_lines_xy :
+                                        draw->guard_band_xy,
+                           draw->bypass_viewport,
+                           draw->rasterizer->clip_halfz,
+                           FALSE);
+
+   draw_pt_so_emit_prepare(mpme->so_emit, false);
+
+   draw_do_flush(draw, DRAW_FLUSH_BACKEND);
+
+}
+
+void
+draw_mesh_middle_end_run(struct draw_pt_middle_end *middle,
+                         struct draw_vertex_info *vert_info,
+                         struct draw_prim_info *prim_info)
+{
+   struct mesh_pipeline_middle_end *mpme = mesh_pipeline_middle_end(middle);
+
+   draw_pt_post_vs_run(mpme->post_vs, vert_info, prim_info);
+
+   /* just for primgen query */
+   draw_pt_so_emit(mpme->so_emit, 1, vert_info, prim_info);
+   draw_pipeline_run_linear(mpme->draw, vert_info, prim_info);
+}
+
+struct draw_pt_middle_end *
+draw_pt_mesh_pipeline_or_emit(struct draw_context *draw)
+{
+   struct mesh_pipeline_middle_end *mpme =
+      CALLOC_STRUCT(mesh_pipeline_middle_end);
+   if (!mpme)
+      goto fail;
+
+   mpme->base.prepare = mesh_middle_end_prepare;
+   mpme->base.destroy = mesh_pipeline_destroy;
+   mpme->draw = draw;
+
+   mpme->post_vs = draw_pt_post_vs_create(draw);
+   if (!mpme->post_vs)
+      goto fail;
+
+   mpme->so_emit = draw_pt_so_emit_create(draw);
+   if (!mpme->so_emit)
+      goto fail;
+
+   return &mpme->base;
+ fail:
+   if (mpme)
+      mesh_pipeline_destroy(&mpme->base);
+
+   return NULL;
+}

src/gallium/auxiliary/meson.build

@@ -67,6 +67,7 @@ files_libgallium = files(
   'draw/draw_pt_fetch.c',
   'draw/draw_pt_fetch_shade_emit.c',
   'draw/draw_pt_fetch_shade_pipeline.c',
+  'draw/draw_pt_mesh_pipeline.c',
   'draw/draw_pt.h',
   'draw/draw_pt_post_vs.c',
   'draw/draw_pt_so_emit.c',