draw: add a mesh primitive assembler.

This is assembles prims from mesh vertex and per-primitive outputs.

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

src/gallium/auxiliary/draw/draw_mesh_prim.c

@@ -0,0 +1,230 @@
+/**************************************************************************
+ *
+ * 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.
+ *
+ **************************************************************************/
+
+/*
+ * Mesh primitive assembler
+ *
+ * This takes vertex and per-primitive data, and assembles a linear set
+ * of draw compatible vertices.
+ */
+#include "draw_mesh_prim.h"
+
+#include "draw/draw_context.h"
+#include "draw/draw_private.h"
+#include "util/u_debug.h"
+#include "util/u_memory.h"
+#include "util/u_prim.h"
+
+#include "pipe/p_defines.h"
+
+struct draw_mesh_prim
+{
+   struct draw_context *draw;
+
+   struct draw_prim_info *output_prims;
+   struct draw_vertex_info *output_verts;
+
+   const struct draw_prim_info *input_prims;
+   const struct draw_vertex_info *input_verts;
+
+   unsigned num_prims;
+   const char *per_prim;
+   uint32_t num_per_prim;
+   uint32_t added_prim_size;
+   int cull_prim_idx;
+};
+
+static void
+add_prim(struct draw_mesh_prim *asmblr, unsigned length)
+{
+   struct draw_prim_info *output_prims = asmblr->output_prims;
+
+   output_prims->primitive_lengths = realloc(output_prims->primitive_lengths, sizeof(unsigned) * (output_prims->primitive_count + 1));
+   output_prims->primitive_lengths[output_prims->primitive_count] = length;
+   output_prims->primitive_count++;
+}
+
+
+/*
+ * Copy the vertex header along with its data from the current
+ * vertex buffer into a buffer holding vertices arranged
+ * into decomposed primitives (i.e. buffer without the
+ * adjacency vertices)
+ */
+static void
+copy_verts(struct draw_mesh_prim *asmblr,
+           unsigned *indices, unsigned num_indices)
+{
+   char *output = (char*)asmblr->output_verts->verts;
+   const char *input = (const char*)asmblr->input_verts->verts;
+
+   for (unsigned i = 0; i < num_indices; ++i) {
+      unsigned idx = indices[i];
+      unsigned output_offset =
+         asmblr->output_verts->count * asmblr->output_verts->stride;
+      unsigned input_offset = asmblr->input_verts->stride * idx;
+      memcpy(output + output_offset, input + input_offset,
+             asmblr->input_verts->vertex_size);
+
+      memcpy(output + output_offset + asmblr->input_verts->vertex_size,
+             asmblr->per_prim + (asmblr->num_prims * asmblr->added_prim_size * 8),
+             asmblr->added_prim_size);
+      asmblr->output_verts->count += 1;
+   }
+   ++asmblr->num_prims;
+}
+
+static bool
+cull_prim(struct draw_mesh_prim *asmblr)
+{
+   if (asmblr->cull_prim_idx == -1)
+      return false;
+
+   const uint32_t *cull_prim_ptr = (uint32_t *)(asmblr->per_prim + (asmblr->num_prims * asmblr->added_prim_size * 8));
+   cull_prim_ptr += (asmblr->cull_prim_idx * 4);
+
+   return (*cull_prim_ptr) ? true : false;
+}
+
+
+static void
+prim_point(struct draw_mesh_prim *asmblr,
+           unsigned idx)
+{
+   unsigned indices[1];
+
+   indices[0] = idx;
+
+   if (cull_prim(asmblr)) {
+      ++asmblr->num_prims;
+      return;
+   }
+   add_prim(asmblr, 1);
+   copy_verts(asmblr, indices, 1);
+}
+
+
+static void
+prim_line(struct draw_mesh_prim *asmblr,
+          unsigned i0, unsigned i1)
+{
+   unsigned indices[2];
+
+   indices[0] = i0;
+   indices[1] = i1;
+
+   if (cull_prim(asmblr)) {
+      ++asmblr->num_prims;
+      return;
+   }
+   add_prim(asmblr, 2);
+   copy_verts(asmblr, indices, 2);
+}
+
+
+static void
+prim_tri(struct draw_mesh_prim *asmblr,
+         unsigned i0, unsigned i1, unsigned i2)
+{
+   unsigned indices[3];
+
+   indices[0] = i0;
+   indices[1] = i1;
+   indices[2] = i2;
+
+   if (cull_prim(asmblr)) {
+      ++asmblr->num_prims;
+      return;
+   }
+   add_prim(asmblr, 3);
+   copy_verts(asmblr, indices, 3);
+}
+
+
+#define FUNC assembler_run_linear
+#define GET_ELT(idx) (start + (idx))
+#include "draw_mesh_prim_tmp.h"
+
+#define FUNC assembler_run_elts
+#define LOCAL_VARS   const ushort *elts = input_prims->elts;
+#define GET_ELT(idx) (elts[start + (idx)])
+#include "draw_mesh_prim_tmp.h"
+
+
+void
+draw_mesh_prim_run(struct draw_context *draw,
+                   unsigned num_per_prim_inputs,
+                   void *per_prim_inputs,
+                   int cull_prim_idx,
+                   const struct draw_prim_info *input_prims,
+                   const struct draw_vertex_info *input_verts,
+                   struct draw_prim_info *output_prims,
+                   struct draw_vertex_info *output_verts)
+{
+   struct draw_mesh_prim asmblr_mesh;
+   struct draw_mesh_prim *asmblr = &asmblr_mesh;
+   unsigned start, i;
+   unsigned max_primitives = input_prims->primitive_count;
+   unsigned max_verts = u_vertices_per_prim(input_prims->prim) * max_primitives;
+
+   asmblr->output_prims = output_prims;
+   asmblr->output_verts = output_verts;
+   asmblr->input_prims = input_prims;
+   asmblr->input_verts = input_verts;
+   asmblr->num_prims = 0;
+   asmblr->num_per_prim = num_per_prim_inputs;
+   asmblr->per_prim = per_prim_inputs;
+   asmblr->cull_prim_idx = cull_prim_idx;
+
+   output_prims->linear = TRUE;
+   output_prims->elts = NULL;
+   output_prims->start = 0;
+   output_prims->prim = input_prims->prim;
+   output_prims->flags = 0x0;
+   output_prims->primitive_lengths = MALLOC(sizeof(unsigned));
+   output_prims->primitive_lengths[0] = 0;
+   output_prims->primitive_count = 0;
+
+   asmblr->added_prim_size = asmblr->num_per_prim * (4 * sizeof(float));
+   output_verts->vertex_size = input_verts->vertex_size + asmblr->added_prim_size;
+   output_verts->stride = output_verts->vertex_size;
+   output_verts->verts = (struct vertex_header*)MALLOC(
+      output_verts->vertex_size * max_verts);
+   output_verts->count = 0;
+
+   for (start = i = 0; i < input_prims->primitive_count;
+        start += input_prims->primitive_lengths[i], i++) {
+      unsigned count = input_prims->primitive_lengths[i];
+      if (input_prims->linear) {
+         assembler_run_linear(asmblr, input_prims, input_verts,
+                              start, count);
+      } else {
+         assembler_run_elts(asmblr, input_prims, input_verts,
+                            start, count);
+      }
+   }
+
+   output_prims->count = output_verts->count;
+}

src/gallium/auxiliary/draw/draw_mesh_prim.h

@@ -0,0 +1,42 @@
+/**************************************************************************
+ *
+ * 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.
+ *
+ **************************************************************************/
+
+#ifndef DRAW_MESH_PRIM_H
+#define DRAW_MESH_PRIM_H
+
+struct draw_context;
+struct draw_prim_info;
+struct draw_vertex_info;
+
+void
+draw_mesh_prim_run(struct draw_context *draw,
+                   unsigned num_per_prim_inputs,
+                   void *per_prim_inputs,
+                   int cull_prim_idx,
+                   const struct draw_prim_info *in_prim_info,
+                   const struct draw_vertex_info *in_vert_info,
+                   struct draw_prim_info *out_prim_info,
+                   struct draw_vertex_info *out_vert_info);
+#endif

src/gallium/auxiliary/draw/draw_mesh_prim_tmp.h

@@ -0,0 +1,30 @@
+#define FUNC_VARS                               \
+   struct draw_mesh_prim *asmblr,              \
+   const struct draw_prim_info *input_prims,    \
+   const struct draw_vertex_info *input_verts,  \
+   unsigned start,                              \
+   unsigned count
+
+#define FUNC_ENTER                                                \
+   /* declare more local vars */                                  \
+   const enum mesa_prim prim = input_prims->prim;                 \
+   const unsigned prim_flags = input_prims->flags;                \
+   const boolean last_vertex_last = false;                          \
+   switch (prim) {                                                  \
+   case MESA_PRIM_POINTS:                                           \
+   case MESA_PRIM_LINES:                                            \
+   case MESA_PRIM_TRIANGLES:                                        \
+      break;                                                        \
+   default:                                                         \
+      assert(!"unexpected primitive type in prim assembler");       \
+      return;                                                       \
+   }
+
+
+#define POINT(i0)                             prim_point(asmblr, i0)
+#define LINE(flags, i0, i1)                   prim_line(asmblr, i0, i1)
+#define TRIANGLE(flags, i0, i1, i2)           prim_tri(asmblr, i0, i1, i2)
+#define QUAD(flags, i0, i1, i2, i3)
+#define PASS_QUADS
+
+#include "draw_decompose_tmp.h"

src/gallium/auxiliary/meson.build

@@ -36,6 +36,9 @@ files_libgallium = files(
   'draw/draw_gs_tmp.h',
   'draw/draw_mesh.c',
   'draw/draw_mesh.h',
+  'draw/draw_mesh_prim.c',
+  'draw/draw_mesh_prim.h',
+  'draw/draw_mesh_prim_tmp.h',
   'draw/draw_pipe_aaline.c',
   'draw/draw_pipe_aapoint.c',
   'draw/draw_pipe.c',