draw: implement primitive assembler

Input assembler needs to be able to decompose adjacency primitives
into something that can be understood by the rest of the pipeline.
The specs say that the adjacency primitives are *only* visible
in the geometry shader, for everything else they need to be
decomposed. Which in most of the cases is not an issue, because
the geometry shader always decomposes them for us, but without
geometry shader we were passing unchanged adjacency primitives
to the rest of the pipeline and causing crashes everywhere. This
commit introduces a primitive assembler which, if geometry
shader is missing and the input primitive is one of the
adjacency primitives, decomposes them into something
that the rest of the pipeline can understand.

Signed-off-by: Zack Rusin <[email protected]>
Reviewed-by: Jose Fonseca <[email protected]>
Reviewed-by: Roland Scheidegger <[email protected]>
Reviewed-by: Brian Paul <[email protected]>

1 files changed, 225 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/draw/draw_prim_assembler.c b/src/gallium/auxiliary/draw/draw_prim_assembler.c
new file mode 100644
index 00000000000..4da24a6e7dc
--- /dev/null
+++ b/src/gallium/auxiliary/draw/draw_prim_assembler.c
@@ -0,0 +1,225 @@
+/**************************************************************************
+ *
+ * Copyright 2013 VMware, Inc.
+ * 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 VMWARE 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.
+ *
+ **************************************************************************/
+
+#include "draw_prim_assembler.h"
+
+#include "util/u_debug.h"
+#include "util/u_memory.h"
+#include "util/u_prim.h"
+
+#include "pipe/p_defines.h"
+
+struct draw_assembler
+{
+   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;
+};
+
+boolean
+draw_prim_assembler_is_required(const struct draw_context *draw,
+                                const struct draw_prim_info *prim_info,
+                                const struct draw_vertex_info *vert_info)
+{
+   switch (prim_info->prim) {
+   case PIPE_PRIM_LINES_ADJACENCY:
+   case PIPE_PRIM_LINE_STRIP_ADJACENCY:
+   case PIPE_PRIM_TRIANGLES_ADJACENCY:
+   case PIPE_PRIM_TRIANGLE_STRIP_ADJACENCY:
+      return TRUE;
+   default:
+      return FALSE;
+   }
+}
+
+/*
+ * 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_assembler *asmblr,
+           unsigned *indices, unsigned num_indices)
+{
+   unsigned i;
+
+   char *output = (char*)asmblr->output_verts->verts;
+   const char *input = (const char*)asmblr->input_verts->verts;
+
+   for (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);
+      asmblr->output_verts->count += 1;
+   }
+}
+
+static void
+prim_point(struct draw_assembler *asmblr,
+           unsigned idx)
+{
+   unsigned indices[1];
+
+   indices[0] = idx;
+
+   copy_verts(asmblr, indices, 1);
+}
+
+static void
+prim_line(struct draw_assembler *asmblr,
+          unsigned i0, unsigned i1)
+{
+   unsigned indices[2];
+
+   indices[0] = i0;
+   indices[1] = i1;
+
+   copy_verts(asmblr, indices, 2);
+}
+
+static void
+prim_line_adj(struct draw_assembler *asmblr,
+              unsigned i0, unsigned i1, unsigned i2, unsigned i3)
+{
+   unsigned indices[2];
+
+   indices[0] = i1;
+   indices[1] = i2;
+
+   copy_verts(asmblr, indices, 2);
+}
+
+static void
+prim_tri(struct draw_assembler *asmblr,
+         unsigned i0, unsigned i1, unsigned i2)
+{
+   unsigned indices[3];
+
+   indices[0] = i0;
+   indices[1] = i1;
+   indices[2] = i2;
+
+   copy_verts(asmblr, indices, 3);
+}
+
+static void
+prim_tri_adj(struct draw_assembler *asmblr,
+             unsigned i0, unsigned i1, unsigned i2,
+             unsigned i3, unsigned i4, unsigned i5)
+{
+   unsigned indices[3];
+
+   indices[0] = i0;
+   indices[1] = i2;
+   indices[2] = i4;
+
+   copy_verts(asmblr, indices, 3);
+}
+
+
+
+#define FUNC assembler_run_linear
+#define GET_ELT(idx) (start + (idx))
+#include "draw_prim_assembler_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_prim_assembler_tmp.h"
+
+
+
+/*
+ * Primitive assembler breaks up adjacency primitives and assembles
+ * the base primitives they represent, e.g. vertices forming
+ * PIPE_PRIM_TRIANGLE_STRIP_ADJACENCY
+ * become vertices forming PIPE_PRIM_TRIANGLES 
+ * This is needed because specification says that the adjacency
+ * primitives are only visible in the geometry shader so we need
+ * to get rid of them so that the rest of the pipeline can
+ * process the inputs.
+ */
+void
+draw_prim_assembler_run(struct draw_context *draw,
+                        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_assembler asmblr;
+   unsigned start, i;
+   unsigned assembled_prim = u_assembled_primitive(input_prims->prim);
+   unsigned max_primitives = u_decomposed_prims_for_vertices(
+      input_prims->prim, input_prims->count);
+   unsigned max_verts = u_vertices_per_prim(assembled_prim) * max_primitives;
+
+   asmblr.draw = draw;
+   asmblr.output_prims = output_prims;
+   asmblr.output_verts = output_verts;
+   asmblr.input_prims = input_prims;
+   asmblr.input_verts = input_verts;
+
+   output_prims->linear = TRUE;
+   output_prims->elts = NULL;
+   output_prims->start = 0;
+   output_prims->prim = u_assembled_primitive(input_prims->prim);
+   output_prims->flags = 0x0;
+   output_prims->primitive_lengths = MALLOC(sizeof(unsigned));
+   output_prims->primitive_lengths[0] = 0;
+   output_prims->primitive_count = 1;
+
+   output_verts->vertex_size = input_verts->vertex_size;
+   output_verts->stride = input_verts->stride;
+   output_verts->verts = (struct vertex_header*)MALLOC(
+      input_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->primitive_lengths[0] = output_verts->count;
+   output_prims->count = output_verts->count;
+}