Cycles: fully decouple triangle and curve primitive storage from BVH2

Previously the storage here was optimized to avoid indirections in BVH2
traversal. This helps improve performance a bit, but makes performance
and memory usage of Embree and OptiX BVHs a bit worse also. It also adds
code complexity in other parts of the code.

Now decouple triangle and curve primitive storage from BVH2.
* Reduced peak memory usage on all devices
* Bit better performance for OptiX and Embree
* Bit worse performance for CUDA
* Simplified code:
** Intersection.prim/object now matches ShaderData.prim/object
** No more offset manipulation for mesh displacement before a BVH is built
** Remove primitive packing code and flags for Embree and OptiX
** Curve segments are now stored in a KernelCurve struct
* Also happens to fix a bug in baking with incorrect prim/object

Fixes T91968, T91770, T91902

Differential Revision: https://developer.blender.org/D12766

1 files changed, 0 insertions, 61 deletions

diff --git a/intern/cycles/bvh/bvh2.cpp b/intern/cycles/bvh/bvh2.cpp
index 379ae9b25ff..4a90a1e8796 100644
--- a/intern/cycles/bvh/bvh2.cpp
+++ b/intern/cycles/bvh/bvh2.cpp
@@ -439,61 +439,20 @@ void BVH2::refit_primitives(int start, int end, BoundBox &bbox, uint &visibility
 
 /* Triangles */
 
-void BVH2::pack_triangle(int idx, float4 tri_verts[3])
-{
-  int tob = pack.prim_object[idx];
-  assert(tob >= 0 && tob < objects.size());
-  const Mesh *mesh = static_cast<const Mesh *>(objects[tob]->get_geometry());
-
-  int tidx = pack.prim_index[idx];
-  Mesh::Triangle t = mesh->get_triangle(tidx);
-  const float3 *vpos = &mesh->verts[0];
-  float3 v0 = vpos[t.v[0]];
-  float3 v1 = vpos[t.v[1]];
-  float3 v2 = vpos[t.v[2]];
-
-  tri_verts[0] = float3_to_float4(v0);
-  tri_verts[1] = float3_to_float4(v1);
-  tri_verts[2] = float3_to_float4(v2);
-}
-
 void BVH2::pack_primitives()
 {
   const size_t tidx_size = pack.prim_index.size();
-  size_t num_prim_triangles = 0;
-  /* Count number of triangles primitives in BVH. */
-  for (unsigned int i = 0; i < tidx_size; i++) {
-    if ((pack.prim_index[i] != -1)) {
-      if ((pack.prim_type[i] & PRIMITIVE_ALL_TRIANGLE) != 0) {
-        ++num_prim_triangles;
-      }
-    }
-  }
   /* Reserve size for arrays. */
-  pack.prim_tri_index.clear();
-  pack.prim_tri_index.resize(tidx_size);
-  pack.prim_tri_verts.clear();
-  pack.prim_tri_verts.resize(num_prim_triangles * 3);
   pack.prim_visibility.clear();
   pack.prim_visibility.resize(tidx_size);
   /* Fill in all the arrays. */
-  size_t prim_triangle_index = 0;
   for (unsigned int i = 0; i < tidx_size; i++) {
     if (pack.prim_index[i] != -1) {
       int tob = pack.prim_object[i];
       Object *ob = objects[tob];
-      if ((pack.prim_type[i] & PRIMITIVE_ALL_TRIANGLE) != 0) {
-        pack_triangle(i, (float4 *)&pack.prim_tri_verts[3 * prim_triangle_index]);
-        pack.prim_tri_index[i] = 3 * prim_triangle_index;
-        ++prim_triangle_index;
-      }
-      else {
-        pack.prim_tri_index[i] = -1;
-      }
       pack.prim_visibility[i] = ob->visibility_for_tracing();
     }
     else {
-      pack.prim_tri_index[i] = -1;
       pack.prim_visibility[i] = 0;
     }
   }
@@ -522,10 +481,8 @@ void BVH2::pack_instances(size_t nodes_size, size_t leaf_nodes_size)
 
   /* reserve */
   size_t prim_index_size = pack.prim_index.size();
-  size_t prim_tri_verts_size = pack.prim_tri_verts.size();
 
   size_t pack_prim_index_offset = prim_index_size;
-  size_t pack_prim_tri_verts_offset = prim_tri_verts_size;
   size_t pack_nodes_offset = nodes_size;
   size_t pack_leaf_nodes_offset = leaf_nodes_size;
   size_t object_offset = 0;
@@ -535,7 +492,6 @@ void BVH2::pack_instances(size_t nodes_size, size_t leaf_nodes_size)
 
     if (geom->need_build_bvh(params.bvh_layout)) {
       prim_index_size += bvh->pack.prim_index.size();
-      prim_tri_verts_size += bvh->pack.prim_tri_verts.size();
       nodes_size += bvh->pack.nodes.size();
       leaf_nodes_size += bvh->pack.leaf_nodes.size();
     }
@@ -545,8 +501,6 @@ void BVH2::pack_instances(size_t nodes_size, size_t leaf_nodes_size)
   pack.prim_type.resize(prim_index_size);
   pack.prim_object.resize(prim_index_size);
   pack.prim_visibility.resize(prim_index_size);
-  pack.prim_tri_verts.resize(prim_tri_verts_size);
-  pack.prim_tri_index.resize(prim_index_size);
   pack.nodes.resize(nodes_size);
   pack.leaf_nodes.resize(leaf_nodes_size);
   pack.object_node.resize(objects.size());
@@ -559,8 +513,6 @@ void BVH2::pack_instances(size_t nodes_size, size_t leaf_nodes_size)
   int *pack_prim_type = (pack.prim_type.size()) ? &pack.prim_type[0] : NULL;
   int *pack_prim_object = (pack.prim_object.size()) ? &pack.prim_object[0] : NULL;
   uint *pack_prim_visibility = (pack.prim_visibility.size()) ? &pack.prim_visibility[0] : NULL;
-  float4 *pack_prim_tri_verts = (pack.prim_tri_verts.size()) ? &pack.prim_tri_verts[0] : NULL;
-  uint *pack_prim_tri_index = (pack.prim_tri_index.size()) ? &pack.prim_tri_index[0] : NULL;
   int4 *pack_nodes = (pack.nodes.size()) ? &pack.nodes[0] : NULL;
   int4 *pack_leaf_nodes = (pack.leaf_nodes.size()) ? &pack.leaf_nodes[0] : NULL;
   float2 *pack_prim_time = (pack.prim_time.size()) ? &pack.prim_time[0] : NULL;
@@ -609,18 +561,14 @@ void BVH2::pack_instances(size_t nodes_size, size_t leaf_nodes_size)
       int *bvh_prim_index = &bvh->pack.prim_index[0];
       int *bvh_prim_type = &bvh->pack.prim_type[0];
       uint *bvh_prim_visibility = &bvh->pack.prim_visibility[0];
-      uint *bvh_prim_tri_index = &bvh->pack.prim_tri_index[0];
       float2 *bvh_prim_time = bvh->pack.prim_time.size() ? &bvh->pack.prim_time[0] : NULL;
 
       for (size_t i = 0; i < bvh_prim_index_size; i++) {
         if (bvh->pack.prim_type[i] & PRIMITIVE_ALL_CURVE) {
           pack_prim_index[pack_prim_index_offset] = bvh_prim_index[i] + geom_prim_offset;
-          pack_prim_tri_index[pack_prim_index_offset] = -1;
         }
         else {
           pack_prim_index[pack_prim_index_offset] = bvh_prim_index[i] + geom_prim_offset;
-          pack_prim_tri_index[pack_prim_index_offset] = bvh_prim_tri_index[i] +
-                                                        pack_prim_tri_verts_offset;
         }
 
         pack_prim_type[pack_prim_index_offset] = bvh_prim_type[i];
@@ -633,15 +581,6 @@ void BVH2::pack_instances(size_t nodes_size, size_t leaf_nodes_size)
       }
     }
 
-    /* Merge triangle vertices data. */
-    if (bvh->pack.prim_tri_verts.size()) {
-      const size_t prim_tri_size = bvh->pack.prim_tri_verts.size();
-      memcpy(pack_prim_tri_verts + pack_prim_tri_verts_offset,
-             &bvh->pack.prim_tri_verts[0],
-             prim_tri_size * sizeof(float4));
-      pack_prim_tri_verts_offset += prim_tri_size;
-    }
-
     /* merge nodes */
     if (bvh->pack.leaf_nodes.size()) {
       int4 *leaf_nodes_offset = &bvh->pack.leaf_nodes[0];