Merge branch 'blender-v2.93-release'

1 files changed, 23 insertions, 2 deletions

diff --git a/source/blender/blenkernel/intern/object_dupli.cc b/source/blender/blenkernel/intern/object_dupli.cc
index ddf7826969b..835b62c06bf 100644
--- a/source/blender/blenkernel/intern/object_dupli.cc
+++ b/source/blender/blenkernel/intern/object_dupli.cc
@@ -36,6 +36,7 @@
 #include "BLI_math.h"
 #include "BLI_rand.h"
 #include "BLI_span.hh"
+#include "BLI_vector.hh"
 
 #include "DNA_anim_types.h"
 #include "DNA_collection_types.h"
@@ -73,6 +74,7 @@ using blender::Array;
 using blender::float3;
 using blender::float4x4;
 using blender::Span;
+using blender::Vector;
 
 /* -------------------------------------------------------------------- */
 /** \name Internal Duplicate Context
@@ -90,6 +92,13 @@ struct DupliContext {
   Object *object;
   float space_mat[4][4];
 
+  /**
+   * A stack that contains all the "parent" objects of a particular instance when recursive
+   * instancing is used. This is used to prevent objects from instancing themselves accidentally.
+   * Use a vector instead of a stack because we want to use the #contains method.
+   */
+  Vector<Object *> *instance_stack;
+
   int persistent_id[MAX_DUPLI_RECUR];
   int level;
 
@@ -113,7 +122,8 @@ static void init_context(DupliContext *r_ctx,
                          Depsgraph *depsgraph,
                          Scene *scene,
                          Object *ob,
-                         const float space_mat[4][4])
+                         const float space_mat[4][4],
+                         Vector<Object *> &instance_stack)
 {
   r_ctx->depsgraph = depsgraph;
   r_ctx->scene = scene;
@@ -122,6 +132,7 @@ static void init_context(DupliContext *r_ctx,
 
   r_ctx->object = ob;
   r_ctx->obedit = OBEDIT_FROM_OBACT(ob);
+  r_ctx->instance_stack = &instance_stack;
   if (space_mat) {
     copy_m4_m4(r_ctx->space_mat, space_mat);
   }
@@ -150,6 +161,7 @@ static void copy_dupli_context(
   }
 
   r_ctx->object = ob;
+  r_ctx->instance_stack = ctx->instance_stack;
   if (mat) {
     mul_m4_m4m4(r_ctx->space_mat, (float(*)[4])ctx->space_mat, mat);
   }
@@ -235,12 +247,19 @@ static void make_recursive_duplis(const DupliContext *ctx,
                                   const float space_mat[4][4],
                                   int index)
 {
+  if (ctx->instance_stack->contains(ob)) {
+    /* Avoid recursive instances. */
+    printf("Warning: '%s' object is trying to instance itself.\n", ob->id.name + 2);
+    return;
+  }
   /* Simple preventing of too deep nested collections with #MAX_DUPLI_RECUR. */
   if (ctx->level < MAX_DUPLI_RECUR) {
     DupliContext rctx;
     copy_dupli_context(&rctx, ctx, ob, space_mat, index);
     if (rctx.gen) {
+      ctx->instance_stack->append(ob);
       rctx.gen->make_duplis(&rctx);
+      ctx->instance_stack->remove_last();
     }
   }
 }
@@ -1588,7 +1607,9 @@ ListBase *object_duplilist(Depsgraph *depsgraph, Scene *sce, Object *ob)
 {
   ListBase *duplilist = (ListBase *)MEM_callocN(sizeof(ListBase), "duplilist");
   DupliContext ctx;
-  init_context(&ctx, depsgraph, sce, ob, nullptr);
+  Vector<Object *> instance_stack;
+  instance_stack.append(ob);
+  init_context(&ctx, depsgraph, sce, ob, nullptr, instance_stack);
   if (ctx.gen) {
     ctx.duplilist = duplilist;
     ctx.gen->make_duplis(&ctx);