From c5569ba140382015c32bd638532097ea05168607 Mon Sep 17 00:00:00 2001
From: Jacques Lucke <jacques@blender.org>
Date: Fri, 18 Dec 2020 13:28:43 +0100
Subject: Geometry Nodes: do not crash when there are undefined nodes

Undefined geometry nodes will just output a default value now.
---
 source/blender/modifiers/intern/MOD_nodes.cc | 29 ++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

(limited to 'source/blender/modifiers/intern')

diff --git a/source/blender/modifiers/intern/MOD_nodes.cc b/source/blender/modifiers/intern/MOD_nodes.cc
index 6bb747fa715..bbf0c7601f5 100644
--- a/source/blender/modifiers/intern/MOD_nodes.cc
+++ b/source/blender/modifiers/intern/MOD_nodes.cc
@@ -300,13 +300,28 @@ class GeometryNodesEvaluator {
   void execute_node(const DNode &node, GeoNodeExecParams params)
   {
     const bNode &bnode = params.node();
+
+    /* Use the geometry-node-execute callback if it exists. */
     if (bnode.typeinfo->geometry_node_execute != nullptr) {
       bnode.typeinfo->geometry_node_execute(params);
       return;
     }
 
-    /* Use the multi-function implementation of the node. */
-    const MultiFunction &fn = *mf_by_node_.lookup(&node);
+    /* Use the multi-function implementation if it exists. */
+    const MultiFunction *multi_function = mf_by_node_.lookup_default(&node, nullptr);
+    if (multi_function != nullptr) {
+      this->execute_multi_function_node(node, params, *multi_function);
+      return;
+    }
+
+    /* Just output default values if no implementation exists. */
+    this->execute_unknown_node(node, params);
+  }
+
+  void execute_multi_function_node(const DNode &node,
+                                   GeoNodeExecParams params,
+                                   const MultiFunction &fn)
+  {
     MFContextBuilder fn_context;
     MFParamsBuilder fn_params{fn, 1};
     Vector<GMutablePointer> input_data;
@@ -341,6 +356,16 @@ class GeometryNodesEvaluator {
     }
   }
 
+  void execute_unknown_node(const DNode &node, GeoNodeExecParams params)
+  {
+    for (const DOutputSocket *socket : node.outputs()) {
+      if (socket->is_available()) {
+        const CPPType &type = *blender::nodes::socket_cpp_type_get(*socket->typeinfo());
+        params.set_output_by_copy(socket->identifier(), {type, type.default_value()});
+      }
+    }
+  }
+
   void forward_to_inputs(const DOutputSocket &from_socket, GMutablePointer value_to_forward)
   {
     Span<const DInputSocket *> to_sockets_all = from_socket.linked_sockets();
-- 
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