From 50cabead7f6c3f41df9d8ce839cd75c54fb10877 Mon Sep 17 00:00:00 2001
From: Brecht Van Lommel <brecht@blender.org>
Date: Wed, 18 Oct 2023 15:39:38 +0200
Subject: [PATCH] Fix #113871: Cycles shader with volume shader and AOV output
 renders black

---
 intern/cycles/scene/shader.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/intern/cycles/scene/shader.cpp b/intern/cycles/scene/shader.cpp
index 2d9561fe0ab..c56eace8217 100644
--- a/intern/cycles/scene/shader.cpp
+++ b/intern/cycles/scene/shader.cpp
@@ -348,13 +348,22 @@ void Shader::tag_update(Scene *scene)
   has_displacement = has_displacement || output->input("Displacement")->link;
 
   if (!has_surface) {
+    /* If we need to output surface AOVs, add a Transparent BSDF so that the
+     * surface shader runs. */
     foreach (ShaderNode *node, graph->nodes) {
       if (node->special_type == SHADER_SPECIAL_TYPE_OUTPUT_AOV) {
         foreach (const ShaderInput *in, node->inputs) {
           if (in->link) {
+            TransparentBsdfNode *transparent = graph->create_node<TransparentBsdfNode>();
+            graph->add(transparent);
+            graph->connect(transparent->output("BSDF"), output->input("Surface"));
             has_surface = true;
+            break;
           }
         }
+        if (has_surface) {
+          break;
+        }
       }
     }
   }