From 420555c69c982def7afd4bb69387d20e48ea319d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fernando=20Garc=C3=ADa=20Li=C3=B1=C3=A1n?=
 <fernandogarcialinan@gmail.com>
Date: Sat, 24 Jul 2021 19:47:09 +0200
Subject: [PATCH] Fix issue with Effect techniques that have the highest index
 and a scheme

We previously used the last technique, but now we use the last technique that has no scheme.
---
 simgear/scene/material/Effect.cxx | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/simgear/scene/material/Effect.cxx b/simgear/scene/material/Effect.cxx
index d0b648ef..47af7ed2 100644
--- a/simgear/scene/material/Effect.cxx
+++ b/simgear/scene/material/Effect.cxx
@@ -240,11 +240,19 @@ Effect::Effect(const Effect& rhs, const CopyOp& copyop)
     _name += " clone";
 }
 
-// Assume that the last technique is always valid.
+// Try to use the state set of the last technique without a scheme.
 StateSet* Effect::getDefaultStateSet()
 {
-    Technique* tniq = techniques.back().get();
-    if (!tniq)
+    if (techniques.empty())
+        return 0;
+    auto it = std::find_if(techniques.rbegin(), techniques.rend(),
+                           [](const osg::ref_ptr<Technique> &t) {
+                               return t && t->getScheme().empty();
+                           });
+    if (it == techniques.rend())
+        return 0;
+    Technique* tniq = (*it);
+    if (tniq->passes.empty())
         return 0;
     Pass* pass = tniq->passes.front().get();
     return pass;