From 89e3bc8d562c23e1e527826b27c5f1e2bf094077 Mon Sep 17 00:00:00 2001
From: sfan5 <sfan5@live.de>
Date: Wed, 26 Mar 2025 18:28:25 +0100
Subject: [PATCH] Improve std::hash<SMaterial> implementation

---
 irr/include/SMaterial.h | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/irr/include/SMaterial.h b/irr/include/SMaterial.h
index d48328a31..d5b9341f4 100644
--- a/irr/include/SMaterial.h
+++ b/irr/include/SMaterial.h
@@ -483,9 +483,15 @@ struct std::hash<irr::video::SMaterial>
 	/// @brief std::hash specialization for video::SMaterial
 	std::size_t operator()(const irr::video::SMaterial &m) const noexcept
 	{
-		// basic implementation that hashes the two things most likely to differ
-		auto h1 = std::hash<irr::video::ITexture*>{}(m.getTexture(0));
-		auto h2 = std::hash<int>{}(m.MaterialType);
-		return (h1 << 1) ^ h2;
+		std::size_t ret = 0;
+		for (auto h : { // the three members most likely to differ
+			std::hash<irr::video::ITexture*>{}(m.getTexture(0)),
+			std::hash<int>{}(m.MaterialType),
+			std::hash<irr::u32>{}(m.ColorParam.color)
+		}) {
+			ret += h;
+			ret ^= (ret << 6) + (ret >> 2); // distribute bits
+		}
+		return ret;
 	}
 };