From 448e81e4a0d69d7530b54ac9286b9a50f68766c3 Mon Sep 17 00:00:00 2001
From: assiduous <assiduous@diligentgraphics.com>
Date: Fri, 1 Dec 2023 18:54:19 -0800
Subject: [PATCH] MathLib: updated BoundBox

---
 Common/interface/AdvancedMath.hpp             | 30 +++++++++++++++++++
 .../src/Common/MathLibTest.cpp                |  9 ++++++
 2 files changed, 39 insertions(+)

diff --git a/Common/interface/AdvancedMath.hpp b/Common/interface/AdvancedMath.hpp
index 212f78da1..85aaf7266 100644
--- a/Common/interface/AdvancedMath.hpp
+++ b/Common/interface/AdvancedMath.hpp
@@ -230,6 +230,36 @@ struct BoundBox
 
         return NewBB;
     }
+
+    BoundBox Combine(const BoundBox& Box) const
+    {
+        return {
+            (std::min)(Min, Box.Min),
+            (std::max)(Max, Box.Max),
+        };
+    }
+
+    constexpr bool IsValid() const
+    {
+        return (Max.x >= Min.x &&
+                Max.y >= Min.y &&
+                Max.z >= Min.z);
+    }
+
+    explicit constexpr operator bool() const
+    {
+        return IsValid();
+    }
+
+    constexpr bool operator==(const BoundBox& rhs) const
+    {
+        return Min == rhs.Min && Max == rhs.Max;
+    }
+
+    constexpr bool operator!=(const BoundBox& rhs) const
+    {
+        return !(*this == rhs);
+    }
 };
 
 struct OrientedBoundingBox
diff --git a/Tests/DiligentCoreTest/src/Common/MathLibTest.cpp b/Tests/DiligentCoreTest/src/Common/MathLibTest.cpp
index 6d5c24cfc..c135b8731 100644
--- a/Tests/DiligentCoreTest/src/Common/MathLibTest.cpp
+++ b/Tests/DiligentCoreTest/src/Common/MathLibTest.cpp
@@ -2647,6 +2647,15 @@ TEST(Common_AdvancedMath, TransformBoundBox)
     }
 }
 
+TEST(Common_AdvancedMath, CombineBoundBoxes)
+{
+    const BoundBox BB1{float3{1, 2, 3}, float3{4, 5, 6}};
+    const BoundBox BB2{float3{-2, -3, -4}, float3{50, 60, 70}};
+    const BoundBox RefBB{float3{-2, -3, -4}, float3{50, 60, 70}};
+    EXPECT_EQ(BB1.Combine(BB2), RefBB);
+    EXPECT_EQ(BB2.Combine(BB1), RefBB);
+}
+
 TEST(Common_AdvancedMath, CheckBox2DBox2DOverlap)
 {
     // clang-format off