From 60a3e2aedda225591f10a360575250b201aadd53 Mon Sep 17 00:00:00 2001
From: Keuin <keuinx@gmail.com>
Date: Tue, 12 Apr 2022 13:03:05 +0800
Subject: Add vec3::mod2.

---
 test.cpp | 7 +++++++
 vec.h    | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/test.cpp b/test.cpp
index 8c450f9..1b765aa 100644
--- a/test.cpp
+++ b/test.cpp
@@ -67,4 +67,11 @@ TEST(Vec, Norm) {
 TEST(Vec, UnitVec) {
     vec3d a{1, 2, 2}, b{1.0 / 3, 2.0 / 3, 2.0 / 3};
     ASSERT_EQ(a.unit_vec(), b);
+}
+
+TEST(Vec, Mod2) {
+    vec3i a{1, 2, 3};
+    vec3d b{2.5, 3, 1.2};
+    ASSERT_EQ(a.mod2(), 14);
+    ASSERT_LE(abs(b.mod2() - (2.5 * 2.5 + 3 * 3 + 1.2 * 1.2)), 1e-10);
 }
\ No newline at end of file
diff --git a/vec.h b/vec.h
index 017b0a9..bf40e7d 100644
--- a/vec.h
+++ b/vec.h
@@ -71,6 +71,11 @@ struct vec3 {
         }
     }
 
+    // Squared module
+    T mod2() const {
+        return x * x + y * y + z * z;
+    }
+
     vec3 unit_vec() const {
         return *this * (1.0 / norm());
     }
-- 
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