From 2a65ece16cd237d56c9dac8d9d3d680e9d34b774 Mon Sep 17 00:00:00 2001
From: Richard Qin <richard.qin.x@gmail.com>
Date: Mon, 9 Mar 2026 02:21:09 +0800
Subject: Create class vec3

---
 vec3.cc | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 vec3.cc

(limited to 'vec3.cc')

diff --git a/vec3.cc b/vec3.cc
new file mode 100644
index 0000000..38844c7
--- /dev/null
+++ b/vec3.cc
@@ -0,0 +1,105 @@
+#include "vec3.h"
+
+double vec3::x() const { return e[0]; }
+double vec3::y() const { return e[1]; }
+double vec3::z() const { return e[2]; }
+
+vec3 vec3::operator-() const {
+    return vec3(-e[0], -e[1], -e[2]);
+}
+
+double vec3::operator[](int i) const{
+    return e[i];
+}
+
+double& vec3::operator[](int i){
+    return e[1];
+}
+
+vec3& vec3::operator+=(const vec3 &v)
+{
+    e[0] += v.e[0];
+    e[1] += v.e[1];
+    e[2] += v.e[2];
+    return *this;
+}
+
+vec3& vec3::operator*=(double t)
+{
+    e[0] *= t;
+    e[1] *= t;
+    e[2] *= t;
+    return *this;
+}
+
+vec3& vec3::operator/=(double t)
+{
+    return *this *= 1 / t;
+}
+
+double vec3::length() const
+{
+    return std::sqrt(length_squared());
+}
+
+double vec3::length_squared() const
+{
+    return e[0] * e[0] + e[1] * e[1] + e[2] * e[2];
+}
+
+// point3 is just an alias for vec3, but useful for geometric clarity in the code.
+using point3 = vec3;
+
+// Vector Utility Functions
+
+inline std::ostream &operator<<(std::ostream &out, const vec3 &v)
+{
+    return out << v.e[0] << ' ' << v.e[1] << ' ' << v.e[2];
+}
+
+inline vec3 operator+(const vec3 &u, const vec3 &v)
+{
+    return vec3(u.e[0] + v.e[0], u.e[1] + v.e[1], u.e[2] + v.e[2]);
+}
+
+inline vec3 operator-(const vec3 &u, const vec3 &v)
+{
+    return vec3(u.e[0] - v.e[0], u.e[1] - v.e[1], u.e[2] - v.e[2]);
+}
+
+inline vec3 operator*(const vec3 &u, const vec3 &v)
+{
+    return vec3(u.e[0] * v.e[0], u.e[1] * v.e[1], u.e[2] * v.e[2]);
+}
+
+inline vec3 operator*(double t, const vec3 &v)
+{
+    return vec3(t * v.e[0], t * v.e[1], t * v.e[2]);
+}
+
+inline vec3 operator*(const vec3 &v, double t)
+{
+    return t * v;
+}
+
+inline vec3 operator/(const vec3 &v, double t)
+{
+    return (1 / t) * v;
+}
+
+inline double dot(const vec3 &u, const vec3 &v)
+{
+    return u.e[0] * v.e[0] + u.e[1] * v.e[1] + u.e[2] * v.e[2];
+}
+
+inline vec3 cross(const vec3 &u, const vec3 &v)
+{
+    return vec3(u.e[1] * v.e[2] - u.e[2] * v.e[1],
+                u.e[2] * v.e[0] - u.e[0] * v.e[2],
+                u.e[0] * v.e[1] - u.e[1] * v.e[0]);
+}
+
+inline vec3 unit_vector(const vec3 &v)
+{
+    return v / v.length();
+}
-- 
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