From 4014436905aace9acd47dde245b88bd5f69335ec Mon Sep 17 00:00:00 2001
From: Richard Qin <richard.qin.x@gmail.com>
Date: Mon, 9 Mar 2026 23:31:27 +0800
Subject: Sending Rays Into the Scene

---
 src/vec3.h | 98 +++++++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 71 insertions(+), 27 deletions(-)

(limited to 'src/vec3.h')

diff --git a/src/vec3.h b/src/vec3.h
index 56490bc..a8b8265 100644
--- a/src/vec3.h
+++ b/src/vec3.h
@@ -21,38 +21,82 @@
 #include <cmath>
 #include <iostream>
 
-class vec3{
-  public:
-    std::array<double, 3> e;
+class vec3
+{
+public:
+  std::array<double, 3> e;
 
-    vec3() : e{0, 0, 0} {}
-    vec3(double e0, double e1, double e2) : e{e0, e1, e2} {}
+  vec3() : e { 0, 0, 0 } {}
+  vec3( double e0, double e1, double e2 ) : e { e0, e1, e2 } {}
 
-    double x() const;
-    double y() const;
-    double z() const;
+  double x() const;
+  double y() const;
+  double z() const;
 
-    vec3 operator-() const;
-    double operator[](int i) const;
-    double &operator[](int i);
-    vec3& operator+=(const vec3 & other);
-    vec3& operator*=(double t);
-    vec3& operator/=(double t);
-    double length() const;
-    double length_squared() const;
+  vec3 operator-() const;
+  double operator[]( int i ) const;
+  double& operator[]( int i );
+  vec3& operator+=( const vec3& other );
+  vec3& operator*=( double t );
+  vec3& operator/=( double t );
+  double length() const;
+  double length_squared() const;
+};
 
+// 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 { 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 { 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 { 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 { 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 {
+    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 std::ostream &operator<<(std::ostream &out, const vec3 &v);
-inline vec3 operator+(const vec3 &u, const vec3 &v);
-inline vec3 operator-(const vec3 &u, const vec3 &v);
-inline vec3 operator*(const vec3 &u, const vec3 &v);
-inline vec3 operator*(double t, const vec3 &v);
-inline vec3 operator*(const vec3 &v, double t);
-inline vec3 operator/(const vec3 &v, double t);
-inline double dot(const vec3 &u, const vec3 &v);
-inline vec3 cross(const vec3 &u, const vec3 &v);
-inline vec3 unit_vector(const vec3 &v);
+inline vec3 unit_vector( const vec3& v )
+{
+  return v / v.length();
+}
 
 #endif
-- 
cgit v1.2.3