From a65f49049ed9322c53750b8c60da8cbb05d53110 Mon Sep 17 00:00:00 2001
From: Stephen Seo <seo.disparate@gmail.com>
Date: Fri, 10 May 2024 13:24:11 +0900
Subject: [PATCH] Add Vec3 negate and Vec3 normalize functions

---
 src/sc_sacd.cpp |  8 +++++++
 src/sc_sacd.h   |  5 ++++
 src/test.cpp    | 62 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+)

diff --git a/src/sc_sacd.cpp b/src/sc_sacd.cpp
index ac1f5c5..7b96a9d 100644
--- a/src/sc_sacd.cpp
+++ b/src/sc_sacd.cpp
@@ -684,6 +684,14 @@ SC_SACD_Vec3 SC_SACD_Vec3_Div(SC_SACD_Vec3 vec, float scalar) {
   return vec / scalar;
 }
 
+SC_SACD_Vec3 SC_SACD_Vec3_Negate(SC_SACD_Vec3 vec) {
+  return SC_SACD_Vec3{-vec.x, -vec.y, -vec.z};
+}
+
+SC_SACD_Vec3 SC_SACD_Vec3_Normalize(SC_SACD_Vec3 vec) {
+  return vec / SC_SACD_Vec3_Length(vec);
+}
+
 SC_SACD_Vec3 SC_SACD_Vec3_Project(SC_SACD_Vec3 vec, SC_SACD_Vec3 target) {
   float upper_dot_product = SC_SACD_Dot_Product(vec, target);
   float lower_dot_product = SC_SACD_Dot_Product(target, target);
diff --git a/src/sc_sacd.h b/src/sc_sacd.h
index 8b400a9..ae05156 100644
--- a/src/sc_sacd.h
+++ b/src/sc_sacd.h
@@ -142,6 +142,11 @@ SC_SACD_EXPORT SC_SACD_Vec3 SC_SACD_Vec3_Difference(SC_SACD_Vec3 a,
 SC_SACD_EXPORT SC_SACD_Vec3 SC_SACD_Vec3_Mult(SC_SACD_Vec3 vec, float scalar);
 SC_SACD_EXPORT SC_SACD_Vec3 SC_SACD_Vec3_Div(SC_SACD_Vec3 vec, float scalar);
 
+SC_SACD_EXPORT SC_SACD_Vec3 SC_SACD_Vec3_Negate(SC_SACD_Vec3 vec);
+
+/// Turns vec into a unit vector and returns the unit vector.
+SC_SACD_EXPORT SC_SACD_Vec3 SC_SACD_Vec3_Normalize(SC_SACD_Vec3 vec);
+
 /// Projects "vec" onto "target".
 SC_SACD_EXPORT SC_SACD_Vec3 SC_SACD_Vec3_Project(SC_SACD_Vec3 vec,
                                                  SC_SACD_Vec3 target);
diff --git a/src/test.cpp b/src/test.cpp
index ea8e03c..1fe322c 100644
--- a/src/test.cpp
+++ b/src/test.cpp
@@ -840,6 +840,68 @@ int main() {
     CHECK_FLOAT(result.z, 3.0F);
   }
 
+  // Test negate.
+  {
+      SC_SACD_Vec3 vec{1.0F, 2.0F, 3.0F};
+      vec = SC_SACD_Vec3_Negate(vec);
+      CHECK_FLOAT(vec.x, -1.0F);
+      CHECK_FLOAT(vec.y, -2.0F);
+      CHECK_FLOAT(vec.z, -3.0F);
+  }
+
+  // Test normalize.
+  {
+      SC_SACD_Vec3 vec{1.0F, 0.0F, 0.0F};
+      vec = SC_SACD_Vec3_Normalize(vec);
+      CHECK_FLOAT(vec.x, 1.0F);
+      CHECK_FLOAT(vec.y, 0.0F);
+      CHECK_FLOAT(vec.z, 0.0F);
+
+      vec.x = 0.0F;
+      vec.y = -1.0F;
+      vec = SC_SACD_Vec3_Normalize(vec);
+      CHECK_FLOAT(vec.x, 0.0F);
+      CHECK_FLOAT(vec.y, -1.0F);
+      CHECK_FLOAT(vec.z, 0.0F);
+
+      vec.y = 0.0F;
+      vec.z = 0.7F;
+      vec = SC_SACD_Vec3_Normalize(vec);
+      CHECK_FLOAT(vec.x, 0.0F);
+      CHECK_FLOAT(vec.y, 0.0F);
+      CHECK_FLOAT(vec.z, 1.0F);
+
+      vec.x = 1.0F;
+      vec = SC_SACD_Vec3_Normalize(vec);
+      CHECK_FLOAT(vec.x, std::sqrt(0.5F));
+      CHECK_FLOAT(vec.y, 0.0F);
+      CHECK_FLOAT(vec.z, std::sqrt(0.5F));
+
+      vec.x = 1.0F;
+      vec.y = 1.0F;
+      vec.z = 1.0F;
+      vec = SC_SACD_Vec3_Normalize(vec);
+      CHECK_FLOAT(vec.x, std::sqrt(1.0F / 3.0F));
+      CHECK_FLOAT(vec.y, std::sqrt(1.0F / 3.0F));
+      CHECK_FLOAT(vec.z, std::sqrt(1.0F / 3.0F));
+
+      vec.x = 1.0F;
+      vec.y = -1.0F;
+      vec.z = -1.0F;
+      vec = SC_SACD_Vec3_Normalize(vec);
+      CHECK_FLOAT(vec.x, std::sqrt(1.0F / 3.0F));
+      CHECK_FLOAT(vec.y, -std::sqrt(1.0F / 3.0F));
+      CHECK_FLOAT(vec.z, -std::sqrt(1.0F / 3.0F));
+
+      vec.x = 1.0F;
+      vec.y = 2.0F;
+      vec.z = 3.0F;
+      vec = SC_SACD_Vec3_Normalize(vec);
+      CHECK_FLOAT(vec.x, std::sqrt(1.0F / 14.0F));
+      CHECK_FLOAT(vec.y, std::sqrt(4.0F / 14.0F));
+      CHECK_FLOAT(vec.z, std::sqrt(9.0F / 14.0F));
+  }
+
   std::cout << "Checks checked: " << checks_checked << '\n'
             << "Checks passed:  " << checks_passed << '\n';