From 0d3871ff24243c680537ccacb4e0eceb66f93b4f Mon Sep 17 00:00:00 2001
From: Camden Dixie O'Brien <cobrien@witekio.com>
Date: Tue, 23 Sep 2025 15:35:26 +0100
Subject: [PATCH] Create vec3 module

---
 CMakeLists.txt |  1 +
 include/vec3.h | 16 ++++++++++++++++
 src/vec3.c     | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+)
 create mode 100644 include/vec3.h
 create mode 100644 src/vec3.c

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 661a5a4..bd5e3ab 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,6 +10,7 @@ endmacro()
 
 add_library(batomorph
   src/ff.c
+  src/vec3.c
 )
 configure_target(batomorph)
 target_include_directories(batomorph PUBLIC include)
diff --git a/include/vec3.h b/include/vec3.h
new file mode 100644
index 0000000..5ef216b
--- /dev/null
+++ b/include/vec3.h
@@ -0,0 +1,16 @@
+#ifndef VEC3_H
+#define VEC3_H
+
+typedef struct {
+	double x, y, z;
+} vec3_t;
+
+vec3_t vec3_scale(vec3_t v, double s);
+vec3_t vec3_add(vec3_t v, vec3_t u);
+vec3_t vec3_sub(vec3_t v, vec3_t u);
+double vec3_dot(vec3_t v, vec3_t u);
+vec3_t vec3_cross(vec3_t v, vec3_t u);
+double vec3_len(vec3_t v);
+vec3_t vec3_unit(vec3_t v);
+
+#endif
diff --git a/src/vec3.c b/src/vec3.c
new file mode 100644
index 0000000..c71291d
--- /dev/null
+++ b/src/vec3.c
@@ -0,0 +1,51 @@
+#include "vec3.h"
+
+#include <math.h>
+
+vec3_t vec3_scale(vec3_t v, double s)
+{
+	v.x *= s;
+	v.y *= s;
+	v.z *= s;
+	return v;
+}
+
+vec3_t vec3_add(vec3_t v, vec3_t u)
+{
+	v.x += u.x;
+	v.y += u.y;
+	v.z += u.z;
+	return v;
+}
+
+vec3_t vec3_sub(vec3_t v, vec3_t u)
+{
+	v.x -= u.x;
+	v.y -= u.y;
+	v.z -= u.z;
+	return v;
+}
+
+double vec3_dot(vec3_t v, vec3_t u)
+{
+	return v.x * u.x + v.y * u.y + v.z * u.z;
+}
+
+vec3_t vec3_cross(vec3_t v, vec3_t u)
+{
+	return (vec3_t) {
+		.x = v.y * u.z - v.z * u.y,
+		.y = v.z * u.x - v.x * u.z,
+		.z = v.x * u.y - v.y * u.x,
+	};
+}
+
+double vec3_len(vec3_t v)
+{
+	return sqrt(v.x * v.x + v.y * v.y + v.z * v.z);
+}
+
+vec3_t vec3_unit(vec3_t v)
+{
+	return vec3_scale(v, 1.0 / vec3_len(v));
+}