feat: Add vec3::rotate function for quaternion rotation.

1 files changed, 15 insertions, 0 deletions

diff --git a/src/util/mini_math.h b/src/util/mini_math.h
index f847cc1..f60e27e 100644
--- a/src/util/mini_math.h
+++ b/src/util/mini_math.h
@@ -97,6 +97,10 @@ struct vec2 {
 };
 #endif /* defined(USE_VEC2) */
 
+#if defined(USE_QUAT)
+struct quat;
+#endif
+
 #if defined(USE_VEC3)
 struct vec3 {
   union {
@@ -110,6 +114,11 @@ struct vec3 {
   }
   VEC_OPERATORS(vec3, 3) // Operators only touch x,y,z (indices 0,1,2)
 
+#if defined(USE_QUAT)
+  // Rotate this vector by a quaternion
+  vec3 rotate(const quat& q) const;
+#endif
+
   static vec3 cross(vec3 a, vec3 b) {
     return {a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z,
             a.x * b.y - a.y * b.x};
@@ -427,6 +436,12 @@ inline quat slerp(quat a, quat b, float t) {
         s1 = std::sin(th) / s0, s2 = std::sin(th0 - th) / s0;
   return a * s2 + b * s1;
 }
+
+#if defined(USE_VEC3)
+inline vec3 vec3::rotate(const quat& q) const {
+  return q.rotate(*this);
+}
+#endif
 #endif /* defined(USE_QUAT) */
 
 template <typename T> inline T lerp(const T& a, const T& b, float t) {