diff --git a/Minecraft.World/Util/Vec3.cpp b/Minecraft.World/Util/Vec3.cpp
index 4bedbf5a6..810456f27 100644
--- a/Minecraft.World/Util/Vec3.cpp
+++ b/Minecraft.World/Util/Vec3.cpp
@@ -40,7 +40,7 @@ double Vec3::distanceTo(const Vec3& p) const {
     return std::sqrt(xd * xd + yd * yd + zd * zd);
 }
 
-double Vec3::distanceToSqr(const Vec3& p) {
+double Vec3::distanceToSqr(const Vec3& p) const {
     double xd = p.x - x;
     double yd = p.y - y;
     double zd = p.z - z;
diff --git a/Minecraft.World/Util/Vec3.h b/Minecraft.World/Util/Vec3.h
index 9d17f528a..bd470f663 100644
--- a/Minecraft.World/Util/Vec3.h
+++ b/Minecraft.World/Util/Vec3.h
@@ -18,7 +18,7 @@ public:
     Vec3 cross(const Vec3& p) const;
     Vec3 add(double x, double y, double z) const;
     double distanceTo(const Vec3& p) const;
-    double distanceToSqr(const Vec3& p);
+    double distanceToSqr(const Vec3& p) const;
     double distanceToSqr(double x2, double y2, double z2) const;
     Vec3 scale(double l) const;
     double length() const;