update vertical damping & add rigidbody:get_vdamping

src/physics/Hitbox.hpp

@@ -54,7 +54,7 @@ struct Hitbox {
     glm::vec3 velocity;
     float linearDamping = 0.5;
     float friction = 1.0f;
-    bool verticalDamping = false;
+    float verticalDamping = 1.0f;
     bool grounded = false;
     float gravityScale = 1.0f;
     bool crouching = false;