fix scroll node, improve animation panel

src/node_scroll.h

@@ -4,14 +4,14 @@
 class NodeScroll : public NodeBorder
 {
     bool m_dragging = false;
-    float m_scroll_dir = 1.f;
+    float m_drag_dir = 1.f;
     glm::vec2 m_drag_start = glm::vec2(0);
     glm::vec2 m_offset_start = glm::vec2(0);
     glm::vec2 m_offset = glm::vec2(0);
-    glm::vec2 m_mask = glm::vec2(1, 0);
+    glm::vec2 m_mask = glm::vec2(0, 1);
     glm::vec4 m_scrollbar_color = { .3, .3, .3, 1 };
 public:
-    NodeScroll();
+    enum class kScrollDirection : uint8_t { Vertical, Horizontal } m_direction;
     virtual Node* clone_instantiate() const override;
     virtual void clone_copy(Node* dest) const override;
     virtual kEventResult handle_event(Event* e) override;