refactor layout.h into single file per Node* classes

engine/node_panel_brush.h

@@ -0,0 +1,30 @@
+#pragma once
+#include "node.h"
+#include "node_button_custom.h"
+#include "node_image.h"
+
+class NodeButtonBrush : public NodeButtonCustom
+{
+public:
+    int m_brushID;
+    bool m_selected = false;
+    NodeImage* img;
+    virtual Node* clone_instantiate() const override;
+    virtual void init() override;
+    void set_icon(const char* path);
+    virtual void draw() override;
+};
+
+class NodePanelBrush : public Node
+{
+    std::vector<NodeButtonBrush*> m_brushes;
+    NodeButtonBrush* m_current = nullptr;
+    Node* m_container;
+public:
+    std::function<void(Node* target, int id)> on_brush_changed;
+    virtual Node* clone_instantiate() const override;
+    virtual void init() override;
+    void handle_click(Node* target);
+    std::vector<std::string> FindAllBrushes(std::string folder);
+    uint16_t get_texture_id(int index) const;
+};