destroy all textures on window destruction and restore OpenGL objects when Android resumes the app

engine/layout.h

@@ -92,6 +92,7 @@ class LayoutManager
     std::string m_path;
     struct stat m_file_info { 0 };
 public:
+    bool m_loaded = false;
     std::function<void()> on_loaded;
     bool load(const char* path);
     bool reload();
@@ -218,6 +219,13 @@ public:
         return o;
     }
 
+    virtual void restore_context()
+    {
+        for (auto& c : m_children)
+        {
+            c->restore_context();
+        }
+    };
     void update(float width, float height, float zoom);
     void update();
     void update_internal(const glm::vec2& origin, const glm::mat4& proj);
@@ -275,39 +283,6 @@ public:
     void mouse_release() { root()->current_mouse_capture = nullptr;  m_mouse_captured = false; }
     void key_capture() { root()->current_key_capture = this; m_key_captured = true; }
     void key_release() { root()->current_key_capture = nullptr;  m_key_captured = false; }
-
-//     class iterator
-//     {
-//         std::stack<Node*> m_nodes;
-//         Node* m_current;
-//     public:
-//         iterator(Node* root)
-//         {
-//             m_current = root;
-//             if (root)
-//                 m_nodes.push(root);
-//         }
-//         iterator& operator++() 
-//         { 
-//             m_nodes.pop();
-//             for (auto& c : m_current->m_children)
-//                 m_nodes.push(c.get());
-//             m_current = m_nodes.size() ? m_nodes.top() : nullptr;
-//             return *this;
-//         }
-//         Node& operator*() { return *m_current; }
-//         Node* operator->() { return m_current; }
-//         bool operator==(const iterator& rhs) { return m_current == rhs.m_current; }
-//         bool operator!=(const iterator& rhs) { return m_current != rhs.m_current; }
-//     };
-//     iterator begin()
-//     {
-//         return this;
-//     }
-//     iterator end()
-//     {
-//         return nullptr;
-//     }
 };
 
 class NodeBorder : public Node
@@ -421,6 +396,11 @@ public:
         m_text_mesh.update(font_id, m_text.c_str());
         SetSize(m_text_mesh.bb);
     }
+    virtual void restore_context() override
+    {
+        Node::restore_context();
+        create();
+    }
     virtual void parse_attributes(kAttribute ka, const tinyxml2::XMLAttribute* attr) override
     {
         Node::parse_attributes(ka, attr);
@@ -507,6 +487,11 @@ public:
             m_sz = (m_region.zw - m_region.xy) / tex_sz;
         }
     }
+    virtual void restore_context() override
+    {
+        Node::restore_context();
+        create();
+    }
     virtual void parse_attributes(kAttribute ka, const tinyxml2::XMLAttribute* attr) override
     {
         Node::parse_attributes(ka, attr);
@@ -1711,6 +1696,12 @@ public:
         TextureManager::load("data/Icons/Round-Hard.png");
         m_brush.m_tex_id = const_hash("data/Icons/Round-Hard.png");
     }
+    virtual void restore_context() override
+    {
+        NodeBorder::restore_context();
+        init_controls();
+        m_rtt.create(m_rtt.getWidth(), m_rtt.getHeight());
+    }
     void draw_stroke()
     {
         m_rtt.bindFramebuffer();
@@ -1880,6 +1871,13 @@ public:
         m_sampler.create();
         m_face_plane.create<1>(2, 2);
     }
+    virtual void restore_context() override
+    {
+        Node::restore_context();
+        m_canvas->create(512, 512);
+        m_sampler.create();
+        m_face_plane.create<1>(2, 2);
+    }
     virtual void draw() override
     {
         using namespace ui;