add viewport node, return ptr instead of ref for layout[id] to check wether is valid or not

engine/layout.h

@@ -49,6 +49,7 @@ enum class kWidget : uint16_t
     Button    = const_hash("button"),
     ButtonCustom = const_hash("button-custom"),
     PopupMenu = const_hash("popup-menu"),
+    Viewport  = const_hash("viewport"),
     Ref       = const_hash("ref"),
 };
 
@@ -104,7 +105,7 @@ public:
     std::function<void()> on_loaded;
     bool load(const char* path);
     bool reload();
-    class Node& operator[](uint16_t id) { return *m_layouts[id]; }
+    class Node* operator[](uint16_t id) { return m_layouts[id].get(); }
     //Node& operator[](const char* ids) { return m_layouts[const_hash(ids)]; }
 };
 
@@ -617,7 +618,7 @@ public:
         SetWidthP(100);
         SetHeightP(100);
         SetPositioning(YGPositionTypeAbsolute);
-        m_template = (*m_manager)[const_hash("message-box")].m_children[0]->clone();
+        m_template = (*m_manager)[const_hash("message-box")]->m_children[0]->clone();
         add_child(m_template);
         btnOk = m_template->find<NodeButton>("btn-ok");
         btnOk->on_click = [&] { destroy(); };
@@ -703,7 +704,7 @@ public:
         SetWidthP(100);
         SetHeightP(100);
         SetPositioning(YGPositionTypeAbsolute);
-        m_template = (*m_manager)[const_hash("settings")].m_children[0]->clone();
+        m_template = (*m_manager)[const_hash("settings")]->m_children[0]->clone();
         add_child(m_template);
         btnOk = m_template->find<NodeButton>("btn-ok");
         btnOk->on_click = [&] { destroy(); };
@@ -764,3 +765,55 @@ public:
         }
     }
 };
+
+class NodeViewport : public Node
+{
+public:
+    std::unique_ptr<Plane> m_faces;
+    std::unique_ptr<Sampler> m_sampler;
+    uint16_t m_tex_id;
+    
+    virtual void draw() override 
+    {
+        static float angle = 0;
+        angle += 0.05;
+        glm::mat4 cam = glm::lookAt(glm::vec3(sinf(angle)*10, 0, -10), glm::vec3(0, 0, 0), glm::vec3(0, -1, 0));
+        glm::mat4 proj = glm::perspective<float>(glm::radians(45.f), m_clip.z / m_clip.w, .1f, 100);
+
+        GLint vp[4];
+        GLfloat cc[4];
+        glGetIntegerv(GL_VIEWPORT, vp);
+        glGetFloatv(GL_COLOR_CLEAR_VALUE, cc);
+
+        glClearColor(1, 0, 0, 1);
+        glClear(GL_COLOR_BUFFER_BIT);
+        auto box = m_clip;
+        glViewport(box.x, (int)(vp[3] - box.y - box.w), box.z, box.w);
+        TextureManager::get(m_tex_id).bind();
+        m_sampler->bind(0);
+        glEnable(GL_BLEND);
+        ShaderManager::use(kShader::Texture);
+        ShaderManager::u_int(kShaderUniform::Tex, 0);
+        ShaderManager::u_mat4(kShaderUniform::MVP, proj * cam);
+        m_faces->draw_fill();
+        m_sampler->unbind();
+        TextureManager::get(m_tex_id).unbind();
+        glDisable(GL_BLEND);
+
+        glViewport(vp[0], vp[1], vp[2], vp[3]);
+        glClearColor(cc[0], cc[1], cc[2], cc[3]);
+    }
+    virtual Node* clone_instantiate() const override
+    {
+        return new NodeViewport;
+    }
+    virtual void create() override
+    {
+        m_faces = std::make_unique<Plane>();
+        m_faces->create<1>(10, 10);
+        m_sampler = std::make_unique<Sampler>();
+        m_sampler->create();
+        TextureManager::load("data/uvs.jpg");
+        m_tex_id = const_hash("data/uvs.jpg");
+    }
+};