[Add] Desktop and draggable UI windows.

client/src/main.cpp

@@ -5,6 +5,7 @@
 
 #include "terminal.h"
 #include "gfx/shape_renderer.h"
+#include "ui/desktop.h"
 #include "ui/ui_window.h"
 
 const int SCREEN_WIDTH  = 1280;
@@ -63,13 +64,17 @@ int main(int argc, char** argv) {
   /* Init shape renderer. */
   ShapeRenderer* shape_renderer_instance = new ShapeRenderer(SCREEN_WIDTH, SCREEN_HEIGHT);
 
-  /* Create UI window. */
-  UIWindow* test_window = new UIWindow("Terminal", 100, 100, 800, 500);
-
   /* Create terminal. */
   Terminal* term = new Terminal();
+
+  /* Create UI window and pass it a terminal. */
+  UIWindow* test_window = new UIWindow("Terminal", 100, 100, 800, 500);
   test_window->set_content(term);
 
+  /* Create desktop and add the window. */
+  Desktop* desktop = new Desktop();
+  desktop->add_window(test_window);
+
   bool running = true;
   while(running) {
     /* Event handling. */
@@ -77,6 +82,7 @@ int main(int argc, char** argv) {
     while(SDL_PollEvent(&event)) {
       if(event.type == SDL_EVENT_QUIT) { running = false; }
       /* Pass input to terminal. */
+      desktop->handle_event(&event);
       term->handle_input(&event);
     }
 
@@ -84,13 +90,14 @@ int main(int argc, char** argv) {
     glClearColor(0.1f, 0.1f, 0.1, 1.0f);
     glClear(GL_COLOR_BUFFER_BIT);
 
-    test_window->render(shape_renderer_instance, txt_render_instance, SCREEN_HEIGHT);
+    desktop->render(shape_renderer_instance, txt_render_instance, SCREEN_HEIGHT);
 
     /* It's really odd to call it SwapWindow now, rather than SwapBuffer. */
     SDL_GL_SwapWindow(window);
   }
 
   /* Cleanup. */
+  delete desktop;
   delete term;
   delete test_window;
   delete shape_renderer_instance;

client/src/ui/desktop.cpp

@@ -0,0 +1,29 @@
+#include "desktop.h"
+#include "gfx/shape_renderer.h"
+#include "gfx/txt_renderer.h"
+#include "ui/ui_window.h"
+
+Desktop::Desktop(void) {}
+
+/* Desktop won't own the windows, so doesn't delete them. */
+Desktop::~Desktop(void) {}
+
+void Desktop::add_window(UIWindow* window) {
+  _windows.push_back(window);
+}
+
+void Desktop::handle_event(SDL_Event* event) {
+  /* Just pass the even to all windows for the moment.
+   * TODO: Only send event to the focused window.
+   */
+  for(auto win : _windows) {
+    win->handle_event(event);
+  }
+}
+
+void Desktop::render(ShapeRenderer* shape_renderer, TextRenderer* txt_renderer,
+                     int screen_height) {
+  for(auto win: _windows) {
+    win->render(shape_renderer, txt_renderer, screen_height);
+  }
+}

client/src/ui/desktop.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <vector>
+#include <SDL3/SDL.h>
+
+#include "gfx/shape_renderer.h"
+#include "gfx/txt_renderer.h"
+#include "ui/ui_window.h"
+
+class Desktop {
+public:
+  Desktop(void);
+  ~Desktop(void);
+
+  void add_window(UIWindow* window);
+  void handle_event(SDL_Event* event);
+  void render(ShapeRenderer* shape_renderer, TextRenderer* txt_renderer, int screen_height);
+
+private:
+  std::vector<UIWindow*> _windows;
+};

client/src/ui/ui_window.cpp

@@ -1,4 +1,5 @@
 #include "ui_window.h"
+#include <SDL3/SDL_events.h>
 #include "gfx/shape_renderer.h"
 #include "gfx/txt_renderer.h"
 
@@ -9,6 +10,7 @@ UIWindow::UIWindow(const char* title, int x, int y, int width, int height) {
   _width        = width;
   _height       = height;
   _content      = nullptr;
+  _is_dragging  = false;
 }
 
 void UIWindow::set_content(Terminal* term) {
@@ -45,3 +47,27 @@ void UIWindow::render(ShapeRenderer* shape_renderer, TextRenderer* txt_renderer,
   }
 }
 
+void UIWindow::handle_event(SDL_Event* event) {
+  int title_bar_height = 30;
+
+  if(event->type == SDL_EVENT_MOUSE_BUTTON_DOWN) {
+    int mouse_x = event->button.x;
+    int mouse_y = event->button.y;
+
+    /* Is click within title bar? */
+    if(mouse_x >= _x && mouse_x <= _x + _width &&
+       mouse_y >= _y && mouse_y <= _y + title_bar_height) {
+      _is_dragging = true;
+      _drag_offset_x = mouse_x - _x;
+      _drag_offset_y = mouse_y - _y;
+    }
+  } else if(event->type == SDL_EVENT_MOUSE_BUTTON_UP) {
+    _is_dragging = false;
+  } else if(event->type == SDL_EVENT_MOUSE_MOTION) {
+    if(_is_dragging) {
+      _x = event->motion.x - _drag_offset_x;
+      _y = event->motion.y - _drag_offset_y;
+    }
+  }
+}
+

client/src/ui/ui_window.h

@@ -11,11 +11,15 @@ public:
   UIWindow(const char* title, int x, int y, int width, int height);
 
   void render(ShapeRenderer* shape_renderer, TextRenderer* txt_renderer, int screen_height);
+  void handle_event(SDL_Event* event);
   void set_content(Terminal* term);
 
 private:
   int _x, _y, _width, _height;
   std::string _title;
   Terminal* _content;
+
+  bool _is_dragging;
+  int _drag_offset_x, _drag_offset_y;
 };