I can now apply shaders to any GUI element, but I need a shader manager that will allow for hot reloading and tracking input/output variables.

guecs.cpp

@@ -65,6 +65,33 @@ namespace guecs {
     shape->setFillColor(color);
   }
 
+  void Shader::init(lel::Cell &cell) {
+    ptr = std::make_shared<sf::Shader>();
+    bool good = ptr->loadFromFile(name, sf::Shader::Type::Fragment);
+    dbc::check(good, fmt::format("failed to load shader {}", name));
+    ptr->setUniform("u_resolution", sf::Vector2f({float(cell.w), float(cell.h)}));
+
+    clock = std::make_shared<sf::Clock>();
+  }
+
+  void Shader::step() {
+    sf::Time u_time = clock->getElapsedTime();
+    float current_time = u_time.asSeconds();
+
+    if(current_time < u_time_end) {
+      ptr->setUniform("u_time", current_time);
+    } else {
+      active = false;
+    }
+  }
+
+  void Shader::run() {
+    active = true;
+    sf::Time u_time = clock->getElapsedTime();
+    u_time_end = u_time.asSeconds() + duration;
+    ptr->setUniform("u_duration", duration);
+    ptr->setUniform("u_time_end", u_time_end);
+  }
 
   UI::UI() {
     $font = make_shared<sf::Font>(FONT_FILE_NAME);
@@ -114,6 +141,10 @@ namespace guecs {
       rect.init(cell);
     });
 
+    $world.query<lel::Cell, Shader>([](auto, auto& cell, auto& shader) {
+        shader.init(cell);
+    });
+
     $world.query<Rectangle, Meter>([](auto, auto& bg, auto &) {
         bg.shape->setFillColor(ColorValue::BLACK);
     });
@@ -152,27 +183,31 @@ namespace guecs {
       window.draw(*bg.shape);
     }
 
-    $world.query<Rectangle>([&](auto, auto& rect) {
-        window.draw(*rect.shape);
+    $world.query<Shader>([&](auto, auto& shader) {
+      if(shader.active) shader.step();
     });
 
-    $world.query<lel::Cell, Meter>([&](auto, auto& cell, const auto &meter) {
+    $world.query<Rectangle>([&](auto ent, auto& rect) {
+        render_helper(window, ent, true, rect.shape);
+    });
+
+    $world.query<lel::Cell, Meter>([&](auto ent, auto& cell, const auto &meter) {
         float level = std::clamp(meter.percent, 0.0f, 1.0f) * float(cell.w);
         // ZED: this 6 is a border width, make it a thing
         meter.bar.shape->setSize({std::max(level, 0.0f), float(cell.h - 6)});
-        window.draw(*meter.bar.shape);
+        render_helper(window, ent, true, meter.bar.shape);
     });
 
-    $world.query<Sprite>([&](auto, auto& sprite) {
-        window.draw(*sprite.sprite);
+    $world.query<Sprite>([&](auto ent, auto& sprite) {
+        render_helper(window, ent, false, sprite.sprite);
     });
 
-    $world.query<Label>([&](auto, auto& text) {
-        window.draw(*text.text);
+    $world.query<Label>([&](auto ent, auto& text) {
+        render_helper(window, ent, false, text.text);
     });
 
-    $world.query<Textual>([&](auto, auto& text) {
-        window.draw(*text.text);
+    $world.query<Textual>([&](auto ent, auto& text) {
+        render_helper(window, ent, true, text.text);
     });
   }
 
@@ -183,6 +218,11 @@ namespace guecs {
       if((x >= cell.x && x <= cell.x + cell.w) &&
           (y >= cell.y && y <= cell.y + cell.h))
       {
+        if($world.has<Shader>(ent)) {
+          auto& shader = $world.get<Shader>(ent);
+          shader.run();
+        }
+
         if(auto action_data = get_if<ActionData>(ent)) {
           clicked.action(ent, action_data->data);
         } else {