Add WorkFactory which allows to delay creation of the next Work

src/jngl.hpp

@@ -1,4 +1,4 @@
-// Copyright 2012-2023 Jan Niklas Hasse <[email protected]>
+// Copyright 2012-2024 Jan Niklas Hasse <[email protected]>
 // For conditions of distribution and use, see copyright notice in LICENSE.txt
 /// Includes all JNGL headers except for init.hpp
 /// @file
@@ -21,6 +21,7 @@
 #include "jngl/Vertex.hpp"
 #include "jngl/Video.hpp"
 #include "jngl/Widget.hpp"
+#include "jngl/WorkFactory.hpp"
 #include "jngl/debug.hpp"
 #include "jngl/effects.hpp"
 #include "jngl/font.hpp"

src/jngl/WorkFactory.cpp

@@ -0,0 +1,27 @@
+// Copyright 2024 Jan Niklas Hasse <[email protected]>
+// For conditions of distribution and use, see copyright notice in LICENSE.txt
+#include "WorkFactory.hpp"
+#include <cassert>
+
+namespace jngl {
+
+WorkFactory::WorkFactory(std::function<std::shared_ptr<Work>()> factory)
+: factory(std::move(factory)) {
+}
+
+void WorkFactory::step() {
+	assert(factory); // we should only be stepped once
+	factory = nullptr;
+	work->step();
+}
+
+void WorkFactory::draw() const {
+	work->draw();
+}
+
+void WorkFactory::onLoad() {
+	work = factory();
+	jngl::setWork(work);
+}
+
+} // namespace jngl

src/jngl/WorkFactory.hpp

@@ -0,0 +1,23 @@
+// Copyright 2024 Jan Niklas Hasse <[email protected]>
+// For conditions of distribution and use, see copyright notice in LICENSE.txt
+/// @file
+#pragma once
+
+#include "work.hpp"
+
+namespace jngl {
+
+class WorkFactory : public jngl::Work {
+public:
+    explicit WorkFactory(std::function<std::shared_ptr<Work>()>);
+
+private:
+    void step() override;
+    void draw() const override;
+    void onLoad() override;
+
+    std::shared_ptr<Work> work;
+    std::function<std::shared_ptr<Work>()> factory;
+};
+
+} // namespace jngl