1 files changed, 75 insertions, 0 deletions
diff --git a/src/core/application.cpp b/src/core/application.cpp
new file mode 100644
index 0000000..fd04e62
--- /dev/null
+++ b/src/core/application.cpp
@@ -0,0 +1,75 @@
+#include "core/application.h"
+
+#include "core/assert.h"
+#include "core/log.h"
+
+#include <chrono>
+
+namespace Hsdbg
+{
+    namespace
+    {
+        using Clock = std::chrono::steady_clock;
+
+        constexpr float MAX_DELTA_TIME = 0.25f;
+
+        // the run loop has nothing to block on until the window owns it, so it is
+        // time boxed for now to keep the app from spinning forever
+        constexpr float PLACEHOLDER_RUN_TIME = 1.0f;
+    }
+
+    Application* Application::s_instance = nullptr;
+
+    Application::Application(const ApplicationSpec& spec)
+        : m_spec(spec)
+    {
+        HSDBG_ASSERT(s_instance == nullptr, "an Application instance already exists");
+        s_instance = this;
+
+        Log::info("{}: starting up", m_spec.name);
+    }
+
+    Application::~Application()
+    {
+        Log::info("{}: shutting down after {} frames", m_spec.name, m_frame_count);
+
+        s_instance = nullptr;
+    }
+
+    auto Application::get() -> Application&
+    {
+        HSDBG_ASSERT(s_instance != nullptr, "no Application instance has been created");
+        return *s_instance;
+    }
+
+    auto Application::run() -> void
+    {
+        m_running = true;
+
+        auto last_frame_time = Clock::now();
+
+        while (m_running)
+        {
+            const auto now = Clock::now();
+            const float elapsed = std::chrono::duration<float>(now - last_frame_time).count();
+            last_frame_time = now;
+
+            m_delta_time = elapsed < MAX_DELTA_TIME ? elapsed : MAX_DELTA_TIME;
+            m_time += m_delta_time;
+            m_frame_count += 1;
+
+            update();
+        }
+    }
+
+    auto Application::close() -> void
+    {
+        m_running = false;
+    }
+
+    auto Application::update() -> void
+    {
+        if (m_time >= PLACEHOLDER_RUN_TIME)
+            close();
+    }
+}