feat: Step 1 SDL3 window + Vulkan context + clear screen

src/CortexEngine.App/Program.cs

@@ -0,0 +1,58 @@
+using System;
+using Engine.Core;
+using Engine.Graphics;
+
+namespace CortexEngine.App;
+
+class Program
+{
+    static void Main(string[] args)
+    {
+        Console.WriteLine("Cortex Engine Step 1 — Starting up...");
+
+        try
+        {
+            using var window = new Sdl3Window("Cortex Engine — Step 1", 1280, 720);
+            var timing = new Timing();
+            var input = new InputMapping();
+            using var vulkan = new VulkanContext(window, enableValidation: true);
+            using var swapchain = new Swapchain(vulkan);
+            using var renderer = new ClearRenderer(vulkan, swapchain);
+
+            var frames = 0;
+            var lastFpsTime = 0.0;
+
+            while (!window.ShouldClose)
+            {
+                timing.Tick();
+                window.PumpEvents();
+                input.BeginFrame();
+                // Note: SDL events are already polled in PumpEvents.
+                // In a real engine, the window would expose an event iterator.
+
+                // Animate clear color over time.
+                var t = (float)timing.TotalTime;
+                var r = MathF.Sin(t * 0.5f) * 0.5f + 0.5f;
+                var g = MathF.Sin(t * 0.7f + 2.0f) * 0.5f + 0.5f;
+                var b = MathF.Sin(t * 0.9f + 4.0f) * 0.5f + 0.5f;
+
+                renderer.RenderFrame(r, g, b);
+
+                frames++;
+                if (timing.TotalTime - lastFpsTime >= 1.0)
+                {
+                    Console.WriteLine($"FPS: {frames}, Delta: {timing.DeltaTime * 1000.0:F2} ms");
+                    frames = 0;
+                    lastFpsTime = timing.TotalTime;
+                }
+            }
+
+            Console.WriteLine("Shutting down...");
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"Fatal error: {ex}");
+            Environment.Exit(1);
+        }
+    }
+}