Prepare shader reload.

- Expose wait until gpus is idle to api
- Alt+R to reload

JulietApp/main.cpp

@@ -1,6 +1,7 @@
 #include <main.h>
 
 #include <Core/Application/ApplicationManager.h>
+#include <Core/Common/EnumUtils.h>
 #include <Core/HAL/Display/Display.h>
 #include <Core/HAL/Event/SystemEvent.h>
 #include <Core/HAL/Filesystem/Filesystem.h>
@@ -158,6 +159,9 @@ void JulietApplication::Shutdown()
 
 void JulietApplication::Update()
 {
+    bool        reloadShaders         = false;
+    static bool reloadShadersDebounce = false;
+
     SystemEvent evt;
     while (GetEvent(evt))
     {
@@ -168,6 +172,23 @@ void JulietApplication::Update()
                 Running = false;
             }
         }
+
+        if (evt.Type == EventType::Key_Down)
+        {
+        }
+
+        // Shader hot reload using keyboard.
+        // TODO: Add Input debounce in the library. (Just pressed vs pressed)
+        if (!reloadShadersDebounce && ((GetKeyModState() & KeyMod::Alt) != KeyMod::None) && IsKeyDown(ScanCode::R))
+        {
+            reloadShaders         = true;
+            reloadShadersDebounce = true;
+        }
+
+        if (reloadShadersDebounce && !IsKeyDown(ScanCode::R))
+        {
+            reloadShadersDebounce = false;
+        }
     }
 
     Game.Update(0.0f);
@@ -177,6 +198,12 @@ void JulietApplication::Update()
         ReloadCode(GameCode);
     }
 
+    if (reloadShaders)
+    {
+        // We need to wait for the gpu to be idle to recreate our graphics pipelines
+        WaitUntilGPUIsIdle(GraphicsDevice);
+    }
+
     // Draw here for now
     // 1) Acquire a Command Buffer
     CommandList* cmdList = AcquireCommandList(GraphicsDevice, QueueType::Graphics);