Add mouse hook to the color picker.

Source/Engine/Platform/Base/ScreenUtilsBase.cpp

@@ -9,3 +9,6 @@ Color32 ScreenUtilsBase::GetPixelAt(int32 x, int32 y) {
 Int2 ScreenUtilsBase::GetScreenCursorPosition() {
     return { 0, 0 };
 }
+
+void ScreenUtilsBase::BlockAndReadMouse() {
+}

Source/Engine/Platform/Base/ScreenUtilsBase.h

@@ -26,4 +26,9 @@ public:
     /// </summary>
     /// <returns>Cursor position, in screen coordinates.</returns>
     API_FUNCTION() static Int2 GetScreenCursorPosition();
+
+    /// <summary>
+    /// Blocks mouse input and runs a callback
+    /// </summary>
+    API_FUNCTION() static void BlockAndReadMouse();
 };

Source/Engine/Platform/Windows/WindowsScreenUtils.cpp

@@ -7,8 +7,10 @@
 #if PLATFORM_WINDOWS
 #pragma comment(lib, "Gdi32.lib")
 #endif
+#include <Engine/Core/Log.h>
 
-Color32 ScreenUtils::GetPixelAt(int32 x, int32 y) {
+Color32 ScreenUtils::GetPixelAt(int32 x, int32 y)
+{
     HDC deviceContext = GetDC(NULL);
     COLORREF color = GetPixel(deviceContext, x, y);
     ReleaseDC(NULL, deviceContext);
@@ -17,10 +19,45 @@ Color32 ScreenUtils::GetPixelAt(int32 x, int32 y) {
     return returnColor;
 }
 
-Int2 ScreenUtils::GetScreenCursorPosition() {
+Int2 ScreenUtils::GetScreenCursorPosition()
+{
     POINT cursorPos;
     GetCursorPos(&cursorPos);
 
     Int2 returnCursorPos = { cursorPos.x, cursorPos.y };
     return returnCursorPos;
 }
+
+static HHOOK _mouseCallbackHook;
+LRESULT CALLBACK ScreenUtilsMouseCallback(
+    _In_ int nCode,
+    _In_ WPARAM wParam,
+    _In_ LPARAM lParam
+)
+{
+    LOG(Warning, "Hell lag. {0}", GetCurrentThreadId());
+    if (wParam != WM_LBUTTONDOWN) { // Return as early as possible.
+        return CallNextHookEx(NULL, nCode, wParam, lParam);
+    }
+
+    if (nCode < 0) {
+        return CallNextHookEx(NULL, nCode, wParam, lParam);
+    }
+
+
+    if (nCode >= 0 && wParam == WM_LBUTTONDOWN) { // Now try to run our code.
+        LOG(Warning, "Mouse callback hit. Skipping event. (hopefully)");
+        UnhookWindowsHookEx(_mouseCallbackHook);
+        return 1;
+    }
+}
+
+void ScreenUtils::BlockAndReadMouse()
+{
+    _mouseCallbackHook = SetWindowsHookEx(WH_MOUSE_LL, ScreenUtilsMouseCallback, NULL, NULL);
+    if (_mouseCallbackHook == NULL)
+    {
+        LOG(Warning, "Failed to set mouse hook.");
+        LOG(Warning, "Error: {0}", GetLastError());
+    }
+}

Source/Engine/Platform/Windows/WindowsScreenUtils.h

@@ -11,6 +11,7 @@ public:
     // [ScreenUtilsBase]
     static Color32 GetPixelAt(int32 x, int32 y);
     static Int2 GetScreenCursorPosition();
+    static void BlockAndReadMouse();
 };
 
 #endif