Remove Vulkan dependency when not needed

Author: lambda-pixel

3rdparty/imgui/CMakeLists.txt

@@ -1,5 +1,3 @@
-find_package(Vulkan REQUIRED)
-
 set(IMGUI_SRC
     imgui/imgui.cpp
     imgui/imgui_draw.cpp
@@ -32,8 +30,11 @@ endif()
 add_library(imgui ${IMGUI_SRC})
 target_include_directories(imgui PUBLIC imgui)
 
-target_link_libraries(imgui PUBLIC Vulkan::Vulkan)
-
 if (USE_SDL)
     target_link_libraries(imgui PUBLIC SDL3::SDL3)
 endif()
+
+if (USE_VULKAN)
+    find_package(Vulkan REQUIRED)
+    target_link_libraries(imgui PUBLIC Vulkan::Vulkan)
+endif()

src/GUI/Window/WindowSystem.cpp

@@ -4,6 +4,10 @@
 #include <chrono>
 #include <thread>
 
+#ifdef USE_VULKAN
+    #include <vulkan/vulkan.h>
+#endif
+
 #ifdef USE_SDL
     #include <SDL3/SDL_vulkan.h>
 
@@ -17,8 +21,6 @@
     #include <backends/imgui_impl_win32.h>
 #endif
 
-#include <backends/imgui_impl_vulkan.h>
-
 
 WindowSystem::WindowSystem(
 #ifdef USE_SDL
@@ -55,6 +57,7 @@ WindowSystem::~WindowSystem()
 }
 
 
+#ifdef USE_VULKAN
 void WindowSystem::getVkInstanceExtensions(std::vector<const char*>& extensions) const
 {
 #ifdef USE_SDL
@@ -69,6 +72,7 @@ void WindowSystem::getVkInstanceExtensions(std::vector<const char*>& extensions)
     extensions.push_back("VK_KHR_win32_surface");
 #endif
 }
+#endif
 
 
 void WindowSystem::collectEvents()