add validation layer checking (c++20 black magic)

src/Engine.cpp

@@ -34,6 +34,8 @@ void Engine::draw() {
 
 bool Engine::createInstance() {
 
+    uint32_t errorCount = 0;
+
     // create the appInfo filled with information about our app
     constexpr vk::ApplicationInfo appInfo { // using the c++ api instead of the c api
         .pApplicationName = "maiden",
@@ -46,9 +48,31 @@ bool Engine::createInstance() {
     // get necessary extensions that our windowing library requires
     uint32_t instanceExtensionsCount = 0;
     char const* const* instanceExtensions{ SDL_Vulkan_GetInstanceExtensions(&instanceExtensionsCount) };
-    // check if these extensions are available
+
+    // get required validation layers as specified by our app
+    std::vector<const char*> requiredValidationLayers;
+    if(enableValidationLayers) requiredValidationLayers.assign(validationLayers.begin(), validationLayers.end());
+
+    auto validationLayerProperties = context_.enumerateInstanceLayerProperties();
+    auto unsupportedLayer = std::ranges::find_if(requiredValidationLayers, [&validationLayerProperties](const auto& requiredLayer) {
+        return std::ranges::none_of(validationLayerProperties, [requiredLayer](const auto& layerProperty) {
+            return strcmp(layerProperty.layerName, requiredLayer) == 0;
+        });
+    }); // TODO: what black magic even is this
+    if(unsupportedLayer != requiredValidationLayers.end()) {
+        std::cout << "[" << __FUNCTION__ << ": " << __LINE__ << "] Required validation layer not supported: " << *unsupportedLayer << std::endl;
+        errorCount++;
+    }
+
+    // get all available extensions
     auto extensionProperties = context_.enumerateInstanceExtensionProperties();
-    uint32_t errorCount = 0;
+
+    // print if we feel like it
+    std::cout << "Available Vulkan Extensions: " << std::endl;
+    for(const auto& extensionProperty : extensionProperties) {
+        std::cout << "\t" << extensionProperty.extensionName << std::endl;
+    }
+
     for(uint32_t i = 0; i < instanceExtensionsCount; i++) { // for each extension that we require
         bool found = false;
         for(const auto& extensionProperty : extensionProperties) { // see if it matches any extensions that are provided
@@ -64,7 +88,7 @@ bool Engine::createInstance() {
             errorCount++;
         } else {
 	        // in case you're curious
-            std::cout << "[" << __FUNCTION__ << ": " << __LINE__ << "] SDL3 extension located: " << instanceExtensions[i] << std::endl;
+            //std::cout << "[" << __FUNCTION__ << ": " << __LINE__ << "] SDL3 extension located: " << instanceExtensions[i] << std::endl;
         }
     } // if any weren't then we must exit
     if(errorCount != 0) return false;
@@ -76,10 +100,6 @@ bool Engine::createInstance() {
     };
 
     instance_ = vk::raii::Instance(context_, instanceCreateInfo);
-    if(instance_ != nullptr) {
-        return true;
-    } else {
-        return false;
-    }
+    return (instance_ != nullptr);
 }
 

src/Engine.hpp

@@ -28,4 +28,7 @@ private:
     vk::raii::Context context_;
     vk::raii::Instance instance_ = nullptr;
 
+    static constexpr bool enableValidationLayers = true; // TODO: only true in debug mode
+    const std::vector<const char*> validationLayers = { "VK_LAYER_KHRONOS_validation" };
+
 };