Merge #6243

6243: Followup fixes for physical devices r=def- a=Jupeyy

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## Checklist

- [ ] Tested the change ingame
- [ ] Provided screenshots if it is a visual change
- [ ] Tested in combination with possibly related configuration options
- [ ] Written a unit test (especially base/) or added coverage to integration test
- [ ] Considered possible null pointers and out of bounds array indexing
- [ ] Changed no physics that affect existing maps
- [ ] Tested the change with [ASan+UBSan or valgrind's memcheck](https://github.com/ddnet/ddnet/#using-addresssanitizer--undefinedbehavioursanitizer-or-valgrinds-memcheck) (optional)


Co-authored-by: Jupeyy <jupjopjap@gmail.com>

src/engine/client/backend/backend_base.h

@@ -50,6 +50,7 @@ enum EGFXWarningType
 {
 	GFX_WARNING_TYPE_NONE = 0,
 	GFX_WARNING_TYPE_INIT_FAILED,
+	GFX_WARNING_TYPE_INIT_FAILED_MISSING_INTEGRATED_GPU_DRIVER,
 	GFX_WARNING_LOW_ON_MEMORY,
 	GFX_WARNING_MISSING_EXTENSION,
 	GFX_WARNING_TYPE_UNKNOWN,

src/engine/client/backend/vulkan/backend_vulkan.cpp

@@ -1210,7 +1210,7 @@ protected:
 			m_RecreateSwapChain = true;
 			break;
 		default:
-			m_ErrorHelper = "unknown error";
+			m_ErrorHelper = "unknown error: ";
 			m_ErrorHelper.append(std::to_string(CallResult));
 			pCriticalError = m_ErrorHelper.c_str();
 			break;
@@ -3720,11 +3720,20 @@ public:
 
 		std::vector<VkPhysicalDevice> vDeviceList(DevicesCount);
 		Res = vkEnumeratePhysicalDevices(m_VKInstance, &DevicesCount, vDeviceList.data());
-		if(Res != VK_SUCCESS)
+		if(Res != VK_SUCCESS && Res != VK_INCOMPLETE)
 		{
 			SetError(EGFXErrorType::GFX_ERROR_TYPE_INIT, CheckVulkanCriticalError(Res));
 			return false;
 		}
+		if(DevicesCount == 0)
+		{
+			SetWarning(EGFXWarningType::GFX_WARNING_TYPE_INIT_FAILED_MISSING_INTEGRATED_GPU_DRIVER, "No vulkan compatible devices found.");
+			return false;
+		}
+		// make sure to use the correct amount of devices available
+		// the amount of physical devices can be smaller than the amount of devices reported
+		// see vkEnumeratePhysicalDevices for details
+		vDeviceList.resize(DevicesCount);
 
 		size_t Index = 0;
 		std::vector<VkPhysicalDeviceProperties> vDevicePropList(vDeviceList.size());

src/engine/client/backend_sdl.cpp

@@ -311,6 +311,9 @@ void CCommandProcessor_SDL_GL::HandleWarning()
 	case GFX_WARNING_TYPE_INIT_FAILED:
 		Warn.m_vWarnings.emplace_back(Localizable("Could not initialize the given graphics backend, reverting to the default backend now.", "Graphics error"));
 		break;
+	case GFX_WARNING_TYPE_INIT_FAILED_MISSING_INTEGRATED_GPU_DRIVER:
+		Warn.m_vWarnings.emplace_back(Localizable("Could not initialize the given graphics backend, this is probably caused because you didn't install the driver of the integrated graphics card.", "Graphics error"));
+		break;
 	case GFX_WARNING_MISSING_EXTENSION:
 		// ignore this warning for now
 		return;