Implemented command line device selection and gpu listing (Refs #129)

base/vulkanexamplebase.cpp

@@ -789,11 +789,63 @@ void VulkanExampleBase::initVulkan()
 		vkTools::exitFatal("Could not enumerate physical devices : \n" + vkTools::errorString(err), "Fatal error");
 	}
 
-	// Note :
+	// GPU selection
-	// This example will always use the first physical device reported,
+
-	// change the vector index if you have multiple Vulkan devices installed
+	// Select physical device to be used for the Vulkan example
-	// and want to use another one
+	// Defaults to the first device unless specified by command line
-	physicalDevice = physicalDevices[0];
+	uint32_t selectedDevice = 0;
+
+#if !defined(__ANDROID__)	
+	// GPU selection via command line argument
+	for (size_t i = 0; i < args.size(); i++)
+	{
+		// Select GPU
+		if ((args[i] == std::string("-g")) || (args[i] == std::string("-gpu")))
+		{
+			char* endptr;
+			uint32_t index = strtol(args[i + 1], &endptr, 10);
+			if (endptr != args[i + 1]) 
+			{ 
+				if (index > gpuCount - 1)
+				{
+					std::cerr << "Selected device index " << index << " is out of range, reverting to device 0 (use -listgpus to show available Vulkan devices)" << std::endl;
+				} 
+				else
+				{
+					std::cout << "Selected Vulkan device " << index << std::endl;
+					selectedDevice = index;
+				}
+			};
+			break;
+		}
+		// List available GPUs
+		if (args[i] == std::string("-listgpus"))
+		{
+			uint32_t gpuCount = 0;
+			VK_CHECK_RESULT(vkEnumeratePhysicalDevices(instance, &gpuCount, nullptr));
+			if (gpuCount == 0) 
+			{
+				std::cerr << "No Vulkan devices found!" << std::endl;
+			}
+			else 
+			{
+				// Enumerate devices
+				std::cout << "Available Vulkan devices" << std::endl;
+				std::vector<VkPhysicalDevice> devices(gpuCount);
+				VK_CHECK_RESULT(vkEnumeratePhysicalDevices(instance, &gpuCount, devices.data()));
+				for (uint32_t i = 0; i < gpuCount; i++) {
+					VkPhysicalDeviceProperties deviceProperties;
+					vkGetPhysicalDeviceProperties(devices[i], &deviceProperties);
+					std::cout << "Device [" << i << "] : " << deviceProperties.deviceName << std::endl;
+					std::cout << " Type: " << vkTools::physicalDeviceTypeString(deviceProperties.deviceType) << std::endl;
+					std::cout << " API: " << (deviceProperties.apiVersion >> 22) << "." << ((deviceProperties.apiVersion >> 12) & 0x3ff) << "." << (deviceProperties.apiVersion & 0xfff) << std::endl;
+				}
+			}
+		}
+	}
+#endif
+
+	physicalDevice = physicalDevices[selectedDevice];
 
 	// Vulkan device creation
 	// This is handled by a separate class that gets a logical device representation
@@ -851,6 +903,7 @@ void VulkanExampleBase::setupConsole(std::string title)
 	AttachConsole(GetCurrentProcessId());
 	FILE *stream;
 	freopen_s(&stream, "CONOUT$", "w+", stdout);
+	freopen_s(&stream, "CONOUT$", "w+", stderr);
 	SetConsoleTitle(TEXT(title.c_str()));
 }