Ch03PhysicalDeviceSelection.diff

diff --git "a/G:\\Java-Dev\\Vulkan-Tutorial-Java\\src\\main\\java\\javavulkantutorial\\Ch02ValidationLayers.java" "b/G:\\Java-Dev\\Vulkan-Tutorial-Java\\src\\main\\java\\javavulkantutorial\\Ch03PhysicalDeviceSelection.java"
index 4bf9c62..a6e48df 100644
--- "a/G:\\Java-Dev\\Vulkan-Tutorial-Java\\src\\main\\java\\javavulkantutorial\\Ch02ValidationLayers.java"
+++ "b/G:\\Java-Dev\\Vulkan-Tutorial-Java\\src\\main\\java\\javavulkantutorial\\Ch03PhysicalDeviceSelection.java"
@@ -8,6 +8,7 @@ import java.nio.IntBuffer;
 import java.nio.LongBuffer;
 import java.util.HashSet;
 import java.util.Set;
+import java.util.stream.IntStream;
 
 import static java.util.stream.Collectors.toSet;
 import static org.lwjgl.glfw.GLFW.*;
@@ -19,7 +20,7 @@ import static org.lwjgl.system.MemoryUtil.NULL;
 import static org.lwjgl.vulkan.EXTDebugUtils.*;
 import static org.lwjgl.vulkan.VK10.*;
 
-public class Ch02ValidationLayers {
+public class Ch03PhysicalDeviceSelection {
 
     private static class HelloTriangleApplication {
 
@@ -66,11 +67,23 @@ public class Ch02ValidationLayers {
 
         }
 
+        private class QueueFamilyIndices {
+
+            // We use Integer to use null as the empty value
+            private Integer graphicsFamily;
+
+            private boolean isComplete() {
+                return graphicsFamily != null;
+            }
+
+        }
+
         // ======= FIELDS ======= //
 
         private long window;
         private VkInstance instance;
         private long debugMessenger;
+        private VkPhysicalDevice physicalDevice;
 
         // ======= METHODS ======= //
 
@@ -102,6 +115,7 @@ public class Ch02ValidationLayers {
         private void initVulkan() {
             createInstance();
             setupDebugMessenger();
+            pickPhysicalDevice();
         }
 
         private void mainLoop() {
@@ -200,6 +214,66 @@ public class Ch02ValidationLayers {
             }
         }
 
+        private void pickPhysicalDevice() {
+
+            try(MemoryStack stack = stackPush()) {
+
+                IntBuffer deviceCount = stack.ints(0);
+
+                vkEnumeratePhysicalDevices(instance, deviceCount, null);
+
+                if(deviceCount.get(0) == 0) {
+                    throw new RuntimeException("Failed to find GPUs with Vulkan support");
+                }
+
+                PointerBuffer ppPhysicalDevices = stack.mallocPointer(deviceCount.get(0));
+
+                vkEnumeratePhysicalDevices(instance, deviceCount, ppPhysicalDevices);
+
+                for(int i = 0;i < ppPhysicalDevices.capacity();i++) {
+
+                    VkPhysicalDevice device = new VkPhysicalDevice(ppPhysicalDevices.get(i), instance);
+
+                    if(isDeviceSuitable(device)) {
+                        physicalDevice = device;
+                        return;
+                    }
+                }
+
+                throw new RuntimeException("Failed to find a suitable GPU");
+            }
+        }
+
+        private boolean isDeviceSuitable(VkPhysicalDevice device) {
+
+            QueueFamilyIndices indices = findQueueFamilies(device);
+
+            return indices.isComplete();
+        }
+
+        private QueueFamilyIndices findQueueFamilies(VkPhysicalDevice device) {
+
+            QueueFamilyIndices indices = new QueueFamilyIndices();
+
+            try(MemoryStack stack = stackPush()) {
+
+                IntBuffer queueFamilyCount = stack.ints(0);
+
+                vkGetPhysicalDeviceQueueFamilyProperties(device, queueFamilyCount, null);
+
+                VkQueueFamilyProperties.Buffer queueFamilies = VkQueueFamilyProperties.malloc(queueFamilyCount.get(0), stack);
+
+                vkGetPhysicalDeviceQueueFamilyProperties(device, queueFamilyCount, queueFamilies);
+
+                IntStream.range(0, queueFamilies.capacity())
+                        .filter(index -> (queueFamilies.get(index).queueFlags() & VK_QUEUE_GRAPHICS_BIT) != 0)
+                        .findFirst()
+                        .ifPresent(index -> indices.graphicsFamily = index);
+
+                return indices;
+            }
+        }
+
         private PointerBuffer validationLayersAsPointerBuffer(MemoryStack stack) {
 
             PointerBuffer buffer = stack.mallocPointer(VALIDATION_LAYERS.size());