add debug messenger to graphics context

examples/graphics_context.zig

@@ -35,6 +35,7 @@ pub const GraphicsContext = struct {
     vkb: BaseWrapper,
 
     instance: Instance,
+    debug_messenger: vk.DebugUtilsMessengerEXT,
     surface: vk.SurfaceKHR,
     pdev: vk.PhysicalDevice,
     props: vk.PhysicalDeviceProperties,
@@ -51,7 +52,8 @@ pub const GraphicsContext = struct {
 
         var extension_names: std.ArrayList([*:0]const u8) = .empty;
         defer extension_names.deinit(allocator);
-        // these extensions are to support vulkan in mac os
+        try extension_names.append(allocator, vk.extensions.ext_debug_utils.name);
+        // the following extensions are to support vulkan in mac os
         // see https://github.com/glfw/glfw/issues/2335
         try extension_names.append(allocator, vk.extensions.khr_portability_enumeration.name);
         try extension_names.append(allocator, vk.extensions.khr_get_physical_device_properties_2.name);
@@ -81,6 +83,22 @@ pub const GraphicsContext = struct {
         self.instance = Instance.init(instance, vki);
         errdefer self.instance.destroyInstance(null);
 
+        self.debug_messenger = try self.instance.createDebugUtilsMessengerEXT(&.{
+            .message_severity = .{
+                //.verbose_bit_ext = true,
+                //.info_bit_ext = true,
+                .warning_bit_ext = true,
+                .error_bit_ext = true,
+            },
+            .message_type = .{
+                .general_bit_ext = true,
+                .validation_bit_ext = true,
+                .performance_bit_ext = true,
+            },
+            .pfn_user_callback = &debugUtilsMessengerCallback,
+            .p_user_data = null,
+        }, null);
+
         self.surface = try createSurface(self.instance, window);
         errdefer self.instance.destroySurfaceKHR(self.surface, null);
 
@@ -107,6 +125,7 @@ pub const GraphicsContext = struct {
     pub fn deinit(self: GraphicsContext) void {
         self.dev.destroyDevice(null);
         self.instance.destroySurfaceKHR(self.surface, null);
+        self.instance.destroyDebugUtilsMessengerEXT(self.debug_messenger, null);
         self.instance.destroyInstance(null);
 
         // Don't forget to free the tables to prevent a memory leak.
@@ -196,6 +215,17 @@ const QueueAllocation = struct {
     present_family: u32,
 };
 
+fn debugUtilsMessengerCallback(severity: vk.DebugUtilsMessageSeverityFlagsEXT, msg_type: vk.DebugUtilsMessageTypeFlagsEXT, callback_data: ?*const vk.DebugUtilsMessengerCallbackDataEXT, _: ?*anyopaque) callconv(.c) vk.Bool32 {
+    const severity_str = if (severity.verbose_bit_ext) "verbose" else if (severity.info_bit_ext) "info" else if (severity.warning_bit_ext) "warning" else if (severity.error_bit_ext) "error" else "unknown";
+
+    const type_str = if (msg_type.general_bit_ext) "general" else if (msg_type.validation_bit_ext) "validation" else if (msg_type.performance_bit_ext) "performance" else if (msg_type.device_address_binding_bit_ext) "device addr" else "unknown";
+
+    const message: [*c]const u8 = if (callback_data) |cb_data| cb_data.p_message else "NO MESSAGE!";
+    std.debug.print("[{s}][{s}]. Message:\n  {s}\n", .{ severity_str, type_str, message });
+
+    return .false;
+}
+
 fn pickPhysicalDevice(
     instance: Instance,
     allocator: Allocator,