working on vtable

src/vulkan/Instance.zig

@@ -1,4 +1,6 @@
+const std = @import("std");
 const vk = @import("vulkan");
+const PhysicalDevice = @import("PhysicalDevice").PhysicalDevice;
 const Object = @import("object.zig").Object;
 
 pub const Instance = extern struct {
@@ -6,4 +8,6 @@ pub const Instance = extern struct {
     const ObjectType: vk.ObjectType = .instance;
 
     object: Object,
+    physical_devices: std.ArrayList(*PhysicalDevice),
+    alloc_callbacks: vk.AllocationCallbacks,
 };

src/vulkan/object.zig

@@ -23,15 +23,14 @@ pub const Object = extern struct {
 };
 
 pub inline fn fromHandle(comptime T: type, comptime VkT: type, handle: VkT) !*T {
-    if (handle == .null_handle) {
-        return error.NullHandle;
+    comptime {
+        if (!@hasDecl(T, "object") or !@hasDecl(T, "ObjectType") or @TypeOf(T.ObjectType) != vk.ObjectType) {
+            @compileError("Object type \"" ++ @typeName(T) ++ "\" is malformed.");
+        }
     }
 
-    if (!@hasDecl(T, "object")) {
-        return error.NotAnObject;
-    }
-    if (!@hasDecl(T, "ObjectType") || @TypeOf(T.ObjectType) != vk.ObjectType) {
-        @panic("Object type \"" ++ @typeName(T) ++ "\" is malformed.");
+    if (handle == .null_handle) {
+        return error.NullHandle;
     }
 
     const dispatchable: *T = @ptrFromInt(@intFromEnum(handle));
@@ -40,3 +39,12 @@ pub inline fn fromHandle(comptime T: type, comptime VkT: type, handle: VkT) !*T
     }
     return dispatchable;
 }
+
+pub inline fn toHandle(comptime T: type, handle: *T) usize {
+    comptime {
+        if (!@hasDecl(T, "object") or !@hasDecl(T, "ObjectType") or @TypeOf(T.ObjectType) != vk.ObjectType) {
+            @compileError("Object type \"" ++ @typeName(T) ++ "\" is malformed.");
+        }
+    }
+    return @intFromPtr(handle);
+}