architectural rework

.gdb_history

@@ -97,3 +97,26 @@ q
 run
 bt
 q
+run
+bt
+q
+run
+b
+bt
+q
+run
+bt
+q
+run
+bt
+q
+run
+bt
+q
+run
+bt
+q
+run
+bt
+q
+q

build.zig

@@ -15,33 +15,25 @@ const implementations = [_]ImplementationDesc{
     },
 };
 
-pub fn build(b: *std.Build) !void {
+pub fn build(b: *std.Build) void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
 
-    const common_mod = b.createModule(.{
+    const base_mod = b.createModule(.{
         .root_source_file = b.path("src/vulkan/lib.zig"),
         .target = target,
         .optimize = optimize,
         .link_libc = true,
     });
 
-    const interface_dependency = b.dependency("interface", .{
-        .target = target,
-        .optimize = optimize,
-    });
-
     const vulkan_headers = b.dependency("vulkan_headers", .{});
 
     const vulkan = b.dependency("vulkan_zig", .{
         .registry = vulkan_headers.path("registry/vk.xml"),
     }).module("vulkan-zig");
 
-    const interface_mod = interface_dependency.module("interface");
+    base_mod.addImport("vulkan", vulkan);
-
+    base_mod.addSystemIncludePath(vulkan_headers.path("include"));
-    common_mod.addImport("vulkan", vulkan);
-    common_mod.addImport("interface", interface_mod);
-    common_mod.addSystemIncludePath(vulkan_headers.path("include"));
 
     for (implementations) |impl| {
         const lib_mod = b.createModule(.{
@@ -50,16 +42,15 @@ pub fn build(b: *std.Build) !void {
             .link_libc = true,
             .optimize = optimize,
             .imports = &.{
-                .{ .name = "common", .module = common_mod },
+                .{ .name = "base", .module = base_mod },
                 .{ .name = "vulkan", .module = vulkan },
-                .{ .name = "interface", .module = interface_mod },
             },
         });
 
         lib_mod.addSystemIncludePath(vulkan_headers.path("include"));
 
         if (impl.custom) |custom| {
-            try custom(b, lib_mod);
+            custom(b, lib_mod) catch continue;
         }
 
         const lib = b.addLibrary(.{

build.zig.zon

@@ -18,10 +18,6 @@
             .hash = "cpuinfo-0.1.0-V7dMLcghAADJuG7dkd3MnwDPZ232pBK_8uGjxY43eP5u",
             .lazy = true,
         },
-        .interface = .{
-            .url = "git+https://github.com/nilslice/zig-interface#19f2c937b77e42b15bc8cacaa2894ce5b783d94d",
-            .hash = "interface-0.0.2-GFlWJ7KOAQAkHikqZU0XV86AhX7R9jCyGza85lTIqcEU",
-        },
     },
 
     .paths = .{

src/soft/Instance.zig

@@ -1,55 +1,40 @@
 const std = @import("std");
 const vk = @import("vulkan");
-const common = @import("common");
+const base = @import("base");
 const PhysicalDevice = @import("PhysicalDevice.zig");
 
-const dispatchable = common.dispatchable;
+const dispatchable = base.dispatchable;
+const VulkanAllocator = base.VulkanAllocator;
 
 const Self = @This();
-pub const ObjectType: vk.ObjectType = .instance;
 
-common_instance: common.Instance,
+export fn __vkImplInstanceInit(base_instance: *base.Instance, allocator: *const std.mem.Allocator) ?*anyopaque {
-physical_device: vk.PhysicalDevice, // Software driver only has one physical device (CPU)
+    return realVkImplInstanceInit(base_instance, allocator.*) catch return null;
+}
 
-pub fn create(p_infos: ?*const vk.InstanceCreateInfo, callbacks: ?*const vk.AllocationCallbacks, p_instance: *vk.Instance) callconv(vk.vulkan_call_conv) vk.Result {
+// Pure Zig implementation to leverage `errdefer` and avoid memory leaks or complex resources handling
-    const allocator = std.heap.c_allocator;
+fn realVkImplInstanceInit(base_instance: *base.Instance, allocator: std.mem.Allocator) !?*anyopaque {
-
+    base_instance.dispatch_table = .{
-    const dispatchable_instance = dispatchable.Dispatchable(Self).create(allocator) catch return .error_out_of_host_memory;
+        .destroyInstance = deinit,
-    const instance = dispatchable_instance.object;
-    common.Instance.init(&instance.common_instance, p_infos, callbacks) catch return .error_initialization_failed;
-
-    instance.common_instance.vtable = .{
-        .destroyInstance = destroy,
-        .enumeratePhysicalDevices = enumeratePhysicalDevices,
         .enumerateInstanceVersion = null,
         //.enumerateInstanceLayerProperties = null,
         .enumerateInstanceExtensionProperties = null,
-        .getPhysicalDeviceProperties = PhysicalDevice.getProperties,
     };
 
-    const dispatchable_physical_device = dispatchable.Dispatchable(PhysicalDevice).create(allocator) catch return .error_out_of_host_memory;
+    // Software driver only has one physical device (the CPU)
-    PhysicalDevice.init(dispatchable_physical_device.object) catch return .error_initialization_failed;
+    const dispatchable_physical_device = try PhysicalDevice.init(base_instance, allocator);
-    instance.physical_device = @enumFromInt(dispatchable_physical_device.toHandle());
+    errdefer dispatchable_physical_device.destroy(allocator);
 
-    p_instance.* = @enumFromInt(dispatchable_instance.toHandle());
+    try base_instance.physical_devices.append(allocator, @enumFromInt(dispatchable_physical_device.toHandle()));
-    return .success;
+
+    const self = try allocator.create(Self);
+    errdefer allocator.destroy(self);
+    return @ptrCast(self);
 }
 
-pub fn enumeratePhysicalDevices(p_instance: vk.Instance, count: *u32, p_devices: ?[*]vk.PhysicalDevice) callconv(vk.vulkan_call_conv) vk.Result {
+pub fn deinit(base_instance: *const base.Instance, allocator: std.mem.Allocator) !void {
-    const instance = dispatchable.fromHandleObject(Self, @intFromEnum(p_instance)) catch return .error_initialization_failed;
+    for (base_instance.physical_devices.items) |physical_device| {
-    count.* = 1;
+        const dispatchable_physical_device = try dispatchable.fromHandle(base.PhysicalDevice, @intFromEnum(physical_device));
-    if (p_devices) |devices| {
-        devices[0] = instance.physical_device;
-    }
-    return .success;
-}
-
-pub fn destroy(p_instance: vk.Instance, callbacks: ?*const vk.AllocationCallbacks) callconv(vk.vulkan_call_conv) void {
-    const allocator = std.heap.c_allocator;
-    _ = callbacks;
-
-    const dispatchable_instance = dispatchable.fromHandle(Self, @intFromEnum(p_instance)) catch return;
-    const dispatchable_physical_device = dispatchable.fromHandle(PhysicalDevice, @intFromEnum(dispatchable_instance.object.physical_device)) catch return;
         dispatchable_physical_device.destroy(allocator);
-    dispatchable_instance.destroy(allocator);
+    }
 }

src/soft/PhysicalDevice.zig

@@ -1,41 +1,30 @@
 const std = @import("std");
 const vk = @import("vulkan");
 const Instance = @import("Instance.zig");
-const common = @import("common");
+const base = @import("base");
 const root = @import("root");
 const cpuinfo = @import("cpuinfo");
 
-const dispatchable = common.dispatchable;
+const dispatchable = base.dispatchable;
 
 const Self = @This();
-pub const ObjectType: vk.ObjectType = .physical_device;
 
-instance: *const Instance,
+pub fn init(instance: *const base.Instance, allocator: std.mem.Allocator) !*dispatchable.Dispatchable(base.PhysicalDevice) {
-common_physical_device: common.PhysicalDevice,
+    const dispatchable_physical_device = try base.PhysicalDevice.init(instance, allocator);
+    errdefer dispatchable_physical_device.destroy(allocator);
 
-pub fn init(self: *Self) !void {
+    const base_physical_device = dispatchable_physical_device.object;
-    const allocator = std.heap.c_allocator;
 
-    self.common_physical_device.props = .{
+    base_physical_device.props.api_version = @bitCast(root.VULKAN_VERSION);
-        .api_version = @bitCast(root.VULKAN_VERSION),
+    base_physical_device.props.driver_version = @bitCast(root.DRIVER_VERSION);
-        .driver_version = @bitCast(root.DRIVER_VERSION),
+    base_physical_device.props.device_id = root.DEVICE_ID;
-        .vendor_id = common.VULKAN_VENDOR_ID,
+    base_physical_device.props.device_type = .cpu;
-        .device_id = root.DEVICE_ID,
-        .device_type = .cpu,
-        .device_name = [_]u8{0} ** vk.MAX_PHYSICAL_DEVICE_NAME_SIZE,
-        .pipeline_cache_uuid = undefined,
-        .limits = undefined,
-        .sparse_properties = undefined,
-    };
 
     const info = try cpuinfo.get(allocator);
     defer info.deinit(allocator);
 
-    var writer = std.io.Writer.fixed(self.common_physical_device.props.device_name[0 .. vk.MAX_PHYSICAL_DEVICE_NAME_SIZE - 1]);
+    var writer = std.io.Writer.fixed(base_physical_device.props.device_name[0 .. vk.MAX_PHYSICAL_DEVICE_NAME_SIZE - 1]);
     try writer.print("{s} [Soft Vulkan Driver]", .{info.name});
-}
 
-pub fn getProperties(p_physical_device: vk.PhysicalDevice, properties: *vk.PhysicalDeviceProperties) callconv(vk.vulkan_call_conv) void {
+    return dispatchable_physical_device;
-    const physical_device = dispatchable.fromHandleObject(Self, @intFromEnum(p_physical_device)) catch return;
-    properties.* = physical_device.common_physical_device.props;
 }

src/soft/lib.zig

@@ -1,6 +1,6 @@
 const std = @import("std");
 const vk = @import("vulkan");
-const common = @import("common");
+const base = @import("base");
 
 const Instance = @import("Instance.zig");
 
@@ -8,15 +8,7 @@ pub const VULKAN_VERSION = vk.makeApiVersion(0, 1, 0, 0);
 pub const DRIVER_VERSION = vk.makeApiVersion(0, 0, 0, 1);
 pub const DEVICE_ID = 0x600DCAFE;
 
-const global_pfn_map = std.StaticStringMap(vk.PfnVoidFunction).initComptime(.{
+comptime {
-    .{ "vkGetInstanceProcAddr", @as(vk.PfnVoidFunction, @ptrCast(&common.icd.getInstanceProcAddr)) },
+    _ = base;
-    .{ "vkCreateInstance", @as(vk.PfnVoidFunction, @ptrCast(&Instance.create)) },
+    _ = Instance;
-});
-
-pub export fn vkGetInstanceProcAddr(p_instance: vk.Instance, pName: ?[*:0]const u8) callconv(vk.vulkan_call_conv) vk.PfnVoidFunction {
-    if (pName == null) {
-        return null;
-    }
-    const name = std.mem.span(pName.?);
-    return common.icd.getInstanceProcAddr(global_pfn_map, p_instance, name);
 }

src/vulkan/Instance.zig

@@ -1,48 +1,85 @@
 const std = @import("std");
 const vk = @import("vulkan");
+const root = @import("lib.zig");
 const dispatchable = @import("dispatchable.zig");
+const VulkanAllocator = @import("VulkanAllocator.zig");
+const PhysicalDevice = @import("PhysicalDevice.zig");
+
+extern fn __vkImplInstanceInit(*Self, *const std.mem.Allocator) ?*anyopaque;
 
 const Self = @This();
 pub const ObjectType: vk.ObjectType = .instance;
 
-alloc_callbacks: vk.AllocationCallbacks,
+alloc_callbacks: ?vk.AllocationCallbacks,
+physical_devices: std.ArrayList(vk.PhysicalDevice),
+dispatch_table: DispatchTable,
+driver_data: ?*anyopaque,
 
-vtable: VTable,
+pub const DispatchTable = struct {
+    destroyInstance: ?*const fn (*const Self, std.mem.Allocator) anyerror!void = null,
+    enumerateInstanceVersion: ?vk.PfnEnumerateInstanceVersion = null,
+    //enumerateInstanceLayerProperties: vk.PfnEnumerateInstanceProperties = null,
+    enumerateInstanceExtensionProperties: ?vk.PfnEnumerateInstanceExtensionProperties = null,
+};
 
-pub fn init(self: *Self, p_infos: ?*const vk.InstanceCreateInfo, callbacks: ?*const vk.AllocationCallbacks) !void {
+pub fn create(p_infos: ?*const vk.InstanceCreateInfo, callbacks: ?*const vk.AllocationCallbacks, p_instance: *vk.Instance) callconv(vk.vulkan_call_conv) vk.Result {
-    const infos = p_infos orelse return error.NullCreateInfos;
+    const infos = p_infos orelse return .error_initialization_failed;
     if (infos.s_type != .instance_create_info) {
-        return error.InvalidCreateInfos;
+        return .error_initialization_failed;
     }
 
-    self.vtable = .{};
+    const deref_callbacks = if (callbacks) |c| c.* else null;
 
-    if (callbacks) |c| {
+    const allocator = VulkanAllocator.init(deref_callbacks, .instance).allocator();
-        self.alloc_callbacks = c.*;
+
+    const dispatchable_instance = dispatchable.Dispatchable(Self).create(allocator) catch return .error_out_of_host_memory;
+    const self = dispatchable_instance.object;
+    self.dispatch_table = .{};
+
+    self.alloc_callbacks = deref_callbacks;
+    self.physical_devices = .empty;
+
+    self.driver_data = __vkImplInstanceInit(self, &allocator) orelse return .error_initialization_failed;
+    std.debug.assert(self.physical_devices.items.len != 0);
+
+    p_instance.* = @enumFromInt(dispatchable_instance.toHandle());
+    return .success;
+}
+
+pub fn destroy(p_instance: vk.Instance, callbacks: ?*const vk.AllocationCallbacks) callconv(vk.vulkan_call_conv) void {
+    const allocator = VulkanAllocator.init(if (callbacks) |c| c.* else null, .instance).allocator();
+
+    const dispatchable_instance = dispatchable.fromHandle(Self, @intFromEnum(p_instance)) catch return;
+    defer dispatchable_instance.destroy(allocator);
+
+    const self: *const Self = @ptrCast(dispatchable_instance.object);
+    if (self.dispatch_table.destroyInstance) |pfnDestroyInstance| {
+        pfnDestroyInstance(self, allocator) catch return;
+    } else if (std.process.hasEnvVar(allocator, root.DRIVER_LOGS_ENV_NAME) catch false) {
+        std.log.scoped(.vkDestroyInstance).warn("Missing dispatch implementation", .{});
     }
 }
 
-pub fn getProcAddr(self: *const Self, name: []const u8) vk.PfnVoidFunction {
+pub fn enumeratePhysicalDevices(p_instance: vk.Instance, count: *u32, p_devices: ?[*]vk.PhysicalDevice) callconv(vk.vulkan_call_conv) vk.Result {
+    const self = dispatchable.fromHandleObject(Self, @intFromEnum(p_instance)) catch return .error_unknown;
+    count.* = @intCast(self.physical_devices.items.len);
+    if (p_devices) |devices| {
+        @memcpy(devices[0..self.physical_devices.items.len], self.physical_devices.items);
+    }
+    return .success;
+}
+
+pub fn getProcAddr(name: []const u8) vk.PfnVoidFunction {
     const allocator = std.heap.c_allocator;
 
     const KV = struct { []const u8, vk.PfnVoidFunction };
     const pfn_map = std.StaticStringMap(vk.PfnVoidFunction).init([_]KV{
-        .{ "vkDestroyInstance", @ptrCast(self.vtable.destroyInstance) },
+        .{ "vkDestroyInstance", @ptrCast(&destroy) },
-        .{ "vkEnumeratePhysicalDevices", @ptrCast(self.vtable.enumeratePhysicalDevices) },
+        .{ "vkEnumeratePhysicalDevices", @ptrCast(&enumeratePhysicalDevices) },
-        .{ "vkEnumerateInstanceVersion", @ptrCast(self.vtable.enumerateInstanceVersion) },
+        //.{ "vkGetPhysicalDeviceProperties", @ptrCast(self.dispatch_table.getPhysicalDeviceProperties) },
-        .{ "vkEnumerateInstanceExtensionProperties", @ptrCast(self.vtable.enumerateInstanceExtensionProperties) },
-        .{ "vkGetPhysicalDeviceProperties", @ptrCast(self.vtable.getPhysicalDeviceProperties) },
     }, allocator) catch return null;
     defer pfn_map.deinit(allocator);
 
-    return if (pfn_map.get(name)) |pfn| pfn else null;
+    // Falling back on PhysicalDevice's getProcAddr which will return null if not found
+    return if (pfn_map.get(name)) |pfn| pfn else PhysicalDevice.getProcAddr(name);
 }
-
-pub const VTable = struct {
-    destroyInstance: ?vk.PfnDestroyInstance = null,
-    enumeratePhysicalDevices: ?vk.PfnEnumeratePhysicalDevices = null,
-    enumerateInstanceVersion: ?vk.PfnEnumerateInstanceVersion = null,
-    //enumerateInstanceLayerProperties: vk.PfnEnumerateInstanceProperties = null,
-    enumerateInstanceExtensionProperties: ?vk.PfnEnumerateInstanceExtensionProperties = null,
-    getPhysicalDeviceProperties: ?vk.PfnGetPhysicalDeviceProperties = null,
-};

src/vulkan/PhysicalDevice.zig

@@ -1,8 +1,57 @@
+const std = @import("std");
 const vk = @import("vulkan");
+const root = @import("lib.zig");
 const Instance = @import("Instance.zig");
+const dispatchable = @import("dispatchable.zig");
 
 const Self = @This();
 pub const ObjectType: vk.ObjectType = .physical_device;
 
 props: vk.PhysicalDeviceProperties,
-queue_families: [3]vk.QueueFamilyProperties,
+instance: *const Instance,
+dispatch_table: DispatchTable,
+driver_data: ?*anyopaque,
+
+pub const DispatchTable = struct {};
+
+pub fn init(instance: *const Instance, allocator: std.mem.Allocator) !*dispatchable.Dispatchable(Self) {
+    const dispatchable_physical_device = try dispatchable.Dispatchable(Self).create(allocator);
+    errdefer dispatchable_physical_device.destroy(allocator);
+
+    const self = dispatchable_physical_device.object;
+
+    self.props = .{
+        .api_version = undefined,
+        .driver_version = undefined,
+        .vendor_id = root.VULKAN_VENDOR_ID,
+        .device_id = undefined,
+        .device_type = undefined,
+        .device_name = [_]u8{0} ** vk.MAX_PHYSICAL_DEVICE_NAME_SIZE,
+        .pipeline_cache_uuid = undefined,
+        .limits = undefined,
+        .sparse_properties = undefined,
+    };
+
+    self.driver_data = null;
+    self.instance = instance;
+    self.dispatch_table = .{};
+
+    return dispatchable_physical_device;
+}
+
+pub fn getProperties(p_physical_device: vk.PhysicalDevice, properties: *vk.PhysicalDeviceProperties) callconv(vk.vulkan_call_conv) void {
+    const self = dispatchable.fromHandleObject(Self, @intFromEnum(p_physical_device)) catch return;
+    properties.* = self.props;
+}
+
+pub fn getProcAddr(name: []const u8) vk.PfnVoidFunction {
+    const allocator = std.heap.c_allocator;
+
+    const KV = struct { []const u8, vk.PfnVoidFunction };
+    const pfn_map = std.StaticStringMap(vk.PfnVoidFunction).init([_]KV{
+        .{ "vkGetPhysicalDeviceProperties", @ptrCast(&getProperties) },
+    }, allocator) catch return null;
+    defer pfn_map.deinit(allocator);
+
+    return if (pfn_map.get(name)) |pfn| pfn else null;
+}

src/vulkan/VulkanAllocator.zig

@@ -0,0 +1,65 @@
+const std = @import("std");
+const vk = @import("vulkan");
+
+const Allocator = std.mem.Allocator;
+const Alignment = std.mem.Alignment;
+
+/// A Zig allocator from VkAllocationCallbacks.
+/// Falls back on c_allocator if callbacks passed are null
+const Self = @This();
+
+callbacks: ?vk.AllocationCallbacks,
+scope: vk.SystemAllocationScope,
+
+pub fn init(callbacks: ?vk.AllocationCallbacks, scope: vk.SystemAllocationScope) Self {
+    return .{
+        .callbacks = callbacks,
+        .scope = scope,
+    };
+}
+
+pub fn allocator(self: *const Self) Allocator {
+    if (self.callbacks == null) {
+        return std.heap.c_allocator; // TODO: fallback on a better allocator
+    }
+    return .{
+        .ptr = @constCast(self),
+        .vtable = &.{
+            .alloc = alloc,
+            .resize = resize,
+            .remap = remap,
+            .free = free,
+        },
+    };
+}
+
+fn alloc(context: *anyopaque, len: usize, alignment: Alignment, _: usize) ?[*]u8 {
+    const self: *Self = @ptrCast(@alignCast(context));
+    if (self.callbacks.?.pfn_allocation) |pfn_allocation| {
+        return @ptrCast(pfn_allocation(self.callbacks.?.p_user_data, len, alignment.toByteUnits(), self.scope));
+    }
+    @panic("Null PFN_vkAllocationFunction passed to VkAllocationCallbacks");
+}
+
+fn resize(context: *anyopaque, ptr: []u8, alignment: Alignment, new_len: usize, _: usize) bool {
+    _ = alignment;
+    _ = context;
+    return new_len <= ptr.len;
+}
+
+fn remap(context: *anyopaque, ptr: []u8, alignment: Alignment, new_len: usize, _: usize) ?[*]u8 {
+    const self: *Self = @ptrCast(@alignCast(context));
+    if (self.callbacks.?.pfn_reallocation) |pfn_reallocation| {
+        return @ptrCast(pfn_reallocation(self.callbacks.?.p_user_data, ptr.ptr, new_len, alignment.toByteUnits(), self.scope));
+    }
+    @panic("Null PFN_vkReallocationFunction passed to VkAllocationCallbacks");
+}
+
+fn free(context: *anyopaque, ptr: []u8, alignment: Alignment, _: usize) void {
+    _ = alignment;
+    const self: *Self = @ptrCast(@alignCast(context));
+    if (self.callbacks.?.pfn_free) |pfn_free| {
+        return pfn_free(self.callbacks.?.p_user_data, ptr.ptr);
+    }
+    @panic("Null PFN_vkFreeFunction passed to VkAllocationCallbacks");
+}

src/vulkan/icd.zig

@@ -1,5 +1,6 @@
 const std = @import("std");
 const vk = @import("vulkan");
+const root = @import("lib.zig");
 const c = @cImport({
     @cInclude("vulkan/vk_icd.h");
 });
@@ -11,18 +12,20 @@ pub fn getInstanceProcAddr(global_pfn_map: std.StaticStringMap(vk.PfnVoidFunctio
     const allocator = std.heap.c_allocator;
     const get_proc_log = std.log.scoped(.vkGetInstanceProcAddr);
 
-    if (std.process.hasEnvVar(allocator, "DRIVER_LOGS") catch false) {
+    if (std.process.hasEnvVar(allocator, root.DRIVER_LOGS_ENV_NAME) catch false) {
         get_proc_log.info("Loading {s}...", .{name});
     }
 
     if (global_pfn_map.get(name)) |pfn| {
         return pfn;
     }
-    const instance = dispatchable.fromHandle(Instance, @intFromEnum(p_instance)) catch |e| {
+
-        if (std.process.hasEnvVar(allocator, "DRIVER_LOGS") catch false) {
+    // Checks if instance is NULL
+    _ = dispatchable.fromHandle(Instance, @intFromEnum(p_instance)) catch |e| {
+        if (std.process.hasEnvVar(allocator, root.DRIVER_LOGS_ENV_NAME) catch false) {
             get_proc_log.err("{any}", .{e});
         }
         return null;
     };
-    return instance.object.getProcAddr(name);
+    return Instance.getProcAddr(name);
 }

src/vulkan/lib.zig

@@ -6,8 +6,10 @@ pub const dispatchable = @import("dispatchable.zig");
 
 pub const Instance = @import("Instance.zig");
 pub const PhysicalDevice = @import("PhysicalDevice.zig");
+pub const VulkanAllocator = @import("VulkanAllocator.zig");
 
 pub const VULKAN_VENDOR_ID = @typeInfo(vk.VendorId).@"enum".fields[@typeInfo(vk.VendorId).@"enum".fields.len - 1].value + 1;
+pub const DRIVER_LOGS_ENV_NAME = "DRIVER_LOGS";
 
 pub const std_options: std.Options = .{
     .log_level = .info,
@@ -23,6 +25,29 @@ pub fn logFn(comptime level: std.log.Level, comptime scope: @Type(.enum_literal)
     nosuspend stderr.print(format ++ "\n", args) catch return;
 }
 
+pub fn retrieveDriverDataAs(handle: anytype, comptime T: type) !*T {
+    comptime {
+        switch (@typeInfo(@TypeOf(handle))) {
+            .pointer => |p| std.debug.assert(@hasField(p.child, "driver_data")),
+            else => @compileError("Invalid type passed to 'retrieveDriverDataAs': " ++ @typeName(@TypeOf(handle))),
+        }
+    }
+    return @ptrCast(@alignCast(@field(handle, "driver_data")));
+}
+
+const global_pfn_map = std.StaticStringMap(vk.PfnVoidFunction).initComptime(.{
+    .{ "vkGetInstanceProcAddr", @as(vk.PfnVoidFunction, @ptrCast(&icd.getInstanceProcAddr)) },
+    .{ "vkCreateInstance", @as(vk.PfnVoidFunction, @ptrCast(&Instance.create)) },
+});
+
+pub export fn vkGetInstanceProcAddr(p_instance: vk.Instance, pName: ?[*:0]const u8) callconv(vk.vulkan_call_conv) vk.PfnVoidFunction {
+    if (pName == null) {
+        return null;
+    }
+    const name = std.mem.span(pName.?);
+    return icd.getInstanceProcAddr(global_pfn_map, p_instance, name);
+}
+
 test {
     std.testing.refAllDeclsRecursive(@This());
 }

test/c/main.c

@@ -21,8 +21,13 @@
 
 int main(void)
 {
-	puts("openning ./zig-out/lib/lib" LIBVK ".so");
 	void* lib = dlopen("./zig-out/lib/lib" LIBVK ".so", RTLD_NOW | RTLD_LOCAL);
+	if(!lib)
+	{
+		fprintf(stderr, "Could not open driver lib: %s\n", dlerror());
+		exit(EXIT_FAILURE);
+	}
+	puts("openned ./zig-out/lib/lib" LIBVK ".so");
 
 	PFN_vkGetInstanceProcAddr vkGetInstanceProcAddr = dlsym(lib, "vkGetInstanceProcAddr");