wip: extract create_device() but do not use yet

src/main.zig

@@ -52,8 +52,10 @@ const vertices = [_]Vertex{
 
 const indices = [_]Index{ 4, 5, 6, 6, 5, 7 };
 
+const InstancePair = std.meta.Tuple(&.{ vk.Instance, gfx.InstanceDispatch });
+
 /// note: destroy with vki.destroyInstance(instance, null)
-fn create_instance(vkb: gfx.BaseDispatch) !std.meta.Tuple(&.{ vk.Instance, gfx.InstanceDispatch }) {
+fn create_instance(vkb: gfx.BaseDispatch) !InstancePair {
     var glfw_exts_count: u32 = 0;
     const glfw_exts = c.glfwGetRequiredInstanceExtensions(&glfw_exts_count);
 
@@ -98,6 +100,117 @@ fn create_window(extent: vk.Extent2D, title: [*:0]const u8) !*c.GLFWwindow {
     ) orelse error.WindowInitFailed;
 }
 
+const DevicePair = struct {
+    pdev: vk.PhysicalDevice,
+    dev: vk.Device,
+    graphics: vk.Queue,
+    present: vk.Queue,
+    present_sharing_mode: vk.SharingMode,
+};
+
+fn create_device(ally: std.mem.Allocator, instance: vk.Instance, vki: gfx.InstanceDispatch, surface: vk.SurfaceKHR) !DevicePair {
+    const required_device_extensions = [_][*:0]const u8{
+        vk.extension_info.khr_swapchain.name,
+        vk.extension_info.khr_dynamic_rendering.name,
+    };
+
+    var pdev_count: u32 = undefined;
+
+    _ = try vki.enumeratePhysicalDevices(instance, &pdev_count, null);
+    const pdevs = try ally.alloc(vk.PhysicalDevice, pdev_count);
+    defer ally.free(pdevs);
+    _ = try vki.enumeratePhysicalDevices(instance, &pdev_count, pdevs);
+
+    pdev_search: for (pdevs[0..pdev_count]) |pdev| {
+        // const props = vki.getPhysicalDeviceProperties(pdev);
+        // const feats = vki.getPhysicalDeviceFeatures(pdev);
+
+        var ext_prop_count: u32 = undefined;
+        _ = try vki.enumerateDeviceExtensionProperties(pdev, null, &ext_prop_count, null);
+        const ext_props = try ally.alloc(vk.ExtensionProperties, ext_prop_count);
+        defer ally.free(ext_props);
+        _ = try vki.enumerateDeviceExtensionProperties(pdev, null, &ext_prop_count, ext_props);
+
+        for (required_device_extensions) |required| {
+            for (ext_props) |prop| {
+                if (std.mem.eql(u8, std.mem.span(required), std.mem.sliceTo(&prop.extension_name, 0))) {
+                    break;
+                }
+            } else {
+                continue :pdev_search;
+            }
+        }
+
+        var format_count: u32 = undefined;
+        _ = try vki.getPhysicalDeviceSurfaceFormatsKHR(pdev, surface, &format_count, null);
+        if (format_count == 0) continue :pdev_search;
+
+        var present_mode_count: u32 = undefined;
+        _ = try vki.getPhysicalDeviceSurfacePresentModesKHR(pdev, surface, &present_mode_count, null);
+        if (present_mode_count == 0) continue :pdev_search;
+
+        var fam_prop_count: u32 = undefined;
+        vki.getPhysicalDeviceQueueFamilyProperties(pdev, &fam_prop_count, null);
+        const fam_props = try ally.alloc(vk.QueueFamilyProperties, fam_prop_count);
+        defer ally.free(fam_props);
+        vki.getPhysicalDeviceQueueFamilyProperties(pdev, &fam_prop_count, fam_props);
+
+        var graphics_families = std.ArrayList(u32).init(ally);
+        var present_families = std.ArrayList(u32).init(ally);
+
+        for (fam_props, 0..) |fam, idx| {
+            if (fam.queue_flags.graphics_bit) {
+                graphics_families.append(idx);
+            }
+            if (try vki.getPhysicalDeviceSurfaceSupportKHR(pdev, idx, surface)) {
+                present_families.append(idx);
+            }
+        }
+
+        // only choose the same family if we really have to.
+
+        // at this point, we know this pdev can support _a_ swap chain and has required extensions. try to make a
+        // logical device and queues out of it.
+
+    }
+
+    return error.NoSuitableDevice;
+}
+
+pub fn includes(comptime T: type, us: []const T, vs: []const T) bool {
+    var vidx: usize = 0;
+    var uidx: usize = 0;
+    while (uidx < us.len) {
+        while (vidx < vs.len) : (vidx += 1) {
+            if (us[uidx] == vs[vidx]) break;
+            vidx += 1;
+        } else {
+            return false;
+        }
+        uidx += 1;
+        vidx += 1;
+    }
+    return true;
+}
+
+test "includes" {
+    const u = &.{ 0, 1, 7 };
+    const v = &.{11};
+    const w = &.{};
+    const x = &.{ 0, 1, 3, 5, 7, 9, 11 };
+    const y = &.{2};
+    const z = &.{ 0, 1, 3, 5, 7, 9, 11, 12 };
+
+    const full = &.{ 0, 1, 3, 5, 7, 9, 11 };
+
+    try std.testing.expectEqual(true, includes(usize, u, full));
+    try std.testing.expectEqual(true, includes(usize, v, full));
+    try std.testing.expectEqual(true, includes(usize, w, full));
+    try std.testing.expectEqual(true, includes(usize, x, full));
+    try std.testing.expectEqual(false, includes(usize, y, full));
+    try std.testing.expectEqual(false, includes(usize, z, full));
+}
+
 pub fn main() !void {
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
     defer _ = gpa.deinit();