adding Descriptors fundamental implementation

src/soft/SoftDescriptorPool.zig

@@ -0,0 +1,38 @@
+const std = @import("std");
+const vk = @import("vulkan");
+const base = @import("base");
+
+const VkError = base.VkError;
+const Device = base.Device;
+
+const Self = @This();
+pub const Interface = base.DescriptorPool;
+
+interface: Interface,
+
+pub fn create(device: *base.Device, allocator: std.mem.Allocator, info: *const vk.DescriptorPoolCreateInfo) VkError!*Self {
+    const self = allocator.create(Self) catch return VkError.OutOfHostMemory;
+    errdefer allocator.destroy(self);
+
+    var interface = try Interface.init(device, allocator, info);
+
+    interface.vtable = &.{
+        .destroy = destroy,
+        .freeDescriptorSets = freeDescriptorSets,
+    };
+
+    self.* = .{
+        .interface = interface,
+    };
+    return self;
+}
+
+pub fn destroy(interface: *Interface, allocator: std.mem.Allocator) void {
+    const self: *Self = @alignCast(@fieldParentPtr("interface", interface));
+    allocator.destroy(self);
+}
+
+pub fn freeDescriptorSets(interface: *Interface, sets: []*base.Dispatchable(base.DescriptorSet)) VkError!void {
+    _ = interface;
+    _ = sets;
+}