adding fragment derivatives, base pipeline cache, missing KHR function to avoid CTS crash + lots of minor bugfixes

src/vulkan/PipelineCache.zig

@@ -4,6 +4,7 @@ const vk = @import("vulkan");
 const NonDispatchable = @import("NonDispatchable.zig");
 
 const VkError = @import("error_set.zig").VkError;
+const root = @import("lib.zig");
 
 const Device = @import("Device.zig");
 
@@ -11,6 +12,7 @@ const Self = @This();
 pub const ObjectType: vk.ObjectType = .pipeline_cache;
 
 owner: *Device,
+data_available: bool,
 
 vtable: *const VTable,
 
@@ -18,11 +20,14 @@ pub const VTable = struct {
     destroy: *const fn (*Self, std.mem.Allocator) void,
 };
 
+pub const Header = vk.PipelineCacheHeaderVersionOne;
+
 pub fn init(device: *Device, allocator: std.mem.Allocator, info: *const vk.PipelineCacheCreateInfo) VkError!Self {
     _ = allocator;
-    _ = info;
+    const has_initial_data = info.initial_data_size != 0 or info.p_initial_data != null;
     return .{
         .owner = device,
+        .data_available = !has_initial_data or info.initial_data_size >= dataSize(),
         .vtable = undefined,
     };
 }
@@ -30,3 +35,44 @@ pub fn init(device: *Device, allocator: std.mem.Allocator, info: *const vk.Pipel
 pub inline fn destroy(self: *Self, allocator: std.mem.Allocator) void {
     self.vtable.destroy(self, allocator);
 }
+
+pub fn merge(self: *Self) VkError!void {
+    _ = self;
+}
+
+pub fn getData(self: *Self, data: ?[]u8) vk.Result {
+    if (!self.data_available) {
+        return .success;
+    }
+
+    const cache_header = self.header();
+    const bytes = std.mem.asBytes(&cache_header);
+
+    if (data) |dst| {
+        if (dst.len < bytes.len) {
+            return .incomplete;
+        }
+
+        @memcpy(dst[0..bytes.len], bytes);
+    }
+
+    return .success;
+}
+
+pub inline fn dataSize() usize {
+    return @sizeOf(Header);
+}
+
+pub inline fn availableDataSize(self: *const Self) usize {
+    return if (self.data_available) dataSize() else 0;
+}
+
+fn header(self: *const Self) Header {
+    return .{
+        .header_size = @sizeOf(Header),
+        .header_version = .one,
+        .vendor_id = @intCast(root.VULKAN_VENDOR_ID),
+        .device_id = self.owner.physical_device.props.device_id,
+        .pipeline_cache_uuid = self.owner.physical_device.props.pipeline_cache_uuid,
+    };
+}