Add toggle to Dawn as a dependency flag (#9)

build.zig

@@ -4,6 +4,7 @@ const log = std.log.scoped(.zgpu);
 const default_options = struct {
     const uniforms_buffer_size = 4 * 1024 * 1024;
     const dawn_skip_validation = false;
+    const dawn_allow_unsafe_apis = false;
     const buffer_pool_size = 256;
     const texture_pool_size = 256;
     const texture_view_pool_size = 256;
@@ -32,6 +33,11 @@ pub fn build(b: *std.Build) void {
             "dawn_skip_validation",
             "Disable Dawn validation",
         ) orelse default_options.dawn_skip_validation,
+        .dawn_allow_unsafe_apis = b.option(
+            bool,
+            "dawn_allow_unsafe_apis",
+            "Allow unsafe WebGPU APIs (e.g. timestamp queries)",
+        ) orelse default_options.dawn_allow_unsafe_apis,
         .buffer_pool_size = b.option(
             u32,
             "buffer_pool_size",

src/zgpu.zig

@@ -205,20 +205,26 @@ pub const GraphicsContext = struct {
                 }
             }).callback;
 
-            const toggles = [_][*:0]const u8{"skip_validation"};
+            var toggles: [2][*:0]const u8 = undefined;
+            var num_toggles: usize = 0;
+            if (zgpu_options.dawn_skip_validation) {
+                toggles[num_toggles] = "skip_validation";
+                num_toggles += 1;
+            }
+            if (zgpu_options.dawn_allow_unsafe_apis) {
+                toggles[num_toggles] = "allow_unsafe_apis";
+                num_toggles += 1;
+            }
             const dawn_toggles = wgpu.DawnTogglesDescriptor{
                 .chain = .{ .next = null, .struct_type = .dawn_toggles_descriptor },
-                .enabled_toggles_count = toggles.len,
+                .enabled_toggles_count = num_toggles,
                 .enabled_toggles = &toggles,
             };
 
             var response = Response{};
             adapter.requestDevice(
                 wgpu.DeviceDescriptor{
-                    .next_in_chain = if (zgpu_options.dawn_skip_validation)
-                        @ptrCast(&dawn_toggles)
-                    else
-                        null,
+                    .next_in_chain = @ptrCast(&dawn_toggles),
                     .required_features_count = options.required_features.len,
                     .required_features = options.required_features.ptr,
                     .required_limits = @ptrCast(options.required_limits),