gpu: improve optional handling

Helps hexops/mach#182

gpu/src/Buffer.zig

@@ -43,7 +43,7 @@ pub inline fn getConstMappedRange(buf: Buffer, comptime T: type, offset: usize,
 
 pub inline fn getMappedRange(buf: Buffer, comptime T: type, offset: usize, len: usize) []T {
     const data = buf.vtable.getMappedRange(buf.ptr, offset, @sizeOf(T) * len);
-    return @ptrCast([*]T, data.ptr)[0..len];
+    return @ptrCast([*]T, @alignCast(@alignOf(T), data.ptr))[0..len];
 }
 
 pub inline fn setLabel(buf: Buffer, label: [:0]const u8) void {
@@ -91,7 +91,7 @@ pub const Descriptor = extern struct {
     label: ?[*:0]const u8 = null,
     usage: BufferUsage,
     size: usize,
-    mapped_at_creation: bool,
+    mapped_at_creation: bool = false,
 };
 
 pub const BindingType = enum(u32) {

gpu/src/CommandEncoder.zig

@@ -19,7 +19,7 @@ vtable: *const VTable,
 pub const VTable = struct {
     reference: fn (ptr: *anyopaque) void,
     release: fn (ptr: *anyopaque) void,
-    beginComputePass: fn (ptr: *anyopaque, descriptor: *const ComputePassEncoder.Descriptor) ComputePassEncoder,
+    beginComputePass: fn (ptr: *anyopaque, descriptor: ?*const ComputePassEncoder.Descriptor) ComputePassEncoder,
     beginRenderPass: fn (ptr: *anyopaque, descriptor: *const RenderPassEncoder.Descriptor) RenderPassEncoder,
     clearBuffer: fn (ptr: *anyopaque, buffer: Buffer, offset: u64, size: u64) void,
     copyBufferToBuffer: fn (ptr: *anyopaque, source: Buffer, source_offset: u64, destination: Buffer, destination_offset: u64, size: u64) void,
@@ -45,7 +45,7 @@ pub inline fn release(enc: CommandEncoder) void {
     enc.vtable.release(enc.ptr);
 }
 
-pub inline fn beginComputePass(enc: CommandEncoder, descriptor: *const ComputePassEncoder.Descriptor) ComputePassEncoder {
+pub inline fn beginComputePass(enc: CommandEncoder, descriptor: ?*const ComputePassEncoder.Descriptor) ComputePassEncoder {
     return enc.vtable.beginComputePass(enc.ptr, descriptor);
 }
 

gpu/src/ComputePassEncoder.zig

@@ -20,7 +20,7 @@ pub const VTable = struct {
     insertDebugMarker: fn (ptr: *anyopaque, marker_label: [*:0]const u8) void,
     popDebugGroup: fn (ptr: *anyopaque) void,
     pushDebugGroup: fn (ptr: *anyopaque, group_label: [*:0]const u8) void,
-    setBindGroup: fn (ptr: *anyopaque, group_index: u32, group: BindGroup, dynamic_offsets: []u32) void,
+    setBindGroup: fn (ptr: *anyopaque, group_index: u32, group: BindGroup, dynamic_offsets: ?[]u32) void,
     setLabel: fn (ptr: *anyopaque, label: [:0]const u8) void,
     setPipeline: fn (ptr: *anyopaque, pipeline: ComputePipeline) void,
     writeTimestamp: fn (ptr: *anyopaque, query_set: QuerySet, query_index: u32) void,
@@ -71,7 +71,7 @@ pub inline fn setBindGroup(
     enc: ComputePassEncoder,
     group_index: u32,
     group: BindGroup,
-    dynamic_offsets: []u32,
+    dynamic_offsets: ?[]u32,
 ) void {
     enc.vtable.setBindGroup(enc.ptr, group_index, group, dynamic_offsets);
 }

gpu/src/ComputePipeline.zig

@@ -34,7 +34,7 @@ pub inline fn getBindGroupLayout(pipeline: ComputePipeline, group_index: u32) Bi
 
 pub const Descriptor = struct {
     label: ?[*:0]const u8 = null,
-    layout: PipelineLayout,
+    layout: ?PipelineLayout = null,
     compute: ProgrammableStageDescriptor,
 };
 

gpu/src/NativeInstance.zig

@@ -775,7 +775,7 @@ inline fn convertComputePipelineDescriptor(descriptor: *const ComputePipeline.De
     return .{
         .nextInChain = null,
         .label = if (descriptor.label) |l| l else null,
-        .layout = @ptrCast(c.WGPUPipelineLayout, descriptor.layout.ptr),
+        .layout = if (descriptor.layout) |l| @ptrCast(c.WGPUPipelineLayout, l.ptr) else null,
         .compute = c.WGPUProgrammableStageDescriptor{
             .nextInChain = null,
             .module = @ptrCast(c.WGPUShaderModule, descriptor.compute.module.ptr),
@@ -1842,7 +1842,8 @@ const command_encoder_vtable = CommandEncoder.VTable{
         }
     }).setLabel,
     .beginComputePass = (struct {
-        pub fn beginComputePass(ptr: *anyopaque, d: *const ComputePassEncoder.Descriptor) ComputePassEncoder {
+        pub fn beginComputePass(ptr: *anyopaque, descriptor: ?*const ComputePassEncoder.Descriptor) ComputePassEncoder {
+            if (descriptor) |d| {
                 var few_timestamp_writes: [8]c.WGPUComputePassTimestampWrite = undefined;
                 const timestamp_writes = if (d.timestamp_writes.len <= 8) blk: {
                     for (d.timestamp_writes) |v, i| {
@@ -1873,6 +1874,9 @@ const command_encoder_vtable = CommandEncoder.VTable{
                     .timestampWrites = @ptrCast([*]const c.WGPUComputePassTimestampWrite, timestamp_writes.ptr),
                 };
                 return wrapComputePassEncoder(c.wgpuCommandEncoderBeginComputePass(@ptrCast(c.WGPUCommandEncoder, ptr), &desc));
+            } else {
+                return wrapComputePassEncoder(c.wgpuCommandEncoderBeginComputePass(@ptrCast(c.WGPUCommandEncoder, ptr), null));
+            }
         }
     }).beginComputePass,
     .beginRenderPass = (struct {
@@ -2157,14 +2161,14 @@ const compute_pass_encoder_vtable = ComputePassEncoder.VTable{
             ptr: *anyopaque,
             group_index: u32,
             group: BindGroup,
-            dynamic_offsets: []const u32,
+            dynamic_offsets: ?[]const u32,
         ) void {
             c.wgpuComputePassEncoderSetBindGroup(
                 @ptrCast(c.WGPUComputePassEncoder, ptr),
                 group_index,
                 @ptrCast(c.WGPUBindGroup, group.ptr),
-                @intCast(u32, dynamic_offsets.len),
-                dynamic_offsets.ptr,
+                if (dynamic_offsets) |d| @intCast(u32, d.len) else 0,
+                if (dynamic_offsets) |d| d.ptr else null,
             );
         }
     }).setBindGroup,

gpu/src/RenderPassEncoder.zig

@@ -182,7 +182,7 @@ pub inline fn writeTimestamp(pass: RenderPassEncoder, query_set: QuerySet, query
 pub const Descriptor = struct {
     label: ?[*:0]const u8 = null,
     color_attachments: []const RenderPassColorAttachment,
-    depth_stencil_attachment: ?*const RenderPassDepthStencilAttachment,
+    depth_stencil_attachment: ?*const RenderPassDepthStencilAttachment = null,
     occlusion_query_set: ?QuerySet = null,
     timestamp_writes: ?[]RenderPassTimestampWrite = null,
 };

gpu/src/RenderPipeline.zig

@@ -38,12 +38,12 @@ pub inline fn getBindGroupLayout(pipeline: RenderPipeline, group_index: u32) Bin
 
 pub const Descriptor = struct {
     label: ?[*:0]const u8 = null,
-    layout: ?PipelineLayout,
+    layout: ?PipelineLayout = null,
     vertex: VertexState,
-    primitive: PrimitiveState,
-    depth_stencil: ?*const DepthStencilState,
-    multisample: MultisampleState,
-    fragment: ?*const FragmentState,
+    primitive: PrimitiveState = .{},
+    depth_stencil: ?*const DepthStencilState = null,
+    multisample: MultisampleState = .{},
+    fragment: ?*const FragmentState = null,
 };
 
 pub const CreateStatus = enum(u32) {

gpu/src/structs.zig

@@ -69,7 +69,7 @@ pub const ProgrammableStageDescriptor = struct {
     label: ?[*:0]const u8 = null,
     module: ShaderModule,
     entry_point: [*:0]const u8,
-    constants: ?[]const ConstantEntry,
+    constants: ?[]const ConstantEntry = null,
 };
 
 pub const ComputePassTimestampWrite = struct {
@@ -123,7 +123,7 @@ pub const FragmentState = struct {
 pub const ColorTargetState = extern struct {
     reserved: ?*anyopaque = null,
     format: Texture.Format,
-    blend: *const BlendState,
+    blend: ?*const BlendState = null,
     write_mask: ColorWriteMask = ColorWriteMask.all,
 };