gpu: add foundation for interface

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

gpu/src/Adapter.zig

@@ -0,0 +1,79 @@
+//! A GPUAdapter which identifies an implementation of WebGPU on the system.
+//!
+//! An adapter is both an instance of compute/rendering functionality on the platform, and an
+//! instance of the WebGPU implementation on top of that functionality.
+//!
+//! Adapters do not uniquely represent underlying implementations: calling `requestAdapter()`
+//! multiple times returns a different adapter object each time.
+//!
+//! An adapter object may become invalid at any time. This happens inside "lose the device" and
+//! "mark adapters stale". An invalid adapter is unable to vend new devices.
+//!
+//! Note: This mechanism ensures that various adapter-creation scenarios look similar to
+//! applications, so they can easily be robust to more scenarios with less testing: first
+//! initialization, reinitialization due to an unplugged adapter, reinitialization due to a test
+//! GPUDevice.destroy() call, etc. It also ensures applications use the latest system state to make
+//! decisions about which adapter to use.
+//!
+//! https://gpuweb.github.io/gpuweb/#adapters
+//! https://gpuweb.github.io/gpuweb/#gpuadapter
+
+const FeatureName = @import("feature_name.zig").FeatureName;
+const SupportedLimits = @import("supported_limits.zig").SupportedLimits;
+
+const Adapter = @This();
+
+/// The features which can be used to create devices on this adapter.
+features: []FeatureName,
+
+/// The best limits which can be used to create devices on this adapter.
+///
+/// Each adapter limit will be the same or better than its default value in supported limits.
+limits: SupportedLimits,
+
+/// If set to true indicates that the adapter is a fallback adapter.
+///
+/// An adapter may be considered a fallback adapter if it has significant performance caveats in
+/// exchange for some combination of wider compatibility, more predictable behavior, or improved
+/// privacy. It is not guaranteed that a fallback adapter is available on every system.
+fallback: bool,
+
+// The type erased pointer to the Adapter implementation
+ptr: *anyopaque,
+vtable: *const VTable,
+
+pub const VTable = struct {
+    // TODO:
+    // WGPU_EXPORT void wgpuAdapterRequestDevice(WGPUAdapter adapter, WGPUDeviceDescriptor const * descriptor, WGPURequestDeviceCallback callback, void * userdata);
+    // WGPU_EXPORT WGPUDevice wgpuAdapterCreateDevice(WGPUAdapter adapter, WGPUDeviceDescriptor const * descriptor);
+    // WGPU_EXPORT void wgpuAdapterReference(WGPUAdapter adapter);
+    // WGPU_EXPORT void wgpuAdapterRelease(WGPUAdapter adapter);
+};
+
+/// Tests of the given feature can be used to create devices on this adapter.
+pub fn hasFeature(adapter: Adapter, feature: FeatureName) bool {
+    for (adapter.features) |f| {
+        if (f == feature) return true;
+    }
+    return false;
+}
+
+// TODO:
+// typedef struct WGPUAdapterProperties {
+//     WGPUChainedStructOut * nextInChain;
+//     uint32_t vendorID;
+//     uint32_t deviceID;
+//     char const * name;
+//     char const * driverDescription;
+//     WGPUAdapterType adapterType;
+//     WGPUBackendType backendType;
+// } WGPUAdapterProperties;
+
+// TODO:
+// typedef enum WGPUAdapterType {
+//     WGPUAdapterType_DiscreteGPU = 0x00000000,
+//     WGPUAdapterType_IntegratedGPU = 0x00000001,
+//     WGPUAdapterType_CPU = 0x00000002,
+//     WGPUAdapterType_Unknown = 0x00000003,
+//     WGPUAdapterType_Force32 = 0x7FFFFFFF
+// } WGPUAdapterType;

gpu/src/Device.zig

@@ -0,0 +1,12 @@
+//! A standard interface to a WebGPU implementation.
+//!
+//! Like std.mem.Allocator, but representing a WebGPU implementation.
+
+// The type erased pointer to the Device implementation
+ptr: *anyopaque,
+vtable: *const VTable,
+
+pub const VTable = struct {
+    // TODO(gpu): make these *const fn once stage2 is released.
+    free: fn (ptr: *anyopaque, buf: []u8, buf_align: u29, ret_addr: usize) void,
+};

gpu/src/TODO

@@ -9,7 +9,6 @@
 
 typedef uint32_t WGPUFlags;
 
-typedef struct WGPUAdapterImpl* WGPUAdapter;
 typedef struct WGPUBindGroupImpl* WGPUBindGroup;
 typedef struct WGPUBindGroupLayoutImpl* WGPUBindGroupLayout;
 typedef struct WGPUBufferImpl* WGPUBuffer;
@@ -34,14 +33,6 @@ typedef struct WGPUSwapChainImpl* WGPUSwapChain;
 typedef struct WGPUTextureImpl* WGPUTexture;
 typedef struct WGPUTextureViewImpl* WGPUTextureView;
 
-typedef enum WGPUAdapterType {
-    WGPUAdapterType_DiscreteGPU = 0x00000000,
-    WGPUAdapterType_IntegratedGPU = 0x00000001,
-    WGPUAdapterType_CPU = 0x00000002,
-    WGPUAdapterType_Unknown = 0x00000003,
-    WGPUAdapterType_Force32 = 0x7FFFFFFF
-} WGPUAdapterType;
-
 typedef enum WGPUAddressMode {
     WGPUAddressMode_Repeat = 0x00000000,
     WGPUAddressMode_MirrorRepeat = 0x00000001,
@@ -615,16 +606,6 @@ typedef struct WGPUChainedStructOut {
     WGPUSType sType;
 } WGPUChainedStructOut;
 
-typedef struct WGPUAdapterProperties {
-    WGPUChainedStructOut * nextInChain;
-    uint32_t vendorID;
-    uint32_t deviceID;
-    char const * name;
-    char const * driverDescription;
-    WGPUAdapterType adapterType;
-    WGPUBackendType backendType;
-} WGPUAdapterProperties;
-
 typedef struct WGPUBindGroupEntry {
     WGPUChainedStruct const * nextInChain;
     uint32_t binding;
@@ -762,35 +743,6 @@ typedef struct WGPUInstanceDescriptor {
     WGPUChainedStruct const * nextInChain;
 } WGPUInstanceDescriptor;
 
-typedef struct WGPULimits {
-    uint32_t maxTextureDimension1D;
-    uint32_t maxTextureDimension2D;
-    uint32_t maxTextureDimension3D;
-    uint32_t maxTextureArrayLayers;
-    uint32_t maxBindGroups;
-    uint32_t maxDynamicUniformBuffersPerPipelineLayout;
-    uint32_t maxDynamicStorageBuffersPerPipelineLayout;
-    uint32_t maxSampledTexturesPerShaderStage;
-    uint32_t maxSamplersPerShaderStage;
-    uint32_t maxStorageBuffersPerShaderStage;
-    uint32_t maxStorageTexturesPerShaderStage;
-    uint32_t maxUniformBuffersPerShaderStage;
-    uint64_t maxUniformBufferBindingSize;
-    uint64_t maxStorageBufferBindingSize;
-    uint32_t minUniformBufferOffsetAlignment;
-    uint32_t minStorageBufferOffsetAlignment;
-    uint32_t maxVertexBuffers;
-    uint32_t maxVertexAttributes;
-    uint32_t maxVertexBufferArrayStride;
-    uint32_t maxInterStageShaderComponents;
-    uint32_t maxComputeWorkgroupStorageSize;
-    uint32_t maxComputeInvocationsPerWorkgroup;
-    uint32_t maxComputeWorkgroupSizeX;
-    uint32_t maxComputeWorkgroupSizeY;
-    uint32_t maxComputeWorkgroupSizeZ;
-    uint32_t maxComputeWorkgroupsPerDimension;
-} WGPULimits;
-
 typedef struct WGPUMultisampleState {
     WGPUChainedStruct const * nextInChain;
     uint32_t count;
@@ -1092,11 +1044,6 @@ typedef struct WGPURequiredLimits {
     WGPULimits limits;
 } WGPURequiredLimits;
 
-typedef struct WGPUSupportedLimits {
-    WGPUChainedStructOut * nextInChain;
-    WGPULimits limits;
-} WGPUSupportedLimits;
-
 typedef struct WGPUTextureDescriptor {
     WGPUChainedStruct const * nextInChain;
     char const * label;
@@ -1221,16 +1168,6 @@ typedef void (*WGPURequestDeviceCallback)(WGPURequestDeviceStatus status, WGPUDe
 WGPU_EXPORT WGPUInstance wgpuCreateInstance(WGPUInstanceDescriptor const * descriptor);
 WGPU_EXPORT WGPUProc wgpuGetProcAddress(WGPUDevice device, char const * procName);
 
-// Methods of Adapter
-WGPU_EXPORT WGPUDevice wgpuAdapterCreateDevice(WGPUAdapter adapter, WGPUDeviceDescriptor const * descriptor);
-WGPU_EXPORT size_t wgpuAdapterEnumerateFeatures(WGPUAdapter adapter, WGPUFeatureName * features);
-WGPU_EXPORT bool wgpuAdapterGetLimits(WGPUAdapter adapter, WGPUSupportedLimits * limits);
-WGPU_EXPORT void wgpuAdapterGetProperties(WGPUAdapter adapter, WGPUAdapterProperties * properties);
-WGPU_EXPORT bool wgpuAdapterHasFeature(WGPUAdapter adapter, WGPUFeatureName feature);
-WGPU_EXPORT void wgpuAdapterRequestDevice(WGPUAdapter adapter, WGPUDeviceDescriptor const * descriptor, WGPURequestDeviceCallback callback, void * userdata);
-WGPU_EXPORT void wgpuAdapterReference(WGPUAdapter adapter);
-WGPU_EXPORT void wgpuAdapterRelease(WGPUAdapter adapter);
-
 // Methods of BindGroup
 WGPU_EXPORT void wgpuBindGroupSetLabel(WGPUBindGroup bindGroup, char const * label);
 WGPU_EXPORT void wgpuBindGroupReference(WGPUBindGroup bindGroup);

gpu/src/c.zig

@@ -0,0 +1,3 @@
+pub const c = @cImport({
+    @cInclude("webgpu/webgpu.h");
+});

gpu/src/feature_name.zig

@@ -0,0 +1,21 @@
+pub const FeatureName = enum {
+    TODO,
+};
+// TODO:
+// typedef enum WGPUFeatureName {
+//     WGPUFeatureName_Undefined = 0x00000000,
+//     WGPUFeatureName_Depth24UnormStencil8 = 0x00000002,
+//     WGPUFeatureName_Depth32FloatStencil8 = 0x00000003,
+//     WGPUFeatureName_TimestampQuery = 0x00000004,
+//     WGPUFeatureName_PipelineStatisticsQuery = 0x00000005,
+//     WGPUFeatureName_TextureCompressionBC = 0x00000006,
+//     WGPUFeatureName_TextureCompressionETC2 = 0x00000007,
+//     WGPUFeatureName_TextureCompressionASTC = 0x00000008,
+//     WGPUFeatureName_IndirectFirstInstance = 0x00000009,
+//     WGPUFeatureName_DepthClamping = 0x000003E8,
+//     WGPUFeatureName_DawnShaderFloat16 = 0x000003E9,
+//     WGPUFeatureName_DawnInternalUsages = 0x000003EA,
+//     WGPUFeatureName_DawnMultiPlanarFormats = 0x000003EB,
+//     WGPUFeatureName_DawnNative = 0x000003EC,
+//     WGPUFeatureName_Force32 = 0x7FFFFFFF
+// } WGPUFeatureName;

gpu/src/main.zig

@@ -14,5 +14,20 @@
 //!
 //! Note: WebGPU’s coordinate systems match DirectX’s coordinate systems in a graphics pipeline.
 //!
-//! https://gpuweb.github.io/gpuweb 
+//! 
 const std = @import("std");
+const Adapter = @import("Adapter.zig");
+const Device = @import("Device.zig");
+
+const native = @import("native.zig").native;
+
+const FeatureName = @import("feature_name.zig").FeatureName;
+const SupportedLimits = @import("supported_limits.zig").SupportedLimits;
+
+test "syntax" {
+    _ = Adapter;
+    _ = Device;
+    _ = native;
+    _ = FeatureName;
+    _ = SupportedLimits;
+}

gpu/src/native.zig

@@ -0,0 +1,16 @@
+//! A native webgpu.h based implementation of the Device interface.
+const Device = @import("Device.zig");
+
+/// Returns a native WebGPU implementation of the Device interface.
+pub fn native() Device {
+    // TODO: implement Device interface
+    @panic("not implemented");
+
+    // TODO: implement Adapter interface:
+    // typedef struct WGPUAdapterImpl* WGPUAdapter;
+    // // Methods of Adapter
+    // WGPU_EXPORT size_t wgpuAdapterEnumerateFeatures(WGPUAdapter adapter, WGPUFeatureName * features);
+    // WGPU_EXPORT bool wgpuAdapterHasFeature(WGPUAdapter adapter, WGPUFeatureName feature);
+    // WGPU_EXPORT bool wgpuAdapterGetLimits(WGPUAdapter adapter, WGPUSupportedLimits * limits);
+    // WGPU_EXPORT void wgpuAdapterGetProperties(WGPUAdapter adapter, WGPUAdapterProperties * properties);
+}

gpu/src/supported_limits.zig

@@ -0,0 +1,34 @@
+pub const SupportedLimits = struct {};
+// TODO:
+// typedef struct WGPUSupportedLimits {
+//     WGPUChainedStructOut * nextInChain;
+//     WGPULimits limits;
+// } WGPUSupportedLimits;
+// typedef struct WGPULimits {
+//     uint32_t maxTextureDimension1D;
+//     uint32_t maxTextureDimension2D;
+//     uint32_t maxTextureDimension3D;
+//     uint32_t maxTextureArrayLayers;
+//     uint32_t maxBindGroups;
+//     uint32_t maxDynamicUniformBuffersPerPipelineLayout;
+//     uint32_t maxDynamicStorageBuffersPerPipelineLayout;
+//     uint32_t maxSampledTexturesPerShaderStage;
+//     uint32_t maxSamplersPerShaderStage;
+//     uint32_t maxStorageBuffersPerShaderStage;
+//     uint32_t maxStorageTexturesPerShaderStage;
+//     uint32_t maxUniformBuffersPerShaderStage;
+//     uint64_t maxUniformBufferBindingSize;
+//     uint64_t maxStorageBufferBindingSize;
+//     uint32_t minUniformBufferOffsetAlignment;
+//     uint32_t minStorageBufferOffsetAlignment;
+//     uint32_t maxVertexBuffers;
+//     uint32_t maxVertexAttributes;
+//     uint32_t maxVertexBufferArrayStride;
+//     uint32_t maxInterStageShaderComponents;
+//     uint32_t maxComputeWorkgroupStorageSize;
+//     uint32_t maxComputeInvocationsPerWorkgroup;
+//     uint32_t maxComputeWorkgroupSizeX;
+//     uint32_t maxComputeWorkgroupSizeY;
+//     uint32_t maxComputeWorkgroupSizeZ;
+//     uint32_t maxComputeWorkgroupsPerDimension;
+// } WGPULimits;