gpu: add ShaderStage flagset

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

gpu/TODO-webgpu.h

@@ -1,14 +1,5 @@
 typedef uint32_t WGPUFlags;
 
-typedef enum WGPUShaderStage {
-    WGPUShaderStage_None = 0x00000000,
-    WGPUShaderStage_Vertex = 0x00000001,
-    WGPUShaderStage_Fragment = 0x00000002,
-    WGPUShaderStage_Compute = 0x00000004,
-    WGPUShaderStage_Force32 = 0x7FFFFFFF
-} WGPUShaderStage;
-typedef WGPUFlags WGPUShaderStageFlags;
-
 typedef enum WGPUTextureUsage {
     WGPUTextureUsage_None = 0x00000000,
     WGPUTextureUsage_CopySrc = 0x00000001,

gpu/src/types.zig

@@ -338,11 +338,32 @@ pub const MapMode = packed struct {
 
     pub const undef = MapMode{};
 
-    pub fn equal(a: ColorWriteMask, b: ColorWriteMask) bool {
+    pub fn equal(a: MapMode, b: MapMode) bool {
         return @truncate(u2, @bitCast(u32, a)) == @truncate(u2, @bitCast(u32, b));
     }
 };
 
+pub const ShaderStage = packed struct {
+    vertex: bool = false,
+    fragment: bool = false,
+    compute: bool = false,
+
+    _padding: u29 = 0,
+
+    comptime {
+        std.debug.assert(
+            @sizeOf(@This()) == @sizeOf(u32) and
+                @bitSizeOf(@This()) == @bitSizeOf(u32),
+        );
+    }
+
+    pub const none = ShaderStage{};
+
+    pub fn equal(a: ShaderStage, b: ShaderStage) bool {
+        return @truncate(u3, @bitCast(u32, a)) == @truncate(u3, @bitCast(u32, b));
+    }
+};
+
 test "BackendType name" {
     try testing.expectEqualStrings("Vulkan", BackendType.vulkan.name());
 }