gpu: add MapMode flagset

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

gpu/TODO-webgpu.h

@@ -1,13 +1,5 @@
 typedef uint32_t WGPUFlags;
 
-typedef enum WGPUMapMode {
-    WGPUMapMode_None = 0x00000000,
-    WGPUMapMode_Read = 0x00000001,
-    WGPUMapMode_Write = 0x00000002,
-    WGPUMapMode_Force32 = 0x7FFFFFFF
-} WGPUMapMode;
-typedef WGPUFlags WGPUMapModeFlags;
-
 typedef enum WGPUShaderStage {
     WGPUShaderStage_None = 0x00000000,
     WGPUShaderStage_Vertex = 0x00000001,

gpu/src/Buffer.zig

@@ -40,6 +40,6 @@ pub const Usage = packed struct {
     }
 
     pub fn equal(a: Usage, b: Usage) bool {
-        return @truncate(u10, @bitCast(u32, a)) == @truncate(u10, @bitCast(u32, b)) ;
+        return @truncate(u10, @bitCast(u32, a)) == @truncate(u10, @bitCast(u32, b));
     }
 };

gpu/src/types.zig

@@ -319,7 +319,27 @@ pub const ColorWriteMask = packed struct {
     };
 
     pub fn equal(a: ColorWriteMask, b: ColorWriteMask) bool {
-        return @truncate(u4, @bitCast(u32, a)) == @truncate(u4, @bitCast(u32, b)) ;
+        return @truncate(u4, @bitCast(u32, a)) == @truncate(u4, @bitCast(u32, b));
+    }
+};
+
+pub const MapMode = packed struct {
+    read: bool = false,
+    write: bool = false,
+
+    _padding: u30 = 0,
+
+    comptime {
+        std.debug.assert(
+            @sizeOf(@This()) == @sizeOf(u32) and
+                @bitSizeOf(@This()) == @bitSizeOf(u32),
+        );
+    }
+
+    pub const undef = MapMode{};
+
+    pub fn equal(a: ColorWriteMask, b: ColorWriteMask) bool {
+        return @truncate(u2, @bitCast(u32, a)) == @truncate(u2, @bitCast(u32, b));
     }
 };