Abstract-numerics

An abstract-numeric type is one of:

• abstract-float: a 64-bit floating point type.
• abstract-int: a 64-bit signed integer type.

Abstract-numerics allow high-precision values to be computed for constant-expressions. These computations occur at compile time on the CPU — just like your JavaScript or WASM — and not on the GPU.

Abstract-numerics have some special properties:

• Abstract-numeric types can’t be spelled in WGSL source code

  You cannot explicitly name an abstract-numeric type, but they exist as the type of unsuffixed numeric literals, and some constant-expressions.

• Only constant-expressions can be of abstract-numeric type

  Abstract-numeric values must first be converted to a concrete (non-abstract) type for use as an override-expression or as a runtime-expression.

• Abstract-numeric expressions must be finite

  Compilation fails if an abstract-numeric expression overflows, wraps, or produces an infinity or a NaN.

• Unlike other types in WGSL, abstract-numerics support implicit type conversion

  An abstract-int can implicitly convert to a i32, u32, f32 or abstract-float.

  An abstract-float can implicitly convert to a f32.

  Abstract-numeric values can also be explicitly converted using the standard conversion syntax.

  Sometimes no explicit target type is specified to receive an abstract-numeric expression. For example, this occurs when an abstract-numeric expression is the initializer for a var, let, or override declaration. In this situation, a default conversion is performed:

  • An abstract-int value will convert to i32.
  • An abstract-float value will convert to f32.