stride3d/stride · error · NotSupportedException

Unsupported element type for abs

Error message

Unsupported element type for abs: {context.ReverseTypes[x.TypeId].GetElementType()}

What it means

CompileAbs compiles the abs() intrinsic to GLSL.FAbs for float/double elements and GLSL.SAbs for signed/unsigned integers. If the element type of the operand is anything else (e.g. bool, half if unsupported, or a non-scalar element), the switch default throws NotSupportedException at IntrinsicImplementations.cs:99.

Solutions

1. Apply abs() only to int/uint/float/double scalars or vectors of those types.
2. For bools, use the value directly (booleans have no sign); for other numeric types cast first.
3. If a new scalar kind must work, add an arm choosing the appropriate GLSL extended instruction in CompileAbs.

Example fix

// before
bool2 b; abs(b);            // unsupported
// after
int2 v = int2(-1, 2); int2 a = abs(v);

// abs supports int/uint/float/double element types only
if (valueType.GetElementType() is not ScalarType { Type: Scalar.Float or Scalar.Double or Scalar.Int or Scalar.UInt })
    throw new ShaderCompileHint("abs requires numeric scalar element type");

static bool IsAbsSupported(BaseType t) => t.GetElementType() is ScalarType s && s.Type is Scalar.Float or Scalar.Double or Scalar.Int or Scalar.UInt;

try { result = intrinsic.CompileAbs(table, context, builder, functionType, x); }
catch (NotSupportedException ex) when (ex.Message.Contains("element type for abs"))
{ diagnostics.Report(location, ex.Message); }

When it happens

Trigger: Calling abs() on a value whose SPIR-V element scalar type is neither Float, Double, Int, nor UInt — for example a bool vector or an exotic scalar type.

Common situations: Applying abs() to boolean or non-numeric values, or after adding a new scalar type (e.g. float16/int16) without extending the intrinsic implementation.

Related errors

• Unsupported element type for min
• Unsupported element type for max
• Unexpected type for asdouble
• Unsupported base type
• Unsupported type for non-pointer indexer

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/86d2060c404e4ca4. Report an issue: GitHub.

Appendix: source

Thrown at sources/shaders/Stride.Shaders.Parsers/Parsing/SDSL/AST/IntrinsicImplementations.cs:99

    }

    // Derivatives
    public override SpirvValue CompileDdx(SymbolTable table, SpirvContext context, SpirvBuilder builder, FunctionType functionType, SpirvValue x, TextLocation location = default) => CompileFloatUnaryCall(table, context, builder, functionType.ReturnType, Specification.Op.OpDPdx, x);
    public override SpirvValue CompileDdx_coarse(SymbolTable table, SpirvContext context, SpirvBuilder builder, FunctionType functionType, SpirvValue x, TextLocation location = default) => CompileFloatUnaryCall(table, context, builder, functionType.ReturnType, Specification.Op.OpDPdxCoarse, x);
    public override SpirvValue CompileDdx_fine(SymbolTable table, SpirvContext context, SpirvBuilder builder, FunctionType functionType, SpirvValue x, TextLocation location = default) => CompileFloatUnaryCall(table, context, builder, functionType.ReturnType, Specification.Op.OpDPdxFine, x);
    public override SpirvValue CompileDdy(SymbolTable table, SpirvContext context, SpirvBuilder builder, FunctionType functionType, SpirvValue x, TextLocation location = default) => CompileFloatUnaryCall(table, context, builder, functionType.ReturnType, Specification.Op.OpDPdy, x);
    public override SpirvValue CompileDdy_coarse(SymbolTable table, SpirvContext context, SpirvBuilder builder, FunctionType functionType, SpirvValue x, TextLocation location = default) => CompileFloatUnaryCall(table, context, builder, functionType.ReturnType, Specification.Op.OpDPdyCoarse, x);
    public override SpirvValue CompileDdy_fine(SymbolTable table, SpirvContext context, SpirvBuilder builder, FunctionType functionType, SpirvValue x, TextLocation location = default) => CompileFloatUnaryCall(table, context, builder, functionType.ReturnType, Specification.Op.OpDPdyFine, x);
    public override SpirvValue CompileFwidth(SymbolTable table, SpirvContext context, SpirvBuilder builder, FunctionType functionType, SpirvValue x, TextLocation location = default) => CompileFloatUnaryCall(table, context, builder, functionType.ReturnType, Specification.Op.OpFwidth, x);

    // Per component math
    public override SpirvValue CompileAbs(SymbolTable table, SpirvContext context, SpirvBuilder builder, FunctionType functionType, SpirvValue x, TextLocation location = default)
    {
        var instruction = context.ReverseTypes[x.TypeId].GetElementType() switch
        {
            ScalarType { Type: Scalar.Float or Scalar.Double } => builder.InsertData(new GLSLFAbs(context.GetOrRegister(functionType.ReturnType), context.Bound++, context.GetGLSL(), x.Id)),
            ScalarType { Type: Scalar.UInt or Scalar.Int } => builder.InsertData(new GLSLSAbs(context.GetOrRegister(functionType.ReturnType), context.Bound++, context.GetGLSL(), x.Id)),
            _ => throw new NotSupportedException($"Unsupported element type for abs: {context.ReverseTypes[x.TypeId].GetElementType()}"),
        };
        return new(instruction);
    }
    public override SpirvValue CompileFloor(SymbolTable table, SpirvContext context, SpirvBuilder builder, FunctionType functionType, SpirvValue x, TextLocation location = default) => CompileGLSLFloatUnaryCall(table, context, builder, functionType.ReturnType, Specification.GLSLOp.GLSLFloor, x);
    public override SpirvValue CompileCeil(SymbolTable table, SpirvContext context, SpirvBuilder builder, FunctionType functionType, SpirvValue x, TextLocation location = default) => CompileGLSLFloatUnaryCall(table, context, builder, functionType.ReturnType, Specification.GLSLOp.GLSLCeil, x);
    public override SpirvValue CompileTrunc(SymbolTable table, SpirvContext context, SpirvBuilder builder, FunctionType functionType, SpirvValue x, TextLocation location = default) => CompileGLSLFloatUnaryCall(table, context, builder, functionType.ReturnType, Specification.GLSLOp.GLSLTrunc, x);
    public override SpirvValue CompileMin(SymbolTable table, SpirvContext context, SpirvBuilder builder, FunctionType functionType, SpirvValue a, SpirvValue b, TextLocation location = default)
    {
        var instruction = context.ReverseTypes[a.TypeId].GetElementType() switch
        {
            ScalarType { Type: Scalar.Float or Scalar.Double } => builder.InsertData(new GLSLFMin(context.GetOrRegister(functionType.ReturnType), context.Bound++, context.GetGLSL(), a.Id, b.Id)),
            ScalarType { Type: Scalar.UInt } => builder.InsertData(new GLSLUMin(context.GetOrRegister(functionType.ReturnType), context.Bound++, context.GetGLSL(), a.Id, b.Id)),
            ScalarType { Type: Scalar.Int } => builder.InsertData(new GLSLSMin(context.GetOrRegister(functionType.ReturnType), context.Bound++, context.GetGLSL(), a.Id, b.Id)),
            _ => throw new NotSupportedException($"Unsupported element type for min: {context.ReverseTypes[a.TypeId].GetElementType()}"),
        };
        return new(instruction);
    }

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