stride3d/stride · error · NotSupportedException

Unsupported constant vector element type

Error message

Unsupported constant vector element type: {Values[0].GetType()}

What it means

ConstantVector.ToString() renders a SPIR-V constant vector back into SDSL source text. It only knows how to type float element values; any other element type (int, bool, double) hit the throw-all switch arm. The library throws NotSupportedException because printing a vector of that element type as SDSL is not implemented.

Solutions

Use float-valued constant vectors (e.g. cast literals to float) when passing vectors as generic arguments.
Extend the switch in ConstantVector.ToString() to map int => "int", uint => "uint", bool => "bool" etc., mirroring SDSL vector type names.
If you own the input shader, replace the non-float vector generic with a float vector or a scalar constant.

Example fix

// before
var type = Values[0] switch
{
    float => "float",
    _ => throw new NotSupportedException(...),
};
// after
var type = Values[0] switch
{
    float => "float",
    int => "int",
    uint => "uint",
    bool => "bool",
    _ => throw new NotSupportedException($"Unsupported constant vector element type: {Values[0].GetType()}"),
};

Defensive patterns

Strategy: validation

Validate before calling

if (vector.Values.Length == 0 || vector.Values[0] is not float)
    throw new ArgumentException($"ConstantVector must be float-typed to stringify, got {vector.Values.FirstOrDefault()?.GetType()}");

Type guard

bool IsStringifiable(ConstantVector v) => v.Values is { Length: > 0 } && v.Values[0] is float;

Try / catch

try { text = vector.ToString(); }
catch (NotSupportedException ex) { text = $"<{ex.Message}>"; /* fall back to non-string form */ }

Prevention

Only pass float constant vectors as SDSL generic arguments
Add unit tests covering ToString for each element type you use
Extend the switch when adding new supported vector element types

When it happens

Trigger: Calling ToString() (directly or via ShaderClassInstantiation.ToClassNameWithGenerics / error messages / cache keys) on a ConstantVector whose Values[0] is not a float, e.g. an int or bool constant vector produced by TryGetConstantValue.

Common situations: A shader uses integer or boolean constant vectors (e.g. int2 coordinates, bool4 masks) as generic arguments; SDSL grammar/analysis produces a non-float constant vector which later gets stringified when building shader names or diagnostics.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/e3962b3f91bd6237. Report an issue: GitHub.

Appendix: source

Thrown at sources/shaders/Stride.Shaders.Parsers/Spirv/Building/Builder.Class.cs:126

                    hashCode = (hashCode * 397) ^ (current.GetHashCode());
            }

            return hashCode;
        }
    }
}

// Constant vector (generated by TryGetConstantValue)
public class ConstantVector
{
    public required object[] Values;

    public override string ToString()
    {
        var type = Values[0] switch
        {
            float => "float",
            _ => throw new NotSupportedException($"Unsupported constant vector element type: {Values[0].GetType()}"),
        };

        return $"{type}{Values.Length}({string.Join(",", Values)})";
    }
}


public partial class SpirvBuilder
{
    public static void BuildInheritanceListWithoutSelf(IExternalShaderLoader shaderLoader, SpirvContext topLevelContext, ShaderClassInstantiation classSource, ReadOnlySpan<ShaderMacro> macros, SpirvContext declaringContext, List<ShaderClassInstantiation> inheritanceList, ResolveStep resolveStep)
    {
        // Build shader name mapping and collect generic parameter expressions
        var shaderMapping = new Dictionary<int, ShaderClassInstantiation>();
        // Map generic parameter index → resolved expression from classSource
        ConstantExpression[]? resolvedGenericArgs = null;
        string? declaringClassName = null;
        // Also build import-level resolution: map shader name → its import's generic args (as expressions)
        // Used to resolve GenericParamExpr that reference parent shaders' generics

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