What causes "Unsupported int vector size: {v.Length}" in stride3d/stride?

Use int2/int3/int4 for the default value

stride3d/stride · error · NotSupportedException

Unsupported int vector size

Error message

Unsupported int vector size: {v.Length}

What it means

ConvertDefaultValue only supports int vectors of length 2, 3, or 4 (Int2/Int3/Int4). An int-typed constant composite with any other component count falls through to the switch default and throws NotSupportedException.

Solutions

Use int2/int3/int4 for the default value
Replace 1-component composites with a plain int scalar
Split bigger composites into multiple supported vectors

Example fix

// before
int1 Flags = int1(3);
// after
int Flags = 3;

Defensive patterns

Strategy: validation

Validate before calling

if (elemType == "int" && composite.Length is < 2 or > 4)
    throw new ArgumentException("int default vectors must have 2-4 components");

Try / catch

try { result = mixer.MergeSDSL(tree); }
catch (NotSupportedException ex) when (ex.Message.StartsWith("Unsupported int vector size")) {
    fixDefaultValueType(memberName);
}

Prevention

Use plain int for single values
Keep int default vectors at 2-4 components
Check generated shader code for oversized composites

When it happens

Trigger: An int cbuffer member default with component count 1 or >4 (e.g. int5 composite); generated shader code emitting arbitrarily sized int composites that reach ComputeCBufferReflection.

Common situations: ivec1-style constructs ported from GLSL; codegen tools emitting int arrays as single composites; hand-written large int tuples used as defaults.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/79bb36f2e64150d7. Report an issue: GitHub.

Appendix: source

Thrown at sources/shaders/Stride.Shaders.Compilers/SDSL/ShaderMixer.CBuffers.cs:648

            if (value is not ConstantVector cv)
                return value;

            var v = cv.Values;
            return v[0] switch
            {
                float => v.Length switch
                {
                    2 => new Vector2((float)v[0], (float)v[1]),
                    3 => new Vector3((float)v[0], (float)v[1], (float)v[2]),
                    4 => (object)new Vector4((float)v[0], (float)v[1], (float)v[2], (float)v[3]),
                    _ => throw new NotSupportedException($"Unsupported float vector size: {v.Length}"),
                },
                int => v.Length switch
                {
                    2 => new Int2((int)v[0], (int)v[1]),
                    3 => new Int3((int)v[0], (int)v[1], (int)v[2]),
                    4 => (object)new Int4((int)v[0], (int)v[1], (int)v[2], (int)v[3]),
                    _ => throw new NotSupportedException($"Unsupported int vector size: {v.Length}"),
                },
                uint => v.Length switch
                {
                    4 => (object)new UInt4((uint)v[0], (uint)v[1], (uint)v[2], (uint)v[3]),
                    _ => throw new NotSupportedException($"Unsupported uint vector size: {v.Length}"),
                },
                _ => throw new NotSupportedException($"Unsupported constant composite element type: {v[0]?.GetType()}"),
            };
        }
    }
}

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