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

Pad the default to uint4 (e.g. uint4(v, 0))

stride3d/stride · error · NotSupportedException

Unsupported uint vector size

Error message

Unsupported uint vector size: {v.Length}

What it means

For uint constant composites, ConvertDefaultValue only maps length-4 vectors to UInt4. Any other length (1, 2, 3, 5, ...) hits the switch default and throws NotSupportedException, since no UInt1/UInt2/UInt3 mapping exists in this path.

Solutions

Pad the default to uint4 (e.g. uint4(v, 0))
Change the member to int2/int3 so the int branch handles it
Use a plain uint scalar for 1-component values

Example fix

// before
uint2 TileOffset = uint2(4, 8);
// after
uint4 TileOffset = uint4(4, 8, 0, 0);

Defensive patterns

Strategy: validation

Validate before calling

if (elemType == "uint" && composite.Length != 4)
    throw new ArgumentException("uint default composites must have exactly 4 components");

Try / catch

try { result = mixer.MergeSDSL(tree); }
catch (NotSupportedException ex) when (ex.Message.StartsWith("Unsupported uint vector size")) {
    padToUInt4(memberName);
}

Prevention

Prefer int2/int3 over uint2/uint3 for small default vectors
Pad uint defaults to uint4
Avoid uint composites in ported GLSL code without review

When it happens

Trigger: A uint cbuffer member default declared with 2 or 3 components (e.g. uint2(1,2)) reaching ConvertDefaultValue during ComputeCBufferReflection.

Common situations: uvec2/uvec3 defaults ported from GLSL; bitflag packs written as uint2/uint3; codegen emitting shortened uint composites.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/7d8e722d0bf1ba5d. Report an issue: GitHub.

Appendix: source

Thrown at sources/shaders/Stride.Shaders.Compilers/SDSL/ShaderMixer.CBuffers.cs:653

            {
                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()}"),
            };
        }
    }
}

View on GitHub (pinned to 96fad776d2)