stride3d/stride · error · ArgumentOutOfRangeException

Indices for Color run from 0 to 3, inclusive.

Error message

Indices for Color run from 0 to 3, inclusive.

What it means

Color implements an indexer mapping index 0-3 to R, G, B, A respectively. The library throws ArgumentOutOfRangeException from the getter when the supplied index is outside 0-3 because there is no fourth or later component to return. It is a defensive guard against bad indexing logic in caller code.

Solutions

1. Clamp or bounds-check the index to 0..3 before accessing color[index].
2. If you need only RGB, iterate 0..2 and access R/G/B fields directly instead of the indexer.
3. If you intended a Color3, index a Color3 (0..2) rather than a Color.

Example fix

// before
for (int i = 0; i < 5; i++)
    sum += color[i];
// after
for (int i = 0; i < 4; i++)
    sum += color[i];

if (index < 0 || index > 3) throw new ArgumentOutOfRangeException(nameof(index));
var channel = color[index];

bool IsValidColorIndex(int i) => i is >= 0 and <= 3;

try { var c = color[index]; }
catch (ArgumentOutOfRangeException) { /* fall back to default channel or log */ }

When it happens

Trigger: Reading color[index] with index < 0 or index > 3, e.g. iterating a 5-element loop or using a byte component count from another type (Color3 has only 3 components) to index a Color.

Common situations: Looping over '4 bytes per pixel' but starting at 1 instead of 0; copying generic component-access code written for Vector4 (which shares 0-3) from code that also handles Color3; off-by-one when reading the alpha channel.

Related errors

• Indices for Color3 run from 0 to 2, inclusive.
• Indices for Color4 run from 0 to 3, inclusive.
• There must be three and only three input values for Color3.
• There must be 3 or 4 float[] values for Color4.
• There must be four and only four input values for ColorBGRA.

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/76843ec779368e48. Report an issue: GitHub.

Appendix: source

Thrown at sources/core/Stride.Core.Mathematics/Color.cs:232

    /// <summary>
    /// Gets or sets the component at the specified index.
    /// </summary>
    /// <value>The value of the red, green, blue, or alpha component, depending on the index.</value>
    /// <param name="index">The index of the component to access. Use 0 for the red(R) component, 1 for the green(G) component, 2 for the blue(B) component, and 3 for the alpha(A) component.</param>
    /// <returns>The value of the component at the specified index.</returns>
    /// <exception cref="System.ArgumentOutOfRangeException">Thrown when the <paramref name="index"/> is out of the range [0, 3].</exception>
    public byte this[int index]
    {
        readonly get
        {
            return index switch
            {
                0 => R,
                1 => G,
                2 => B,
                3 => A,
                _ => throw new ArgumentOutOfRangeException(nameof(index), "Indices for Color run from 0 to 3, inclusive."),
            };
        }

        set
        {
            switch (index)
            {
                case 0: R = value; break;
                case 1: G = value; break;
                case 2: B = value; break;
                case 3: A = value; break;
                default: throw new ArgumentOutOfRangeException(nameof(index), "Indices for Color run from 0 to 3, inclusive.");
            }
        }
    }

    /// <summary>
    /// Converts the color into a packed integer.

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