stride3d/stride · error · ArgumentOutOfRangeException

Indices for Color4 run from 0 to 3, inclusive.

Error message

Indices for Color4 run from 0 to 3, inclusive.

What it means

The Color4 indexer performs a bounds check on the index parameter and throws ArgumentOutOfRangeException whenever the index is outside [0, 3]. It is a generic guard on component access: any subscript other than 0 (red), 1 (green), 2 (blue) or 3 (alpha) fires it — Color4 has exactly four components, so negative or >= 4 indices are invalid.

Solutions

1. Clamp or check the index to 0..3 before access.
2. Iterate with an explicit bound of 4 for Color4.
3. Access R/G/B/A fields directly for known components.

Example fix

// before
for (int i = 0; i <= 4; i++)
    sum += color4[i];
// after
for (int i = 0; i < 4; i++)
    sum += color4[i];

if (index < 0 || index > 3) throw new ArgumentOutOfRangeException(nameof(index));
var channel = color4[index];

bool IsValidColor4Index(int i) => i is >= 0 and <= 3;

try { var c = color4[index]; }
catch (ArgumentOutOfRangeException) { /* clamp index and retry or default */ }

When it happens

Trigger: Reading color4[index] with index < 0 or index > 3, e.g. a loop bound copied from a larger vector type or a computed index going negative.

Common situations: Generic per-channel loops with wrong upper bounds; math utilities shared with Vector4-like types where a fifth slot was expected; off-by-one in alpha handling.

Related errors

• Indices for Color run from 0 to 3, inclusive.
• Indices for Color3 run from 0 to 2, 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/1c425893ee5a1db8. Report an issue: GitHub.

Appendix: source

Thrown at sources/core/Stride.Core.Mathematics/Color4.cs:243

    /// <summary>
    /// Gets or sets the component at the specified index.
    /// </summary>
    /// <value>The value of the red, green, blue, and alpha components, depending on the index.</value>
    /// <param name="index">The index of the component to access. Use 0 for the alpha component, 1 for the red component, 2 for the green component, and 3 for the blue 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 float this[int index]
    {
        readonly get
        {
            return index switch
            {
                0 => R,
                1 => G,
                2 => B,
                3 => A,
                _ => throw new ArgumentOutOfRangeException(nameof(index), "Indices for Color4 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 Color4 run from 0 to 3, inclusive.");
            }
        }
    }

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

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