MonoGame/MonoGame · error · ArgumentException

The data array is too small.

Error message

The data array is too small.

What it means

ArgumentException from Texture3D.ValidateParams when data.Length < startIndex + elementCount, i.e. the requested window runs past the end of the array. Guarantees the GPU copy stays within the managed buffer.

Source

Thrown at MonoGame.Framework/Graphics/Texture3D.cs:420

            var depth = back - front;

            if (left < 0 || top < 0 || back < 0 || right > texWidth || bottom > texHeight || front > texDepth)
                throw new ArgumentException("Area must remain inside texture bounds");
            // Disallow negative box size
            if (left >= right || top >= bottom || front >= back)
                throw new ArgumentException("Neither box size nor box position can be negative");
            if (level < 0 || level >= LevelCount)
                throw new ArgumentException("level must be smaller than the number of levels in this texture.");
            if (data == null)
                throw new ArgumentNullException("data");
            var tSize = ReflectionHelpers.FastSizeOf<T>();
            var fSize = Format.GetSize();
            if (tSize > fSize || fSize % tSize != 0)
                throw new ArgumentException("Type T is of an invalid size for the format of this texture.", "T");
            if (startIndex < 0 || startIndex >= data.Length)
                throw new ArgumentException("startIndex must be at least zero and smaller than data.Length.", "startIndex");
            if (data.Length < startIndex + elementCount)
                throw new ArgumentException("The data array is too small.");

            var dataByteSize = width*height*depth*fSize;
            if (elementCount * tSize != dataByteSize)
                throw new ArgumentException(string.Format("elementCount is not the right size, " +
                                            "elementCount * sizeof(T) is {0}, but data size is {1}.",
                                            elementCount * tSize, dataByteSize), "elementCount");
        }
	}
}

View on GitHub (pinned to 1d71bbd0ff)

Solutions

1. Size data to at least startIndex + elementCount before the call.
2. Recompute elementCount as data.Length - startIndex when copying the tail.
3. Match elementCount to the volume region's element requirement.

Example fix

// before
var data = new float[128];
texture.SetData(0, 0,0,w, 0,h, 0,d, data, 0, 256);

// after
var data = new float[256];
texture.SetData(0, 0,0,w, 0,h, 0,d, data, 0, 256);

int needed = startIndex + elementCount;
if (data == null || data.Length < needed)
    throw new InvalidOperationException($"data needs {needed} elements, has {(data?.Length ?? 0)}");
texture.SetData(level, l, t, r, b, f, bk, data, startIndex, elementCount);

try
{
    texture.SetData(level, l, t, r, b, f, bk, data, start, count);
}
catch (ArgumentException ex) when (ex.Message == "The data array is too small.")
{
    // resize data to needed size and retry
}

When it happens

Trigger: Box-level SetData/GetData with elementCount larger than the remaining elements from startIndex, or a startIndex that pushes the window past the end.

Common situations: Volume buffer sized for one mip level but used on a larger one; partial fill with a wrong count; reusing a buffer with a stale elementCount.

Related errors

• The data array is too small.
• Neither box size nor box position can be negative
• startIndex must be at least zero and smaller than data.Lengt
• startIndex must be at least zero and smaller than data.Lengt
• Area must remain inside texture bounds

AI-assisted analysis of MonoGame/MonoGame@1d71bbd0ff (2026-08-13). Data as JSON: /api/errors/10b36b1ec316bfdb. Report an issue: GitHub.