MonoGame/MonoGame · error · ArgumentException

Type T is of an invalid size for the format of this texture.

Error message

Type T is of an invalid size for the format of this texture.

What it means

Thrown by Texture2D.ValidateParams as an ArgumentException when the element type T is the wrong size for the texture's SurfaceFormat. The rule is tSize = sizeof(T) and fSize = Format.GetSize(); it throws when tSize > fSize or fSize % tSize != 0. This lets you read/write a block-compressed or larger-pixel format with a smaller type, but forbids a type larger than one pixel or one that doesn't evenly divide the pixel size.

Source

Thrown at MonoGame.Framework/Graphics/Texture2D.cs:794

        private void ValidateParams<T>(int level, int arraySlice, Rectangle? rect, T[] data,
            int startIndex, int elementCount, out Rectangle checkedRect) where T : struct
        {
            var textureBounds = new Rectangle(0, 0, Math.Max(width >> level, 1), Math.Max(height >> level, 1));
            checkedRect = rect ?? textureBounds;
            if (level < 0 || level >= LevelCount)
                throw new ArgumentException("level must be smaller than the number of levels in this texture.", "level");
            if (arraySlice > 0 && !GraphicsDevice.GraphicsCapabilities.SupportsTextureArrays)
                throw new ArgumentException("Texture arrays are not supported on this graphics device", "arraySlice");
            if (arraySlice < 0 || arraySlice >= ArraySize)
                throw new ArgumentException("arraySlice must be smaller than the ArraySize of this texture and larger than 0.", "arraySlice");
            if (!textureBounds.Contains(checkedRect) || checkedRect.Width <= 0 || checkedRect.Height <= 0)
                throw new ArgumentException("Rectangle must be inside the texture bounds", "rect");
            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.");

            int dataByteSize;
            if (Format.IsCompressedFormat())
            {
                int blockWidth, blockHeight;
                Format.GetBlockSize(out blockWidth, out blockHeight);
                // round x and y down to next multiple of block size; width and height up to next multiple of block size
                // we need to use this rather than the old code where because ASTC Compressed Textures are NOT Powers of 2.
                var roundedWidth = (checkedRect.Width + blockWidth - 1) / blockWidth * blockWidth;
                var roundedHeight = (checkedRect.Height + blockHeight - 1) / blockHeight * blockHeight;
                checkedRect = new Rectangle(checkedRect.X / blockWidth * blockWidth, checkedRect.Y / blockHeight * blockHeight,
#if OPENGL
                    // OpenGL only: The last two mip levels require the width and height to be
                    // passed as 2x2 and 1x1, but there needs to be enough data passed to occupy

View on GitHub (pinned to 1d71bbd0ff)

Solutions

1. Match T to the SurfaceFormat: use the format's native struct (e.g. HalfVector4 for Rgba64, byte/int for block formats) or use a type whose size divides the pixel size.
2. Check tSize vs Format.GetSize() before the call: require tSize <= fSize && fSize % tSize == 0.
3. Recreate the texture with SurfaceFormat.Color if you intend to use Color (32-bit) elements.

Example fix

// before
_tex = new Texture2D(GraphicsDevice, w, h, false, SurfaceFormat.Rgba64);
var data = new Color[w * h];
_tex.SetData(data); // sizeof(Color)=4 vs Rgba64=8 -> throws 459

// after
var data = new Rgba64[w * h]; // sizeof == 8, matches SurfaceFormat.Rgba64
_tex.SetData(data);

static void AssertTypeFits<T>(SurfaceFormat format) where T : struct
{
    int tSize = System.Runtime.InteropServices.Marshal.SizeOf<T>();
    int fSize = format.GetSize();
    if (tSize > fSize || fSize % tSize != 0)
        throw new ArgumentException($"sizeof({typeof(T)})={tSize} is invalid for {format} (size {fSize})");
}

static bool TypeMatches<T>(SurfaceFormat format) where T : struct
{
    int tSize = System.Runtime.InteropServices.Marshal.SizeOf<T>();
    int fSize = format.GetSize();
    return tSize <= fSize && fSize % tSize == 0;
}

When it happens

Trigger: Using `SetData<Color>` on a HalfVector2 (8-bit-per-pixel-ish) or compressed (DXT/ASTC) texture where sizeof(Color)==4 is not a divisor/fit; using a struct whose marshalled size doesn't match the format; reading a DXT5 texture with a byte[] where the block math differs.

Common situations: Assuming all textures are 32-bit Color and calling SetData<Color>/GetData<Color> on a Rgba64, HalfSingle, or compressed surface; authoring a custom struct with padding that changes its size; format mismatch after changing a texture's SurfaceFormat.

Related errors

• level must be smaller than the number of levels in this text
• arraySlice must be smaller than the ArraySize of this textur
• Rectangle must be inside the texture bounds
• Texture width must be greater than zero
• Texture height must be greater than zero

AI-assisted analysis of MonoGame/MonoGame@1d71bbd0ff (2026-08-13). Data as JSON: /api/errors/7c9143aae68d4905. Report an issue: GitHub.