stride3d/stride · error · InvalidOperationException

Input and output texture cannot have same size

Error message

Input and output texture cannot have same size [{0}]

What it means

ImageMultiScaler is a scaling pass; it requires input and output textures to have different sizes. PrepareScaling throws InvalidOperationException when an output texture's size equals the input size, since upscaling/downscaling a texture onto one of identical dimensions is unsupported by this effect.

Solutions

  1. Ensure the output is strictly smaller or larger than the input; use a copy/blit (e.g. ImageScaler in copy mode or a SpriteBatch copy) if you need same-size transfer.
  2. Skip adding the texture as a multi-scaler output when its size equals the input size.
  3. Log/compare inputSize vs requested output size during setup to catch the equality early.

Example fix

// before
scaler.SetOutput(0, RenderTexture(inputWidth, inputHeight)); // same size
// after
scaler.SetOutput(0, RenderTexture(inputWidth / 2, inputHeight / 2));
Defensive patterns

Strategy: validation

Validate before calling

if (outputSize == inputSize)
    throw new InvalidOperationException("Use a copy/blit pass, not ImageMultiScaler, for same-size transfer");

Try / catch

try { scaler.Draw(context); }
catch (InvalidOperationException) { FallbackCopyPass(input, output); }

Prevention

When it happens

Trigger: Connecting an output texture with exactly the same dimensions as the input texture (inputSize == outputSize) and rendering, so DrawCore calls PrepareScaling.

Common situations: Auto-sizing an output to match the input 'to keep it simple'; a resize handler that makes the backbuffer equal the source resolution; copy intent where the developer should have used a blit/copy pass instead of a scaler.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/6a33fe4a5d921d97. Report an issue: GitHub.

Appendix: source

Thrown at sources/engine/Stride.Rendering/Rendering/Images/ImageScaler/ImageMultiScaler.cs:139

                {
                    // Verify pixel format
                    if (outputPixelFormat != PixelFormat.None && outputPixelFormat != outputTexture.ViewFormat)
                    {
                        throw new InvalidOperationException("Output texture format [{0}] is not matching other output texture format [{1}]".ToFormat(outputTexture.ViewFormat, outputPixelFormat));
                    }
                    outputPixelFormat = outputTexture.ViewFormat;

                    var outputSize = outputTexture.Size;

                    // Verify pixel format
                    if (outputSize < minSize || outputSize > maxSize)
                    {
                        throw new InvalidOperationException("Unsupported texture size [{0}] out of limit [{1} - {2}]".ToFormat(outputTexture.Size, minSize, maxSize));
                    }

                    if (inputSize == outputSize)
                    {
                        throw new InvalidOperationException("Input and output texture cannot have same size [{0}]".ToFormat(inputSize));
                    }

                    int newScalingDirection = outputSize.CompareTo(inputSize);
                    if (scalingDirection != 0 && Math.Sign(scalingDirection) != Math.Sign(newScalingDirection))
                    {
                        throw new InvalidOperationException("Support only output scaling to the same direction");
                    }
                    scalingDirection = newScalingDirection;

                    // Check that we are scaling to different texture sizes
                    foreach (var existingOutput in outputTextures)
                    {
                        if (existingOutput.Size == outputTexture.Size)
                        {
                            throw new InvalidOperationException("A texture with size [{0}] already exist with the same output size".ToFormat(existingOutput.Size));
                        }
                    }

View on GitHub (pinned to 96fad776d2)