Why is this Texture2D memory leak occurring?

Unity Engine
1

I have a script which is loading a photo into a texture (photoThumbT2D), then rotating it:

                byte[] byteArray = File.ReadAllBytes(path);
           
                UnityEngine.Object.Destroy(photoThumbT2D);
           
                photoThumbT2D = new Texture2D(0, 0);
                photoThumbT2D.LoadImage(byteArray);

                photoThumbT2D = RotateImage(photoThumbT2D, -90);

Where the RotateImage function is adapted from here as:

public static Texture2D RotateImage(Texture2D originTexture, float angle) {
        int width = originTexture.width;
        int height = originTexture.height;
        float halfHeight = height * 0.5f;
        float halfWidth = width * 0.5f;

        Color32[] originPixels = originTexture.GetPixels32();
        Color32[] rotatedPixels = originTexture.GetPixels32();

        int oldX;
        int oldY;

        float phi = Mathf.Deg2Rad * angle;
        float cosPhi = Mathf.Cos(phi);
        float sinPhi = Mathf.Sin(phi);
   
        for (int newY = 0; newY < height; newY++) {
            for (int newX = 0; newX < width; newX++) {
                rotatedPixels[newY * width + newX] = new Color32(0, 0, 0, 0);
                int newXNormToCenter = newX - width / 2;
                int newYNormToCenter = newY - height / 2;
                oldX = (int)(cosPhi * newXNormToCenter + sinPhi * newYNormToCenter + halfWidth);
                oldY = (int)(-sinPhi * newXNormToCenter + cosPhi * newYNormToCenter + halfHeight);
                bool InsideImageBounds = (oldX > -1) && (oldX < width) && (oldY > -1) && (oldY < height);

                if (InsideImageBounds) {
                    rotatedPixels[newY * width + newX] = originPixels[oldY * width + oldX];
                }
            }
        }

        Object.DestroyImmediate(originTexture);
   
        Texture2D result = new Texture2D(width, height);
        result.SetPixels32(rotatedPixels);
        result.Apply();
        return result;
    }

However, this application of RotateImage is leading to a memory leak where the more times it runs the more memory usage piles up in the profiler.

Is there a correct way to clear the textures being created by this? Thanks.

Update: This was a bug, posted about it here: Memory management is broken in Android if >500 MB memory usage (ie. any UI Toolkit build)

2

Can you tell what is piling up? Is it the Texture2D? Are you sure nothing that is calling this is hanging onto the destroyed original texture?

1 Like
3

DestroyImmediate() isn’t supposed to be used in play mode. I would suggest replacing it with Destroy(). See in the unity docs. Unity - Scripting API: Object.DestroyImmediate