I don’t know why you got that error. However, I found a great TextureScaler which has pretty much the same API and uses the GPU instead. It also has better scaling I believe, higher quality end product. Here it is.
using UnityEngine;
/// A unility class with functions to scale Texture2D Data.
///
/// Scale is performed on the GPU using RTT, so it's blazing fast.
/// Setting up and Getting back the texture data is the bottleneck.
/// But Scaling itself costs only 1 draw call and 1 RTT State setup!
/// WARNING: This script override the RTT Setup! (It sets a RTT!)
///
/// Note: This scaler does NOT support aspect ratio based scaling. You will have to do it yourself!
/// It supports Alpha, but you will have to divide by alpha in your shaders,
/// because of premultiplied alpha effect. Or you should use blend modes.
public class GPUTextureScaler
{
/// <summary>
/// Returns a scaled copy of given texture.
/// </summary>
/// <param name="tex">Source texure to scale</param>
/// <param name="width">Destination texture width</param>
/// <param name="height">Destination texture height</param>
/// <param name="mode">Filtering mode</param>
public static Texture2D Scaled(Texture2D src, int width, int height, FilterMode mode = FilterMode.Trilinear)
{
Rect texR = new(0, 0, width, height);
_gpu_scale(src, width, height, mode);
//Get rendered data back to a new texture
Texture2D result = new(width, height, TextureFormat.ARGB32, true);
result.Reinitialize(width, height);
result.ReadPixels(texR, 0, 0, true);
return result;
}
/// <summary>
/// Scales the texture data of the given texture.
/// </summary>
/// <param name="tex">Texure to scale</param>
/// <param name="width">New width</param>
/// <param name="height">New height</param>
/// <param name="mode">Filtering mode</param>
public static void Scale(Texture2D tex, int width, int height, FilterMode mode = FilterMode.Trilinear)
{
Rect texR = new(0, 0, width, height);
_gpu_scale(tex, width, height, mode);
// Update new texture
tex.Reinitialize(width, height);
tex.ReadPixels(texR, 0, 0, true);
tex.Apply(true); //Remove this if you hate us applying textures for you :)
}
// Internal unility that renders the source texture into the RTT - the scaling method itself.
private static void _gpu_scale(Texture2D src, int width, int height, FilterMode fmode)
{
//We need the source texture in VRAM because we render with it
src.filterMode = fmode;
src.Apply(true);
//Using RTT for best quality and performance. Thanks, Unity 5
RenderTexture rtt = new(width, height, 32);
//Set the RTT in order to render to it
Graphics.SetRenderTarget(rtt);
//Setup 2D matrix in range 0..1, so nobody needs to care about sized
GL.LoadPixelMatrix(0, 1, 1, 0);
//Then clear & draw the texture to fill the entire RTT.
GL.Clear(true, true, new Color(0, 0, 0, 0));
Graphics.DrawTexture(new Rect(0, 0, 1, 1), src);
}
}
Credit to the author, which is not me!
I also modified it with some general code quality improvements, but changed nothing about the functionality.
