android - Unity - 检测 Android 上的 OpenGL 是否不支持某个操作

Question

我正在使用在 pastebin 上找到的纹理缩放器代码（下面的代码），由于某种原因它在某些设备上不起作用，它会产生无效的纹理。我确定它不起作用的一种设备是 Nexus 7 平板电脑（2012 年），但它可能不适用于许多其他设备。但在绝大多数设备上它确实有效。

我不确定为什么它不起作用，或者它在什么操作上失败，但鉴于这个缩放器是在 GPU 上完成的，它比我发现的其他版本的缩放器快得多。

然后我想做的是以某种方式检测它不起作用，因此我可以运行较慢版本的缩放算法。关于任何一个的任何想法：

1）如何检测？我想在运行后检查纹理是否无效，但它在不同设备上的行为可能不同（在 Nexus 7 上，它总是将像素颜色变为 205,205,205）

2）为什么它不起作用？我在一些搜索中发现，如果纹理是 NPOT，Nexus 7 上的一些 GPU 操作会失败，但我不知道它是否与此有关。我还认为它可能与 Open GL ES 版本有关，但我不知道如何检查版本（也许 Nexus 7 是 GLES 2.0，而这个缩放器只适用于 GLES 3.0+？）。

谢谢

using UnityEngine;

// from: https://pastebin.com/qkkhWs2J

/// 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 TextureScaler
{

    /// <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 Rect(0,0,width,height);
            _gpu_scale(src,width,height,mode);

            //Get rendered data back to a new texture
            Texture2D result = new Texture2D(width, height, TextureFormat.ARGB32, true);
            result.Resize(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 Rect(0,0,width,height);
            _gpu_scale(tex,width,height,mode);

            // Update new texture
            tex.Resize(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.
    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 RenderTexture(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);
    }
}

标签： androidunity3dtexturesgputexture2d