InvalidProgramException：调用方法时无效的IL代码

我收到此运行时错误： InvalidProgramException: Invalid IL code . 我正在使用unity 5.3.1f1 . 该项目是编辑器扩展 . 代码的简化版本是：

public unsafe class PPAGraph
{
   PaddedImage downSampleImage;
   int downSampleRate;
   internal void  Calculate(PaddedImage sourceImage)
   {
     sourceImage.DownSample(downSampleImage, downSampleRate); 
   }

此行发生此错误 .

InvalidProgramException：Assets.UPlus.TerrEngine.PaddedImage中的IL代码无效：DownSample（Assets.UPlus.TerrEngine.PaddedImage，int）：IL_00a9：stloc.s 15 Assets.UPlus.TerrEngine.PPAGraph.Calculate（Assets.UPlus.TerrEngine . PaddedImage sourceImage，Boolean isRidge，Boolean sketch，Int32 plength，Int32 part）（在Assets / UPlus / TerrEngine / Engine / PPA / PPAGraph.cs：1311）Assets.UPlus.Utils.TerraGodContext.CalcSketchPpa（Assets.UPlus.TerrEngine.PaddedImage sketchImg，Int32 sketchDownSampleRate）（在Assets / UPlus / TerrEngine / UnityEngine / TerraGodContext.cs：70）EditorExtensions.Editor.TerrainGodMainPanel.CreatePanel（）（在Assets / UPlus / TerrEngine / Engine / Editor / TerrainGODMainPanel.cs：45）EditorExtensions . Editor.TerrainGODWindow.OnGUI（）（在Assets / UPlus / TerrEngine / Engine / Editor / TerrainGODWindow.cs：39）System.Reflection.MonoMethod.Invoke（System.Object obj，BindingFlags invokeAttr，System.Reflection.Binder binder，System . Object []参数，System.Globalization.CultureInfo文化）（在/ Users / buil duser / buildslave /单运行时和 - classlibs /建造/ MCS /类/ corlib /的System.Reflection / MonoMethod.cs：222）

DownSample方法是：

public void DownSample(PaddedImage downSampImg, int downsampleRate)
    {
        int dsW = downSampImg.Width;
        int dsH = downSampImg.Height;
        float* dsPix = downSampImg.Pixels,padDSPix=downSampImg.PaddedPixels;
        int pad = Padding;
        int twoPad = pad + pad;
        float* rowMyPix = PaddedPixels;
        rowMyPix += pad*PaddedWidth + pad;
        float* myPix;
        int yStep = downsampleRate * PaddedWidth;
        int dsPad = downSampImg.Padding;
        int twoDSPad = dsPad + dsPad;
        padDSPix += downSampImg.PaddedWidth*dsPad + dsPad;
        if (downSampImg.PixelsPtr != IntPtr.Zero)
        {
            for (int y = 0; y < dsH; y++)
            {
                myPix = rowMyPix;
                for (int x = 0; x < dsW; x++)
                {
                    *padDSPix++ = *dsPix++ = *myPix;
                    myPix += downsampleRate;
                }
                padDSPix += twoDSPad;
                rowMyPix += yStep;
            }
        }
        else
        {
            for (int y = 0; y < dsH; y++)
            {
                myPix = rowMyPix;
                for (int x = 0; x < dsW; x++)
                {
                    *padDSPix++ = *dsPix++ = *myPix;
                    myPix += downsampleRate;
                }
                padDSPix += twoDSPad;
                rowMyPix += yStep;
            }
        }
    }