如何从渲染纹理中读取像素（颜色附件）

Question

我在colo中将颜色和位置纹理渲染到colorattachment0和colorattachment1。正在将颜色纹理绘制到立方体上以进行不同的渲染。我需要从位置纹理读取，我发送到colorattachment1。以下是我的尝试：

public float[] getUV() 
{
    float[] uv = new float[2];
    var pixel = new float[4];
    GL.ReadBuffer(ReadBufferMode.ColorAttachment1);
    GL.ReadPixels((int)curPoint.X, (int)curPoint.Y, 1, 1, OpenTK.Graphics.OpenGL.PixelFormat.Rgba, PixelType.UnsignedByte, pixel);

    uv[0] = pixel[0];
    uv[1] = pixel[1];
    return uv;
} 

我在mousedown事件上调用getUV。以下是我创建fbo的方法：

    GL.Ext.GenFramebuffers(1, out fboHandle);
    GL.Ext.BindFramebuffer(FramebufferTarget.FramebufferExt, fboHandle);
    GL.Ext.FramebufferTexture2D(FramebufferTarget.FramebufferExt, FramebufferAttachment.ColorAttachment0Ext, TextureTarget.Texture2D, colorTexture, 0);
    GL.Ext.FramebufferTexture2D(FramebufferTarget.FramebufferExt, FramebufferAttachment.ColorAttachment1Ext, TextureTarget.Texture2D, uvTexture, 0);
    GL.Ext.FramebufferTexture2D(FramebufferTarget.FramebufferExt, FramebufferAttachment.DepthAttachmentExt, TextureTarget.Texture2D, depthBufferTexture, 0);

从getUV（）返回的值是完全错误的，我想我错过了一步。我已经验证了ColorAttachment1正确渲染，并且我发送给ReadPixels的鼠标坐标是正确的。