这里有一个解决方案，并相应地添加了更正后的代码。我不确定这是不是"***的"方式，但它奏效了。(请参阅抗锯齿圆部分，解决方案来自：http://gamedev.stackexchange.com/questions/34582/how-do-i-use-screen-space-derivatives-to-antialias-a-parametric-shape-in-a-pixel)

    //
//   Project:           Dot Matrix Display (DMD) Shader
//  Inspired from From Mosaic shader Copyright (c) 2010 Rene Schulte


/// <summary>The number pixel blocks.</summary>
/// <type>Single</type>
/// <minValue>2</minValue>
/// <maxValue>500</maxValue>
/// <defaultValue>34</defaultValue>


float BlockCount : register(C0);

/// <summary>The rounding of a pixel block.</summary>
/// <type>Single</type>
/// <minValue>0</minValue>
/// <maxValue>1</maxValue>
/// <defaultValue>0.45</defaultValue>
float Max : register(C2);

/// <summary>The aspect ratio of the image.</summary>
/// <type>Single</type>
/// <minValue>0</minValue>
/// <maxValue>10</maxValue>
/// <defaultValue>1.55</defaultValue>
float AspectRatio : register(C3);

/// <summary>The monochrome color used to tint the input.</summary>
/// <defaultValue>Yellow</defaultValue>
float4 FilterColor : register(C1);

/// <summary>monochrome.</summary>
/// <defaultValue>1</defaultValue>
float IsMonochrome : register(C4);

// Sampler
sampler2D input : register(S0);

// Static computed vars for optimization
static float2 BlockCount2 = float2(BlockCount, BlockCount  / AspectRatio);
static float2 BlockSize2 = 1.0f / BlockCount2; 

float4 setMonochrome(float4 color) : COLOR
{
   float4 monochrome= color;
   if(((int)IsMonochrome) == 1)
   {
      float3 rgb = color.rgb;
      float3 luminance = dot(rgb, float3(0.30, 0.59, 0.11));
     monochrome= float4(luminance * FilterColor.rgb, color.a);
   }
    return monochrome;
}

float4 SetDMD(float2 uv : TEXCOORD, sampler2D samp) : COLOR
{
     // Calculate block center
     float2 blockPos = floor(uv * BlockCount2);
     float2 blockCenter = blockPos * BlockSize2 + BlockSize2 * 0.5;

     // Scale coordinates back to original ratio for rounding
     float2 uvScaled = float2(uv.x * AspectRatio, uv.y);
     float2 blockCenterScaled = float2(blockCenter.x * AspectRatio, blockCenter.y);

     // Round the block by testing the distance of the pixel coordinate to the center
     float dist = length(uvScaled - blockCenterScaled) * BlockCount2;

      float4 insideColor= tex2D(samp, blockCenter);

     float4 outsideColor = insideColor; 
         outsideColor.r = 0; 
         outsideColor.g = 0; 
         outsideColor.b = 0; 
         outsideColor.a = 1; 

      float distFromEdge = Max - dist;  // positive when inside the circle
     float thresholdWidth = .22;  // a constant you'd tune to get the right level of softness
     float antialiasedCircle = saturate((distFromEdge / thresholdWidth) + 0.5);

     return lerp(outsideColor, insideColor, antialiasedCircle);
}

// Shader
float4 main(float2 uv : TEXCOORD) : COLOR
{
     float4 DMD= SetDMD(uv, input);
     DMD = setMonochrome(DMD);

     return DMD;
}

这里是成功解决方案的图像；