这里的POSITION是变量Position的语义，告诉寄存器，此变量的保存位置，通常语义用于着色器的输入和输出，以冒号“：”的方式进一步说明此变量，COLOR也类似

还有什么语义呢？

HLSL核心函数：

float3 Pixels = Texture2DSample(Tex, TexSampler, myUV);
for(int i = 0; i < n; i++) {Pixels += Texture2DSample(Tex, TexSampler, myUV + float2(offset, 0));Pixels += Texture2DSample(Tex, TexSampler, myUV + float2(-offset, 0));Pixels += Texture2DSample(Tex, TexSampler, myUV + float2(0, offset));Pixels += Texture2DSample(Tex, TexSampler, myUV + float2(0, -offset));Pixels += Texture2DSample(Tex, TexSampler, myUV + float2(offset, -offset));Pixels += Texture2DSample(Tex, TexSampler, myUV + float2(-offset, offset));Pixels += Texture2DSample(Tex, TexSampler, myUV + float2(offset, offset));Pixels += Texture2DSample(Tex, TexSampler, myUV + float2(-offset, -offset));
}
Pixels /= 8 + 1;return Pixels;

模糊

float2 myUV = floor(uv * 20) / 20;
float3 Pixels = Texture2DSample(Tex, TexSampler, myUV);return Pixels;

像素化