I’m trying to convert my XNA project to MonoGame, and I had this problem, which took ages to track down because it fails silently with no error message. There’s an easy workaround which I’m now using, but I thought I’d post it here to see if anyone’s heard of it.

Here’s part of my Guassian blur shader, as it was in the XNA project:

```
const float gaussian[] =
{
0.0539909676,
0.241970733,
0.3989423,
0.241970733,
0.0539909676,
};
void AddTap(in out float4 sum, float2 tex_coord, float weight)
{
float4 tex_col = tex2D(TexSampler, tex_coord);
sum += tex_col*weight;
}
float4 GaussianBlurStage1PS(VertexShaderOutput input) : COLOR0
{
float4 sum = float4(0,0,0,0);
// blur in x (horizontal)
for (int i = -1; i <= 1; i++)
AddTap(sum, float2(input.TexCoord.x + float(i)/TexSize, input.TexCoord.y), gaussian[i+1]);
return float4(sum.rgb,1);
}
float4 GaussianBlurStage2PS(VertexShaderOutput input) : COLOR0
{
float4 sum = float4(0,0,0,0);
// blur in y (vertical)
for (int i = -1; i <= 1; i++)
AddTap(sum, float2(input.TexCoord.x, input.TexCoord.y + float(i)/TexSize), gaussian[i+1]);
return float4(sum.rgb,1);
}
```

This doesn’t work, and doesn’t give any error messages. The problem seems to be that it doesn’t like the global const array “gaussian”. If I move this into the functions, it works. But because there are two functions I have to copy the array into each of them, so the code is duplicated. Which… doesn’t really *matter*, but it’s a bit annoying