Hi all,

I am calculating DOG of two images using the following fragment shader. But I am not getting expected result. I have googled a lot but am not able to figure out my mistake here.

```
uniform sampler2D blurImage;
uniform sampler2D moreBlurImage;
void main()
{
float blurGray = texture2D(blurImage,gl_TexCoord[0].xy).r;
float moreBlurGray = texture2D(moreBlurImage, TexCoord).r;
float diffOfGauss = abs(blurGray - moreBlurGray);
gl_FragColor = vec4(vec3(diffOfGauss),1.0);
}
```

Assuming here that the image is in grayscale so r=g=b.