double and float

[haha1234567]

Why doesn't it work?

i have the dll like this:

But in Labview(see attachment ResMap.vi) ,it will be overlap, how can i do it right?  (I mean, what's wrong with the data typ converting?)

void __declspec(dllexport) __stdcall ResMap(float *ResMap,int imgwidth, int imgheight)
{

double dotpitch,e_pixel,d,e_degree,f_eye_cpd,dpp,f_eye_cpp;

dotpitch = Wd / imgwidth;

for (int x=0;x<imgwidth;x++)
 for(int y=0;y<imgheight;y++)
 {
e_pixel =sqrt((double)((x-imgwidth/2)^2 + (y-imgheight/2)^2));

... ...

f_eye_cpp = f_eye_cpd * dpp;
ResMap[x+imgwidth*y]= (float)f_eye_cpp;

... ...

}

}

[smercurio_fc]

I can't open the VI since I only have LabVIEW 8.2. I can say, however, that "float" is actually a vague representation, as it can mean multiple precisions. See here. You need to see how your compiler defines float, and then you can see which LabVIEW data type matches it.

[haha1234567]

Thanks!

[haha1234567]

If I write it as :  void __declspec(dllexport) __stdcall ResMap(double*ResMap,int imgwidth, int imgheight), it still not correct. It compiles in VC without errors, even if i run it in Labview without error-Infos either,but the result is not what i want. Something is went wrong. (The correct Image should like a white "sun" in the black backgrund)

[smercurio_fc]

Unfortunately, as I said, I can't open your VI since I don't have LabVIEW 8.5, and I don't know how your DLL is supposed to be used, otherwise I'd just create my own VI in 8.2. If you resave your VIs in 8.2 I can take a look at them for you. Otherwise, someone with 8.5 can take this up.