Loading an image using DevIL and OpenGL in C++

Question

As the title suggests, I am trying to load an image using DevIL, before passing it to OpenGL. I am using this piece of code as error control

const char* filename = "back.bmp";

if (!ilLoadImage(filename))
{
    throw runtime_error(std::string("Unable to load image") +filename);
}

which, for the if statement, returns the error

error C2664: 'ilLoadImage' : cannot convert parameter 1 from 'const char *' to 'const wchar_t *'

If I define filename as const wchar_t* filename, I get the error

error C2664: 'ilLoadImage' : cannot convert parameter 1 from 'const char *' to 'const wchar_t *'

So for now I will not tire you with my curiosity of why a [filename].bmp file is of type wchar_t*, or what wchar_t is, which Google confused me over, and I will only ask what I must to make it work: Why is it not working? What have I missed? There must be a very short solution for this, I am sure. It just looks like that kind of error.

Thank you.

Blindy Blindy · Accepted Answer · 2011-04-20T18:48:06

If you use Unicode functions, you have to use Unicode text. Specifically, L will return the wide char representation of static text:

ilLoadImage(L"back.bmp");

If you're compiling code for both ANSI and wide strings, use _T() instead, which returns the correct type of string:

ilLoadImage(_T("back.bmp"));

If you're in the latter case and don't know what types of chars you'll need at compile time, use TCHAR, which is either a CHAR or a WCHAR depending on whether UNICODE is defined.

Loading an image using DevIL and OpenGL in C++

2 Answers