I'm not sure how to explain it so erm :3

I'm trying to calculate the normal of a face and I'm using a simple vector type but when I try to compile it the compiler says it's returning an array so erm, I don't get what's wrong. I know Vec3's an array but I don't see how I'm ment to return it?

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well, since your method doesn't have a return type, you shouldn't return any value..

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ummm.. nevermind... i see that you use Vec3...

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Arrays are never copied, but passed by pointer, so the compiler is complaining that you're returning a pointer, but the return type is an array type. Ultimately its preventing you from doing something which would cause undefined behaviour, like a crash or a seg fault. Your function would be returning a pointer to some memory which is allocated in your function, and therefore it will be deallocated as soon as your function returns.

Depending whether you're using C++ or not, the preferred alternative is to use an STL container such as vector, which may be copied any way you like.

If you haven't got the STL containers available, then you should create your array externally from the function, and pass it in as an argument - allowing the function to modify an existing array, rather than attempting to return a whole new array from a function. There are other alternatives, such as creating the array dynamically (Bad solution - its open to all kinds of memory management nightmares), or wrapping the array in a struct (worth considering, if you can justify turning Vec3 into a struct type - struct objects may be copied in full, so can be used as return types for a function)

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If your using C++. Just create a class like this

class Vec3
{
union
{
float xyz;
struct
{
float x, y, z;
};
};

MATH_INLINE void glNormal3d(Vec3& p1, Vec3& p2)
{
Vec3 v = Vec3(x, y, z);
Vec3 v1 = p1 - v;
Vec3 v2 = p2 - p1;
Vec3 normal = Vec3(v1.cross(v2));
normal.normalise();
normal.printVec3();
glNormal3dv(normal.ptr());
}
};

EDIT: Sorry theres no way to delete the post. Just noticed its 3 months old.

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