c – 如何使可移植和编译器无关的glBufferData？

根据这个问题的答案,

OpenGL defines,very clearly,what the byte layout of a std140 interface block is.

C++11 defines a concept called 07001.

The only things C++ tells you about standard layout types with regard to layout is that empty base classes are ignored (so long as it remains standard layout) and that the first NSDM will be at the very beginning of the class. That is,there will never be padding at the front.

The other thing the standard says is that NSDMs of the same access class will be allocated in order,with later ones having larger offsets than earlier ones.

But that’s it,as far as the C++ standard is concerned. [class.mem]/13 states that implementations can add padding between members for various reasons.

那可能但不总是存在填充可能真的搞砸了,最糟糕的部分 – 它取决于编译器.

为了避免错误和恶梦,使用编译器无关的方法不是更好吗？

例如：

class BufferData
{
private:
    GLfloat data[12];

public:
    GLfloat* getCameraPosition()
    {
        return (GLfloat*) &data[0];
    }
    GLfloat* getLightPosition()
    {
        return (GLfloat*) &data[4];
    }
    GLfloat* getLightDiffuse()
    {
        return (GLfloat*) &data[8];
    }
    GLfloat* getData()
    {
        return data;
    }
};

与天真相反：

struct BufferData
{
    GLfloat camera_position[4];
    GLfloat light_position[4];
    GLfloat light_diffuse[4];
};

或者天真的方法是否足够好？

(假设类/结构不仅仅是那个,而且可能会改变)