Hi, Another Game dev here.
Firstly, neat article, thanks for writing it.
I'm curious as to the problem you're exploring/solving here?
"Concatenated struct's in single chunk" is a neat trick. The use case seems a bit broken[1], but I'm assuming that it's from the original video, and your c++-ifying it? Or at least trying to find a nicer way to write this style of code?
If you'r going this route, I'd be tempted not to use pointers at all, and just use offsets and accessors.[2]
* Lack of pointers means you can load in 1 read. (endian needs to be watched, and assumes you can get the entire size elsewhere)
* You can also shuffle it around in memory should you be doing something fancy. (defragging heaps might be useful if doing a sandbox)
* Better encapsulation? maybe..
But the basic point I'd like to make is, there is no nice way to write this type of code, because c and c++ gives us no nice[3] way of expressing it.
[1] Verts and Indices are generally uploaded to a GPU then discarded, but this has the counts, which is needed CPU side for draw calls, in the same chunk so would need to be copied before freeing.
[2]
struct Mesh
{
int32_t num_indices,
num_verts;
// inline to this struct..
// assumes Vector3 is aligned 4 bytes.
// and that Mesh has been alloced to same alignment.
//
// Vector3 positions[num_verts];
// int32_t indices[num_indices];
// Vector2 uvs[num_verts];
inline const Vector3* PositionsBegin() const { return reinterpret_cast<const Vector3*>(this + 1); }
inline const Vector3* PositionsEnd() const { return PositionsBegin() + num_verts; }
inline const int32_t* IndicesBegin() const { return reinterpret_cast<const int32_t*>(PositionsEnd()); }
inline const int32_t* IndicesEnd() const { return IndicesBegin() + num_indices; }
// etc
};
[3] Maintainable, fast at runtime, low mental friction to people other than the author, etc
I'm curious as to the problem you're exploring/solving here?
"Concatenated struct's in single chunk" is a neat trick. The use case seems a bit broken[1], but I'm assuming that it's from the original video, and your c++-ifying it? Or at least trying to find a nicer way to write this style of code?
If you'r going this route, I'd be tempted not to use pointers at all, and just use offsets and accessors.[2]
But the basic point I'd like to make is, there is no nice way to write this type of code, because c and c++ gives us no nice[3] way of expressing it.[1] Verts and Indices are generally uploaded to a GPU then discarded, but this has the counts, which is needed CPU side for draw calls, in the same chunk so would need to be copied before freeing.
[2]
[3] Maintainable, fast at runtime, low mental friction to people other than the author, etc