Suppose I have a loop where I execute two functions:

for(...)
{
   if (x) Do1(x);
   if (y) Do2(y);
}

The problem is, I really always want to execute all the Do2's first then the Do1's. As is, we could get any order of calls.

Suppose I can't run the loop twice for performance reasons(there is other stuff in it) and I don't want to store the state and call info then sort them out afterwards.

Is there an efficient lazy way to make this happen?

On Thursday, 16 June 2016 at 01:57:19 UTC, Joerg Joergonson wrote:
> Suppose I have a loop where I execute two functions:
>
> for(...)
> {
>    if (x) Do1(x);
>    if (y) Do2(y);
> }
>
> The problem is, I really always want to execute all the Do2's first then the Do1's. As is, we could get any order of calls.
>
> Suppose I can't run the loop twice for performance reasons(there is other stuff in it) and I don't want to store the state and call info then sort them out afterwards.
>
> Is there an efficient lazy way to make this happen?

Something like: https://dpaste.dzfl.pl/79b77c934825 ?

On Thursday, 16 June 2016 at 01:57:19 UTC, Joerg Joergonson wrote:
> Is there an efficient lazy way to make this happen?

No, I don't see how that would work.

> Suppose I can't run the loop twice for performance reasons(there is other stuff in it) and I don't want to store the state and call info then sort them out afterwards.

Storing the state is your best bet. Based on your recent post about OpenGL I assume this is for the same project?

If so, you can reuse the storage buffer between frames. Generally speaking it's the allocations that are slow, copying some state to a buffer shouldn't be expensive. Use separate buffers for the Do1 and Do2 calls so you don't have to sort.