Blitting order sort

With only 40 characters or so I don't think you'll need to worry too much about the cost of the sort. Assuming C++, I would just store some sort of handle to the entities in a container such as a std::vector, and then run std::sort() on the container each update using a comparator functor keyed off of the entities' y values.

If somehow this proved not to be performant enough (unlikely, I think), you could update each entity's handle within the container only when its y position is modified. Typically this update will require very few swaps due to coherency. I can't imagine it getting a whole lot faster than this.

If the above solution(s) won't work for you for some reason, perhaps you could post some more info, such as programming language and graphics API.

[Edited by - jyk on October 10, 2006 10:10:26 PM]

yeah i'm sorry, i was pretty vague, i'm using c++ and using DirectDraw at the moment, so its nothing more than which order the characters are blitted to the screen. imagine an old rpg like final fantasy 3 or chrono trigger :) you know... its characters like these.

To do this correctly, you'd need to give each object a Z value, and sort them in descending order. Then just blit them all in order, and the furthest ones will be blitted first, the nearest ones blitted last.

Or if you just want the player to be blitted on top, and don't care about the other characters, just blit all the characters (ignoring the player) and then blit the player last. The characters will be all jumbled up, but the player will always be on top.

Quote:

Original post by Sc4Freak To do this correctly, you'd need to give each object a Z value, and sort them in descending order. Then just blit them all in order, and the furthest ones will be blitted first, the nearest ones blitted last.

My interpretation of his initial post was that he already understands the above, and was just asking how to perform the sort optimally (could be wrong though).