Approach for Creating background in games

What are the best (considered by professionals) approaches while creating a platformer based game for Creating game levels & background (static ones).

Create a single background and scale it?

or Display it on-the-fly by loading objects (probably repeating them often).

If the first one is the choice then it would become essential to create each level manually of the game & putting level editors difficult. Also if the later is the choice I find it too proces开发者_JS百科sor intensive....my frame rate almost breaks into half, while trying to manage so many objects together on screen.

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Typically, platformers use "tiles", small images that are placed in a grid, so that

1. The entire background doesn't need to be stored in memory, and
2. so that duplicated pieces of the background don't need to be duplicated in memory, and
3. so that drawing individual pieces can be done more locally (for cache efficiency).

For example, in something like Super Mario Brothers, a huge amount of screen real estate is covered by "sky". They just have one sky tile, maybe 16x16, maybe 128x128, maybe something else entirely (but usually powers of two so the math is easy, and all tiles are the same size) that is all blue. It seems likely (to me) that their tile size is the size of one of the "blocks" that you can hit and destroy.

Anyway- so the "level data" would be an array of what tile goes in one space in the grid, probably oriented in memory as columns for locality of access too. Then when it's time to draw, you start at (for instance) the top left, then go down, then over one column and down again...

As for the "on the fly loading," that can be done but you've got to make sure that you do that loading asynchronously (so that the game doesn't pause) and that you make sure that the data that you need is available long before you actually need it.