Space Invaders collision detection. 1 bullet check all invaders?
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I have developed a grid of invaders that I can shoot a bullet towards.

The only solution I know of for collision detection is using two `Rectangles` and the `Intersects` method.

Now, it is my feeling that it is not efficient to compare each bullet to every invader on the screen.

Is there another solution I can use here that is more intelligent and only compares some invaders.

**I propose** to use a flag for the X axis, that is populated with the X position of the bullet when fired. The invader sprites will have access to this flag and will only run the intersects method if the invader sprite is on that X position (+/- a few px). This would greatly reduce the number of comparisons.

Any ideas? Thanks.