New answers tagged spritesheet
Performance-wise, flipping it at load time will be fine. (Or at instance-render-time, for that matter, if the platform lets you do that.) But you might want separate sprite sheets for left and right anyway, so they can be slightly different, not exact reflections. For example, a little bit of lighting always from the left (for both left- and right-running) ...
Top 50 recent answers are included