Movement Compensation on Scaled Games?

[Ydt]

Maybe this is a silly question.. But for example I have a project that that moves an entity at 1 pixel per tick. When scaling down to smaller screens this entity moves across the screen much faster then anticipated because there are less pixels (I think?). What methods do I take to insure everything is moving at a constant speed across all screen sizes?

 

Any insight or tips with this issue would be much appreciated!

[rich]

Delta Timers ftw.

[Ydt]

Delta Timers ftw.

 

I had a feeling it was delta timers, but I wanted to be sure. For some reason I understood them to be used only for keeping frame rate independent rate of motion.

 

Thanks for the reply!

[rich]

They primarily are, but the concept can extend into distance travelled equally as well. Personally we make all our games at fixed sizes (as in fixed pixel widths), so all you actually need is a delta timer for the frame rate.

[Paul-Andre]

I would make them go at a constant speed, and then scale the whole game.

[Murzy]

Basically you need to use delta timing to solve the problem, like the people before me have already mentioned. It's pretty easy to add to a project even if you haven't thought of it before. Generally you would design your game by using delta timing from the scratch, so instead of having a 1px / step movement rate you have something like 30px / second and then you just multiply this speed with the time every step of your game takes to execute.

 

However there still might be problems if you arent scaling your game from a fixed size to the screen size on devices but instead make the play area larger. Generally this is something you want to think beforehand when designing the game – whether the bigger playarea is going to be a problem, or is it just more graphically pleasing without big impact on the gameplay itself for users that have bigger screens at their disposal.

[Gio]

Defining your speed as pixels per second (rather than per tick) is a good suggestion.

 

However even better in my opinion (as this is what we do in our engine), is defining speed as "world units" per second. Then to compensate for different screen sizes, you can set a scale in the canvas transform so that 1 world unit isn't necessarily 1 pixel on the screen - it can be more or less depending on your screen size. The advantage of this approach is that you set this scale only once, and don't have to worry about changing speed values for all your objects.