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[theman515]

hey guys,

does anyone know the magnitude of a realistic gravity vector for a game with a 800x600 window and a 1.8 meter tall main character that is 38 pixels tall.

thanks in advance 

[dustin]

In a very general sense...


38 pixels/1.8 meters = 21 pixels/meter

21 pixels/meter * 9.8 meters/seconds^2 (gravity) = 205.8 pixels/seconds^2

somehow I feel like that's not what your asking but I can't think of what else you might mean.

[MattG]

use meters as units not pixels. Dont fix your physics to a window size or doing anything but that size will break your game.

[theman515]

ok, how to convert pixel movement to meters then?

as for my original question, i slept on it and did this math:

9.8 m/s^2 * 38 pixels/1.8 meters * 1 sec/100 ms * 1 sec/100 ms (since it's seconds squared and the delta T returned from my engine is milliseconds)

and i got something like .02 p/ms^2 which works fine but will it break if the window size changes?

[Zaphos]

The window size in itself isn't relevant, but if the height in pixels of the character scales with the window size then you would expect to similarly scale the gravity vector (same as you'd rescale any movement vector).  In games with pixel art and no zooming/whatever (or where the zoom is handled transparently, so your movement code still 'sees' the original res, etc), this may not really be a concern.  It's a common sense sort of issue anyway; I'm sure you can figure out if you need to rescale and how much.

[theman515]

alright, thanks guys. i think i got it.