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Asked: 2026-06-02T03:59:48+00:00

in my game I get the acceleration from the accelerometer. Computing my calculation, I

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in my game I get the acceleration from the accelerometer.
Computing my calculation, I have to apply a coefficient to turn unit of measurementin pixel unit.

I apply the coefficient founded for an Android app (in a sample):

 DisplayMetrics metrics = new DisplayMetrics();
 getWindowManager().getDefaultDisplay().getMetrics(metrics);
 mXDpi = metrics.xdpi;
 mYDpi = metrics.ydpi;
 mMetersToPixelsX = mXDpi / 0.0254f;
 mMetersToPixelsY = mYDpi / 0.0254f;

to my acceleration, getting pixels/s^2. in this way i can use pixel everywhere in my code instead of thinking all in meters.

It is right?

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1 Answer

  1. Editorial Team

    It’s going to depend on what sort of physics you want to impose. (This assumes you want Newtonian mechanics.) If you want to track the motion of the device, then you need to integrate the acceleration to get velocity and then integrate the velocity to get position. Or I suppose, you could skip the intermediate step and translate from ‘acceleration’ to change in position by using 0.5*acceleration^2 (and then multiply that result by an appropriate scaling factor that you will probably need to determine by experiment). (That second method may not properly handle constant motion.) For each independent dimension, velocity and position would be a cumulative sum with these recurrence relations:

    velocity[t] = acceleration[t] *(t -(t-1) ) + velocity[t-1]
position[t] = position[t-1] + velocity[t]*(t -(t-1) )
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