Jump to content
  • Advertisement
Sign in to follow this  

Converting Screen-Space Coordinates to Real-World Coordinates

This topic is 2847 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts


I am working on an application for Android - what we need is for the output of the Accelerometer to be transformed by the orientation of the device.

There are two sensors: Accelerometer and Orientation.

Accelerometer returns (in screen-space)... acceleration for X, Y, and Z.
Orientation returns angles for X, Y, and Z.

Screen-Space to Android seems to be equivalent to Object-Space. If I push the phone 'forward' from the top of it, it will show acceleration with Y = acceleration.

My thought: I need to convert the output from the orientation into a vector, which will give me the Y vector (forward) (ignoring z):

vec.x = Math.cos(x) * Math.cos(y);
vec.y = Math.sin(x) * Math.cos(y);
vec.z = Math.sin(y);

From there, am I correct in that I would need to generate a rotation matrix (equivalent to a modelview matrix), from which I would rotate the acceleration vector given by the acceleration sensor?

Basically, I want to cancel out the affect of rotation on the device - gravity should (though wouldn't due to errors) always show as Z = -G, but as is the acceleration is affected by rotation (as it is in screenspace/object space).

Share this post

Link to post
Share on other sites
Sign in to follow this  

  • Advertisement

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!