Gyroscope input issues about shadereditor HOT 3 OPEN

Well, the code in GyroscopeListener is based on the documentation, so I think it's correct. But I may be wrong, of course!

Unfortunately, I haven't got a shader at hand to test whether this correct or not at the moment. But since this open source, you may of course play around with it and see if you can make it work for your sample 😉

Something tells me either the rotation angles should all be negated, or the vector should rather be multiplied by the inverse of deltaRotationMatrix there in order to make sense.

I think inversing isn't required because:

However, since the matrix is a rotation matrix, its transpose is also its inverse, conveniently, it is often the inverse of the rotation that is needed for rendering; it can therefore be used with OpenGL ES directly.

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Well, the code in GyroscopeListener is based on the documentation, so I think it's correct. But I may be wrong, of course!

Looking at the comment in the example code:
// rotationCurrent = rotationCurrent * deltaRotationMatrix;
I believe rotationCurrent here is meant to be a matrix, not a vector as in the case of GyroscopeListener.rotation. A rotation matrix can be inverted as needed (and will be by default when provided to OpenGL), a rotated vector cannot be inverted in the same way to get the "inverse-rotated" vector.

I think inversing isn't required because:

However, since the matrix is a rotation matrix, its transpose is also its inverse, conveniently, it is often the inverse of the rotation that is needed for rendering; it can therefore be used with OpenGL ES directly.

Here's how I understand it: If the gyroscope uniform were a matrix, you'd be right. But it's a vector, so the transposition does not happen.

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I made a shader to explore the different orientation vectors: https://gist.github.com/planiitis/d940919503d442f0c7287ae10f74b466

Set Sensor Delay to Game or UI for best results.

The shader provides a view of the gyroscope, gravity, magnetic and linear vectors, as well as rotationMatrix. Assuming the device is in its non-rotated screen configuration, you can turn the device around to get a "camera view" of the various vectors.

• The four small circles around the horizon (denoted by a purple line) show the cardinal directions given by rotationMatrix.
• A green circle shows the direction of magnetic, pointing to magnetic north.
• The red and purple circles show gravity and gravity + linear, both negated so that they point downwards for convenience and a more intuitive view.
• The yellow line goes through the gravity and gyroscope circles.
• The yellow circle represents the gyroscope vector.

Current code negates the x and y coordinates of the gyroscope vector. That makes the gyroscope circle move correctly with respect to the others when rotating the device about its x or y coordinate. However, rotation around the device's z coordinate is still backwards: Try laying the device on a level, non-magnetic surface with its screen facing up, then rotate the device clockwise. If the magnetic circle is in view, you should see it stay in place relative to yourself, or moving counter-clockwise relative to the device screen, as expected. However, the yellow line that points to the gyroscope vector will rotate clockwise relative to the device screen, rotating at double speed relative to yourself.

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