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Accounts for any rotation in the GDX-FOR while trying to detect freefall

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This commit is contained in:
Ian Honohan 2019-02-05 12:12:17 -08:00
parent 884fd54d2b
commit 5a2eb3b296
1 changed files with 26 additions and 1 deletions
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27
src/extensions/scratch3_gdx_for/index.js
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@ -68,6 +68,12 @@ const FACING_THRESHOLD = 9;
*/ */
const FREEFALL_THRESHOLD = 0.5; const FREEFALL_THRESHOLD = 0.5;
/**
* Factor used to account for influence of rotation during freefall.
* @type {number}
*/
const FREEFALL_ROTATION_FACTOR = 0.3;
/** /**
* Acceleration due to gravity, in m/s^2. * Acceleration due to gravity, in m/s^2.
* @type {number} * @type {number}
@ -800,6 +806,14 @@ class Scratch3GdxForBlocks {
return this.accelMagnitude() - GRAVITY; return this.accelMagnitude() - GRAVITY;
} }
spinMagnitude () {
return this.magnitude(
this._peripheral.getSpinSpeedX(),
this._peripheral.getSpinSpeedY(),
this._peripheral.getSpinSpeedZ()
);
}
isFacing (args) { isFacing (args) {
switch (args.FACING) { switch (args.FACING) {
case FaceValues.UP: case FaceValues.UP:
@ -812,7 +826,18 @@ class Scratch3GdxForBlocks {
} }
isFreeFalling () { isFreeFalling () {
return this.accelMagnitude() < FREEFALL_THRESHOLD; const accelMag = this.accelMagnitude();
const spinMag = this.spinMagnitude();
// We want to account for rotation during freefall,
// so we tack on a an estimated "rotational effect"
// The FREEFALL_ROTATION_FACTOR const is used to both scale the
// gyro measurements and convert them to radians/second.
// So, we compare our accel magnitude against:
// FREEFALL_THRESHOLD + (some_scaled_magnitude_of_rotation).
const ffThresh = FREEFALL_THRESHOLD + (FREEFALL_ROTATION_FACTOR * spinMag);
return accelMag < ffThresh;
} }
} }