Padding should be adjusted as Motion Blur velocity changes.

[Stephen Thompson]

I've discovered that the padding needs to be adjusted as the velocity values change, otherwise the blur effect is clipped. I raised this possibility a few months back (#208) however got no response.

I've fixed my own motion blur filter by extending the existing velocityChanged method and calculated the padding based on the largest velocity value (I'm not sure if this is perfect but it seems to work fine for our needs).

velocityChanged() {
    this.uniforms.uVelocity[0] = this._velocity.x;
    this.uniforms.uVelocity[1] = this._velocity.y;
    // The padding will be increased as the velocity and intern the blur size is changed
    this.padding = ~~(Math.abs(this._velocity.x > this._velocity.y ? this._velocity.x : this._velocity.y)) + 1;
}

[Matt Karl]

Seems reasonable. Good idea.

[Stephen Thompson]

This formula is slightly incorrect, it should be;

this.padding = ~~(Math.max(Math.abs(this._velocity.x), Math.abs(this._velocity.y))) + 1;

This is because velocity moving in a negative direction could be greater then positive direction movement. For example, if vel.x=10 and vel.y=-1000 the original formula would return 11, when in reality the object is moving much faster along the y and the padding should be much greater, ie. => 1001

[Matt Karl]

Let's add this, wanna make a PR @st3v0. You've pretty much done all the hardwork already