maracas.js

function length(v) {
    return Math.sqrt(v.x * v.x + v.y * v.y + v.z * v.z);
}
var LEFT_PALM = 0;
var LEFT_TIP = 1;
var LEFT_BUTTON_FWD = 5;
var LEFT_BUTTON_3 = 3;

var RIGHT_PALM = 2;
var RIGHT_TIP = 3;
var RIGHT_BUTTON_FWD = 11;
var RIGHT_BUTTON_3 
function getModelHoldPosition(whichSide) { 
    var normal;
    var tipPosition;
    if (whichSide == LEFT_PALM) {
        normal = Controller.getSpatialControlNormal(LEFT_PALM);
        tipPosition = Controller.getSpatialControlPosition(LEFT_TIP);
    } else {
        normal = Controller.getSpatialControlNormal(RIGHT_PALM);
        tipPosition = Controller.getSpatialControlPosition(RIGHT_TIP);
    }
    
    var MODEL_FORWARD_OFFSET = 0.00; // put the model a bit forward of fingers
    position = { x: MODEL_FORWARD_OFFSET * normal.x,
                 y: MODEL_FORWARD_OFFSET * normal.y, 
                 z: MODEL_FORWARD_OFFSET * normal.z }; 

    position.x += tipPosition.x;
    position.y += tipPosition.y;
    position.z += tipPosition.z;
    
    return position;
}

function printVector(v) {
	print(v.x + ", " + v.y + ", " + v.z + "\n");
}

function vMinus(a, b) { 
	var rval = { x: a.x - b.x, y: a.y - b.y, z: a.z - b.z };
	return rval;
}

//  First, load two percussion sounds to be used on the sticks

var drum1 = new Sound("http://highfidelity-public.s3-us-west-1.amazonaws.com/sounds/MusicalInstruments/shaker.raw");
var drum2 = new Sound("http://highfidelity-public.s3-us-west-1.amazonaws.com/sounds/MusicalInstruments/shaker.raw");


var pitch = 0.0;
var yaw = 0.0;
var roll = -50.0;
var rotation = Quat.fromPitchYawRollDegrees(pitch, yaw, roll)

var originalProperties = {
    position: { x: MyAvatar.position.x,
                y: MyAvatar.position.y,
                z: MyAvatar.position.z },

    radius : 0.1,

    color: { red: 0,
             green: 255,
             blue: 0 },
    modelURL: "http://blog.maximillianmerlin.com/models/SingleShaker.fbx",
    
    modelRotation: rotation
};
var shaker1 = Models.addModel(originalProperties);
var shaker2 = Models.addModel(originalProperties);
//  State Machine:
//  0 = not triggered 
//  1 = triggered, waiting to stop to play sound
var state = new Array();
state[0] = 0; 
state[1] = 0; 
var strokeSpeed = new Array();
strokeSpeed[0] = 0.0; 
strokeSpeed[1] = 0.0;

function checkSticks(deltaTime) {
Models.editModel(shaker1, {
        position: getModelHoldPosition(LEFT_PALM)
    });
	Models.editModel(shaker2, {
        position: getModelHoldPosition(RIGHT_PALM)
    });
	for (var palm = 0; palm < 2; palm++) {
		var palmVelocity = Controller.getSpatialControlVelocity(palm * 2 + 1);
		var speed = length(palmVelocity);
		
		const TRIGGER_SPEED = 0.30;			//    Lower this value to let you 'drum' more gently
		const STOP_SPEED = 0.01; 			//    Speed below which a sound will trigger 
		const GAIN = 0.5;					//    Loudness compared to stick velocity
		const AVERAGING = 0.2;				//    How far back to sample trailing velocity

		//   Measure trailing average stroke speed to ultimately set volume
		strokeSpeed[palm] = (1.0 - AVERAGING) * strokeSpeed[palm] + AVERAGING * (speed * GAIN);

		if (state[palm] == 0) {
			//  Waiting for downward speed to indicate stroke
			if ((palmVelocity.y < 0.0) && (strokeSpeed[palm] > TRIGGER_SPEED)) {
				state[palm] = 1;
			}
		} else if (state[palm] == 1) {
			//   Waiting for change in velocity direction or slowing to trigger drum sound
			if ((palmVelocity.y > 0.0) || (speed < STOP_SPEED)) {
				state[palm] = 0;
				var options = new AudioInjectionOptions();
				options.position = Controller.getSpatialControlPosition(palm * 2 + 1);
				if (strokeSpeed[palm] > 1.0) { strokeSpeed[palm] = 1.0; }
				options.volume = strokeSpeed[palm];
//print(newProperties);
				if (palm == 0) {
					Audio.playSound(drum1, options);
				} else {
					Audio.playSound(drum2, options);
				}
			}
		}
	}
}

// Connect a call back that happens every frame
Script.update.connect(checkSticks);