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further work on compound implementation
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@liabru
liabru committed Feb 1, 2015
1 parent f554d6c commit d2f79b4
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Showing 5 changed files with 129 additions and 72 deletions.
24 changes: 18 additions & 6 deletions demo/js/Demo.js
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Original file line number Diff line number Diff line change
Expand Up @@ -244,28 +244,35 @@

Demo.reset();

var bodyA = Bodies.rectangle(100, 200, 50, 50),
var bodyA = Bodies.rectangle(100, 200, 50, 50, { isStatic: true }),
bodyB = Bodies.rectangle(200, 200, 50, 50),
bodyC = Bodies.rectangle(300, 200, 50, 50),
bodyD = Bodies.rectangle(400, 200, 50, 50),
bodyE = Bodies.rectangle(550, 200, 50, 50),
bodyF = Bodies.rectangle(700, 200, 50, 50),
bodyG = Bodies.circle(400, 100, 25);
bodyG = Bodies.circle(400, 100, 25),
partA = Bodies.rectangle(600, 200, 120, 50),
partB = Bodies.rectangle(660, 200, 50, 190),
compound = Body.create({
parts: [partA, partB],
isStatic: true
});

World.add(_world, [bodyA, bodyB, bodyC, bodyD, bodyE, bodyF, bodyG]);
World.add(_world, [bodyA, bodyB, bodyC, bodyD, bodyE, bodyF, bodyG, compound]);

var counter = 0,
scaleFactor = 1.01;

_sceneEvents.push(
Events.on(_engine, 'tick', function(event) {
Events.on(_engine, 'beforeUpdate', function(event) {
counter += 1;

if (counter === 40)
Body.setStatic(bodyG, true);

if (scaleFactor > 1) {
Body.scale(bodyF, scaleFactor, scaleFactor);
Body.scale(compound, 0.995, 0.995);

// modify bodyE vertices
bodyE.vertices[0].x -= 0.2;
Expand All @@ -277,7 +284,11 @@

// make bodyA move up and down and rotate constantly
Body.setPosition(bodyA, { x: 100, y: 300 + 100 * Math.sin(_engine.timing.timestamp * 0.005) });
Body.setAngularVelocity(bodyA, 0.02);
Body.rotate(bodyA, 0.02);

// make compound body move up and down and rotate constantly
Body.setPosition(compound, { x: 600, y: 300 + 100 * Math.sin(_engine.timing.timestamp * 0.005) });
Body.rotate(compound, 0.02);

// every 1.5 sec
if (counter >= 60 * 1.5) {
Expand All @@ -293,9 +304,10 @@
);

var renderOptions = _engine.render.options;
renderOptions.wireframes = false;
renderOptions.showAxes = true;
renderOptions.showCollisions = true;
renderOptions.showPositions = true;
renderOptions.showConvexHulls = true;
};

Demo.compositeManipulation = function() {
Expand Down
159 changes: 99 additions & 60 deletions src/body/Body.js
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@ var Body = {};
id: Common.nextId(),
type: 'body',
label: 'Body',
parts: [],
angle: 0,
vertices: Vertices.fromPath('L 0 0 L 40 0 L 40 40 L 0 40'),
position: { x: 0, y: 0 },
Expand Down Expand Up @@ -118,7 +119,7 @@ var Body = {};
isStatic: body.isStatic,
isSleeping: body.isSleeping,
parent: body.parent || body,
parts: body.parts || [body]
parts: body.parts
});

Vertices.rotate(body.vertices, body.angle, body.position);
Expand Down Expand Up @@ -313,26 +314,31 @@ var Body = {};
* @param {bool} [autoHull=true]
*/
Body.setParts = function(body, parts, autoHull) {
autoHull = typeof autoHull !== 'undefined' ? autoHull : true;
var i;

// ensure the body is always at index 0
var index = Common.indexOf(parts, body);
if (index > -1) {
parts.splice(index, 1);
}
// add all the parts, ensuring that the first part is always the parent body
parts = parts.slice(0);
body.parts.length = 0;
body.parts.push(body);
body.parent = body;

parts.unshift(body);
body.parts = parts;
for (i = 0; i < parts.length; i++) {
var part = parts[i];
if (part !== body) {
part.parent = body;
body.parts.push(part);
}
}

if (parts.length === 1)
if (body.parts.length === 1)
return;

var i;
autoHull = typeof autoHull !== 'undefined' ? autoHull : true;

// find the convex hull of all parts to set on the parent body
if (autoHull) {
var vertices = [];
for (i = 1; i < parts.length; i++) {
for (i = 0; i < parts.length; i++) {
vertices = vertices.concat(parts[i].vertices);
}

Expand All @@ -342,36 +348,22 @@ var Body = {};
hullCentre = Vertices.centre(hull);

Body.setVertices(body, hull);
Body.setPosition(body, hullCentre);
}

// find the combined properties of all parts to set on the parent body
var mass = 0,
area = 0,
inertia = 0,
centroid = { x: 0, y: 0 };

for (i = 1; i < parts.length; i++) {
var part = parts[i];
part.parent = body;
mass += part.mass;
area += part.area;
inertia += part.inertia;
Vector.add(centroid, part.position, centroid);
Vertices.translate(body.vertices, hullCentre);
}

centroid = Vector.div(centroid, parts.length - 1);
// sum the properties of all compound parts of the parent body
var total = _totalProperties(body);

body.area = area;
body.area = total.area;
body.parent = body;
body.position.x = centroid.x;
body.position.y = centroid.y;
body.positionPrev.x = centroid.x;
body.positionPrev.y = centroid.y;

Body.setMass(body, mass);
Body.setInertia(body, inertia);
Body.setPosition(body, centroid);
body.position.x = total.centre.x;
body.position.y = total.centre.y;
body.positionPrev.x = total.centre.x;
body.positionPrev.y = total.centre.y;

Body.setMass(body, total.mass);
Body.setInertia(body, total.inertia);
Body.setPosition(body, total.centre);
};

/**
Expand All @@ -382,14 +374,16 @@ var Body = {};
*/
Body.setPosition = function(body, position) {
var delta = Vector.sub(position, body.position);

body.position.x = position.x;
body.position.y = position.y;
body.positionPrev.x += delta.x;
body.positionPrev.y += delta.y;

Vertices.translate(body.vertices, delta);
Bounds.update(body.bounds, body.vertices, body.velocity);
for (var i = 0; i < body.parts.length; i++) {
var part = body.parts[i];
part.position.x += delta.x;
part.position.y += delta.y;
Vertices.translate(part.vertices, delta);
Bounds.update(part.bounds, part.vertices, body.velocity);
}
};

/**
Expand All @@ -400,13 +394,15 @@ var Body = {};
*/
Body.setAngle = function(body, angle) {
var delta = angle - body.angle;

body.angle = angle;
body.anglePrev += delta;

Vertices.rotate(body.vertices, delta, body.position);
Axes.rotate(body.axes, delta);
Bounds.update(body.bounds, body.vertices, body.velocity);
for (var i = 0; i < body.parts.length; i++) {
var part = body.parts[i];
part.angle += delta;
Vertices.rotate(part.vertices, delta, body.position);
Axes.rotate(part.axes, delta);
Bounds.update(part.bounds, part.vertices, body.velocity);
}
};

/**
Expand Down Expand Up @@ -464,21 +460,35 @@ var Body = {};
* @param {vector} [point]
*/
Body.scale = function(body, scaleX, scaleY, point) {
// scale vertices
Vertices.scale(body.vertices, scaleX, scaleY, point);
for (var i = 0; i < body.parts.length; i++) {
var part = body.parts[i];

// update properties
body.axes = Axes.fromVertices(body.vertices);
body.area = Vertices.area(body.vertices);
Body.setMass(body, body.density * body.area);
// scale vertices
Vertices.scale(part.vertices, scaleX, scaleY, body.position);

// update inertia (requires vertices to be at origin)
Vertices.translate(body.vertices, { x: -body.position.x, y: -body.position.y });
Body.setInertia(body, Vertices.inertia(body.vertices, body.mass));
Vertices.translate(body.vertices, { x: body.position.x, y: body.position.y });
// update properties
part.axes = Axes.fromVertices(part.vertices);

// update bounds
Bounds.update(body.bounds, body.vertices, body.velocity);
if (!body.isStatic) {
part.area = Vertices.area(part.vertices);
Body.setMass(part, body.density * part.area);

// update inertia (requires vertices to be at origin)
Vertices.translate(part.vertices, { x: -part.position.x, y: -part.position.y });
Body.setInertia(part, Vertices.inertia(part.vertices, part.mass));
Vertices.translate(part.vertices, { x: part.position.x, y: part.position.y });
}

// update bounds
Bounds.update(part.bounds, part.vertices, body.velocity);
}

if (!body.isStatic) {
var total = _totalProperties(body);
body.area = total.area;
Body.setMass(body, total.mass);
Body.setInertia(body, total.inertia);
}
};

/**
Expand Down Expand Up @@ -545,6 +555,35 @@ var Body = {};
body.torque += (offset.x * force.y - offset.y * force.x) * body.inverseInertia;
};

/**
* Returns the sums of the properties of all compound parts of the parent body.
* @method _totalProperties
* @private
* @param {body} body
* @return {}
*/
var _totalProperties = function(body) {
var properties = {
mass: 0,
area: 0,
inertia: 0,
centre: { x: 0, y: 0 }
};

// sum the properties of all compound parts of the parent body
for (var i = body.parts.length === 1 ? 0 : 1; i < body.parts.length; i++) {
var part = body.parts[i];
properties.mass += part.mass;
properties.area += part.area;
properties.inertia += part.inertia;
Vector.add(properties.centre, part.position, properties.centre);
}

properties.centre = Vector.div(properties.centre, body.parts.length - 1);

return properties;
};

/*
*
* Properties Documentation
Expand Down
6 changes: 6 additions & 0 deletions src/body/Composite.js
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Original file line number Diff line number Diff line change
Expand Up @@ -78,6 +78,12 @@ var Composite = {};
switch (obj.type) {

case 'body':
// skip adding compound parts
if (obj.parent !== obj) {
Common.log('Composite.add: skipped adding a compound body part (you must add its parent instead)', 'warn');
break;
}

Composite.addBody(composite, obj);
break;
case 'constraint':
Expand Down
4 changes: 2 additions & 2 deletions src/core/Sleeping.js
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Original file line number Diff line number Diff line change
Expand Up @@ -67,8 +67,8 @@ var Sleeping = {};
continue;

var collision = pair.collision,
bodyA = collision.bodyA,
bodyB = collision.bodyB;
bodyA = collision.bodyA.parent,
bodyB = collision.bodyB.parent;

// don't wake if at least one body is static
if ((bodyA.isSleeping && bodyB.isSleeping) || bodyA.isStatic || bodyB.isStatic)
Expand Down
8 changes: 4 additions & 4 deletions src/render/Render.js
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Original file line number Diff line number Diff line change
Expand Up @@ -399,7 +399,7 @@ var Render = {};
var sprite = part.render.sprite,
texture = _getTexture(render, sprite.texture);

if (options.showSleeping && part.isSleeping)
if (options.showSleeping && body.isSleeping)
c.globalAlpha = 0.5;

c.translate(part.position.x, part.position.y);
Expand All @@ -412,7 +412,7 @@ var Render = {};
c.rotate(-part.angle);
c.translate(-part.position.x, -part.position.y);

if (options.showSleeping && part.isSleeping)
if (options.showSleeping && body.isSleeping)
c.globalAlpha = 1;
} else {
// part polygon
Expand All @@ -429,7 +429,7 @@ var Render = {};
}

if (!options.wireframes) {
if (options.showSleeping && part.isSleeping) {
if (options.showSleeping && body.isSleeping) {
c.fillStyle = Common.shadeColor(part.render.fillStyle, 50);
} else {
c.fillStyle = part.render.fillStyle;
Expand All @@ -442,7 +442,7 @@ var Render = {};
} else {
c.lineWidth = 1;
c.strokeStyle = '#bbb';
if (options.showSleeping && part.isSleeping)
if (options.showSleeping && body.isSleeping)
c.strokeStyle = 'rgba(255,255,255,0.2)';
c.stroke();
}
Expand Down

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