p2s
Version:
A JavaScript 2D physics engine.
150 lines (130 loc) • 5.57 kB
HTML
<html>
<head>
<title>Heightfield demo - p2.js physics engine</title>
<script src="../build/p2.js"></script>
<script src="../build/p2.renderer.js"></script>
<link href="css/demo.css" rel="stylesheet"/>
<meta name="description" content="">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
</head>
<body>
<script>
// Create demo application
var app = new p2.WebGLRenderer(function(){
var world = new p2.World({
gravity : [0,-10]
});
this.setWorld(world);
world.solver.tolerance = 0.01;
// Set large friction - needed for powerful vehicle engine!
world.defaultContactMaterial.friction = 10;
// Create ground
var data = [];
var numDataPoints = 200;
for(var i=0; i<numDataPoints; i++){
data.push(0.5*Math.cos(0.2*i) * Math.sin(0.5*i) + 0.6*Math.sin(0.1*i) * Math.sin(0.05*i));
}
var heightfieldShape = new p2.Heightfield({
heights: data,
elementWidth: 1
});
var heightfield = new p2.Body({
position:[-10,-1]
});
heightfield.addShape(heightfieldShape);
world.addBody(heightfield);
// Create chassis
var chassisBody = new p2.Body({ mass : 1, position:[-4,1] }),
chassisShape = new p2.Box({ width: 1, height: 0.5 });
chassisBody.addShape(chassisShape);
world.addBody(chassisBody);
// Create wheels
var wheelBody1 = new p2.Body({ mass : 1, position:[chassisBody.position[0] - 0.5,0.7] }),
wheelBody2 = new p2.Body({ mass : 1, position:[chassisBody.position[0] + 0.5,0.7] }),
wheelShapeLeft = new p2.Circle({ radius: 0.3 }),
wheelShapeRight = new p2.Circle({ radius: 0.3 });
wheelBody1.addShape(wheelShapeLeft);
wheelBody2.addShape(wheelShapeRight);
world.addBody(wheelBody1);
world.addBody(wheelBody2);
// Disable collisions between chassis and wheels
var WHEELS = 1, // Define bits for each shape type
CHASSIS = 2,
GROUND = 4,
OTHER = 8;
wheelShapeLeft.collisionGroup = wheelShapeRight.collisionGroup = WHEELS; // Assign groups
chassisShape.collisionGroup = CHASSIS;
heightfieldShape .collisionGroup = GROUND;
wheelShapeLeft.collisionMask = wheelShapeRight.collisionMask = GROUND | OTHER; // Wheels can only collide with ground
chassisShape.collisionMask = GROUND | OTHER; // Chassis can only collide with ground
heightfieldShape.collisionMask = WHEELS | CHASSIS | OTHER; // Ground can collide with wheels and chassis
// Constrain wheels to chassis
var c1 = new p2.PrismaticConstraint(chassisBody,wheelBody1,{
localAnchorA : [-0.5,-0.3],
localAnchorB : [0,0],
localAxisA : [0,1],
disableRotationalLock : true,
});
var c2 = new p2.PrismaticConstraint(chassisBody,wheelBody2,{
localAnchorA : [ 0.5,-0.3],
localAnchorB : [0,0],
localAxisA : [0,1],
disableRotationalLock : true,
});
c1.setLimits(-0.4, 0.2);
c2.setLimits(-0.4, 0.2);
world.addConstraint(c1);
world.addConstraint(c2);
// Add springs for the suspension
var stiffness = 100,
damping = 5,
restLength = 0.5;
// Left spring
world.addSpring(new p2.LinearSpring(chassisBody, wheelBody1, {
restLength : restLength,
stiffness : stiffness,
damping : damping,
localAnchorA : [-0.5,0],
localAnchorB : [0,0],
}));
// Right spring
world.addSpring(new p2.LinearSpring(chassisBody, wheelBody2, {
restLength : restLength,
stiffness : stiffness,
damping : damping,
localAnchorA : [0.5,0],
localAnchorB : [0,0],
}));
this.newShapeCollisionGroup = OTHER;
this.newShapeCollisionMask = GROUND|WHEELS|CHASSIS|OTHER;
// Apply current engine torque after each step
var torque = 0;
world.on("postStep",function(evt){
wheelBody1.angularForce += torque;
wheelBody2.angularForce += torque;
});
app.followBody = chassisBody; // Make camera follow
// Change the current engine torque with the left/right keys
this.on("keydown",function(evt){
t = 5;
switch(evt.keyCode){
case 39: // right
torque = -t;
break;
case 37: // left
torque = t;
break;
}
});
this.on("keyup",function(){
torque = 0;
});
world.on("addBody",function(evt){
evt.body.setDensity(1);
});
});
</script>
</body>
</html>