cannon-es-control
Version:
A lightweight 3D physics engine written in JavaScript with control system tools
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HTML
<html lang="en">
<head>
<meta charset="utf-8" />
<title>cannon.js - splitsolver demo</title>
<link rel="stylesheet" href="css/style.css" type="text/css" />
<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0" />
</head>
<body>
<script type="module">
import * as CANNON from '../dist/cannon-es-control.js'
import { Demo } from './js/Demo.js'
/**
* This demonstrates why it can be good to use the SplitSolver.
* If you have put a nonzero tolerance on a solver, it will in stop iterating when
* the total error is small, in other words: when the system is solved "good enough".
* When simulating larger systems with more equations, the error will add up,
* and the solver will need more iterations/work to reach the "good enough" level.
*
* The SplitSolver splits the system into independent parts, and runs a subsolver
* on each part. The total error in a subsystem will many times be smaller than in
* the large system, so we can many times cut down on the total number of iterations we do.
*
* Another interesting fact is that we *could* run the subsystems in separate threads and
* speed up the computing even more. However, CANNON runs in one thread for now.
*
* The first scene uses the split solver and the second one does not. Turn on the
* profiling plot and enjoy!
*/
const demo = new Demo()
demo.addScene('With SplitSolver', () => {
createScene({ split: true })
})
demo.addScene('Without SplitSolver', () => {
createScene({ split: false })
})
demo.start()
function createScene(options) {
const world = setupWorld(demo)
const solver = new CANNON.GSSolver()
solver.iterations = 50
solver.tolerance = 0.0001
if (options.split) {
world.solver = new CANNON.SplitSolver(solver)
} else {
world.solver = solver
}
// Static ground plane
const groundShape = new CANNON.Plane()
const groundBody = new CANNON.Body({ mass: 0 })
groundBody.addShape(groundShape)
groundBody.quaternion.setFromEuler(-Math.PI / 2, 0, 0)
world.addBody(groundBody)
demo.addVisual(groundBody)
// Shape
const size = 0.5
// const shape = new CANNON.Sphere(size)
const shape = new CANNON.Box(new CANNON.Vec3(size * 0.5, size * 0.5, size * 0.5))
// Shape on plane
const N = 5
for (let i = 0; i < N; i++) {
for (let j = 0; j < N; j++) {
const shapeBody = new CANNON.Body({ mass: 1 })
shapeBody.addShape(shape)
shapeBody.position.set((i - N * 0.5) * size * 2 * 1.1, size * 1.05, (j - N * 0.5) * size * 2 * 1.1)
world.addBody(shapeBody)
demo.addVisual(shapeBody)
}
}
// Shape on top
const shapeBody = new CANNON.Body({ mass: 1 })
shapeBody.addShape(shape)
shapeBody.position.set(-size, size * 5, size)
world.addBody(shapeBody)
demo.addVisual(shapeBody)
}
function setupWorld(demo) {
const world = demo.getWorld()
world.gravity.set(0, -10, 0)
// Tweak contact properties.
// Contact stiffness - use to make softer/harder contacts
world.defaultContactMaterial.contactEquationStiffness = 1e7
// Stabilization time in number of timesteps
world.defaultContactMaterial.contactEquationRelaxation = 5
return world
}
</script>
</body>
</html>