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import RAPIER from "./rapier.es.js";
RAPIER.init().then(() => {
const CLICK_IMPULSE_MULTIPLIER = 300_000;
const GRAVITY = { x: 0.0, y: 2000 };
const LINEAR_DAMPING = 0.5;
const OBJ_BASE_RADIUS = 30;
const OBJ_BASE_SIZE = { x: OBJ_BASE_RADIUS * 2, y: OBJ_BASE_RADIUS * 2 };
const OBJ_MASS = 100;
const STEP_MS = 33;
const TARGET_WIDTH_FACTOR = 0.05;
const VIEWPORT_SIZE = {
x: document.documentElement.clientWidth,
y: document.documentElement.clientHeight,
};
const WIDTH_JUMP_FACTOR = 5;
let world = new RAPIER.World(GRAVITY);
const wallColliderDescs = {
x: RAPIER.ColliderDesc.cuboid(VIEWPORT_SIZE.x, 1).setRestitution(1),
y: RAPIER.ColliderDesc.cuboid(1, VIEWPORT_SIZE.y).setRestitution(1),
};
world.createCollider(wallColliderDescs.x);
world.createCollider(wallColliderDescs.x.setTranslation(0, VIEWPORT_SIZE.y));
world.createCollider(wallColliderDescs.y);
world.createCollider(wallColliderDescs.y.setTranslation(VIEWPORT_SIZE.x, 0));
let objRigidBodyDesc = RAPIER.RigidBodyDesc.dynamic()
.setTranslation(VIEWPORT_SIZE.x / 2, VIEWPORT_SIZE.y / 3)
.setLinearDamping(LINEAR_DAMPING)
.setCcdEnabled(true);
let obj = world.createRigidBody(objRigidBodyDesc);
world.createCollider(
RAPIER.ColliderDesc.ball(OBJ_BASE_RADIUS).setMass(OBJ_MASS),
obj,
);
const objElement = document.querySelector("div#throwable");
const objSize = {
x: OBJ_BASE_SIZE.x,
y: OBJ_BASE_SIZE.y,
};
let objVelocityLastFrame = null;
let mainLoop = () => {
world.step();
const objPosition = obj.translation();
objElement.style.left = `${objPosition.x}px`;
objElement.style.top = `${objPosition.y}px`;
const objVelocity = obj.linvel();
if (objVelocityLastFrame !== null) {
// Just delta velocity across a frame, technically
const objAcceleration = {
x: objVelocity.x - objVelocityLastFrame.x,
y: objVelocity.y - objVelocityLastFrame.y,
};
let targetWidth =
OBJ_BASE_SIZE.x + TARGET_WIDTH_FACTOR * Math.abs(objAcceleration.y);
let targetHeight =
OBJ_BASE_SIZE.y + TARGET_WIDTH_FACTOR * Math.abs(objAcceleration.x);
objSize.x = objSize.x + (targetWidth - objSize.x) / WIDTH_JUMP_FACTOR;
objSize.y = objSize.y + (targetHeight - objSize.y) / WIDTH_JUMP_FACTOR;
}
objVelocityLastFrame = objVelocity;
objElement.style.width = `${objSize.x}px`;
objElement.style.height = `${objSize.y}px`;
setTimeout(mainLoop, STEP_MS);
};
document.addEventListener("click", (e) => {
const clickPosition = { x: e.clientX, y: e.clientY };
const objPosition = obj.translation();
const direction = {
x: clickPosition.x - objPosition.x,
y: clickPosition.y - objPosition.y,
};
const distance = Math.sqrt(direction.x ** 2 + direction.y ** 2);
obj.setLinvel({x: 0, y: 0});
if (distance > 0) {
obj.applyImpulse({
x: (direction.x * CLICK_IMPULSE_MULTIPLIER) / distance,
y: (direction.y * CLICK_IMPULSE_MULTIPLIER) / distance,
});
}
});
mainLoop();
});
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