我正在尝试使用verlet integration制作柔软的身体球。
我基本上创建一个网格并用弹簧连接每个顶点。我使用three.js来渲染球体。我相信一切正常，但我不确定如何获得理想的结果。如果连接太弱则我的球会坍塌，如果太僵硬则会爆炸。有些事似乎不对。问题发生在物体掉落并撞击地面的那一刻。我将发布我的代码的主要部分，但是我不确定我的方法是否有效并且可以用于产生我想要的结果。
function verletStick3D(p1, p2, distance, rigid){
this.type = "stick";
this.p1 = p1;
this.p2 = p2;
this.distance = distance;
this.rigid = rigid;
this.update = function(){
var dx = this.p1.x - this.p2.x;
var dy = this.p1.y - this.p2.y;
var dz = this.p1.z - this.p2.z;
var distance = Math.sqrt(dx * dx + dy * dy + dz * dz);
var difference = this.distance - distance;
var percent = difference / distance / 2;
var offsetX = dx * percent * this.rigid;
var offsetY = dy * percent * this.rigid;
var offsetZ = dz * percent * this.rigid;
this.p1.x += offsetX;
this.p1.y += offsetY;
this.p1.z += offsetZ;
this.p2.x -= offsetX;
this.p2.y -= offsetY;
this.p2.z -= offsetZ;
}
}
function verletPoint3D(x, y,z, maxX, maxZ, bounce = 0.9, friction =
1.0, gravity = {x:0, y:-0.03, z:0}){
y = y + 10;
this.type = "point";
this.x=x;
this.y=y;
this.z=z;
this.xOld=x;
this.yOld=y;
this.zOld=z;
this.bounce = bounce;
this.friction = friction;
this.gravity = gravity;
this.update = function(){
var vx = (this.x - this.xOld) * this.friction;
var vy = (this.y - this.yOld) * this.friction;
var vz = (this.z - this.zOld) * this.friction;
this.xOld = this.x;
this.yOld = this.y;
this.zOld = this.z;
this.x += vx;
this.y += vy;
this.z += vz;
this.y += this.gravity.y;
this.x += this.gravity.x;
this.z += this.gravity.z;
}
this.setGravity = function(gravity){
this.gravity = gravity;
}
this.constrain = function(){
var vx = (this.x - this.xOld) ;
var vy = (this.y - this.yOld) ;
if(this.x > this.maxX){
this.x = width;
this.xOld = this.x + vx * this.bounce;
}
if(this.x < this.minX){
this.x ;
this.xOld = this.x + vx * this.bounce;
}
if(this.z > this.maxZ ){
this.z = height ;
this.zOld = this.z + vz * this.bounce;
}
if(this.z < this.minZ){
this.z = 0;
this.zOld = this.z + vz * this.bounce;
}
if(this.y < 0){
this.y = 0;
this.yOld = this.y + vy * this.bounce;
}
}
}
function verletFromMesh(vertices, faces, maxX, maxY){
var points = [];
for(var i = 0; i < vertices.length; i++){
var p = new verletPoint3D(vertices[i].x, vertices[i].y, vertices[i].z, maxX, maxY, 0.9, 0.9);
points.push(p);
}
var springs = []
/*
for(var i = 0; i < faces.length; i++){
var face = faces[i];
var p1 = face.a;
var p2 = face.b;
var p3 = face.c;
springs.push(new verletStick( p1,p2, distance3D(p1, p2), 1.0) )
springs.push(new verletStick( p2,p3, distance3D(p2, p3), 1.0) )
springs.push(new verletStick( p3,p1, distance3D(p3, p1), 1.0) )
}*/
for(var i = 0; i < points.length; i++){
var p1 = points[i];
for(var j= i+1; j < points.length; j++){
var p2 = points[j];
if(p1.x == p2.x && p1.y == p2.y && p1.z == p2.z)
continue;
var dist = distance3D(p1, p2)
springs.push(new verletStick3D( p1,p2, dist, 1.0) )
}
}
return new verletObj(points, springs);
}
答案 0 :(得分：1)
你的数学运算方式，特别是在设置偏移量dx * percent * this.rigid;时，似乎这些动态力量的行为是静态的，因此进展得太远了。
Ps：你有没看过这个post？这是关于摩擦的，但我认为答案在这里很明显：
在移动的物体上引入一个小的，恒定的加速度 指向与运动相反的方向。并确保它不能 实际上扭转了运动;如果你在集成中检测到它 步骤，只需将速度设置为零。
希望这会让你以某种方式朝着正确的方向前进。