javascript - //Ball to ball elastic collision: ball bounces in an unequal proportion -

this first post :/

anyway, i've been working on game requires ball ball collision , can't seem find solution problem, collision balls going correct directions messes velocity.

once balls hits each other, horizontal(x) bounces off hard while vertical(y) bounces off softly. have no idea cause or causes of this, tried reduce x-velocity dividing means won't in proportion y value.

this code collision:

function resolvecollision(b1, b2){     var dot = function(v1, v2) {         return v1.x * v2.x + v1.y * v2.y;     };     v1x = b1.vx/2     v2x = b2.vx/2     v1y = b1.vy     v2y = b2.vy     var length = function(v) {         return math.sqrt(v.x * v.x + v.y * v.y);     };      var delta = {x: b1.x - b2.x,                   y: b1.y - b2.y};     var d = math.sqrt((delta.x * delta.x) + (delta.y * delta.y));     var dn = {x: delta.x / d,               y: delta.y / d}      var dt = {x: dn.y,               y: -dn.x};     if (d === 0){         b2.x += 0.01;         }     var m1 = b1.m;     var m2 = b2.m;     var m = m1 + m2;      var mt = {x: dn.x * (b1.r + b2.r - d),               y: dn.y * (b1.r + b2.r - d)};      b1.x = b1.x + mt.x * m2 / m     b1.y = b1.y + mt.y * m2 / m     b2.x = b2.x + mt.x * m1 / m     b2.y = b2.y + mt.y * m1 / m      var v1 = {x: v1x, y: v1y};     var v2 = {x: v2x, y: v2y};      var v1n = {         x: dn.x * (v1.x * v1.x + dn.y * dn.y),         y: dn.y * (v1.x * v1.x + dn.y * dn.y)     };      var v1t = {         x: dt.x * (v1.x * v1.x + dt.y * dt.y),         y: dt.y * (v1.x * v1.x + dt.y * dt.y)     };      var v2n = {         x: dn.x * (v2.x * v2.x + dn.y * dn.y),         y: dn.y * (v2.x * v2.x + dn.y * dn.y)     };      var v2t = {         x: dt.x * (v2.x * v2.x + dt.y * dt.y),         y: dt.y * (v2.x * v2.x + dt.y * dt.y)     };      b1.velocity = {         x: v1t.x + dn.x * ((m1 - m2) / m * length(v1n) + 2 * m2 / m * length(v2n)),         y: v1t.y + dn.y * ((m1 - m2) / m * length(v1n) + 2 * m2 / m * length(v2n))     };     b2.velocity = {         x: v2t.x - dn.x * ((m2 - m1) / m * length(v2n) + 2 * m1 / m * length(v1n)),         y: v2t.y - dn.y * ((m2 - m1) / m * length(v2n) + 2 * m1 / m * length(v1n))     };     b1.vx = b1.velocity.x;     b1.vy = b1.velocity.y;     b2.vx = b2.velocity.x;     b2.vy = b2.velocity.y; }     

also if can tell me how make player(circle) pushes ball further without bouncing off great.

this files if wants have look, in app.js: https://www.mediafire.com/?d6dpqn1cmwzp756

just couldn't understand trying achieve, i'm trying replicate: http://www.haxball.com

i'm not english native speaker apologise grammar mistakes. me fix please, it's driving me crazy! :/

looking forward responses :d

1) should clarify code, stands bit complex, in bug source.
2) you're doing strange things v1n/t v2n/t : projecting + squaring speed on x ...??? didn't try understand b1.velocity code. ouch ! :-)

so here code simplifications : untested, solve issue :

function resolvecollision(b1, b2) {     var v1x = b1.vx,         v2x = b2.vx,         v1y = b1.vy,         v2y = b2.vy;      // collision vector     var delta = {         x: b2.x - b1.x,         y: b2.y - b1.y     };     var d = length(delta);      // normalized collision vector     var dn = {         x: delta.x / d,         y: delta.y / d     }      // normalized tangent collision vector     var dt = {         x: dn.y,         y: -dn.x     };      var m1 = b1.m;     var m2 = b2.m;     var m = m1 + m2;      /*         // test separation tricks in second time     if (d === 0) {         b2.x += 0.01;     }     var mt = {         x: dn.x * (b1.r + b2.r - d),         y: dn.y * (b1.r + b2.r - d)     };         b1.x = b1.x + mt.x * m2 / m     b1.y = b1.y + mt.y * m2 / m     b2.x = b2.x + mt.x * m1 / m     b2.y = b2.y + mt.y * m1 / m     */      // projection of v1 on collision vector     var v1proj = {         n: dn.x * v1x + dn.y * v1y,         t: dt.x * v1x + dt.y * v1y     };      // projection of v2 on collision vector     var v2proj = {         n: dn.x * v2x + dn.y * v1y,         t: dt.y * v2x + dt.y * v2y     };      // solving collision on normal     var newv1projn = ((m1 - m2) * v1proj.n + 2 * m2 * v2proj.n) / m;     var newv2projn = ((m2 - m1)* v2proj.n + 2 * m1 * v1proj.n) / m;      // re-building speed vector out of projected vectors     b1.vx = newv1projn * dn.x + v1proj.t * dt.x;     b1.vy = newv1projn * dn.y + v1proj.t * dt.y;      b2.vx = newv2projn * dn.x + v2proj.t * dt.x;     b2.vy = newv2projn * dn.y + v2proj.t * dt.y; }  function dot(v1, v2) {     return v1.x * v2.x + v1.y * v2.y; };  function length(v) {     return math.sqrt(v.x * v.x + v.y * v.y); };