var UpdateMotion = function (body, res){ 
body.standing = false ; 
if (res.collision.y) { 
if (body.bounciness > 0 && Math.abs(body.vel.y) > body.minBounceVelocity) { 
body.vel.y *= - body.bounciness; 
} 
 else { 
if (body.vel.y > 0) { 
body.standing = true ; 
} 
body.vel.y = 0; 
} 
} 
if (res.collision.x) { 
if (body.bounciness > 0 && Math.abs(body.vel.x) > body.minBounceVelocity) { 
body.vel.x *= - body.bounciness; 
} 
 else { 
body.vel.x = 0; 
} 
} 
if (res.collision.slope) { 
var s = res.collision.slope; 
if (body.bounciness > 0) { 
var proj = body.vel.x * s.nx + body.vel.y * s.ny; 
body.vel.x = (body.vel.x - s.nx * proj * 2) * body.bounciness; 
body.vel.y = (body.vel.y - s.ny * proj * 2) * body.bounciness; 
} 
 else { 
var lengthSquared = s.x * s.x + s.y * s.y; 
var dot = (body.vel.x * s.x + body.vel.y * s.y) / lengthSquared; 
body.vel.x = s.x * dot; 
body.vel.y = s.y * dot; 
var angle = Math.atan2(s.x, s.y); 
if (angle > body.slopeStanding.min && angle < body.slopeStanding.max) { 
body.standing = true ; 
} 
} 
} 
body.pos.x = res.pos.x; 
body.pos.y = res.pos.y; 
} 
; 
module.exports = UpdateMotion;