topical media & game development

talk show tell print

mobile-query-three-plugins-ogsworkshop-examples-physicsr45-Collisions.js / js



  

author: bartek drozdz / everyday3d.com/

  
  
  THREE.PlaneCollider = function( point, normal ) {
  
          this.point = point;
          this.normal = normal;
  
  };
  
  THREE.SphereCollider = function( center, radius ) {
  
          this.center = center;
          this.radius = radius;
          this.radiusSq = radius * radius;
  
  };
  
  THREE.BoxCollider = function( min, max ) {
  
          this.min = min;
          this.max = max;
          this.dynamic = true;
  
          this.normal = new THREE.Vector3();
  
  };
  
  THREE.MeshCollider = function( mesh, box ) {
  
          this.mesh = mesh;
          this.box = box;
          this.numFaces = this.mesh.geometry.faces.length;
  
          this.normal = new THREE.Vector3();
  
  };
  
  THREE.CollisionSystem = function() {
  
          this.collisionNormal = new THREE.Vector3();
          this.colliders = [];
          this.hits = [];
  
          // console.log("Collision system init / 004");
  
  };
  
  THREE.Collisions = new THREE.CollisionSystem();
  
  THREE.CollisionSystem.prototype.merge = function( collisionSystem ) {
  
          Array.prototype.push.apply( this.colliders, collisionSystem.colliders );
          Array.prototype.push.apply( this.hits, collisionSystem.hits );
  
  };
  
  THREE.CollisionSystem.prototype.rayCastAll = function( ray ) {
  
          ray.direction.normalize();
  
          this.hits.length = 0;
  
          var i, l, d, collider,
                  ld = 0;
  
          for ( i = 0, l = this.colliders.length; i < l; i++ ) {
  
                  collider = this.colliders[ i ];
  
                  d = this.rayCast( ray, collider );
  
                  if ( d < Number.MAX_VALUE ) {
  
                          collider.distance = d;
  
                          if ( d > ld )
                                  this.hits.push( collider );
                          else
                                  this.hits.unshift( collider );
  
                          ld = d;
  
                  }
  
          }
  
          return this.hits;
  
  };
  
  THREE.CollisionSystem.prototype.rayCastNearest = function( ray ) {
  
          var cs = this.rayCastAll( ray );
  
          if( cs.length == 0 ) return null;
  
          var i = 0;
  
          while( cs[ i ] instanceof THREE.MeshCollider ) {
  
          var dist_index = this.rayMesh ( ray, cs[ i ] );
  
                  if( dist_index.dist < Number.MAX_VALUE ) {
  
                          cs[ i ].distance = dist_index.dist;
              cs[ i ].faceIndex = dist_index.faceIndex;
                          break;
  
                  }
  
                  i++;
  
          }
  
          if ( i > cs.length ) return null;
  
          return cs[ i ];
  
  };
  
  THREE.CollisionSystem.prototype.rayCast = function( ray, collider ) {
  
          if ( collider instanceof THREE.PlaneCollider )
                  return this.rayPlane( ray, collider );
  
          else if ( collider instanceof THREE.SphereCollider )
                  return this.raySphere( ray, collider );
  
          else if ( collider instanceof THREE.BoxCollider )
                  return this.rayBox( ray, collider );
  
          else if ( collider instanceof THREE.MeshCollider && collider.box )
                  return this.rayBox( ray, collider.box );
  
  };
  
  THREE.CollisionSystem.prototype.rayMesh = function( r, me ) {
  
          var rt = this.makeRayLocal( r, me.mesh );
  
          var d = Number.MAX_VALUE;
      var nearestface;
  
          for( var i = 0; i < me.numFaces; i++ ) {
          var face = me.mesh.geometry.faces[i];
          var p0 = me.mesh.geometry.vertices[ face.a ].position;
          var p1 = me.mesh.geometry.vertices[ face.b ].position;
          var p2 = me.mesh.geometry.vertices[ face.c ].position;
          var p3 = face instanceof THREE.Face4 ? me.mesh.geometry.vertices[ face.d ].position : null;
  
          if (face instanceof THREE.Face3) {
              var nd = this.rayTriangle( rt, p0, p1, p2, d, this.collisionNormal, me.mesh );
  
              if( nd < d ) {
  
                  d = nd;
                  nearestface = i;
                  me.normal.copy( this.collisionNormal );
                  me.normal.normalize();
  
              }
          
          }
          
          else if (face instanceof THREE.Face4) {
              
              var nd = this.rayTriangle( rt, p0, p1, p3, d, this.collisionNormal, me.mesh );
              
              if( nd < d ) {
  
                  d = nd;
                  nearestface = i;
                  me.normal.copy( this.collisionNormal );
                  me.normal.normalize();
  
              }
              
              nd = this.rayTriangle( rt, p1, p2, p3, d, this.collisionNormal, me.mesh );
              
              if( nd < d ) {
  
                  d = nd;
                  nearestface = i;
                  me.normal.copy( this.collisionNormal );
                  me.normal.normalize();
  
              }
              
          }
  
          }
  
          return {dist: d, faceIndex: nearestface};
  
  };
  
  THREE.CollisionSystem.prototype.rayTriangle = function( ray, p0, p1, p2, mind, n, mesh ) {
  
          var e1 = THREE.CollisionSystem.__v1,
                  e2 = THREE.CollisionSystem.__v2;
          
          n.set( 0, 0, 0 );
  
          // do not crash on quads, fail instead
  
          e1.sub( p1, p0 );
          e2.sub( p2, p1 );
          n.cross( e1, e2 )
  
          var dot = n.dot( ray.direction );
          if ( !( dot < 0 ) ) {
                  
                  if ( mesh.doubleSided || mesh.flipSided ) {
                  
                          n.multiplyScalar (-1.0);
                          dot *= -1.0;
                  
                  } else {
                          
                          return Number.MAX_VALUE;
                  
                  }
          
          }
  
          var d = n.dot( p0 );
          var t = d - n.dot( ray.origin );
  
          if ( !( t <= 0 ) ) return Number.MAX_VALUE;
          if ( !( t >= dot * mind ) ) return Number.MAX_VALUE;
  
          t = t / dot;
  
          var p = THREE.CollisionSystem.__v3;
  
          p.copy( ray.direction );
          p.multiplyScalar( t );
          p.addSelf( ray.origin );
  
          var u0, u1, u2, v0, v1, v2;
  
          if ( Math.abs( n.x ) > Math.abs( n.y ) ) {
  
                  if ( Math.abs( n.x ) > Math.abs( n.z ) ) {
  
                          u0 = p.y  - p0.y;
                          u1 = p1.y - p0.y;
                          u2 = p2.y - p0.y;
  
                          v0 = p.z  - p0.z;
                          v1 = p1.z - p0.z;
                          v2 = p2.z - p0.z;
  
                  } else {
  
                          u0 = p.x  - p0.x;
                          u1 = p1.x - p0.x;
                          u2 = p2.x - p0.x;
  
                          v0 = p.y  - p0.y;
                          v1 = p1.y - p0.y;
                          v2 = p2.y - p0.y;
  
                  }
  
          } else {
  
                  if( Math.abs( n.y ) > Math.abs( n.z ) ) {
  
                          u0 = p.x  - p0.x;
                          u1 = p1.x - p0.x;
                          u2 = p2.x - p0.x;
  
                          v0 = p.z  - p0.z;
                          v1 = p1.z - p0.z;
                          v2 = p2.z - p0.z;
  
                  } else {
  
                          u0 = p.x  - p0.x;
                          u1 = p1.x - p0.x;
                          u2 = p2.x - p0.x;
  
                          v0 = p.y  - p0.y;
                          v1 = p1.y - p0.y;
                          v2 = p2.y - p0.y;
  
                  }
  
          }
  
          var temp = u1 * v2 - v1 * u2;
          if( !(temp != 0) ) return Number.MAX_VALUE;
          //console.log("temp: " + temp);
          temp = 1 / temp;
  
          var alpha = ( u0 * v2 - v0 * u2 ) * temp;
          if( !(alpha >= 0) ) return Number.MAX_VALUE;
          //console.log("alpha: " + alpha);
  
          var beta = ( u1 * v0 - v1 * u0 ) * temp;
          if( !(beta >= 0) ) return Number.MAX_VALUE;
          //console.log("beta: " + beta);
  
          var gamma = 1 - alpha - beta;
          if( !(gamma >= 0) ) return Number.MAX_VALUE;
          //console.log("gamma: " + gamma);
  
          return t;
  
  };
  
  THREE.CollisionSystem.prototype.makeRayLocal = function( ray, m ) {
  
          var mt = THREE.CollisionSystem.__m;
          THREE.Matrix4.makeInvert( m.matrixWorld, mt );
  
          var rt = THREE.CollisionSystem.__r;
          rt.origin.copy( ray.origin );
          rt.direction.copy( ray.direction );
  
          mt.multiplyVector3( rt.origin );
          mt.rotateAxis( rt.direction );
          rt.direction.normalize();
          //m.localRay = rt;
  
          return rt;
  
  };
  
  THREE.CollisionSystem.prototype.rayBox = function( ray, ab ) {
  
          var rt;
  
          if ( ab.dynamic && ab.mesh && ab.mesh.matrixWorld ) {
  
                  rt = this.makeRayLocal( ray, ab.mesh );
  
          } else {
  
                  rt = THREE.CollisionSystem.__r;
                  rt.origin.copy( ray.origin );
                  rt.direction.copy( ray.direction );
  
          }
  
          var xt = 0, yt = 0, zt = 0;
          var xn = 0, yn = 0, zn = 0;
          var ins = true;
  
          if( rt.origin.x < ab.min.x ) {
  
                  xt = ab.min.x - rt.origin.x;
                  //if(xt > ray.direction.x) return return Number.MAX_VALUE;
                  xt /= rt.direction.x;
                  ins = false;
                  xn = -1;
  
          } else if( rt.origin.x > ab.max.x ) {
  
                  xt = ab.max.x - rt.origin.x;
                  //if(xt < ray.direction.x) return return Number.MAX_VALUE;
                  xt /= rt.direction.x;
                  ins = false;
                  xn = 1;
  
          }
  
          if( rt.origin.y < ab.min.y ) {
  
                  yt = ab.min.y - rt.origin.y;
                  //if(yt > ray.direction.y) return return Number.MAX_VALUE;
                  yt /= rt.direction.y;
                  ins = false;
                  yn = -1;
  
          } else if( rt.origin.y > ab.max.y ) {
  
                  yt = ab.max.y - rt.origin.y;
                  //if(yt < ray.direction.y) return return Number.MAX_VALUE;
                  yt /= rt.direction.y;
                  ins = false;
                  yn = 1;
  
          }
  
          if( rt.origin.z < ab.min.z ) {
  
                  zt = ab.min.z - rt.origin.z;
                  //if(zt > ray.direction.z) return return Number.MAX_VALUE;
                  zt /= rt.direction.z;
                  ins = false;
                  zn = -1;
  
          } else if( rt.origin.z > ab.max.z ) {
  
                  zt = ab.max.z - rt.origin.z;
                  //if(zt < ray.direction.z) return return Number.MAX_VALUE;
                  zt /= rt.direction.z;
                  ins = false;
                  zn = 1;
  
          }
  
          if( ins ) return -1;
  
          var which = 0;
          var t = xt;
  
          if( yt > t ) {
  
                  which = 1;
                  t = yt;
  
          }
  
          if ( zt > t ) {
  
                  which = 2;
                  t = zt;
  
          }
  
          switch( which ) {
  
                  case 0:
  
                          var y = rt.origin.y + rt.direction.y * t;
                          if ( y < ab.min.y || y > ab.max.y ) return Number.MAX_VALUE;
                          var z = rt.origin.z + rt.direction.z * t;
                          if ( z < ab.min.z || z > ab.max.z ) return Number.MAX_VALUE;
                          ab.normal.set( xn, 0, 0 );
                          break;
  
                  case 1:
  
                          var x = rt.origin.x + rt.direction.x * t;
                          if ( x < ab.min.x || x > ab.max.x ) return Number.MAX_VALUE;
                          var z = rt.origin.z + rt.direction.z * t;
                          if ( z < ab.min.z || z > ab.max.z ) return Number.MAX_VALUE;
                          ab.normal.set( 0, yn, 0) ;
                          break;
  
                  case 2:
  
                          var x = rt.origin.x + rt.direction.x * t;
                          if ( x < ab.min.x || x > ab.max.x ) return Number.MAX_VALUE;
                          var y = rt.origin.y + rt.direction.y * t;
                          if ( y < ab.min.y || y > ab.max.y ) return Number.MAX_VALUE;
                          ab.normal.set( 0, 0, zn );
                          break;
  
          }
  
          return t;
  
  };
  
  THREE.CollisionSystem.prototype.rayPlane = function( r, p ) {
  
          var t = r.direction.dot( p.normal );
          var d = p.point.dot( p.normal );
          var ds;
  
          if( t < 0 ) ds = ( d - r.origin.dot( p.normal ) ) / t;
          else return Number.MAX_VALUE;
  
          if( ds > 0 ) return ds;
          else return Number.MAX_VALUE;
  
  };
  
  THREE.CollisionSystem.prototype.raySphere = function( r, s ) {
  
          var e = s.center.clone().subSelf( r.origin );
          if ( e.lengthSq < s.radiusSq ) return -1;
  
          var a = e.dot( r.direction.clone() );
          if ( a <= 0 ) return Number.MAX_VALUE;
  
          var t = s.radiusSq - ( e.lengthSq() - a * a );
          if ( t >= 0 ) return Math.abs( a ) - Math.sqrt( t );
  
          return Number.MAX_VALUE;
  
  };
  
  THREE.CollisionSystem.__v1 = new THREE.Vector3();
  THREE.CollisionSystem.__v2 = new THREE.Vector3();
  THREE.CollisionSystem.__v3 = new THREE.Vector3();
  THREE.CollisionSystem.__nr = new THREE.Vector3();
  THREE.CollisionSystem.__m = new THREE.Matrix4();
  THREE.CollisionSystem.__r = new THREE.Ray();
  


(C) Æliens 04/09/2009

You may not copy or print any of this material without explicit permission of the author or the publisher. In case of other copyright issues, contact the author.