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///////////////////////////////////////////////////////////////////////
// Class StageLine
// The line class represents a line intersected with all planes on the scene
///////////////////////////////////////////////////////////////////////
var vecUtils = require("js/helper-classes/3D/vec-utils").VecUtils;
var LinePlaneIntersectRec = require("js/helper-classes/3D/LinePlaneIntersectRec").LinePlaneIntersectRec;
var StageLine = exports.StageLine = Object.create(Object.prototype, {
///////////////////////////////////////////////////////////////////////
// Instance variables
///////////////////////////////////////////////////////////////////////
// the 2 points of the line
_pt0: { value: null, writable: true },
_pt1: { value: null, writable: true },
// cache the 3D min and max points for the line
_minPt: { value: null, writable: true },
_maxPt: { value: null, writable: true },
// the visibility at the start point (this._pt0).
_vis: { value: null, writable: true },
// each line/plane intersection records 2 values: the parameter along
// the line from pt0 to pt1, and the change in visibility (+1 or -1). we
// keep a doubly-linked list of intersection records
_intersectionList: { value: null, writable: true },
_intersectionCount: { value: 0, writable: true },
///////////////////////////////////////////////////////////////////////
// Property accessors
///////////////////////////////////////////////////////////////////////
getMinPoint: { value: function() { return this._minPt.slice(0); } },
getMaxPoint: { value: function() { return this._maxPt.slice(0); } },
getPoint0: { value: function() { return this._pt0.slice(0); } },
getPoint1: { value: function() { return this._pt1.slice(0); } },
getIntersectionCount: { value: function() { return this._intersectionCount; } },
getIntersectionList: { value: function() { return this._intersectionList; } },
getVisibility: { value: function() { return this._vis; } },
setVisibility: { value: function(v) { this._vis = v; } },
///////////////////////////////////////////////////////////////////////
// Methods
///////////////////////////////////////////////////////////////////////
intersectWithPlane: {
value: function( plane )
{
// if the plane is edge-on, ignore it
if ( MathUtils.fpSign( plane.getPlaneEq()[2] ) == 0 ) return;
// do some quick box tests.
var minPt = this.getMinPoint(),
maxPt = this.getMaxPoint();
if (maxPt[0] < plane._rect.getLeft()) return;
if (minPt[0] > plane._rect.getRight()) return;
if (maxPt[1] < plane._rect.getTop()) return;
if (minPt[1] > plane._rect.getBottom()) return;
if (minPt[2] > plane.getZMax()) return;
// get the boundary points for the plane
var boundaryPts = plane.getBoundaryPoints();
// get the points and direction vector for the current line
var pt0 = this.getPoint0(), pt1 = this.getPoint1();
//var lineDir = pt1.subtract( pt0 );
var lineDir = vecUtils.vecSubtract(3, pt1, pt0);
// intersect with the front plane
var planeEq = plane.getPlaneEq();
var t = MathUtils.vecIntersectPlaneForParam( pt0, lineDir, planeEq );
if (t != undefined)
{
if ((MathUtils.fpSign(t) >= 0) && (MathUtils.fpCmp(t,1.0) <= 0))
{
// get the intersection point
var pt = MathUtils.interpolateLine3D( pt0, pt1, t );
// see if the intersection point is contained in the bounds
//var contains = this.boundaryContainsPoint( boundaryPts, plane.isBackFacing(), pt );
var contains = MathUtils.boundaryContainsPoint( boundaryPts, pt, plane.isBackFacing() );
if (contains == MathUtils.INSIDE)
{
// add the intersection
var dot = MathUtils.dot3( pt0, planeEq ) + planeEq[3];
var deltaVis = (dot > 0) ? 1 : -1;
// if (plane.isBackFacing())
// deltaVis = (dot < 0) ? 1 : -1;
this.addIntersection( plane, t, deltaVis );
}
else if (contains == MathUtils.ON)
{
if (MathUtils.fpCmp(t,1.0) < 0)
{
// take the dot product between the line and the normal to the plane
// to determine the change in visibility
var vec = vecUtils.vecSubtract( 3, pt1, pt0 );
var dot = vecUtils.vecDot( 3, vec, plane.getPlaneEq() );
var sign = MathUtils.fpSign( dot );
if (sign == 0)
throw new Error( "coplanar intersection being treated as not coplanar" );
if (!plane.isBackFacing())
{
if (sign < 0)
this.addIntersection( plane, t, 1 );
}
else
{
if (sign > 0)
this.addIntersection( plane, t, -1 );
}
}
}
}
}
else
{
// the line must be parallel to the plane. If the line is in the plane,
// we need to do some special processing
var d0 = vecUtils.vecDot(3, planeEq, pt0) + planeEq[3],
d1 = vecUtils.vecDot(3, planeEq, pt1) + planeEq[3];
if ((MathUtils.fpSign(d0) == 0) && (MathUtils.fpSign(d1) == 0))
this.doCoplanarIntersection( plane );
}
// intersect with the 4 planes formed by the edges of the plane, going back in Z
var bPt1 = boundaryPts[3];
for (var i=0; i<4; i++)
{
// get the 2 points that define the front edge of the plane
var bPt0 = bPt1;
var bPt1 = boundaryPts[i];
// calculate the plane equation. The normal should point towards the OUTSIDE of the boundary
//var vec = bPt1.subtract( bPt0 );
var vec = vecUtils.vecSubtract(3, bPt1, bPt0);
if (plane.isBackFacing())
MathUtils.negate( vec );
planeEq = [-vec[1], vec[0], 0];
var normal = [planeEq[0], planeEq[1], planeEq[2]];
// var d = -planeEq.dot(bPt0);
var d = -vecUtils.vecDot(3, planeEq, bPt0);
planeEq[3] = d;
t = MathUtils.vecIntersectPlaneForParam( pt0, lineDir, planeEq );
if (t)
{
if ((MathUtils.fpSign(t) > 0) && (MathUtils.fpCmp(t,1.0) <= 0)) // the strict vs not-strict inequality comparisons are IMPORTANT!
{
// get the intersection point
var pt = MathUtils.interpolateLine3D( pt0, pt1, t );
// we need to get the parameter on the edge of the projection
// of the intersection point onto the line.
var index = (Math.abs(vec[0]) > Math.abs(vec[1])) ? 0 : 1;
var tEdge = (pt[index] - bPt0[index])/(bPt1[index] - bPt0[index]);
if ((MathUtils.fpSign(tEdge) > 0) && (MathUtils.fpCmp(tEdge,1.0) <= 0))
{
var edgePt = MathUtils.interpolateLine3D( bPt0, bPt1, tEdge );
if (MathUtils.fpCmp(pt[2],edgePt[2]) < 0)
{
// add the intersection
var deltaVis = MathUtils.dot(lineDir,normal) > 0 ? -1 : 1;
this.addIntersection( plane, t, deltaVis );
}
}
}
}
}
}
},
doCoplanarIntersection: {
value: function( plane )
{
// get the boundary points for the plane
var boundaryPts = plane.getBoundaryPoints();
var planeEq = plane.getPlaneEq();
if (plane.isBackFacing())
{
var tmp;
tmp = boundaryPts[0]; boundaryPts[0] = boundaryPts[3]; boundaryPts[3] = tmp;
tmp = boundaryPts[1]; boundaryPts[1] = boundaryPts[2]; boundaryPts[2] = tmp;
}
var pt0 = this.getPoint0(),
pt1 = this.getPoint1();
// keep a couple flags to prevent counting crossings twice in edge cases
var gotEnter = false,
gotExit = false;
var bp1 = boundaryPts[3];
for (var i=0; i<4; i++)
{
var bp0 = bp1;
bp1 = boundaryPts[i];
var vec = vecUtils.vecSubtract(3, bp1, bp0);
var nrm = vecUtils.vecCross(3, vec, planeEq);
nrm[3] = -vecUtils.vecDot(3, bp0, nrm);
var d0 = vecUtils.vecDot(3, nrm, pt0) + nrm[3],
d1 = vecUtils.vecDot(3, nrm, pt1) + nrm[3];
var s0 = MathUtils.fpSign(d0),
s1 = MathUtils.fpSign(d1);
if (s0 != s1)
{
var t = Math.abs(d0)/( Math.abs(d0) + Math.abs(d1) );
if (MathUtils.fpSign(t) === 0)
{
// the first point of the line is on the (infinite) extension of a side of the boundary.
// Make sure the point (pt0) is within the range of the polygon edge
var vt0 = vecUtils.vecSubtract(3, pt0, bp0),
vt1 = vecUtils.vecSubtract(3, bp1, pt0);
var dt0 = vecUtils.vecDot(3, vec, vt0),
dt1 = vecUtils.vecDot(3, vec, vt1);
var st0 = MathUtils.fpSign(dt0), st1 = MathUtils.fpSign(dt1);
if ((st0 >= 0) && (st1 >= 0))
{
if (s1 > 0) // entering the material from the beginning of the line that is to be drawn
{
// see if the start point of the line is at a corner of the bounded plane
var lineDir = vecUtils.vecSubtract(3, pt1, pt0);
vecUtils.vecNormalize(3, lineDir);
var dist = vecUtils.vecDist( 3, pt0, bp1 );
var bp2, bv0, bv1, cross1, cross2, cross3;
if ( MathUtils.fpSign(dist) == 0)
{
bp2 = boundaryPts[(i+1) % 4];
bv0 = vecUtils.vecSubtract(3, bp2, bp1);
bv1 = vecUtils.vecSubtract(3, bp0, bp1);
cross1 = vecUtils.vecCross(3, bv0, lineDir);
cross2 = vecUtils.vecCross(3, lineDir, bv1);
cross3 = vecUtils.vecCross(3, bv0, bv1);
if ( (MathUtils.fpSign(vecUtils.vecDot(3, cross1, cross3)) == 0) && (MathUtils.fpSign(vecUtils.vecDot(3, cross2, cross3)) == 0))
{
gotEnter = true;
this.addIntersection( plane, t, 1 );
}
}
else if (MathUtils.fpSign( vecUtils.vecDist(3, pt0, bp0)) === 0)
{
bp2 = boundaryPts[(i+2) % 4];
bv0 = vecUtils.vecSubtract(3, bp2, bp0);
bv1 = vecUtils.vecSubtract(3, bp1, bp0);
cross1 = vecUtils.vecCross(3, bv0, lineDir);
cross2 = vecUtils.vecCross(3, lineDir, bv1);
cross3 = vecUtils.vecCross(3, bv0, bv1);
if ( (MathUtils.fpSign(vecUtils.vecDot(3, cross1, cross3)) == 0) && (MathUtils.fpSign(vecUtils.vecDot(3, cross2, cross3)) == 0))
{
gotEnter = true;
this.addIntersection( plane, t, 1 );
}
}
else
{
// check if the line is on the edge of the boundary or goes to the interior
gotEnter = true;
this.addIntersection( plane, t, 1 );
}
}
}
}
else if ( (MathUtils.fpSign(t) > 0) && (MathUtils.fpCmp(t,1.0) <= 0))
{
// get the point where the line crosses the edge of the element plane
var pt = MathUtils.interpolateLine3D(pt0, pt1, t );
// we know that the line crosses the infinite extension of the edge. Determine
// if that crossing is within the bounds of the edge
var dot0 = vecUtils.vecDot(3, vecUtils.vecSubtract(3,pt, bp0), vec),
dot1 = vecUtils.vecDot(3, vecUtils.vecSubtract(3,pt, bp1), vec);
if ((MathUtils.fpSign(dot0) > 0) && (MathUtils.fpSign(dot1) < 0))
{
// determine if the line is entering or exiting
if (s0 <= 0) // entering
{
if (!gotEnter)
{
gotEnter = true;
this.addIntersection( plane, t, 1 );
}
}
else if (s0 > 0) // exiting
{
if (!gotExit)
{
gotExit = true;
this.addIntersection( plane, t, -1 );
}
}
else // s0 == 0
{
// TODO
}
}
else if ((MathUtils.fpSign(dot0) == 0) && (MathUtils.fpSign(dot1) < 0))
{
var j = i - 2;
if (j < 0) j += 4;
var bp = boundaryPts[j];
var v0 = vecUtils.vecSubtract( 3, bp, bp0 ),
v1 = vec;
if (s0 <= 0)
{
var v = vecUtils.vecSubtract(3, pt1, pt0);
if ((MathUtils.fpSign(vecUtils.vecCross(3, v0,v)) > 0) && (MathUtils.fpSign(vecUtils.vecCross(3, v,v1)) > 0))
{
gotEnter = true;
this.addIntersection( plane, t, 1 );
}
}
else if (s0 > 0)
{
var v = vecUtils.vecSubtract(3, pt0, pt1); // note the reversed order from the previous case
if ((MathUtils.fpSign(vecUtils.vecCross(3, v0,v)) > 0) && (MathUtils.fpSign(vecUtils.vecCross(3, v,v1)) > 0))
{
gotEnter = true;
this.addIntersection( plane, t, -1 );
}
}
}
else if ((MathUtils.fpSign(dot0) > 0) && (MathUtils.fpSign(dot1) == 0))
{
var j = (i + 1) % 4;
var bp = boundaryPts[j];
var v1 = vec.slice(0),
v0 = vecUtils.vecSubtract( 3, bp, bp1 ),
v1 = vecUtils.vecNegate(3, v1);
if (s0 <= 0)
{
var v = vecUtils.vecSubtract(3, pt1, pt0);
if ((MathUtils.fpSign(vecUtils.vecCross(3, v0,v)) < 0) && (MathUtils.fpSign(vecUtils.vecCross(3, v,v1)) < 0))
{
gotEnter = true;
this.addIntersection( plane, t, 1 );
}
}
else if (s0 > 0)
{
var v = vecUtils.vecSubtract(3, pt0, pt1); // note the reversed order from the previous case
if ((MathUtils.fpSign(vecUtils.vecCross(3, v0,v)) > 0) && (MathUtils.fpSign(vecUtils.vecCross(3, v,v1)) > 0))
{
gotEnter = true;
this.addIntersection( plane, t, -1 );
}
}
}
}
}
}
}
},
removeIntersections: {
value: function()
{
this._intersectionList = null;
this._intersectionCount = 0;
}
},
addIntersection: {
value: function( plane, t, deltaVis )
{
// create the intersection record
var iRec = Object.create(LinePlaneIntersectRec, {});
iRec.setStageLine( this );
iRec.setElementPlanes( plane );
iRec.setT( t );
iRec.setDeltaVis( deltaVis );
// the intersection array needs to be sorted by t
var ptr = this._intersectionList;
var last = null;
while (ptr && (t > ptr.getT()))
{
last = ptr;
ptr = ptr.getNext();
}
if (ptr == null)
{
if (last == null)
this._intersectionList = iRec;
else
{
last.setNext( iRec );
iRec.setPrev( last );
}
}
else
{
if (last != null)
{
last.setNext( iRec );
iRec.setPrev( last );
}
else
this._intersectionList = iRec;
ptr.setPrev( iRec );
iRec.setNext( ptr );
}
this._intersectionCount++;
}
},
boundaryContainsPoint: {
value: function( boundaryPts, backFacing, pt )
{
// the computation is done in 2D.
// this method returns false if the point is 'on' or outside the boundary
var pt1 = boundaryPts[3];
for (var i=0; i<4; i++)
{
var pt0 = pt1;
var pt1 = boundaryPts[i];
//var vec0 = pt1.subtract( pt0 ),
// vec1 = pt.subtract( pt0 );
var vec0 = vecUtils.vecSubtract(3, pt1, pt0),
vec1 = vecUtils.vecSubtract(pt, pt0);
// var cross = vec0.cross( vec1 );
var cross = vecUtils.vecCross(3, vec0, vec1);
var inside;
if (backFacing)
inside = (MathUtils.fpSign(cross[2]) > 0);
else
inside = (MathUtils.fpSign(cross[2]) < 0);
if (!inside) return false;
}
return true;
}
},
setPoints: {
value: function( pt0, pt1 )
{
this._pt0 = pt0.slice(0);
this._pt1 = pt1.slice(0);
// get the 3D bounds
var xMin, xMax, yMin, yMax, zMin, zMax;
if (pt0[0] < pt1[0]) { xMin = pt0[0]; xMax = pt1[0]; } else { xMin = pt1[0]; xMax = pt0[0]; }
if (pt0[1] < pt1[1]) { yMin = pt0[1]; yMax = pt1[1]; } else { yMin = pt1[1]; yMax = pt0[1]; }
if (pt0[2] < pt1[2]) { zMin = pt0[2]; zMax = pt1[2]; } else { zMin = pt1[2]; zMax = pt0[2]; }
this._minPt = [xMin, yMin, zMin];
this._maxPt = [xMax, yMax, zMax];
}
}//,
// getIntersectionParameter: {
// value: function( index )
// {
// var tRtn;
// if (this._paramArray)
// {
// if ((index >= 0) && (index < this._intersectionCount))
// {
// var count = 0;
// var iRec = this._intersectionList;
// while (count < index)
// iRec = iRec.getNext();
// tRtn = iRec.getT();
// }
// }
//
// return tRtn;
// }
// },
//
// getVisibilityChange: {
// value: function( index )
// {
// var delta;
// if ((index >= 0) && (index < this._intersectionCount))
// {
// var count = 0;
// var iRec = this._intersectionList;
// while (count < index)
// iRec = iRec.getNext();
// delta = iRec.getDeltaVis();
// }
//
// return delta;
// }
// }
});