topical media & game development
student-ar-org-papervision3d-core-math-util-TriangleUtil.ax
student-ar-org-papervision3d-core-math-util-TriangleUtil.ax
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package org.papervision3d.core.math.util
{
import org.papervision3d.core.geom.renderables.Triangle3D;
import org.papervision3d.core.geom.renderables.Vertex3D;
import org.papervision3d.core.math.NumberUV;
import org.papervision3d.core.math.Plane3D;
public class @ax-student-ar-org-papervision3d-core-math-util-TriangleUtil
{
Clips a triangle to a plane.
@param tri Triangle to be clipped.
@param plane Plane to clip to.
@param e Epsilon
public static function clipTriangleWithPlane(tri:Triangle3D, plane:Plane3D, e:Number=0.01):Array
{
var points:Array = [tri.v0, tri.v1, tri.v2];
var uvs:Array = [tri.uv0, tri.uv1, tri.uv2];
var out:Array = new Array();
var outuv:Array = new Array();
var isect:Intersection;
var s:Vertex3D = points[points.length-1];
var p:Vertex3D;
var suv:NumberUV = uvs[points.length-1];
var puv:NumberUV;
var cp:uint;
var cs:uint;
for(var i:int = 0; i < points.length; i++)
{
p = points[i];
puv = uvs[i];
cp = ClassificationUtil.classifyPoint(p, plane, e);
cs = ClassificationUtil.classifyPoint(s, plane, e);
if(cp == ClassificationUtil.FRONT)
{
if(cs == ClassificationUtil.FRONT)
{
// output p
out.push(p);
outuv.push(puv);
}
else
{
// compute intersection s, p, plane
isect = Intersection.linePlane(s, p, plane, e);
if( isect.status != Intersection.INTERSECTION )
{
plane.d += 1;
return clipTriangleWithPlane(tri, plane, e);
}
//tri.instance.geometry.vertices.push(isect.vert);
out.push(isect.vert);
outuv.push(InterpolationUtil.interpolateUV(suv, puv, isect.alpha));
// output p
out.push(p);
outuv.push(puv);
}
}
else if(cs == ClassificationUtil.FRONT)
{
isect = Intersection.linePlane(p, s, plane, e);
if( isect.status != Intersection.INTERSECTION )
{
plane.d += 1;
return clipTriangleWithPlane(tri, plane, e);
}
//tri.instance.geometry.vertices.push(isect.vert);
out.push(isect.vert);
outuv.push(InterpolationUtil.interpolateUV(puv, suv, isect.alpha));
}
s = p;
suv = puv;
}
if(out.length == 3)
{
return [new Triangle3D(tri.instance, [out[0], out[1], out[2]], tri.material, [outuv[0], outuv[1], outuv[2]])];
}
else if(out.length == 4)
{
return [new Triangle3D(tri.instance, [out[0], out[1], out[2]], tri.material, [outuv[0], outuv[1], outuv[2]]),
new Triangle3D(tri.instance, [out[0], out[2], out[3]], tri.material, [outuv[0], outuv[2], outuv[3]])];
}
return null;
}
public static function clipTriangleWithPlaneTris(tri:Triangle3D, plane:Plane3D, e:Number=0.01, t1:Triangle3D=null, t2:Triangle3D=null, depth:Number=0):Array
{
if(depth > 420)
return [tri];
var points:Array = tri.vertices;//[tri.v0, tri.v1, tri.v2];
var uvs:Array = tri.uv;//[tri.uv0, tri.uv1, tri.uv2];
var out:Array = new Array();
var outuv:Array = new Array();
var isect:Intersection;
var s:Vertex3D = points[points.length-1];
var p:Vertex3D;
var suv:NumberUV = uvs[points.length-1];
var puv:NumberUV;
var cp:uint;
var cs:uint;
for(var i:int = 0; i < points.length; i++)
{
p = points[i];
puv = uvs[i];
cp = ClassificationUtil.classifyPoint(p, plane, e);
cs = ClassificationUtil.classifyPoint(s, plane, e);
if(cp == ClassificationUtil.FRONT)
{
if(cs == ClassificationUtil.FRONT)
{
// output p
out.push(p);
outuv.push(puv);
}
else
{
// compute intersection s, p, plane
isect = Intersection.linePlane(s, p, plane, e);
if( isect.status != Intersection.INTERSECTION )
{
plane.d -= 0.05;
return clipTriangleWithPlaneTris(tri, plane, e, t1, t2, depth+1);
}
//tri.instance.geometry.vertices.push(isect.vert);
out.push(isect.vert);
outuv.push(InterpolationUtil.interpolateUV(suv, puv, isect.alpha));
// output p
out.push(p);
outuv.push(puv);
}
}
else if(cs == ClassificationUtil.FRONT)
{
isect = Intersection.linePlane(p, s, plane, e);
if( isect.status != Intersection.INTERSECTION )
{
plane.d -= 0.05;
return clipTriangleWithPlaneTris(tri, plane, e, t1, t2, depth+1);
}
//tri.instance.geometry.vertices.push(isect.vert);
out.push(isect.vert);
outuv.push(InterpolationUtil.interpolateUV(puv, suv, isect.alpha));
}
s = p;
suv = puv;
}
if(out.length == 3)
{
t1.reset(tri.instance, [out[0], out[1], out[2]], tri.material, [outuv[0], outuv[1], outuv[2]]);
return [t1];
}
else if(out.length == 4)
{
t1.reset(tri.instance, [out[0], out[1], out[2]], tri.material, [outuv[0], outuv[1], outuv[2]]);
t2.reset(tri.instance, [out[0], out[2], out[3]], tri.material, [outuv[0], outuv[2], outuv[3]]);
return [t1,t2];
}
return null;
}
public static function clipSplitTriangleWithPlane(triangle:Triangle3D, plane:Plane3D, e:Number=0.01):Array
{
var outArr:Array = new Array();
var a1:Array = clipTriangleWithPlane(triangle, plane, e);
var a2:Array = clipTriangleWithPlane(triangle, plane.getTempFlip(), e);
if(a1 == null && a2 ==null){
return null;
}else{
if(a1 != null && a1.length){
outArr = outArr.concat(a1);
}
if(a2 != null && a2.length){
outArr = outArr.concat(a2);
}
}
return outArr;
}
public static function splitTriangleWithPlane(triangle:Triangle3D, plane:Plane3D, e:Number=0.01 ):Array
{
var side:uint = ClassificationUtil.classifyTriangle(triangle, plane);
if(side != ClassificationUtil.STRADDLE){
return null;
}
var pA:Vertex3D;
var pB:Vertex3D;
var uvA:NumberUV;
var uvB:NumberUV;
var sideA:Number;
var sideB:Number;
var isect:Intersection;
var newUV:NumberUV;
var points:Array = [triangle.v0, triangle.v1, triangle.v2];
var uvs:Array = [triangle.uv0, triangle.uv1, triangle.uv2];
var triA:Array = new Array();
var triB:Array = new Array();
var uvsA:Array = new Array();
var uvsB:Array = new Array();
for( var i:int = 0; i < points.length; i++ ){
var j:int = (i+1) % points.length;
pA = points[i];
pB = points[j];
uvA = uvs[i];
uvB = uvs[j];
sideA = plane.distance(pA);
sideB = plane.distance(pB);
if(sideB > e){
if(sideA < -e){
isect = Intersection.linePlane( pA, pB, plane,e);
if( isect.status != Intersection.INTERSECTION ){
plane.d += 1;
return splitTriangleWithPlane(triangle, plane, e);
}
triangle.instance.geometry.vertices.push( isect.vert );
triA.push( isect.vert );
triB.push( isect.vert );
newUV = InterpolationUtil.interpolateUV(uvA, uvB, isect.alpha);
uvsA.push(newUV);
uvsB.push(newUV);
}
triA.push( pB );
uvsA.push( uvB );
}
else if(sideB < -e)
{
if(sideA > e){
isect = Intersection.linePlane( pA, pB, plane,e);
if( isect.status != Intersection.INTERSECTION ){
plane.d += 1;
return splitTriangleWithPlane(triangle, plane, e);
}
triangle.instance.geometry.vertices.push( isect.vert );
triA.push( isect.vert );
triB.push( isect.vert );
newUV = InterpolationUtil.interpolateUV(uvA, uvB, isect.alpha);
uvsA.push(newUV);
uvsB.push(newUV);
}
triB.push( pB );
uvsB.push( uvB );
}else{
triA.push( pB );
triB.push( pB );
uvsA.push( uvB );
uvsB.push( uvB );
}
}
var tris:Array = new Array();
tris.push( new Triangle3D(triangle.instance, [triA[0], triA[1], triA[2]], triangle.material, [uvsA[0], uvsA[1], uvsA[2]]) );
tris.push( new Triangle3D(triangle.instance, [triB[0], triB[1], triB[2]], triangle.material, [uvsB[0], uvsB[1], uvsB[2]]) );
if( triA.length > 3 )
tris.push( new Triangle3D(triangle.instance, [triA[0], triA[2], triA[3]], triangle.material, [uvsA[0], uvsA[2], uvsA[3]]) );
else if( triB.length > 3 )
tris.push( new Triangle3D(triangle.instance, [triB[0], triB[2], triB[3]], triangle.material, [uvsB[0], uvsB[2], uvsB[3]]) );
return tris;
}
}
}
(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.
