So here it is guys ,after several hours the last night and some more like
these a few couples of months ago i finaly manages to write a correct code
to perform Ray-Triangle intersection test using ray.getIntersect() ,method.I
think it is pointless to explain why you would wish to perform such kind of
test ( especially for those who develop FPS games) .So here is how this
should be done(for any question on implementation you van ask me):
private function RayFaceTest():Vector3D{
var intersectVector:Vector3D;
var ray:Ray=new Ray();
for(var i:int=0;i<_objB.faces.length;++i){
var
p0:Vector3D=_objB.sceneTransform.transformVector(_objB.faces[i].vertices[0].position);
var
p1:Vector3D=_objB.sceneTransform.transformVector(_objB.faces[i].vertices[1].position);
var
p2:Vector3D=_objB.sceneTransform.transformVector(_objB.faces[i].vertices[2].position);
ray.orig=_objA.position;
var dd:Vector3D=new Vector3D(0,400,0);
var dird:Vector3D=_objA.transform.transformVector(dd);
ray.dir=dird;
rayDebug(ray.orig,ray.dir);
intersectVector=ray.getIntersect(ray.orig,ray.dir,p0,p1,p2);
if(intersectVector){
break;
}
}
return intersectVector;
}
Explanation:
_objA and _objB are two spheres which have the same Z position. _objA is
movable by keyboard input.We draw a ray from the center of sphere _objA in
the direction of its local Y with the arbitrary length ( I set to 400).So
basically when you rotate _objA around Z the ray direction transforms
according to local _objA Y direction.We test the ray hits against the
triangles of _objB sphere. Notice that right after for loop start we convert
each face 3 vertices coords from obj local space into scene spaceNot doing
so you will never get intersection(actually this was my pitfall ).Then we
cast the ray passing into getIntersect() ray origin,ray direction vectors
,and 3 vertex vectors for the currently tested triangle.
If the intersection occurs intersectVector returns the coords of the hit
otherwise it is null.If it is not null we break fro the loop in order to
return the hit to the function and start the iteration again.This is it .I
hope it was usefull . :))
--
Michael Ivanov ,Programmer
Neurotech Solutions Ltd.
Flex|Air |3D|Unity|
www.neurotechresearch.com
http://blog.alladvanced.net
http://www.meetup.com/GO3D-Games-Opensource-3D/
Tel:054-4962254
[email protected]
[email protected]
