Quote:Original post by taz0010
If your ray-to-plane intersection test part of an oriented bounding box test? Can I get some background info so I know exactly what you want the algorithm to do?
Yes. I have an OBB(!) with BindPoseCenter(Transform reference) and CombinedCenter; Rotation; and the Bounds;
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8 Fields for the Corners:
BackBottomLeft( min ),
BackBottomRight ( max.x;min.y;min.z) ,
FrontBottomRight(max.x,min.y,max.z),
FrontBottomLeft(min.x,min.y,max.z),
BackUpLeft(min.x,max.y,min.z),
BackUpRight(max.x,max.y,min.z),
FrontUpRight( max ),
FrontUpLeft(min.x,max.y,max.z)
And the planes:
v2
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|
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v0-------v1
always like this:
plane( v0, v1, v2 )
directionplane = ( FBR, FBL, FUR )
backplane = ( BBL, BBR, BUL )
rightplane = ( BBR, FBR, BUR )
leftplane = ( FBL, BBL, FUL )
upplane = ( BUL, BUR, FUL )
downplane = ( FBL, FBR, BBL )
my function is following
public bool RayOBB_Geometric(Vector3 Rayorigin, Vector3 Raydirection, List<CollisionPlane> oPlanes) {
List<CollisionPlane> oIntersectedPlanes = new List<CollisionPlane>();
foreach(CollisionPlane oPlane in oPlanes)
if(RayPlane_Geometric(Rayorigin, Raydirection, oPlane.V0, oPlane.V1, oPlane.V2)) {
oIntersectedPlanes.Add(oPlane);
}
if(oIntersectedPlanes.Count > 0)
return true;
return false;
}
And so on.
I think there is something wrong when i update the boundingboxes...
I update them after my animation-skintransformset has been updated.
each bone has an OBB ... i pass the bone-skintransform to the OBBs update method and apply the matrix on the bounding boxes center and rotation.. that works without any problems
i thought about to transform the ray in the obbs space, so that i dont have to apply any rotation on the corners anymore.. but i somehow have to geet the correct data for the corners!!!
Hum... what i recognized: sometimes anything works! and sometimes i get 6 intersected planes on 5 boxes even if there are none oO
look at these screens in that album ( imageshack ): http://img704.imageshack.us/g/almcorrect.png/
on the leg, there are two intersections: correct
but the other one: 4 or 5 intersections, though i clicked on the screen where only one is visible
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The idea is to take a Plane defined by three vectors v0, v1, v2 and a ray defined by its origin and its direction
i first calculate the planes edges:
edge1 = oVert2 - oVert1;
edge2 = oVert3 - oVert1;
then the normal:
normal = cross(edge1, edge2);
now i can check wether the ray is parallel to the plane and additionally, if the distance of the rayorigin and the plane approaches zero:
normaldotdir = dot(normal, direction);
normaldotw = dot(normal, w);
if(normaldotdir > -0.0000001 && normaldotdir < 0.0000001) {
if(normaldotw > -0.0000001 && normaldotw < 0.0000001)
return true;
return false;
}
now we can get the parameter s of the ray if we say, that the point of intersection is:
(origin - v0) + s*direction = w + s*u
the dotproduct of the normal and the equation above has to approach zero to be inside the plane:
dot(normal, (w+s*u)) = dot(normal, w) + dot(normal, s*u) = 0
- dot(normal, w) = s*dot(normal, u)
s = ( - dot(normal, w) / dot(normal, u) )
point of intersection is:
cut = origin + ( s*direction )
now we have to get the u and v coordinates of the directionvectors of the planes
i create the vector from v0 to the point of intersection P(s) = cut and project it to edge1
projected_u = dot(edge1, v0Ps);
dividing projected_u by the lenght of edge1 gives u:
u = projected_u / norm(edge1);
the same for v:
v = dot(edge2, v0Ps) / norm(edge2);
if(u < 0 || u > 1) return false;
if(v < 0 || v > 1) return false;
this test doesnt work somehow, mathematically i think everythings correct...
any help would be appreciated
thank you all in advance!
