collision tree & Decals

[mauro78]

Hi All!

Just a quick question: is it possible to access to collision tree data?

I mean, after a RayCast against the world I know a point of intersection P (eventually a normal) and a pickedbody B.

I need to access or perform a proximity query on a collision tree, couse I need to place "decal" on it ( based on the distance from the collision point P) .
I'm wondering If Newton 2.0 has some sort of helper function about that.

Thanks in advance

p.s.
I know that another solution is to keep a copy of triangles that compose the "collision tree" and do It by myself, but I really like the idea of using Newton API's if available.....

[JernejL]

I believe NewtonTreeCollisionGetVertexListIndexListInAABB does that.

Julio can help explain what the parameters do, it's not yet documented on the wiki.

[mauro78]

I believe NewtonTreeCollisionGetVertexListIndexListInAABB does that.

Julio can help explain what the parameters do, it's not yet documented on the wiki.

Thank you Delfi...sounds good...I hope Julio has more information about that...

Regards

[mauro78]

I believe NewtonTreeCollisionGetVertexListIndexListInAABB does that.

Julio can help explain what the parameters do, it's not yet documented on the wiki.

Code: Select all

NewtonCollision* collision = NewtonBodyGetCollision(pickedBody);
dVector p0, p1;
dVector p(pickedPoint.x,pickedPoint.y,pickedPoint.z);
p1 = p + dVector(2,2,2);
p0 = p + dVector(-2,-2,-2);
            
const dFloat* vertexList; // Call sets this to point to the array
int vertexCount; // Returned number of vertices
int vertexStrideInBytes; // Returned
int indexList[256]; // Array of indices - this is set by the call
int attributeList[256/3]; // Array of face attributes - set by call
int numFaces;
numFaces = NewtonTreeCollisionGetVertexListIndexListInAABB (collision, &p0[0], &p1[0], &vertexList, &vertexCount, &vertexStrideInBytes, &indexList[0],    256,    attributeList);
Decal* pDecal = new Decal(this->m_d3d9Device,camera);
pDecal->Init((float*)vertexList,vertexCount,&indexList[0],numFaces);
g_DecalsList.push_back(pDecal);

It works fairly well; the only problem is that (correct me if I'm wrong) collision meshes are different from geometric meshes...so there's not a 1:1 corrispondence between mesh triangles and newton stored triangles right?

[kallaspriit]

You can try disabling collision tree optimizations, then they should match exactly.

[mauro78]

You can try disabling collision tree optimizations, then they should match exactly.

Thank you for suggestion, It's a lot better.
regards