BEPUphysics

Posted: **Sat Nov 17, 2012 5:15 am**

Hi!

I'm having some problems with the triangle entity. I initialize the triangle with three different points but when I query the triangle vertices in world space (by getting the properties VertexA, VertexB and VertexC) the VertexB and VertexC properties return the same value.

Basically I'm trying to spawn a triangle in the place of a Sphere. In the class holding the Sphere (note the different vertices):

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TriangleManager.AddTriangle(new Vector3(0, 0, 0), new Vector3(1, 1, 0), new Vector3(-1, 1, 0), SphereBody.WorldTransform);

In the class TriangleManager:

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public void AddFragment(Vector3 v0, Vector3 v1, Vector3 v2, Matrix world) {
    TriangleBody = new Triangle(v0, v1, v2, 0.01f) {
        WorldTransform = world,
    };
    Space.Add(TriangleBody);
}

This is how I try to render the triangle:

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VertexBuffer.Set(index++, Semantic.Position, TriangleBody.VertexA);
VertexBuffer.Set(index++, Semantic.Position, TriangleBody.VertexB);
VertexBuffer.Set(index++, Semantic.Position, TriangleBody.VertexC);

Took me quite a while until I enabled wireframe

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if (fragment.VertexB == fragment.VertexC) {
    throw new Exception("degenerate triangle"); // gets thrown
}

Data in LocalVertexA/B/C is correct (as initialized). What am I missing or doing wrong?

Edit:
BEPUphysics 1.2.0, SharpDX fork (commit 87fc56cc9ed4 - latest at time of writing)
Also I *think* the triangles still behave like triangles in terms of physics and raycasts (though that is really hard to say without correct visuals ^^)

Posted: **Sat Nov 17, 2012 6:04 am**

The Triangle.VertexC getter happens to return the transformed version of LocalVertexB, unhelpfully. It's now fixed in the development version.

Thanks for the report!

BEPUphysics

Triangle entity problems

Triangle entity problems

Re: Triangle entity problems