Re: need help with normals

Hi,
I wrote normal calculator for IndexTriangleFanStrip, but it calculates
partially wrong normals, can anyone help me with that ?

    public static Vector3f[] computeNormals(Point3f[] coords, int[]
coordIndices, int[] stripCounts) {
        Vector3f[] normals = new Vector3f[coords.length];
        for (int i = 0; i < normals.length; ++i) {
            normals[i] = new Vector3f();
        }
        Vector3f[] coordVs = new Vector3f[coords.length];
        for (int i = 0; i < coordVs.length; ++i) {
            coordVs[i] = new Vector3f(coords[i]);
        }

        int stripStart = 0;
        for (int i = 0; i < stripCounts.length; ++i) {
            Vector3f x0 = coordVs[coordIndices[stripStart]];
            for (int j = 2; j < stripCounts[i]; ++j) {
                Vector3f x1 = coordVs[coordIndices[stripStart + j]];
                Vector3f x2 = coordVs[coordIndices[stripStart + j - 1]];
                Vector3f d1 = new Vector3f();
                Vector3f d2 = new Vector3f();
                Vector3f cp = new Vector3f();
                d1.sub(x1, x0);
                d2.sub(x2, x0);
                cp.cross(d1, d2);
                normals[coordIndices[stripStart]].add(cp);
                normals[coordIndices[stripStart + j]].add(cp);
                normals[coordIndices[stripStart + j - 1]].add(cp);
            }
            stripStart += stripCounts[i];
        }

        for (int i = 0; i < normals.length; ++i) {
            normals[i].normalize();
        }

        return normals;
    }

Best Wishes
Thorsten