Exemplo n.º 1
0
    //BENDS
    public static void GetBendForce(int a0, int a1, int a2, float[,] positions, float[] energies, float[,] forces, float bendAEq, float bendKEq)
    {
        int c;

        float[] perp = new float[3];
        float[] v10  = new float[3];
        float[] v12  = new float[3];
        float   dot  = 0f;

        float r10;
        float r12;

        float[] force0 = new float[3];
        float[] force2 = new float[3];

        Mathematics.VectorFromArray(positions, a1, a0, v10);
        Mathematics.VectorFromArray(positions, a1, a2, v12);
        r10 = Mathematics.Magnitude3(v10);
        r12 = Mathematics.Magnitude3(v12);

        Mathematics.Divide3(v10, r10);
        Mathematics.Divide3(v12, r12);

        Mathematics.EAngle(
            Mathematics.UnsignedAngleRad3(v10, v12, dot) - bendAEq,
            bendKEq,
            energies
            );

        Mathematics.Cross3(v10, v12, perp);
        Mathematics.Cross3(v10, perp, force0);
        Mathematics.Cross3(v12, perp, force2);

        Mathematics.Multiply3(force0, -energies[1] / r10);
        Mathematics.Multiply3(force2, energies[1] / r12);

        for (c = 0; c < 3; c++)
        {
            forces[a0, c] += force0[c];
            forces[a1, c] -= force0[c] + force2[c];
            forces[a2, c] += force2[c];
        }
    }