LookAt.cs

LookAt.cs

 protected static void LookAt(float eyeX, float eyeY, float eyeZ, float targetX, float targetY, float targetZ, float upX, float upY, float upZ) {
    float len = (float)Math.Sqrt(upX * upX + upY * upY + upZ * upZ);
    upX /= len; upY /= len; upZ /= len;

    float[] f = { targetX - eyeX, targetY - eyeY, targetZ - eyeZ };
    len = (float)Math.Sqrt(f[0] * f[0] + f[1] * f[1] + f[2] * f[2]);
    f[0] /= len; f[1] /= len; f[2] /= len;

    float[] s = { 0f, 0f, 0f };
    s[0] = f[1] * upZ - f[2] * upY;
    s[1] = f[2] * upX - f[0] * upZ;
    s[2] = f[0] * upY - f[1] * upX;
    len = (float)Math.Sqrt(s[0] * s[0] + s[1] * s[1] + s[2] * s[2]);
    s[0] /= len; s[1] /= len; s[2] /= len;

    float[] u = { 0f, 0f, 0f };
    u[0] = s[1] * f[2] - s[2] * f[1];
    u[1] = s[2] * f[0] - s[0] * f[2];
    u[2] = s[0] * f[1] - s[1] * f[0];
    len = (float)Math.Sqrt(s[0] * u[0] + u[1] * u[1] + u[2] * u[2]);
    u[0] /= len; u[1] /= len; u[2] /= len;

    float[] result = {
        s[0], u[0], -f[0], 0.0f,
        s[1], u[1], -f[1], 0.0f,
        s[2], u[2], -f[2], 0.0f,
        0.0f, 0.0f,  0.0f, 1.0f
    };

    GL.MultMatrix(result);
    GL.Translate(-eyeX, -eyeY, -eyeZ);
}