float[] coords = {
   -0.5f, -0.5f, 0, //p1: (x1,y1,z1)
   0.5f, -0.5f, 0,  //p2: (x1,y1,z1)
   0.0f, 0.5f, 0    //p3: (x1,y1,z1)
};