Question

assume variables and the numbers in the 2 examples have the same numbers… Is there any difference in the end contents in these 2 different ways of populating arrays? am I wrong assuming it’s the same?

Basically I’m trying to render graphics with OpenGL the first example doesn’t work but the second does.

Example 1…

The global declaration is.. public static final float camObjCoord[] = new float[8000];

          public void addcube(float highx, float lowx, float highz, float lowz){
    //Constructing new cube...
    Global.cubes = Global.cubes + 1;
    float highy = 4.5f;
    float lowy = 2.5f;

    System.out.println("ADDING A CUBE!!");

    //FRONT
    Global.camObjCoord[Global.i] = highx;
    Global.camObjCoord[Global.i+1] = lowy;
    Global.camObjCoord[Global.i+2] = lowz;

    Global.camObjCoord[Global.i+3] = highx;
    Global.camObjCoord[Global.i+4] = lowy;
    Global.camObjCoord[Global.i+5] = lowz;

    Global.camObjCoord[Global.i+6] = highx;
    Global.camObjCoord[Global.i+7] = highy;
    Global.camObjCoord[Global.i+8] = lowz;

    Global.camObjCoord[Global.i+9] = highx;
    Global.camObjCoord[Global.i+10] = highy;
    Global.camObjCoord[Global.i+11] = lowz;

    //BACK
    Global.camObjCoord[Global.i+12] = highx;
    Global.camObjCoord[Global.i+13] = lowy;
    Global.camObjCoord[Global.i+14] = highz;

    Global.camObjCoord[Global.i+15] = highx;
    Global.camObjCoord[Global.i+16] = highy;
    Global.camObjCoord[Global.i+17] = highz;

    Global.camObjCoord[Global.i+18] = highx;
    Global.camObjCoord[Global.i+19] = lowy;
    Global.camObjCoord[Global.i+20] = highz;

    Global.camObjCoord[Global.i+21] = highx;
    Global.camObjCoord[Global.i+22] = highy;
    Global.camObjCoord[Global.i+23] = highz;

    //LEFT
    Global.camObjCoord[Global.i+24] = highx;
    Global.camObjCoord[Global.i+25] = lowy;
    Global.camObjCoord[Global.i+26] = lowz;

    Global.camObjCoord[Global.i+27] = highx;
    Global.camObjCoord[Global.i+28] = highy;
    Global.camObjCoord[Global.i+29] = lowz;

    Global.camObjCoord[Global.i+30] = highx;
    Global.camObjCoord[Global.i+31] = lowy;
    Global.camObjCoord[Global.i+32] = highz;

    Global.camObjCoord[Global.i+33] = highx;
    Global.camObjCoord[Global.i+34] = highy;
    Global.camObjCoord[Global.i+35] = highz;

    //RIGHT
    Global.camObjCoord[Global.i+36] = highx;
    Global.camObjCoord[Global.i+37] = lowy;
    Global.camObjCoord[Global.i+38] = highz;

    Global.camObjCoord[Global.i+39] = highx;
    Global.camObjCoord[Global.i+40] = highy;
    Global.camObjCoord[Global.i+41] = highz;

    Global.camObjCoord[Global.i+42] = highx;
    Global.camObjCoord[Global.i+43] = lowy;
    Global.camObjCoord[Global.i+44] = lowz;

    Global.camObjCoord[Global.i+45] = highx;
    Global.camObjCoord[Global.i+46] = highy;
    Global.camObjCoord[Global.i+47] = lowz;

    //TOP
    Global.camObjCoord[Global.i+48] = highx;
    Global.camObjCoord[Global.i+49] = highy;
    Global.camObjCoord[Global.i+50] = lowz;

    Global.camObjCoord[Global.i+51] = highx;
    Global.camObjCoord[Global.i+52] = highy;
    Global.camObjCoord[Global.i+53] = lowz;

    Global.camObjCoord[Global.i+54] = highx;
    Global.camObjCoord[Global.i+55] = highy;
    Global.camObjCoord[Global.i+56] = lowz;

    Global.camObjCoord[Global.i+57] = highx;
    Global.camObjCoord[Global.i+58] = highy;
    Global.camObjCoord[Global.i+59] = highz;

    //BOTTOM
    Global.camObjCoord[Global.i+60] = highx;
    Global.camObjCoord[Global.i+61] = lowy;
    Global.camObjCoord[Global.i+62] = lowz;

    Global.camObjCoord[Global.i+63] = highx;
    Global.camObjCoord[Global.i+64] = lowy;
    Global.camObjCoord[Global.i+65] = highz;

    Global.camObjCoord[Global.i+66] = highx;
    Global.camObjCoord[Global.i+67] = lowy;
    Global.camObjCoord[Global.i+68] = lowz;

    Global.camObjCoord[Global.i+69] = highx;
    Global.camObjCoord[Global.i+70] = lowy;
    Global.camObjCoord[Global.i+71] = highz;
}

Example 2…

        final static float camObjCoord[] = new float[] {
            // FRONT
             -2.0f, -1.5f,  2.0f,
              2.0f, -1.5f,  2.0f,
             -2.0f,  1.5f,  2.0f,
              2.0f,  1.5f,  2.0f,
             // BACK
             -2.0f, -1.5f, -2.0f,
             -2.0f,  1.5f, -2.0f,
              2.0f, -1.5f, -2.0f,
              2.0f,  1.5f, -2.0f,
             // LEFT
             -2.0f, -1.5f,  2.0f,
             -2.0f,  1.5f,  2.0f,
             -2.0f, -1.5f, -2.0f,
             -2.0f,  1.5f, -2.0f,
             // RIGHT
              2.0f, -1.5f, -2.0f,
              2.0f,  1.5f, -2.0f,
              2.0f, -1.5f,  2.0f,
              2.0f,  1.5f,  2.0f,
             // TOP
             -2.0f,  1.5f,  2.0f,
              2.0f,  1.5f,  2.0f,
             -2.0f,  1.5f, -2.0f,
              2.0f,  1.5f, -2.0f,
             // BOTTOM
             -2.0f, -1.5f,  2.0f,
             -2.0f, -1.5f, -2.0f,
              2.0f, -1.5f,  2.0f,
              2.0f, -1.5f, -2.0f,
        };

//edit I’m adding addcube(6, 2, 6, 2); to the first example and ARRAY is equal to.. [F@4499e290. Why would the array assignment be messing up?

Answer 1

Your first example assumes that when addcube is called that the Global.i is initialized to some sensible value. Multiple calls to addcube could initialize different parts of the same array if Global.i changes. The addcube method also modifies the value of Glocal.cubes which you aren’t doing in your second example.

Your second example directly creates an array of the exact size required without using the value of Global.i. This makes it much simpler and more robust, but also less configurable.