Okay, if i do the color coded picking, Lets say were using the color light green, is there 3000 different colored light greens that would look the same to the eye? even by adjusting each tile's color up by a unnoticible notch, but 3000 times?

Hi, im new to OpenGL for java, now id like to make a map of tiles (square 1 sided tiles) going 48*48, i have done this using the following code.
int count = 0;
for(int i=0; i < 48*48; i++) {
                        count++;
         gl.glVertex3f(AcrossTwo, DownTwo, -0.4f);
         gl.glVertex3f(AcrossTwo,  DownOne, -0.4f);
         gl.glVertex3f(AcrossOne,  DownOne, -0.4f);
         gl.glVertex3f(AcrossOne, DownTwo, -0.4f);

         AcrossOne+= 1.02f;
         AcrossTwo+= 1.02f;
                        // After 48 tiles have been layed, it moves the position down and resets horizontal back to the start to lay another 48 under it.
         if(count == 48) {
            count = 0;
            DownOne+= 1.02f;
            DownTwo+= 1.02f;
            AcrossOne = 1.0f;
            AcrossTwo = 0.0f;
         }

}

Now this does show the tiles i created, except im completely lost in how i go about accessing them, lets say i click a tile on my screen, id like to be able to change that tile's color. I know this isnt structured properly (Normally id create a Tile class, holding all it's properties) except i don't actually know how to access each vertex3f by a mouse click?

Thanks for whoever helps