/********************************************************************************************
Step6.cpp
	Jim Millard
	for CO311/Spring 2000

   Simple program that displays a 4x4 Blue/Red checkerboard

   Uses the ezwin API
********************************************************************************************/
#include <iostream>
#include <string>
using namespace std;

#include "ezwin.h"
#include "rect.h"

void DrawCheckerboard(SimpleWindow& W);  //required prototype

int ApiMain()
   {
   //create the primary window
   SimpleWindow W("Exercise 3.22, Step 6 (complete)");
   W.Open();

   DrawCheckerboard(W);

   //wait for input prior to quitting
   char ch;
   cout << "Enter a character to continue";
   cin >> ch;

   Terminate();
   return 0;
   }

void DrawCheckerboard(SimpleWindow& W)
   {
   //A stack of useful constants that can later be replaced by function parameters
   const float height=2., //static height of all blocks
               width =2., //static width of all blocks
               xCenter =width/2., //horizontal center of each block
               yCenter =height/2.; //vertical center of each block
   const int BlocksAcross =4, //static width of checkerboard
             BlocksDown =4; //static height of checkerboard
   const color BaseColor = Blue,  //static color of first block
               AltColor  = Red;   //static color of alternate block

   bool doAltColor;  //keeps track of whether we should display in the alternate color
   color currentColor; //the color we're drawing now

   //Draw by rows
   doAltColor = false; //start with the base color
   for(int row = 0; row < BlocksDown; row++)
       {
       //Draw the rectangles across the row
       for (int column = 0; column < BlocksAcross; column++)
           {
           //set the color
           if (doAltColor)
               currentColor = AltColor;
           else
               currentColor = BaseColor;
           doAltColor = !doAltColor;

           RectangleShape Rxy(W, xCenter + width*column, yCenter + row*height, currentColor, width, height);
           Rxy.Draw();
           } //inner for loop

       //reverse the color flag if the number of columns is even
       if (!(BlocksAcross%2))
           doAltColor = !doAltColor;

       } //outer for loop

    return;
    } //DrawCheckerboard