File content as of revision 2:1525f7ae330e:

#include "mbed.h"
#include "NeoStrip.h"
#include "PinDetect.h"
#include "Matrix.h"

#define N 64

NeoStrip strip(p18, N); //8x8 neopixel matrix with each neopixel addressable by its index which range from 0 to 63 
Matrix board(8,7); //the Connect Four game board is a 6x7 matrix, the neopixel matrix is 8x8, created an 8x7 matrix to keep track of moves
             
PinDetect right(p5);
PinDetect left(p7);
PinDetect center(p8);
 
int pos = 0; //current position of led in Neopixel index
int row = 0;
int col = 0;
int winmode = 0; //0 means the game is not won, 1-4 are different ways to win

int red = 0xFF0000;
int blue = 0x0000FF;
int color = red;
int winningcolor = 0;

void alloff() //turn off all neopixel at the beginning
{
    for (int i = 0; i < N; i++)
        strip.setPixel(i, 0, 0, 0);
    strip.write();
}

int matrix2index(int r, int c) //convert row,col of matrix to index of neopixel that range from 0 to 63
{
   return (r-1)*8 + c - 1;
}

//when the game is won, flash the neopixels that lead to winning forever until the game is restarted
void display_winner(int mode, int r, int c, int wincolor)
{
    switch (mode)
    {
        case 1:
            while (1)
                {
                   strip.setPixel(matrix2index(r,c), wincolor);
                   strip.setPixel(matrix2index(r,c+1), wincolor);
                   strip.setPixel(matrix2index(r,c+2), wincolor);
                   strip.setPixel(matrix2index(r,c+3), wincolor);
                   strip.write();
                   wait(0.2);
                   strip.setPixel(matrix2index(r,c), 0, 0, 0);
                   strip.setPixel(matrix2index(r,c+1), 0, 0, 0);
                   strip.setPixel(matrix2index(r,c+2), 0, 0, 0);
                   strip.setPixel(matrix2index(r,c+3), 0, 0, 0);
                   strip.write();
                   wait(0.2);
                }
        case 2:
            while (1)
                {
                   strip.setPixel(matrix2index(r,c), wincolor);
                   strip.setPixel(matrix2index(r+1,c), wincolor);
                   strip.setPixel(matrix2index(r+2,c), wincolor);
                   strip.setPixel(matrix2index(r+3,c), wincolor);
                   strip.write();
                   wait(0.2);
                   strip.setPixel(matrix2index(r,c), 0, 0, 0);
                   strip.setPixel(matrix2index(r+1,c), 0, 0, 0);
                   strip.setPixel(matrix2index(r+2,c), 0, 0, 0);
                   strip.setPixel(matrix2index(r+3,c), 0, 0, 0);
                   strip.write();
                   wait(0.2);
                }
        case 3:
            while (1)
                {
                   strip.setPixel(matrix2index(r,c), wincolor);
                   strip.setPixel(matrix2index(r+1,c+1), wincolor);
                   strip.setPixel(matrix2index(r+2,c+2), wincolor);
                   strip.setPixel(matrix2index(r+3,c+3), wincolor);
                   strip.write();
                   wait(0.2);
                   strip.setPixel(matrix2index(r,c), 0, 0, 0);
                   strip.setPixel(matrix2index(r+1,c+1), 0, 0, 0);
                   strip.setPixel(matrix2index(r+2,c+2), 0, 0, 0);
                   strip.setPixel(matrix2index(r+3,c+3), 0, 0, 0);
                   strip.write();
                   wait(0.2);
                }
        case 4:
            while (1)
                {
                   strip.setPixel(matrix2index(r,c), wincolor);
                   strip.setPixel(matrix2index(r+1,c-1), wincolor);
                   strip.setPixel(matrix2index(r+2,c-2), wincolor);
                   strip.setPixel(matrix2index(r+3,c-3), wincolor);
                   strip.write();
                   wait(0.2);
                   strip.setPixel(matrix2index(r,c), 0, 0, 0);
                   strip.setPixel(matrix2index(r+1,c-1), 0, 0, 0);
                   strip.setPixel(matrix2index(r+2,c-2), 0, 0, 0);
                   strip.setPixel(matrix2index(r+3,c-3), 0, 0, 0);
                   strip.write();
                   wait(0.2);
                }
        default:
            break;
    }
}

void check_winner()
{
    //check 4 in a row
    for (int r = 1; r < 9; r++)    
    {
        for (int c = 1; c < 6; c++)
        {
            if (board.getNumber(r,c) != 0 && board.getNumber(r,c) == board.getNumber(r,c+1) && board.getNumber(r,c+1) == board.getNumber(r,c+2) && board.getNumber(r,c+2) == board.getNumber(r,c+3))
            {//have winner
                row = r; col = c; winmode = 1; winningcolor = color;
                return; //avoid the uncessary of continue to check
            }
        }
    }
    //check 4 in a col
    for (int c = 1; c < 9; c++)
    {
        for (int r = 1; r < 6; r++)
        {
            if (board.getNumber(r,c) != 0 && board.getNumber(r,c) == board.getNumber(r+1,c) && board.getNumber(r+1,c) == board.getNumber(r+2,c) && board.getNumber(r+2,c) == board.getNumber(r+3,c))
            {//have winner
                row = r; col = c; winmode = 2; winningcolor = color;
                return;
            }
        }
    }
    //check 4 in a forward diagonal
    for (int r = 3; r < 6; r++)
    {
        for (int c = 1; c < 5; c++)
        {
            if (board.getNumber(r,c) != 0 && board.getNumber(r,c) == board.getNumber(r+1,c+1) && board.getNumber(r+1,c+1) == board.getNumber(r+2,c+2) && board.getNumber(r+2,c+2) == board.getNumber(r+3,c+3))
            {//have winner
                row = r; col = c; winmode = 3; winningcolor = color;
                return;
            }   
        }
    }
    //check 4 in a reverse diagonal
    for (int r = 3; r < 6; r++)
    {
        for (int c = 4; c < 8; c++)
        {
            if (board.getNumber(r,c) != 0 && board.getNumber(r,c) == board.getNumber(r+1,c-1) && board.getNumber(r+1,c-1) == board.getNumber(r+2,c-2) && board.getNumber(r+2,c-2) == board.getNumber(r+3,c-3))
            {//have winner
                row = r; col = c; winmode = 4; winningcolor = color;
                return;
            }   
        }
    }
}

void right_hit_callback (void) { //move to the flashing neopixel to the right
    //led1 = !led1;
    strip.setPixel(pos, 0, 0, 0); //turn off the current neopixel
    if (pos < 6) pos = pos + 1; //move the neopixel to the right if not out of range
}
void left_hit_callback (void) {  //move the flashing neopixel to the left
    //led3 = !led3;
    strip.setPixel(pos, 0, 0, 0);
    if (pos > 0) pos = pos - 1;
}

void center_hit_callback (void) { //drop the coin
    //turn off the flashing neopixel on top row
    strip.setPixel(pos, 0, 0, 0);
    //then coin need to appear at the current column, on the lowest row that not occupied
    col = pos + 1;
    for(row = 8; row > 1; row-- )
    {
        if (board.getNumber(row,col) == 0) break; //break out of loop when found the lowest unoccupied row
    }
    //convert to neopixel index to turn of that neopixel, but only if not all rows in 6x7 board are occupied 
    if (row > 2) strip.setPixel(matrix2index(row,col), color);
    else return;
    //after added LED to that position
    if (color == red)
    {
        board.add( row, col, 1.0);//update matrix to have a matrix to check winner
        check_winner(); //check if the winning move is made
        color = blue; //change player/color
    }
    else
    {
        board.add( row, col, 2.0);
        check_winner();
        color = red;
    }
}

int main() {
   //initialize the matrix to 0 meaning all rows and cols are unoccupied
   board << 0 << 0 << 0 << 0 << 0 << 0 << 0   
         << 0 << 0 << 0 << 0 << 0 << 0 << 0
         << 0 << 0 << 0 << 0 << 0 << 0 << 0
         << 0 << 0 << 0 << 0 << 0 << 0 << 0
         << 0 << 0 << 0 << 0 << 0 << 0 << 0
         << 0 << 0 << 0 << 0 << 0 << 0 << 0
         << 0 << 0 << 0 << 0 << 0 << 0 << 0
         << 0 << 0 << 0 << 0 << 0 << 0 << 0;
             
    // Use internal pullups for pushbutton
    right.mode(PullUp);    
    left.mode(PullUp);    
    center.mode(PullUp); 
    // Delay for initial pullup to take effect
    wait(.05);
    // Setup Interrupt callback functions for a pb hit
    right.attach_deasserted(&right_hit_callback); //used to move coin
    left.attach_deasserted(&left_hit_callback);  //used to move coin
    center.attach_deasserted(&center_hit_callback); //used to drop coin
    // Start sampling pb inputs using interrupts
    right.setSampleFrequency();
    left.setSampleFrequency();
    center.setSampleFrequency();
    wait(.01);
    
    float bright = 0.2; // 20% is plenty for indoor use
    strip.setBrightness(bright);    // set default brightness
    alloff(); //initial all neopixels to off
    
    while(1)
    {
        //winmode is initialized to 0 (not won and the function return)
        //winmode is changed in check_winner
        //need to call display_winner here rather than calling from interrupt fuction because display_winner loop forever if the game is won
        display_winner(winmode,row,col,winningcolor);
        //flashing the current position indicating which col will the disc be dropped at
        strip.setPixel(pos, color);
        strip.write();
        wait(0.2);
        strip.setPixel(pos, 0, 0, 0);
        strip.write();
        wait(0.2);
    }    
}