File content as of revision 3:04ff8cd27dd1:

#include "mbed.h"
#include "N5110.h"
#define DIRECTION_TOLERANCE 0.05


//pins in
N5110 lcd(p7,p8,p9,p10,p11,p13,p26);

// connections for joystick
DigitalIn button(p19);
AnalogIn xPot(p15);
AnalogIn yPot(p16);
//InterruptIn button(p19);
int i;
int j;
int X;
int Y;

int snakeX[100];
int snakeY[100];

// timer to regularly read the joystick
Ticker pollJoystick;
// Serial for debug
Serial serial(USBTX,USBRX);

// create enumerated type (0,1,2,3 etc. for direction)
// could be extended for diagonals etc.
enum DirectionName {
    UP,
    DOWN,
    LEFT,
    RIGHT,
    CENTRE,
    UNKNOWN
};

// struct for Joystick
typedef struct JoyStick Joystick;
struct JoyStick {
    float x;    // current x value
    float x0;   // 'centred' x value
    float y;    // current y value
    float y0;   // 'centred' y value
    int button; // button state (assume pull-down used, so 1 = pressed, 0 = unpressed)
    DirectionName direction;  // current direction
};
// create struct variable
Joystick joystick;

int printFlag = 0;
int nutFlag =1;
//int buttonFlag = 0;
// function prototypes
//void setPixel(int x, int y);
//void clearPixel(int x, int y);


typedef struct Nut Nut;
struct Nut {
    int X;
    int Y;
    int yes;
};
Nut nut;

typedef struct Snake Snake;
struct Snake {
    int snakeX[100];
    int snakeY[100];
    int node;
    int life;
    DirectionName direction;
};
Snake snake;

DirectionName snakeDirection;

void initNut()
{
    nut.X=rand()%84;
    nut.Y=rand()%48;
    //nutFlag=1;
    }
   
void drawNut()
{
    //int X = rand()%84;
    //int Y = rand()%48;
    if(nutFlag==1){
    lcd.drawCircle(nut.X,nut.Y,2,1);
    }
}

void moveSnake()
{
  
    if(joystick.direction == UNKNOWN||joystick.direction == CENTRE){
        snake.snakeX[0]+=1;
    }
    
    else if(joystick.direction != UNKNOWN&&joystick.direction != CENTRE) {

        if(joystick.direction == DOWN&&snake.direction!=LEFT) {
            snake.direction= RIGHT;
            snake.snakeX[0]+=1;
   
        } else if(joystick.direction == UP&&snake.direction!=RIGHT) {
            snake.direction=LEFT;
            snake.snakeX[0]-=1;
        } else if(joystick.direction == LEFT&&snake.direction!=DOWN) {
            snake.direction=DOWN;
            snake.snakeY[0]-=1;
        } else if(joystick.direction == RIGHT&&snake.direction!=UP) {
            snake.direction=UP;
            snake.snakeY[0]+=1;
        }

    }
    
}

void initSnake()
{

    snake.snakeX[0] = 10; //coordinate of head
    snake.snakeY[0] = 10;
    snake.snakeX[1] = 12;
    snake.snakeY[1] = 10;
    snake.snakeX[2] = 14;
    snake.snakeY[2] = 10;
    snake.snakeX[3] = 16;
    snake.snakeY[3] = 10;
    snake.node = 4; //node of snake

}

void drawSnake()
{

    for(i=0; i<snake.node; i++) {

        lcd.drawRect(snake.snakeX[i],snake.snakeY[i],1,1,1);
        //lcd.setPixel(snake.snakeX[i],snake.snakeY[i]);
    }
}

/*
*/

void startGmae()
{
    //lcd.drawRect(snake.snakeX[0]+10,snake.snakeY[0]+10,10,10,1);
    //nutFlag = 1;
    snake.life = 0;
    //snake.direction=LEFT;

    //if(joystick.direction == UNKNOWN)
    //{
    if(snake.snakeX[0]==nut.X && snake.snakeY[0]==nut.Y) { // if snake got nut
        snake.node++;
        nutFlag=0;   // new nut appear
    }
    
    if(nutFlag==0) { //set nut randomly
        nut.X = rand()%83;
        nut.Y = rand()%47;
        nutFlag = 1;
    }


    for(i=3; i<snake.node; i++) { //if snake collide itself snake die
        if(snake.snakeX[i]==snake.snakeX[0] && snake.snakeY[i]==snake.snakeY[0]) {
            snake.life=1;
            // break;
        }
    }

    for(i=snake.node-1; i>0; i--) { //move snake
        snake.snakeX[i]=snake.snakeX[i-1];
        snake.snakeY[i]=snake.snakeY[i-1];
    }

    if(snake.snakeX[0]<1||snake.snakeX[0]>83||snake.snakeY[0]<1||snake.snakeY[0]>47) {
        snake.life=1; // snake collide the corrider snake die
        //break;
    }


    if(snake.life==1) {
        //break;
    }
    
    //}

}


//while(joystick.direction == UNKNOWN) {


//switch(snake.direction)
//{
// case RIGHT:snake.X[0]+=1;
//  break;    
//  case LEFT:snake.X[0]-=1;
//  break;     
//  case UP:snake.Y[0]-=1;
//  break;
//   case DOWN:snake.Y[0]+=1;
//  break;
// }

//end of while(joystick.direction = UNKNOWN)


// if(joystick.direction == UP&&snake.direction!=DOWN) {
//    snake.direction=UP;
// } else if(joystick.direction == RIGHT&&snake.direction!=LEFT) {
//     snake.direction= RIGHT;
// } else if(joystick.direction == LEFT&&snake.direction!=RIGHT) {
//     snake.direction=LEFT;
//  } else(joystick.direction == DOWN&&snake.direction!=UP) {
//     snake.direction=DOWN;
//  }



// read default positions of the joystick to calibrate later readings
void calibrateJoystick()
{
    button.mode(PullDown);
    // must not move during calibration
    joystick.x0 = xPot;  // initial positions in the range 0.0 to 1.0 (0.5 if centred exactly)
    joystick.y0 = yPot;
}


void updateJoystick()
{
    // read current joystick values relative to calibrated values (in range -0.5 to 0.5, 0.0 is centred)
    joystick.x = xPot - joystick.x0;
    joystick.y = yPot - joystick.y0;
    // read button state
    joystick.button = button;

    // calculate direction depending on x,y values
    // tolerance allows a little lee-way in case joystick not exactly in the stated direction
    if ( fabs(joystick.y) < DIRECTION_TOLERANCE && fabs(joystick.x) < DIRECTION_TOLERANCE) {
        joystick.direction = CENTRE;
    } else if ( joystick.y > DIRECTION_TOLERANCE && fabs(joystick.x) < DIRECTION_TOLERANCE) {
        joystick.direction = UP;
        //snake.direction = UP;
    } else if ( joystick.y < DIRECTION_TOLERANCE && fabs(joystick.x) < DIRECTION_TOLERANCE) {
        joystick.direction = DOWN;
    } else if ( joystick.x > DIRECTION_TOLERANCE && fabs(joystick.y) < DIRECTION_TOLERANCE) {
        joystick.direction = RIGHT;
    } else if ( joystick.x < DIRECTION_TOLERANCE && fabs(joystick.y) < DIRECTION_TOLERANCE) {
        joystick.direction = LEFT;
    } else {
        joystick.direction = UNKNOWN;
    }
    // set flag for printing
    printFlag = 1;
}

void updateSnake()
{
    // get direction of joystick and update snake
    if (joystick.direction == UP) {
        snake.snakeX[0]--;
        if(snake.snakeY[0]<1) {
            snake.snakeY[0]=1;
        }//will stop at the top edge

    }
    if (joystick.direction == DOWN) {
        snake.snakeX[0]++;
        if(snake.snakeY[0]>43) {
            snake.snakeY[0]=43;
        }//will stop at the bottom edge
    }
    if (joystick.direction == LEFT) {
        snake.snakeY[0]--;
        if(snake.snakeX[0]<1) {
            snake.snakeX[0]=1;
        }//will stop at the left edge

    }
    if (joystick.direction == RIGHT) {
        snake.snakeY[0]++;
        if(snake.snakeX[0]>87) {
            snake.snakeX[0]=87;
        }//will stop at the right edge

    }

}



//main code
int main()
{
    lcd.init();
    lcd.setBrightness(0.5); // put LED backlight on 50%
    lcd.printString("press to start",0,0);
    calibrateJoystick();  // get centred values of joystick
    pollJoystick.attach(&updateJoystick,1.0/10.0);  // read joystick 10 times per second
    lcd.refresh();
    initNut();
    initSnake();

//infinite while loop
    while(1) {
        lcd.clear();
        updateSnake();
        drawSnake();
        drawNut();
        moveSnake();
        startGmae();
        lcd.refresh();
        
        wait(0.1);

    }
    //wait(0.5);
    //if(snake.life==1) {
    // lcd.printString("lost",24,42);
    // break;


}