arduino shake

shake.c

#include "LedControl.h"

#define FIELD_SIZE 8
#define MAX_LENGTH 16

LedControl lc(12, 10, 11, 1);

typedef struct {
  byte x, y;
} Position;

typedef struct {
  Position pos;
  byte direction; // 0 - up, 1 - right, 2 - bottom, 3 - left
} Head;

Position body[MAX_LENGTH];
byte bodyLength = 1;
byte nextBodyIndex = 0;
Head head = { 1, 1, 0 };
bool gameOver = false;
bool appleVisible = false;
bool appleDeadTicks = 0;
Position applePos;


inline void shift(byte *value, byte max, byte init, byte direction) {
  *value = *value == max ? init : *value + direction;
}

void renderGameOver() {
  int limit = FIELD_SIZE - 1;
  
  for (byte i = 1; i < limit; ++i) {
    lc.setLed(0, i, i, true);
    lc.setLed(0, i, limit - i, true);
  }

  delay(500);
  lc.clearDisplay(0);
  delay(500);
}

inline byte getBodyIndex(byte i) {
  return i <= nextBodyIndex ? nextBodyIndex - i : MAX_LENGTH + nextBodyIndex - i;
}

#define IS_EQUAL(a, b) (a.x == b.x && a.y == b.y)

bool shakeCollided() {
  for (int i = 0; i < bodyLength; ++i) {
    auto v = getBodyIndex(i);
    
    if (IS_EQUAL(head.pos, body[v])) {
      return true;
    }
  }
  
  return false;
}

bool appleEaten() {
  return IS_EQUAL(applePos, head.pos);
}

void generateApple() {
  appleVisible = true;
  
  do {
     applePos.x = random(0, 7);
     applePos.y = random(0, 7);
  } while(IS_EQUAL(applePos, head.pos));
}

void setup() {
  lc.shutdown(0, false);
  lc.setIntensity(0, 5);
  lc.clearDisplay(0);

  Serial.begin(9200);

  generateApple();
}

void loop() {
  if (gameOver) {
    lc.clearDisplay(0);
    renderGameOver();
    return;
  }
  
  auto xAxis = analogRead(A0);
  auto yAxis = analogRead(A1);

  if (xAxis < 400) {
    if (head.direction != 3) head.direction = 1;
  } else if (xAxis > 600) {
    if (head.direction != 1) head.direction = 3;
  } else if (yAxis < 400) {
    if (head.direction != 2) head.direction = 0;
  } else if (yAxis > 600) {
    if (head.direction != 0) head.direction = 2;
  }

  nextBodyIndex = (nextBodyIndex + 1) % MAX_LENGTH;
  body[nextBodyIndex] = head.pos;

  if (head.direction == 0) {
    shift(&head.pos.y, 7, 0, 1);
  } else if (head.direction == 2) {
    shift(&head.pos.y, 0, 7, -1);
  } else if (head.direction == 1) {
    shift(&head.pos.x, 7, 0, 1);
  } else if (head.direction == 3) {
    shift(&head.pos.x, 0, 7, -1);
  }

  if (shakeCollided()) {
    gameOver = true;
    return;
  }

  if (appleEaten()) {
    appleVisible = false;
    appleDeadTicks = 3;
    bodyLength += 1;
  }

  if (!appleVisible) {
    if (appleDeadTicks > 0) {
      appleDeadTicks -= 1;
    } else {
      generateApple();
    }
  }
  
  lc.clearDisplay(0);
  lc.setLed(0, head.pos.x, head.pos.y, true);

  if (appleVisible) {
    lc.setLed(0, applePos.x, applePos.y, true);
  }

  for (int i = 0; i < bodyLength; ++i) {
    int v = getBodyIndex(i);
    lc.setLed(0, body[v].x, body[v].y, true); 
  }

  delay(100);
}