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Optimize for speed
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- only iterate once over body per loop()
- set pixel immediately when snake is moved
- check for collision with body immediately when snake is moved
- remove redundant checks for head out of matrix and full matrix
- use bitmap to see if orb is placed on a free pixel
- remove all debug output to serial monitor
- remove redundant code
- pause game during crash animation
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@lmoellendorf
lmoellendorf committed Mar 16, 2024
1 parent d53922c commit 9eafa0f
Showing 1 changed file with 64 additions and 137 deletions.
201 changes: 64 additions & 137 deletions examples/me_led_matrix_snake/me_led_matrix_snake.ino
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Original file line number Diff line number Diff line change
Expand Up @@ -10,12 +10,6 @@ enum direction {
RIGHT = KEY_2,
};

enum states {
MOVE,
GROW,
CRASH,
};

const int max_body_len = MATRIX_HEIGHT * MATRIX_WIDTH;

struct pixel {
Expand All @@ -31,27 +25,23 @@ struct snake {
Me4Button button = Me4Button(PORT_9);
MeLEDMatrix matrix = MeLEDMatrix(PORT_10);

struct pixel orb = {
.x = -1,
.y = -1,
};

struct pixel orb;
struct snake snake;
uint8_t dir = UP;
uint8_t bitmap[MATRIX_WIDTH] = { 0 };
int state = MOVE;
uint8_t dir = UP;
int crash_counter = 0;
int brightness = Brightness_8;
bool score = false;

void setPixel(int x, int y, size_t len, uint8_t bitmap[]) {
bool setPixel(int x, int y, size_t len, uint8_t bitmap[]) {
if (!bitmap
|| x >= len
|| x < 0
|| y >= MATRIX_HEIGHT
|| y < 0)
return;
return false;
bitmap[x] |= 1 << y;
return true;
}

void resetSnake(void) {
Expand All @@ -60,136 +50,85 @@ void resetSnake(void) {
snake.len = 1;
}

void gameOver() {
crash_counter = 7;
resetSnake();
}
void newOrb() {
/* check if there is room for orb */
if (snake.len >= max_body_len) {
resetSnake();
}

void printOrb() {
Serial.print("Orb: ");
Serial.print(orb.x);
Serial.print(":");
Serial.println(orb.y);
do {
/* add a new orb */
orb.x = random(0, MATRIX_WIDTH);
orb.y = random(0, MATRIX_HEIGHT);
/* check if the orb is below the snake */
} while (bitmap[orb.x] & (1 << orb.y));
}

void printSnakeBody(int x, int y) {
Serial.print("Snake: ");
Serial.print(x);
Serial.print(":");
Serial.println(y);
}
void moveSnake() {
struct pixel head, tail;

head.x = snake.body[0].x;
head.y = snake.body[0].y;
tail.x = snake.body[snake.len - 1].x;
tail.y = snake.body[snake.len - 1].y;

void moveSnake() {
/* move (only the old part of) the snake body into the latest direction */
for (int i = snake.len - 1; i > 0; i--) {
snake.body[i].x = snake.body[i - 1].x;
snake.body[i].y = snake.body[i - 1].y;
}
switch (dir) {
case UP:
Serial.println("UP");
snake.body[0].y++;
head.y++;
break;
case DOWN:
Serial.println("DOWN");
snake.body[0].y--;
head.y--;
break;
case RIGHT:
Serial.println("RIGHT");
snake.body[0].x++;
head.x++;
break;
case LEFT:
Serial.println("LEFT");
snake.body[0].x--;
head.x--;
break;
default:
Serial.println("INVALID");
break;
}
}

bool isCollision() {
/* detect collision with border */
if (snake.body[0].x < 0
|| snake.body[0].x > 15
|| snake.body[0].y < 0
|| snake.body[0].y > 7) {
Serial.println("Snake hit border!");
return true;
}
/* detect collision with snake */
for (int i = 1; i < snake.len; i++) {
if (snake.body[0].x == snake.body[i].x
&& snake.body[0].y == snake.body[i].y) {
Serial.println("Snake hit itself!");
return true;
/* move the snake body */
for (int i = snake.len - 1; i > 0; i--) {
snake.body[i].x = snake.body[i - 1].x;
snake.body[i].y = snake.body[i - 1].y;
/* draw snake body */
setPixel(snake.body[i].x, snake.body[i].y, MATRIX_WIDTH, bitmap);
/* check if head hits the body */
if (head.x == snake.body[i].x && head.y == snake.body[i].y) {
crash_counter = 7;
}
}
return false;
}

bool reachedOrb() {
/* snake head reaches the orb */
if (snake.body[0].x == orb.x && snake.body[0].y == orb.y) {
return true;
}
return false;
}

void growSnake() {
bool orb_placed = false;

score = true;
Serial.print("Snake ate ");
printOrb();
/* append a copy of the last element to the body */
snake.body[snake.len].x = snake.body[snake.len - 1].x;
snake.body[snake.len].y = snake.body[snake.len - 1].y;
snake.len++;
if (snake.len >= max_body_len) {
/* maximum length - reset game! */
if (head.x == orb.x && head.y == orb.y) {
/* append a copy of tail to the body */
snake.body[snake.len].x = tail.x;
snake.body[snake.len].y = tail.y;
snake.len++;
score = true;
resetSnake();
/* draw new snake tail */
setPixel(tail.x, tail.y, MATRIX_WIDTH, bitmap);
newOrb();
}
Serial.print("Snake length: ");
Serial.println(snake.len);
/* add a new orb */
while (!orb_placed) {
orb.x = random(0, MATRIX_WIDTH);
orb.y = random(0, MATRIX_HEIGHT);
orb_placed = true;
/* check if the orb is below the snake */
for (int i = 0; i < snake.len; i++) {
if (snake.body[i].x == orb.x && snake.body[i].y == orb.y)
orb_placed = false;
}
}
Serial.print("New ");
printOrb();
}

void drawMatrix() {
memset(bitmap, 0, MATRIX_WIDTH);
/* draw orb */
setPixel(orb.x, orb.y, MATRIX_WIDTH, bitmap);
/* draw snake */
for (int i = 0; i < snake.len; i++) {
setPixel(snake.body[i].x, snake.body[i].y, MATRIX_WIDTH, bitmap);
printSnakeBody(snake.body[i].x, snake.body[i].y);
/* draw snake head */
if (!setPixel(head.x, head.y, MATRIX_WIDTH, bitmap)) {
/* head hit border */
crash_counter = 7;
}
matrix.drawBitmap(0, 0, MATRIX_WIDTH, bitmap);
snake.body[0].x = head.x;
snake.body[0].y = head.y;
}

void setup() {
resetSnake();
orb.x = random(0, MATRIX_WIDTH);
orb.y = random(0, MATRIX_HEIGHT);
Serial.begin(9600);
newOrb();
matrix.setBrightness(Brightness_8);
}

void loop() {
/* remember the current snake length */
uint8_t key_pressed;

key_pressed = button.pressed();
Expand All @@ -216,14 +155,17 @@ void loop() {
break;
}

if (!(millis() % 300)) {
if (crash_counter > 0) {
if (crash_counter > 0) {
if (!(millis() % 300)) {
matrix.setColorIndex(crash_counter % 2);
matrix.drawBitmap(0, 0, MATRIX_WIDTH, bitmap);
crash_counter--;
return;
if (!crash_counter) {
matrix.setColorIndex(true);
resetSnake();
}
}
matrix.setColorIndex(true);
return;
}

if (!(millis() % 60)) {
Expand All @@ -240,26 +182,11 @@ void loop() {
}

if (!(millis() % 600)) {
printOrb();
switch (state) {
case MOVE:
moveSnake();
if (isCollision())
state = CRASH;
else if (reachedOrb())
state = GROW;
break;

case GROW:
growSnake();
state = MOVE;
break;

case CRASH:
gameOver();
state = MOVE;
break;
}
drawMatrix();
/* clear bitmap */
memset(bitmap, 0, MATRIX_WIDTH);
/* draw orb */
setPixel(orb.x, orb.y, MATRIX_WIDTH, bitmap);
moveSnake();
matrix.drawBitmap(0, 0, MATRIX_WIDTH, bitmap);
}
}

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