EE 入门（二） - 使用 ESP32 与 SPI 显示屏绘图、显示图片、跑贪吃蛇

[env:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino
lib_deps =
  bodmer/TFT_eSPI@^2.5.0
  Bodmer/TFT_eWidget@^0.0.5
monitor_speed = 115200
build_flags =
  -Os
  -DCORE_DEBUG_LEVEL=ARDUHAL_LOG_LEVEL_DEBUG
  -DUSER_SETUP_LOADED=1

  ; Define the TFT driver, pins etc here:
  ; 显示屏驱动要对得上
  -DILI9488_DRIVER=1
  # 宽度与高度
  -DTFT_WIDTH=480
  -DTFT_HEIGHT=320
  # SPI 引脚的接线方式，
  -DTFT_MISO=12
  -DTFT_MOSI=13
  # SCLK 在显示屏上对应的引脚可能叫 SCK，是同一个东西
  -DTFT_SCLK=14
  -DTFT_CS=15
  # DC 在显示屏上对应的引脚可能叫 RS 或者 DC/RS，是同一个东西
  -DTFT_DC=4
  -DTFT_RST=2
  # 背光暂时直接接在 3V3 上
  ; -DTFT_BL=27
  # 触摸，暂时不用
  ;-DTOUCH_CS=22
  -DLOAD_GLCD=1
  # 其他配置，保持默认即可
  -DLOAD_FONT2=1
  -DLOAD_FONT4=1
  -DLOAD_FONT6=1
  -DLOAD_FONT7=1
  -DLOAD_FONT8=1
  -DLOAD_GFXFF=1
  -DSMOOTH_FONT=1
  -DSPI_FREQUENCY=27000000

#include <math.h>
#include <stdio.h>
#include <TFT_eSPI.h> // Hardware-specific library

#define WIDTH 480
#define HEIGHT 320

// 四个方向键对应的 GPIO 引脚
#define BUTTON_UP_PIN     5
#define BUTTON_LEFT_PIN   18
#define BUTTON_DOWN_PIN   19
#define BUTTON_RIGHT_PIN  21

TFT_eSPI tft = TFT_eSPI(); // Invoke custom library

typedef struct Position // 坐标结构
{
  int x;
  int y;
} Pos;

Pos SNAKE[3000] = {0};
Pos DIRECTION;
Pos EGG;
long SNAKE_LEN;

void setup()
{
  Serial.begin(115200);
  tft.begin();
  tft.setRotation(1); // landscape

  tft.fillScreen(TFT_BLACK);
  // Swap the colour byte order when rendering
  tft.setSwapBytes(true);

  // initialize the pushbutton pin as an input: the default state is LOW
  pinMode(BUTTON_UP_PIN, INPUT);
  pinMode(BUTTON_LEFT_PIN, INPUT);
  pinMode(BUTTON_DOWN_PIN, INPUT);
  pinMode(BUTTON_RIGHT_PIN, INPUT);

  init_game();
}

void loop()
{
  command(); // 获取按键消息
  move();    // 修改头节点坐标-蛇的移动
  eat_egg();
  draw(); // 作图
  eat_self();
  delay(100);
}

void init_game() {
  // 初始化小蛇
  SNAKE_LEN = 1;
  SNAKE[0].x =  random(50, WIDTH - 50); // 头节点位置随机化
  SNAKE[0].y =  random(50, HEIGHT - 50);
  DIRECTION.x = pow(-1, random()); // 初始化方向向量
  DIRECTION.y = 0;
  creat_egg();

  Serial.println("GAM STARTED, Having Fun~");
}

void creat_egg()
{
  while (true)
  {
    int ok = 0;
    EGG.x = random(50, WIDTH - 50); // 头节点位置随机化
    EGG.y = random(50, HEIGHT - 50);
    for (int i = 0; i < SNAKE_LEN; i++)
    {
      if (SNAKE[i].x == 0 && SNAKE[i].y == 0)
        continue;
      if (fabs(SNAKE[i].x - EGG.x) <= 10 && fabs(SNAKE[i].y - EGG.y) <= 10)
        ok = -1;
      break;
    }
    if (ok == 0)
      return;
  }
}

void command() // 获取按键命令命令
{
  if (digitalRead(BUTTON_LEFT_PIN) == HIGH) {
      if (DIRECTION.x != 1 || DIRECTION.y != 0)
      { // 如果不是反方向，按键才有效
        Serial.println("Turn Left!");
        DIRECTION.x = -1;
        DIRECTION.y = 0;
      }
  } else if (digitalRead(BUTTON_RIGHT_PIN) == HIGH) {
      if (DIRECTION.x != -1 || DIRECTION.y != 0)
      {
        Serial.println("Turn Right!");
        DIRECTION.x = 1;
        DIRECTION.y = 0;
      }
  } else if (digitalRead(BUTTON_UP_PIN) == HIGH) {
      if (DIRECTION.x != 0 || DIRECTION.y != 1)
      {  // 注意 Y 轴，向上是负轴，因为屏幕左上角是原点 (0,0)
        Serial.println("Turn Up!");
        DIRECTION.x = 0;
        DIRECTION.y = -1;
      }
  } else if (digitalRead(BUTTON_DOWN_PIN) == HIGH) {
      if (DIRECTION.x != 0 || DIRECTION.y != -1)
      {
        Serial.println("Turn Down!");
        DIRECTION.x = 0;
        DIRECTION.y = 1;
      }
  }
}

void move() // 修改各节点坐标以达到移动的目的
{
  // 覆盖尾部走过的痕迹
  tft.drawRect(SNAKE[SNAKE_LEN - 1].x - 5, SNAKE[SNAKE_LEN - 1].y - 5, 10, 10, TFT_BLACK);

  for (int i = SNAKE_LEN - 1; i > 0; i--)
  {
    SNAKE[i].x = SNAKE[i - 1].x;
    SNAKE[i].y = SNAKE[i - 1].y;
  }
  SNAKE[0].x += DIRECTION.x * 10; // 每次移动10pix
  SNAKE[0].y += DIRECTION.y * 10;

  if (SNAKE[0].x >= WIDTH) // 如果越界，从另一边出来
    SNAKE[0].x = 0;
  else if (SNAKE[0].x <= 0)
    SNAKE[0].x = WIDTH;
  else if (SNAKE[0].y >= HEIGHT)
    SNAKE[0].y = 0;
  else if (SNAKE[0].y <= 0)
    SNAKE[0].y = HEIGHT;
}

void eat_egg()
{
  if (fabs(SNAKE[0].x - EGG.x) <= 5 && fabs(SNAKE[0].y - EGG.y) <= 5)
  {
    // shade old egg
    tft.drawCircle(EGG.x, EGG.y, 5, TFT_BLACK);
    creat_egg();
    // add snake node
    SNAKE_LEN += 1;
    for (int i = SNAKE_LEN - 1; i > 0; i--)
    {
      SNAKE[i].x = SNAKE[i - 1].x;
      SNAKE[i].y = SNAKE[i - 1].y;
    }
    SNAKE[0].x += DIRECTION.x * 10; // 每次移动10pix
    SNAKE[0].y += DIRECTION.y * 10;
  }
}

void draw() // 画出蛇和食物
{
  for (int i = 0; i < SNAKE_LEN; i++)
  {
    tft.drawRect(SNAKE[i].x - 5, SNAKE[i].y - 5, 10, 10, TFT_BLUE);
  }
  tft.drawCircle(EGG.x, EGG.y, 5, TFT_RED);
}

void eat_self()
{
  if (SNAKE_LEN == 1)
    return;
  for (int i = 1; i < SNAKE_LEN; i++)
    if (fabs(SNAKE[i].x - SNAKE[0].x) <= 5 && fabs(SNAKE[i].y - SNAKE[0].y) <= 5)
    {
      delay(1000);
      tft.setTextColor(TFT_RED, TFT_BLACK);
      tft.drawString("GAME OVER!", 200, 150, 4);
      delay(3000);

      setup();
      break;
    }
}