/*
	項目名稱：貪吃蛇
	作者：	  微涼秋意
	開發(fā)環(huán)境：VS2022+easyx
*/
#include<time.h>		 //輔助生成隨機(jī)數(shù)種子
#include<stdio.h>		 //C語言標(biāo)準(zhǔn)輸入輸出庫
#include<conio.h>		 //鍵盤輸入
#include<graphics.h>	//easyx圖像庫，提供函數(shù)，繪圖和貼圖
#define MAX_SNAKE 500	//蛇的最大節(jié)數(shù)
#define WIN_WIDTH 640	//游戲窗口的寬度
#define WIN_HEIGHT 480  //游戲窗口的高度

//枚舉
enum Dir
{
	//枚舉，從上往下代表0，1，2，3
	UP,
	DOWN,
	LEFT,
	RIGHT
};
//食物結(jié)構(gòu)體
struct Food
{
	int x;
	int y;
	DWORD color;
	bool flag;	//是否被吃掉，決定是否重新生成
}food;
//蛇每個節(jié)點(diǎn)的位置和顏色
struct P 
{
	int x;
	int y;
	DWORD color;//DWORD是數(shù)據(jù)類型，可包含字符串
};
//設(shè)計蛇的結(jié)構(gòu)體
struct Snake         
{
	int num;	//當(dāng)前節(jié)數(shù)
	int dir;	//方向
	int score;	//得分
	int size;	//蛇的寬和高
	int speed;	//移動速度
	struct P coor[MAX_SNAKE]; //表示每節(jié)蛇的坐標(biāo),數(shù)組表示
}snake;
//初始化游戲函數(shù)
void GameInit()
{
	//設(shè)置隨機(jī)數(shù)種子
	srand((unsigned int)time(NULL));
	snake.num = 3;
	snake.dir = RIGHT;//初識移動方向為右
	snake.score = 0;
	snake.size = 10;
	snake.speed = 10;
	//初始化蛇有三個節(jié)點(diǎn)
	snake.coor[0].x = 320;
	snake.coor[0].y = 240;
	snake.coor[0].color = (RGB(rand()%256, rand() % 256, rand() % 256));//隨機(jī)生成顏色
	snake.coor[1].x = 310;
	snake.coor[1].y = 240;
	snake.coor[1].color = (RGB(rand()%256, rand() % 256, rand() % 256));//隨機(jī)生成顏色
	snake.coor[2].x = 300;
	snake.coor[2].y = 240;
	snake.coor[2].color = (RGB(rand()%256, rand() % 256, rand() % 256));//隨機(jī)生成顏色
	//初始化食物
	food.x = rand() % (WIN_WIDTH/10)*10;//這樣寫的目的是讓食物坐標(biāo)為10的倍數(shù)
	food.y = rand() % (WIN_HEIGHT/10)*10;
	food.color = RGB(rand() % 256, rand() % 256, rand() % 256);//隨機(jī)生成食物顏色
	food.flag = true;
}
//繪制游戲所需資源
void DrawGame()
{
	cleardevice();//刷新窗口
	//繪制蛇
	for (int i = 0; i < snake.num; i++) {
		//設(shè)置圖形填充顏色
		setfillcolor(snake.coor[i].color);
		//畫矩形
		fillrectangle(snake.coor[i].x, snake.coor[i].y, snake.coor[i].x + 10, snake.coor[i].y+10);
	}
	//繪制食物(橢圓)
	if (food.flag) {
		setfillcolor(food.color);
		solidellipse(food.x, food.y, food.x + 10, food.y + 10);
	}
	//繪制分?jǐn)?shù)
	char temp[20] = " ";
	sprintf(temp, "分?jǐn)?shù)：%d", snake.score);
	outtextxy(10, 10, temp);//報錯的話是因為字符集問題
	/*解決方案如下:
	* 1、打開項目屬性，把常規(guī)改為多字節(jié)
	* 2、打開項目屬性，C/C++常規(guī)設(shè)置里把SDL檢查關(guān)掉
	*/
}
//蛇移動
void MoveSnake()
{
	//從尾部開始移動
	for (int i =snake.num-1 ;i > 0;i--) {
		snake.coor[i].x = snake.coor[i - 1].x;
		snake.coor[i].y = snake.coor[i - 1].y;
	}
	switch (snake.dir) {
	case UP:
		snake.coor[0].y -= snake.speed;
		if (snake.coor[0].y < 0) {
			snake.coor[0].y = WIN_HEIGHT;
		}
		break;
	case DOWN:
		snake.coor[0].y += snake.speed;
		if (snake.coor[0].y > WIN_HEIGHT) {
			snake.coor[0].y = 0;
		}
		break;
	case LEFT:
		snake.coor[0].x -= snake.speed;
		if (snake.coor[0].x < 0) {
			snake.coor[0].x = WIN_WIDTH;
		}
		break;
	case RIGHT:
		snake.coor[0].x += snake.speed;
		if (snake.coor[0].x > WIN_WIDTH) {
			snake.coor[0].x = 0;
		}
		break;
	}
}
void GameControl()
{
	//獲取鍵盤輸入，_getch();不回顯函數(shù)：
	char key = _getch();
	
	switch (key)
	{
	//72代表上，80代表下，75代表左，77代表右
	case 72:
		if (snake.dir!=DOWN)//如果正在往下，則不能掉頭往上
		{
			snake.dir = UP;
		}
		break;
	case 80:
		if (snake.dir != UP)//如果正在往上，則不能掉頭往下
		{
			snake.dir = DOWN;
		}
		break;
	case 75:
		if (snake.dir !=RIGHT)//如果正在往右，則不能掉頭往左
		{
			snake.dir = LEFT;
		}
		break;
	case 77:
		if (snake.dir != LEFT)//如果正在往左，則不能掉頭往右
		{
			snake.dir = RIGHT;
		}
		break;
	}
}
//吃食物
void CreatFood()
{
	if (!food.flag) {
		food.x = rand() % (WIN_WIDTH / 10) * 10;//這樣寫的目的是讓食物坐標(biāo)為10的倍數(shù)
		food.y = rand() % (WIN_HEIGHT / 10) * 10;
		food.color = RGB(rand() % 256, rand() % 256, rand() % 256);//隨機(jī)生成食物顏色
		food.flag = true;
	}
}
void EatFood()
{
	//食物存在且坐標(biāo)對應(yīng),吃掉后節(jié)數(shù)加一，食物變?yōu)椴淮嬖?
	if (food.flag && snake.coor[0].x == food.x && snake.coor[0].y == food.y)
	{
		food.flag = false;
		snake.num++;
		snake.score += 10;
		snake.coor[snake.num].color = food.color;
		CreatFood();
	}
}
int main(void)
{
	//1.創(chuàng)建窗口，initgraoh初始化 graphics 圖形窗口
	initgraph(WIN_WIDTH,WIN_HEIGHT);
	setbkcolor(RGB(190,190,190));//設(shè)置顏色
	cleardevice();				 //刷新窗口
	GameInit();				     //調(diào)用初始化

	while (1)
	{
		DrawGame();
		MoveSnake();
		if (_kbhit()) {
			//_kbhit檢測是否有鍵盤輸入
			GameControl();
		}
		EatFood();
		Sleep(75);
	} 
	getchar();//防止閃退
	return 0;
}