贪吃蛇小游戏的几个问题
下面这个代码中1.蛇是如何实现移动的？
2.蛇是如何死的？
3.蛇所吃的食物是怎么生成的？
#include "graphics.h"
#include <stdlib.h>
#define MAP_W 40
#define MAP_H 30
const int GCOLOR[] = {DARKGRAY, GREEN, RED};
int gw, gh;
struct SNAKE {
int dir, head, inc, tail;
int pool[MAP_W* MAP_H];
} game;
inline void drawAt( const int &i ) {
int x = ( i % MAP_W ) * gw, y = ( i / MAP_W ) * gh;
setfillcolor( GCOLOR[game.pool[i] >> 16] );
bar( x, y, x + gw, y + gh );
}
void newFruit( void ) {
int nf;
while ( game.pool[nf = random( MAP_W * MAP_H )] >> 16 );
game.pool[nf] = 0x20000, drawAt( nf );
}
int moveSnake( const int dx, const int dy, const bool u = false ) {
if ( u && dx + ( game.dir & 3 ) == 1 && dy + ( game.dir >> 2 ) == 1 ) return 1;
int nh;
if ( dx && !dy ) {
nh = game.head % MAP_W + dx;
if ( nh < 0 || nh >= MAP_W ) return 0;
nh = game.head + dx;
} else {
nh = game.head / MAP_W + dy;
if ( nh < 0 || nh >= MAP_H ) return 0;
nh = game.head + dy * MAP_W;
}
int s = game.pool[nh] >> 16;
if ( s == 1 ) return 0;
if ( s == 2 ) game.inc += 5, newFruit();
if ( game.inc > 0 ) --game.inc;
else {
game.tail = game.pool[s = game.tail] & 0xffff;
game.pool[s] = 0, drawAt( s );
}
game.pool[game.head] |= nh;
game.pool[game.head = nh] = 0x10000, drawAt( nh );
game.dir = ( dx + 1 ) | ( ( dy + 1 ) << 2 );
return 1;
}
void gameInit( void ) {
int data[] = {6, 0, 2, 0, 0x10000};
memset( game.pool, 0, sizeof( game.pool ) );
memmove( &game, data, sizeof( data ) );
}
void gameScene( void ) {
PIMAGE img = newimage();
getimage(img, "界面.png",600,600);
putimage(0, 0, img);
setfillcolor( GREEN );
bar( 0, 0, gw, gh );
newFruit();
for ( int c = -1; is_run(); delay_fps( 60 ), --c ) {
while ( kbhit() ) {
int key = getch() | 0x20;
if ( key == ( 27 | 0x20 ) ) return;
if ( key == 'a' || key == 'd' ) {
if ( !moveSnake( ( ( key - 'a' ) >> 1 << 1 ) - 1, 0, true ) ) return;
} else if ( key == 's' || key == 'w' ) {
if ( !moveSnake( 0, 1 - ( ( key - 's' ) >> 2 << 1 ), true ) ) return;
}
}
if ( c < 0 ) {
if ( !moveSnake( ( game.dir & 3 ) - 1, ( game.dir >> 2 ) - 1 ) ) return;
c = 20;
}
}
}
int jiemian()
{
initgraph( 600, 600 );
PIMAGE img = newimage();
getimage(img, "界面.png",600,600);
putimage(0, 0, img);
key_msg k = {0};
for ( ; is_run(); delay_fps(120))
{
mouse_msg msg={0};
if (mousemsg())
{
msg = getmouse();
if(msg.is_down()&&msg.x>=50&&msg.x<=200&&msg.y>=350&&msg.y<=460)
{
cleardevice();
delimage(img);
randomize();
gameInit();
gameScene();
}
}
}
}
int main( void ) {
setinitmode( INIT_ANIMATION );
initgraph( 640, 480 );
gw = getwidth() / MAP_W, gh = getheight() / MAP_H;
jiemian();
return 0;
}
