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#include <conio.h>
#include <stdio.h>
#include <c64.h>
#include <joystick.h>
#include <stdint.h>
struct screen {
unsigned char grid[25][40];
};
enum direction {
UP,
DOWN,
LEFT,
RIGHT,
};
struct player {
char x;
char y;
enum direction dir;
unsigned char joy;
unsigned char prev_joy;
unsigned char next_char;
};
#define SCREEN (*(struct screen*) 0x0400)
#define SCREEN_AT(x, y) (SCREEN.grid[y][x])
#define MAX_PLAYERS 2
#define EMPTY '\x20'
#define PLAYER '\x71'
#define CHR_V '\x42'+128
#define CHR_H '\x43'+128
#define CHR_DR '\xed'+128
#define CHR_RD '\xee'+128
#define CHR_UR '\xf0'+128
#define CHR_RU '\xfd'+128
static void update_player(struct player *p) {
/* has direction been changed? */
if (p->joy == p->prev_joy) {
if (p->dir == DOWN || p->dir == UP) {
p->next_char = CHR_V;
} else if (p->dir == LEFT || p->dir == RIGHT) {
p->next_char = CHR_H;
}
return;
}
if (JOY_UP(p->joy) && p->dir != DOWN) {
switch (p->dir) {
case RIGHT: p->next_char = CHR_RU; break;
case LEFT: p->next_char = CHR_DR; break;
}
p->dir = UP;
} else if (JOY_DOWN(p->joy) && p->dir != UP) {
switch (p->dir) {
case RIGHT: p->next_char = CHR_RD; break;
case LEFT: p->next_char = CHR_UR; break;
}
p->dir = DOWN;
} else if (JOY_LEFT(p->joy) && p->dir != RIGHT) {
switch (p->dir) {
case UP: p->next_char = CHR_RD; break;
case DOWN: p->next_char = CHR_RU; break;
}
p->dir = LEFT;
} else if (JOY_RIGHT(p->joy) && p->dir != LEFT) {
switch (p->dir) {
case UP: p->next_char = CHR_UR; break;
case DOWN: p->next_char = CHR_DR; break;
}
p->dir = RIGHT;
}
p->prev_joy = p->joy;
}
static char move_player(struct player *p) {
int res = 1;
SCREEN_AT(p->x, p->y) = p->next_char;
switch (p->dir) {
case UP: p->y--; break;
case DOWN: p->y++; break;
case LEFT: p->x--; break;
case RIGHT: p->x++; break;
}
if (SCREEN_AT(p->x, p->y) != EMPTY || p->x < 0 || p->x >= 40 || p->y < 0 || p->y >= 25) {
res = 0;
}
SCREEN_AT(p->x, p->y) = PLAYER;
return res;
}
static void play_game(char n_players) {
uint16_t busy_wait = 300;
struct player players[MAX_PLAYERS] = {
{ 5, 12, RIGHT, 0, 0, CHR_H },
{ 35, 12, LEFT, 0, 0, CHR_H },
};
clrscr();
while(1) {
char i;
uint16_t n;
for (i=0; i<n_players; i++) {
if (!move_player(&players[i])) {
return;
}
}
/* "sleep" for a bit, but keep reading joystick changes */
for (n=0; n<busy_wait; n++) {
for (i=0; i<n_players; i++) {
char tmp = joy_read(i);
if (tmp) {
players[i].joy = tmp;
}
}
}
for (i=0; i<n_players; i++) {
update_player(&players[i]);
}
}
}
int main() {
joy_install(joy_static_stddrv);
/* use uppercase character set */
*((unsigned char*)0xD018) = 0x14;
while(1) {
play_game(2);
printf("game over!");
}
}
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