mirror of
https://github.com/sehugg/8bitworkshop.git
synced 2024-12-29 11:31:42 +00:00
329 lines
7.7 KiB
C
329 lines
7.7 KiB
C
/*
|
|
A character-based surround-the-opponent game.
|
|
Reads from nametable RAM to determine collisions, and also
|
|
to help the AI avoid walls.
|
|
For more information, see "Making Arcade Games in C".
|
|
*/
|
|
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <nes.h>
|
|
#include <joystick.h>
|
|
|
|
#include "neslib.h"
|
|
|
|
// VRAM buffer module
|
|
#include "vrambuf.h"
|
|
//#link "vrambuf.c"
|
|
|
|
// link the pattern table into CHR ROM
|
|
//#link "chr_generic.s"
|
|
|
|
#define COLS 32
|
|
#define ROWS 27
|
|
|
|
// read a character from VRAM.
|
|
// this is tricky because we have to wait
|
|
// for VSYNC to start, then set the VRAM
|
|
// address to read, then set the VRAM address
|
|
// back to the start of the frame.
|
|
byte getchar(byte x, byte y) {
|
|
// compute VRAM read address
|
|
word addr = NTADR_A(x,y);
|
|
// result goes into rd
|
|
byte rd;
|
|
// wait for VBLANK to start
|
|
ppu_wait_nmi();
|
|
// set vram address and read byte into rd
|
|
vram_adr(addr);
|
|
vram_read(&rd, 1);
|
|
// scroll registers are corrupt
|
|
// fix by setting vram address
|
|
vram_adr(0x0);
|
|
return rd;
|
|
}
|
|
|
|
void cputcxy(byte x, byte y, char ch) {
|
|
vrambuf_put(NTADR_A(x,y), &ch, 1);
|
|
}
|
|
|
|
void cputsxy(byte x, byte y, const char* str) {
|
|
vrambuf_put(NTADR_A(x,y), str, strlen(str));
|
|
}
|
|
|
|
void clrscr() {
|
|
vrambuf_clear();
|
|
ppu_off();
|
|
vram_adr(0x2000);
|
|
vram_fill(0, 32*28);
|
|
vram_adr(0x0);
|
|
ppu_on_bg();
|
|
}
|
|
|
|
////////// GAME DATA
|
|
|
|
typedef struct {
|
|
byte x;
|
|
byte y;
|
|
byte dir;
|
|
word score;
|
|
char head_attr;
|
|
char tail_attr;
|
|
int collided:1;
|
|
int human:1;
|
|
} Player;
|
|
|
|
Player players[2];
|
|
|
|
byte attract;
|
|
byte gameover;
|
|
byte frames_per_move;
|
|
|
|
#define START_SPEED 12
|
|
#define MAX_SPEED 5
|
|
#define MAX_SCORE 7
|
|
|
|
///////////
|
|
|
|
const char BOX_CHARS[8] = { '+','+','+','+','-','-','!','!' };
|
|
|
|
void draw_box(byte x, byte y, byte x2, byte y2, const char* chars) {
|
|
byte x1 = x;
|
|
cputcxy(x, y, chars[2]);
|
|
cputcxy(x2, y, chars[3]);
|
|
cputcxy(x, y2, chars[0]);
|
|
cputcxy(x2, y2, chars[1]);
|
|
while (++x < x2) {
|
|
cputcxy(x, y, chars[5]);
|
|
cputcxy(x, y2, chars[4]);
|
|
}
|
|
while (++y < y2) {
|
|
cputcxy(x1, y, chars[6]);
|
|
cputcxy(x2, y, chars[7]);
|
|
}
|
|
}
|
|
|
|
void draw_playfield() {
|
|
draw_box(1,2,COLS-2,ROWS-1,BOX_CHARS);
|
|
cputcxy(9,1,players[0].score+'0');
|
|
cputcxy(28,1,players[1].score+'0');
|
|
if (attract) {
|
|
cputsxy(3,ROWS-1,"ATTRACT MODE - PRESS ENTER");
|
|
} else {
|
|
cputsxy(1,1,"PLYR1:");
|
|
cputsxy(20,1,"PLYR2:");
|
|
}
|
|
}
|
|
|
|
typedef enum { D_RIGHT, D_DOWN, D_LEFT, D_UP } dir_t;
|
|
const char DIR_X[4] = { 1, 0, -1, 0 };
|
|
const char DIR_Y[4] = { 0, 1, 0, -1 };
|
|
|
|
void init_game() {
|
|
memset(players, 0, sizeof(players));
|
|
players[0].head_attr = '1';
|
|
players[1].head_attr = '2';
|
|
players[0].tail_attr = 0x06;
|
|
players[1].tail_attr = 0x07;
|
|
frames_per_move = START_SPEED;
|
|
}
|
|
|
|
void reset_players() {
|
|
players[0].x = players[0].y = 5;
|
|
players[0].dir = D_RIGHT;
|
|
players[1].x = COLS-6;
|
|
players[1].y = ROWS-6;
|
|
players[1].dir = D_LEFT;
|
|
players[0].collided = players[1].collided = 0;
|
|
}
|
|
|
|
void draw_player(Player* p) {
|
|
cputcxy(p->x, p->y, p->head_attr);
|
|
}
|
|
|
|
void move_player(Player* p) {
|
|
cputcxy(p->x, p->y, p->tail_attr);
|
|
p->x += DIR_X[p->dir];
|
|
p->y += DIR_Y[p->dir];
|
|
if (getchar(p->x, p->y) != 0)
|
|
p->collided = 1;
|
|
draw_player(p);
|
|
}
|
|
|
|
void human_control(Player* p) {
|
|
byte dir = 0xff;
|
|
byte joy;
|
|
joy = joy_read (JOY_1);
|
|
// start game if attract mode
|
|
if (attract && (joy & JOY_START_MASK))
|
|
gameover = 1;
|
|
// do not allow movement unless human player
|
|
if (!p->human) return;
|
|
if (joy & JOY_LEFT_MASK) dir = D_LEFT;
|
|
if (joy & JOY_RIGHT_MASK) dir = D_RIGHT;
|
|
if (joy & JOY_UP_MASK) dir = D_UP;
|
|
if (joy & JOY_DOWN_MASK) dir = D_DOWN;
|
|
// don't let the player reverse
|
|
if (dir < 0x80 && dir != (p->dir ^ 2)) {
|
|
p->dir = dir;
|
|
}
|
|
}
|
|
|
|
byte ai_try_dir(Player* p, dir_t dir, byte shift) {
|
|
byte x,y;
|
|
dir &= 3;
|
|
x = p->x + (DIR_X[dir] << shift);
|
|
y = p->y + (DIR_Y[dir] << shift);
|
|
if (x < COLS && y < ROWS && getchar(x, y) == 0) {
|
|
p->dir = dir;
|
|
return 1;
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
void ai_control(Player* p) {
|
|
dir_t dir;
|
|
if (p->human) return;
|
|
dir = p->dir;
|
|
if (!ai_try_dir(p, dir, 0)) {
|
|
ai_try_dir(p, dir+1, 0);
|
|
ai_try_dir(p, dir-1, 0);
|
|
} else {
|
|
ai_try_dir(p, dir-1, 0) && ai_try_dir(p, dir-1, 1+(rand() & 3));
|
|
ai_try_dir(p, dir+1, 0) && ai_try_dir(p, dir+1, 1+(rand() & 3));
|
|
ai_try_dir(p, dir, rand() & 3);
|
|
}
|
|
}
|
|
|
|
void flash_colliders() {
|
|
byte i;
|
|
// flash players that collided
|
|
for (i=0; i<56; i++) {
|
|
//cv_set_frequency(CV_SOUNDCHANNEL_0, 1000+i*8);
|
|
//cv_set_attenuation(CV_SOUNDCHANNEL_0, i/2);
|
|
if (players[0].collided) players[0].head_attr ^= 0x80;
|
|
if (players[1].collided) players[1].head_attr ^= 0x80;
|
|
vrambuf_flush();
|
|
vrambuf_flush();
|
|
draw_player(&players[0]);
|
|
draw_player(&players[1]);
|
|
}
|
|
//cv_set_attenuation(CV_SOUNDCHANNEL_0, 28);
|
|
}
|
|
|
|
void make_move() {
|
|
byte i;
|
|
for (i=0; i<frames_per_move; i++) {
|
|
human_control(&players[0]);
|
|
vrambuf_flush();
|
|
}
|
|
ai_control(&players[0]);
|
|
ai_control(&players[1]);
|
|
// if players collide, 2nd player gets the point
|
|
move_player(&players[1]);
|
|
move_player(&players[0]);
|
|
}
|
|
|
|
void declare_winner(byte winner) {
|
|
byte i;
|
|
clrscr();
|
|
for (i=0; i<ROWS/2-3; i++) {
|
|
draw_box(i,i,COLS-1-i,ROWS-1-i,BOX_CHARS);
|
|
vrambuf_flush();
|
|
}
|
|
cputsxy(12,10,"WINNER:");
|
|
cputsxy(12,13,"PLAYER ");
|
|
cputcxy(12+7, 13, '1'+winner);
|
|
vrambuf_flush();
|
|
delay(75);
|
|
gameover = 1;
|
|
}
|
|
|
|
#define AE(tl,tr,bl,br) (((tl)<<0)|((tr)<<2)|((bl)<<4)|((br)<<6))
|
|
|
|
// this is attribute table data,
|
|
// each 2 bits defines a color palette
|
|
// for a 16x16 box
|
|
const unsigned char Attrib_Table[0x40]={
|
|
AE(3,3,1,0),AE(3,3,0,0),AE(3,3,0,0),AE(3,3,0,0), AE(2,2,0,0),AE(2,2,0,0),AE(2,2,0,0),AE(2,2,0,1),
|
|
AE(1,0,1,0),AE(0,0,0,0),AE(0,0,0,0),AE(0,0,0,0), AE(0,0,0,0),AE(0,0,0,0),AE(0,0,0,0),AE(0,1,0,1),
|
|
AE(1,0,1,0),AE(0,0,0,0),AE(0,0,0,0),AE(0,0,0,0), AE(0,0,0,0),AE(0,0,0,0),AE(0,0,0,0),AE(0,1,0,1),
|
|
AE(1,0,1,0),AE(0,0,0,0),AE(0,0,0,0),AE(0,0,0,0), AE(0,0,0,0),AE(0,0,0,0),AE(0,0,0,0),AE(0,1,0,1),
|
|
AE(1,0,1,0),AE(0,0,0,0),AE(0,0,0,0),AE(0,0,0,0), AE(0,0,0,0),AE(0,0,0,0),AE(0,0,0,0),AE(0,1,0,1),
|
|
AE(1,0,1,0),AE(0,0,0,0),AE(0,0,0,0),AE(0,0,0,0), AE(0,0,0,0),AE(0,0,0,0),AE(0,0,0,0),AE(0,1,0,1),
|
|
AE(1,0,1,0),AE(0,0,0,0),AE(0,0,0,0),AE(0,0,0,0), AE(0,0,0,0),AE(0,0,0,0),AE(0,0,0,0),AE(0,1,0,1),
|
|
AE(1,1,1,1),AE(1,1,1,1),AE(1,1,1,1),AE(1,1,1,1), AE(1,1,1,1),AE(1,1,1,1),AE(1,1,1,1),AE(1,1,1,1),
|
|
};
|
|
|
|
/*{pal:"nes",layout:"nes"}*/
|
|
const unsigned char Palette_Table[16]={
|
|
0x00,
|
|
0x01,0x28,0x31,0x00,
|
|
0x04,0x24,0x34,0x00,
|
|
0x09,0x29,0x39,0x00,
|
|
0x06,0x26,0x36
|
|
};
|
|
|
|
// put 8x8 grid of palette entries into the PPU
|
|
void setup_attrib_table() {
|
|
vram_adr(0x23c0);
|
|
vram_write(Attrib_Table, 0x40);
|
|
}
|
|
|
|
void setup_palette() {
|
|
int i;
|
|
// only set palette entries 0-15 (background only)
|
|
for (i=0; i<16; i++)
|
|
pal_col(i, Palette_Table[i] ^ attract);
|
|
}
|
|
|
|
void play_round() {
|
|
ppu_off();
|
|
setup_attrib_table();
|
|
setup_palette();
|
|
clrscr();
|
|
draw_playfield();
|
|
reset_players();
|
|
while (1) {
|
|
make_move();
|
|
if (gameover) return; // attract mode -> start
|
|
if (players[0].collided || players[1].collided) break;
|
|
}
|
|
flash_colliders();
|
|
// add scores to players that didn't collide
|
|
if (players[0].collided) players[1].score++;
|
|
if (players[1].collided) players[0].score++;
|
|
// increase speed
|
|
if (frames_per_move > MAX_SPEED) frames_per_move--;
|
|
// game over?
|
|
if (players[0].score != players[1].score) {
|
|
if (players[0].score >= MAX_SCORE)
|
|
declare_winner(0);
|
|
else if (players[1].score >= MAX_SCORE)
|
|
declare_winner(1);
|
|
}
|
|
}
|
|
|
|
void play_game() {
|
|
gameover = 0;
|
|
init_game();
|
|
if (!attract)
|
|
players[0].human = 1;
|
|
while (!gameover) {
|
|
play_round();
|
|
}
|
|
}
|
|
|
|
void main() {
|
|
joy_install (joy_static_stddrv);
|
|
vrambuf_clear();
|
|
set_vram_update(updbuf);
|
|
while (1) {
|
|
attract = 1;
|
|
play_game();
|
|
attract = 0;
|
|
play_game();
|
|
}
|
|
}
|