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8bitworkshop/presets/nes/siegegame.c
2018-07-28 11:01:38 -04:00

287 lines
6.8 KiB
C

#include <stdlib.h>
#include <string.h>
#include <conio.h>
#include <nes.h>
#include <joystick.h>
#include "neslib.h"
//#link "tileset1.c"
extern unsigned char palSprites[16];
extern unsigned char TILESET[8*256];
#define COLS 32
#define ROWS 28
typedef unsigned char byte;
typedef signed char sbyte;
typedef unsigned short word;
// 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 = 0x2020+x+y*32;
byte rd;
// wait for VBLANK to start
waitvsync();
// set VRAM read address in PPU
PPU.vram.address = addr>>8;
PPU.vram.address = addr&0xff;
// read the char from PPUDATA
rd = PPU.vram.data; // discard
rd = PPU.vram.data; // keep this one
// reset the VRAM address to start of frame
PPU.vram.address = 0x00;
PPU.vram.address = 0x00;
// return result
return rd;
}
void vdelay(byte count) {
while (count--) waitvsync();
}
////////// 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 credits = 0;
byte frames_per_move;
#define START_SPEED 12
#define MAX_SPEED 5
#define MAX_SCORE 7
///////////
const char BOX_CHARS[8] = { 17, 8, 20, 18, 11, 11, 14, 14 };
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(0,1,COLS-1,ROWS-1,BOX_CHARS);
cputsxy(0,0,"Plyr1:");
cputsxy(20,0,"Plyr2:");
cputcxy(7,0,players[0].score+'0');
cputcxy(27,0,players[1].score+'0');
}
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 = 1;
players[1].tail_attr = 9;
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) != ' ')
p->collided = 1;
draw_player(p);
}
void human_control(Player* p) {
byte dir = 0xff;
byte joy;
if (!p->human) return;
joy = joy_read (JOY_1);
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) == ' ') {
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);
}
}
byte gameover;
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;
vdelay(2);
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]);
vdelay(1);
}
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);
vdelay(1);
}
cputsxy(12,10,"WINNER:");
cputsxy(12,13,"PLAYER ");
cputcxy(12+7, 13, '1'+winner);
vdelay(75);
gameover = 1;
}
#define AE(a,b,c,d) (((a)<<0)|((b)<<2)|((c)<<4)|((d)<<6))
// this is attribute table data,
// each 2 bits defines a color palette
// for a 16x16 box
const unsigned char Attrib_Table[0x40]={
AE(3,3,1,1),AE(3,3,1,1),AE(3,3,1,1),AE(3,3,1,1), AE(2,2,1,1),AE(2,2,1,1),AE(2,2,1,1),AE(2,2,1,1),
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),
};
// put 8x8 grid of palette entries into the PPU
void setup_attrib_table() {
byte index;
waitvsync(); // wait for VBLANK
PPU.vram.address = 0x23;
PPU.vram.address = 0xc0;
for( index = 0; index < 0x40; ++index ){
PPU.vram.data = Attrib_Table[index];
}
}
void play_round() {
reset_players();
clrscr();
setup_attrib_table();
draw_playfield();
while (1) {
make_move();
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();
players[0].human = 1;
while (!gameover) {
play_round();
}
}
void main() {
vram_write((unsigned char*)TILESET, 0x0, sizeof(TILESET));
joy_install (joy_static_stddrv);
play_game();
}