408 lines
9.1 KiB
C
408 lines
9.1 KiB
C
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/*
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* An Astrocade port of the Cosmic Impalas game
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* described in the book
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* "Making 8-bit Arcade Games in C"
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*/
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#include <string.h>
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//#resource "astrocade.inc"
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#include "acbios.h"
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//#link "acbios.s"
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#include "aclib.h"
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//#link "aclib.s"
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#include "acextra.h"
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//#link "acextra.c"
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//#link "hdr_autostart.s"
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//
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// GAME GRAPHICS
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//
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const byte player_bitmap[] =
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{3,14,/*{w:12,h:16,bpp:2,brev:1}*/0x00,0x3C,0x00,0x00,0x18,0x00,0x00,0x3C,0x00,0x00,0x18,0x00,0x04,0x18,0x20,0x0C,0x3C,0x30,0x3C,0x3C,0x3C,0x1F,0xE7,0xF4,0x1F,0x66,0xF4,0x17,0xE7,0xE4,0x17,0xE7,0xE4,0x1C,0x7E,0x34,0x1C,0xFF,0x34,0x3C,0x18,0x3C,0x0C,0x18,0x30,0x04,0x18,0x20};
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const byte bomb_bitmap[] =
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{1,5,/*{w:4,h:5,bpp:2,brev:1}*/0x88,0x55,0x77,0x55,0x88};
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const byte bullet_bitmap[] =
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{1,5,/*{w:4,h:5,bpp:2,brev:1}*/0x14,0x28,0x14,0x14,0x28};
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const byte enemy1_bitmap[] =
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{2,8,/*{w:8,h:8,bpp:2,brev:1}*/0x00,0x00,0x70,0x38,0xF8,0x7C,0xFC,0xFC,0xFE,0xFC,0xFE,0xFF,0xFC,0xFF,0xF8,0x7F,0xF0,0x3F,0x88,0x47,0xF0,0x3F,0xF0,0x3F,0xD0,0x2F,0x8C,0xC7,0x48,0x48,0x80,0x04};
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const byte enemy2_bitmap[] =
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{2,8,/*{w:8,h:8,bpp:2,brev:1}*/0x00,0x00,0x30,0x0C,0x14,0x28,0x2E,0x74,0x08,0x10,0x20,0x04,0xE0,0x07,0xD0,0x0B,0xB0,0x0D,0xB2,0x4D,0x19,0x98,0x8E,0x71,0x82,0x41,0xB1,0x8D,0x59,0x9A,0x4A,0x52};
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const byte enemy3_bitmap[] =
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{2,8,/*{w:8,h:8,bpp:2,brev:1}*/0x00,0x00,0x00,0x00,0x04,0x20,0x05,0xA0,0x05,0xA0,0x25,0xA4,0xA7,0xE5,0xF7,0xEF,0xF7,0xEF,0xFE,0x7F,0xFC,0x3F,0xBC,0x3D,0xE4,0x27,0x20,0x00,0x00,0x00,0x00,0x00};
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const byte enemy4_bitmap[] =
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{2,8,/*{w:8,h:8,bpp:2,brev:1}*/0x00,0x00,0x00,0x00,0xF0,0x0F,0xF8,0x1F,0xD8,0x1B,0xF8,0x1F,0xF8,0x1F,0xF8,0x1F,0xF0,0x0F,0xA8,0x15,0xCC,0x33,0xE8,0x17,0x66,0x66,0x33,0xCC,0x61,0x86,0x40,0x02};
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const byte* const enemy_bitmaps[4] = {
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enemy1_bitmap,
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enemy2_bitmap,
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enemy3_bitmap,
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enemy4_bitmap
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};
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#define COLOR_BUNKER 1
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#define COLOR_GROUND 2
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#define COLOR_SCORE 3
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//
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// GAME CODE
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//
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#define MAXLIVES 5
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#define PLYRHEIGHT 14
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#define ENEMY_SPACING_X 17
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#define ENEMY_SPACING_Y 11
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#define ENEMY_MARCH_X 1
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#define ENEMY_MARCH_Y 2
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typedef struct {
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byte x,y;
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const byte* shape; // need const here
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} Enemy;
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#define MAX_ENEMIES 28
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Enemy enemies[MAX_ENEMIES];
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byte enemy_index;
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byte num_enemies;
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typedef struct {
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int right:1;
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int down:1;
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} MarchMode;
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MarchMode this_mode, next_mode;
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byte attract;
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word score;
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byte lives;
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const byte player_y = VHEIGHT-PLYRHEIGHT-1;
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byte player_x;
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byte bullet_x;
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byte bullet_y;
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byte bomb_x;
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byte bomb_y;
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void draw_lives() {
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byte i;
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byte n = lives;
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byte y = 0;
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byte x = PIXWIDTH-4*6;
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hw_xpand = XPAND_COLORS(0, COLOR_SCORE);
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for (i=0; i<MAXLIVES; i++) {
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draw_char(i<n?'|':' ', x, y, M_MOVE);
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x += 4;
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}
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}
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void draw_score() {
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byte x = 10*8;
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byte y = 0;
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hw_xpand = XPAND_COLORS(0, COLOR_SCORE);
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draw_bcd_word(score, x, y, M_MOVE);
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}
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void draw_bunker(byte x, byte y, byte y2, byte h, byte w) {
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byte i,a=0,b=0;
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for (i=0; i<h; i++) {
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a = y-y2-i*2;
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b = y-i;
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vline(x+i, a, b, M_XOR, COLOR_BUNKER);
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vline(x+h*2+w-i-1, a, b, M_XOR, COLOR_BUNKER);
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}
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for (i=0; i<w; i++) {
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vline(x+h+i, a, b, M_XOR, COLOR_BUNKER);
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}
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}
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void draw_playfield() {
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byte i;
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clrscr();
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draw_string(0, 0, COLOR_SCORE, "PLAYER 1");
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draw_score();
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draw_lives();
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for (i=0; i<PIXWIDTH; i++)
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pixel(i, VHEIGHT-1, COLOR_GROUND, M_OR);
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// TODO: const
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draw_bunker(20, 65, 15, 15, 20);
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draw_bunker(100, 65, 15, 15, 20);
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}
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void add_score(word pts) {
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if (attract) return;
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score = bcd_add(score, pts);
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draw_score();
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}
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void xor_player_derez() {
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byte i,j;
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byte x = player_x+13;
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byte y = player_y+PLYRHEIGHT-1;
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byte* rand = (byte*) &clrscr; // use code as random #'s
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for (j=1; j<=0xf; j++) {
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for (i=0; i<100; i++) {
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signed char xx = x + (*rand++ & 0xf) - 15;
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signed char yy = y - (*rand++ & j);
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pixel(xx, yy, *rand++, M_XOR);
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}
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}
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}
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void destroy_player() {
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xor_player_derez(); // xor derez pattern
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render_sprite(player_bitmap, player_x, VHEIGHT-PLYRHEIGHT, M_XOR); // erase ship via xor
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xor_player_derez(); // xor 2x to erase derez pattern
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player_x = 0xff;
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lives--;
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}
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void init_enemies() {
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byte i,x,y,bm;
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x = 0;
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y = ENEMY_SPACING_Y;
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bm=0;
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for (i=0; i<MAX_ENEMIES; i++) {
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Enemy* e = &enemies[i];
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e->x = x;
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e->y = y;
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e->shape = enemy_bitmaps[bm];
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x += ENEMY_SPACING_X;
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if (x >= PIXWIDTH-ENEMY_SPACING_X*2) {
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x = 0;
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y += ENEMY_SPACING_Y;
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bm++; // TODO: can overflow
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}
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}
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enemy_index = 0;
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num_enemies = MAX_ENEMIES;
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this_mode.right = 1;
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this_mode.down = 0;
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next_mode.right = 1;
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next_mode.down = 0;
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}
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void delete_enemy(Enemy* e) {
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erase_sprite(e->shape, e->x, e->y);
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memmove(e, e+1, sizeof(Enemy)*(enemies-e+MAX_ENEMIES-1));
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num_enemies--; // update_next_enemy() will check enemy_index
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}
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void update_next_enemy() {
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Enemy* e;
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if (enemy_index >= num_enemies) {
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enemy_index = 0;
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memcpy(&this_mode, &next_mode, sizeof(this_mode));
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}
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e = &enemies[enemy_index];
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erase_sprite(e->shape, e->x, e->y);
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if (this_mode.down) {
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e->y += ENEMY_MARCH_Y;
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// if too close to ground, end game
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if (e->y > VHEIGHT-ENEMY_SPACING_Y) {
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destroy_player();
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lives = 0;
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}
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next_mode.down = 0;
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} else {
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if (this_mode.right) {
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e->x += ENEMY_MARCH_X;
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if (e->x >= PIXWIDTH-ENEMY_SPACING_X) {
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next_mode.down = 1;
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next_mode.right = 0;
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}
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} else {
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e->x -= ENEMY_MARCH_X;
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if (e->x == 0) {
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next_mode.down = 1;
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next_mode.right = 1;
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}
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}
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}
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render_sprite(e->shape, e->x, e->y, M_XOR);
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enemy_index++;
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}
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char in_rect(Enemy* e, byte x, byte y, byte w, byte h) {
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byte ew = e->shape[0]*8;
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byte eh = e->shape[1];
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return (x >= e->x-w && x <= e->x+ew && y >= e->y-h && y <= e->y+eh);
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}
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Enemy* find_enemy_at(byte x, byte y) {
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byte i;
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for (i=0; i<num_enemies; i++) {
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Enemy* e = &enemies[i];
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if (in_rect(e, x, y, 0, 2)) {
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return e;
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}
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}
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return NULL;
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}
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void check_bullet_hit(byte x, byte y) {
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Enemy* e = find_enemy_at(x,y);
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if (e) {
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delete_enemy(e);
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add_score(0x25);
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}
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}
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void fire_bullet() {
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bullet_x = player_x + 4;
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bullet_y = VHEIGHT-PLYRHEIGHT-6;
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render_sprite(bullet_bitmap, bullet_x, bullet_y, M_XOR); // draw
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}
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void move_bullet() {
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byte leftover;
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hw_intst; // reset intercept counters
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render_sprite(bullet_bitmap, bullet_x, bullet_y, M_XOR); // erase
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leftover = (hw_intst & 0xf0); // any pixels leftover?
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if (leftover || bullet_y < 10) {
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erase_sprite(bullet_bitmap, bullet_x, bullet_y);
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check_bullet_hit(bullet_x, bullet_y+2);
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bullet_y = 0;
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} else {
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bullet_y -= 4;
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render_sprite(bullet_bitmap, bullet_x, bullet_y, M_XOR); // draw
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}
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}
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void drop_bomb() {
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Enemy* e = &enemies[enemy_index];
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bomb_x = e->x + 7;
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bomb_y = e->y + 16;
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render_sprite(bomb_bitmap, bomb_x, bomb_y, M_XOR);
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}
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void move_bomb() {
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hw_intst; // reset intercept counters
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render_sprite(bomb_bitmap, bomb_x, bomb_y, M_XOR); // erase
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if (bomb_y > VHEIGHT-12) {
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bomb_y = 0;
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} else if (hw_intst & 0xf0) { // any pixels leftover?
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erase_sprite(bomb_bitmap, bomb_x, bomb_y); // erase bunker
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if (bomb_y > VHEIGHT-23) {
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// player was hit (probably)
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destroy_player();
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}
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bomb_y = 0;
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} else {
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bomb_y += 3;
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render_sprite(bomb_bitmap, bomb_x, bomb_y, M_XOR);
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}
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}
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byte frame;
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signed char player_dir = 0;
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void move_player() {
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if (attract) {
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if (bullet_y == 0) fire_bullet();
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player_dir = 0;
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} else {
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byte mask = hw_p1ctrl;
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if (mask & 0x4) {
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if (player_x > 0)
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player_x--;
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}
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if (mask & 0x8) {
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if (player_x < PIXWIDTH-16)
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player_x++;
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}
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if (mask & 0x10) {
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if (bullet_y == 0) {
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fire_bullet();
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}
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}
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}
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// move player
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render_sprite(player_bitmap, player_x, player_y, M_MOVE);
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}
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void play_round() {
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draw_playfield();
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player_x = PIXWIDTH/2-8;
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bullet_y = 0;
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bomb_y = 0;
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frame = 0;
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while (player_x != 0xff && num_enemies) {
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move_player();
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if (bullet_y) {
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move_bullet();
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}
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update_next_enemy();
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if (frame & 1) {
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if (bomb_y == 0) {
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drop_bomb();
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} else {
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move_bomb();
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}
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}
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frame++;
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}
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}
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void init_game() {
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score = 0;
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lives = 5;
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}
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void game_over_msg() {
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byte i;
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byte x=16;
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byte y=10;
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hw_xpand = XPAND_COLORS(0, COLOR_SCORE);
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for (i=0; i<50; i++) {
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draw_string(x, y+0*8, COLOR_SCORE, " *************** ");
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draw_string(x, y+1*8, COLOR_SCORE, "*** ***");
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draw_string(x, y+2*8, COLOR_SCORE, "** GAME OVER **");
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draw_string(x, y+3*8, COLOR_SCORE, "*** ***");
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draw_string(x, y+4*8, COLOR_SCORE, " *************** ");
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}
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}
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void play_game() {
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attract = 0;
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init_game();
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init_enemies();
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while (lives) {
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play_round();
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if (num_enemies == 0) {
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init_enemies();
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}
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}
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game_over_msg();
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}
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void attract_mode() {
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attract = 1;
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while (1) {
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init_enemies();
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play_round();
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}
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}
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void setup_registers() {
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hw_col0r = 0x00;
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hw_col1r = 0x2f;
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hw_col2r = 0xef;
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hw_col3r = 0xaf;
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hw_horcb = 0;
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hw_verbl = VHEIGHT*2;
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}
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void main() {
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setup_registers();
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// NOTE: initializers don't get run, so we init here
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while (1) {
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//attract_mode();
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play_game();
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}
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}
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