aboutsummaryrefslogtreecommitdiff
path: root/game/src/game.c
blob: 2fea5a35c1a172c99fc225d2b5d70679490a11e1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
#include <stdint.h>
#include <string.h>

#include "ubox.h"
#include "spman.h"
#include "mplayer.h"
#include "ap.h"

#include "helpers.h"
#include "main.h"

#define LOCAL
#include "game.h"

// generated
#include "map.h"
#include "player.h"
#include "enemy.h"

#define BG_TILE_MAP 0x1800

void init_map_entities()
{
    const uint8_t *m = cur_map;
    uint8_t typ, last = 0;
    uint16_t i;

    // init sprite and patterns
    spman_init();

    // this sets everything to 0, which is useful as
    // entity ET_UNUSED is 0
    memset(entities, 0, sizeof(struct entity) * MAX_ENTITIES);

    // get to the beginning of the entities:
    // map size + 3 bytes of header (the map size and the entities size)
    m += (uint16_t)(m[0] | m[1] << 8) + 3;

    // the entity list ends with 255
    while (*m != 0xff)
    {
        // first byte is type + direction flag on MSB
        // remove MSB
        typ = m[0] & (~DIR_FLAG);

        entities[last].type = typ;
        entities[last].x = m[1];
        entities[last].y = m[2];
        // in the map: param is 1 (int) to look left
        entities[last].dir = m[0] & DIR_FLAG ? DIR_LEFT : DIR_RIGHT;

        switch (typ)
        {
            // can be only one; always first entity
            // because our entities are sorted by type!
            case ET_PLAYER:
                // 3 frames x 2 sprites = 6
                entities[last].pat = spman_alloc_pat(PAT_PLAYER, player_sprite[0], 6, 0);
                spman_alloc_pat(PAT_PLAYER_FLIP, player_sprite[0], 6, 1);
                entities[last].update = update_player;
                break;

            case ET_ENEMY:
                // 3 frames
                entities[last].pat = spman_alloc_pat(PAT_ENEMY, enemy_sprite[0], 3, 0);
                spman_alloc_pat(PAT_ENEMY_FLIP, enemy_sprite[0], 3, 1);
                entities[last].update = update_enemy;
                break;
        }

        // next entity
        last++;

        // all our entities are 3 bytes
        m += 3;
    }

    // count how many batteries are in the map
    batteries = 0;
    for (i = 0; i < MAP_W * MAP_H; ++i)
        if (cur_map_data[i] == BATTERY_TILE)
            batteries++;

}

void draw_map()
{
    // draw the map!
    //
    //  - is not compressed (which limits how many maps we can store)
    //  - our map is just the tile numbers
    //
    // so we do it in one call by coping our map to the background tile map
    // addr in the VDP VRAM
    ubox_wait_vsync();
    ubox_write_vm((uint8_t *)BG_TILE_MAP, MAP_W * MAP_H, cur_map_data);
}

void draw_hud()
{
    uint8_t i;

    put_text(0, 21, "LIVES");

    for (i = 0; i < MAX_LIVES; ++i)
        if (i < lives)
            // our hearts tile
            ubox_put_tile(1 + i, 22, 193);
        else
            ubox_put_tile(1 + i, 22, WHITESPACE_TILE);
}

// x and y in pixels
void erase_battery(uint8_t x, uint8_t y)
{
    uint8_t t;
    int8_t mod;

    // find out the bg tile to use

    // border of the map
    if ((x >> 3) == 0)
        mod = 1;
    else
        mod = -1;

    switch (cur_map_data[mod + (x >> 3) + (y >> 3) * MAP_W])
    {
        case 12:
            t = 13;
            break;
        case 13:
            t = 12;
            break;
        default:
            // this is next to a wall
            if (mod == 1)
                t = 13;
            else
                t = 12;
            break;
    }

    // change the map data so we don't pick it up again
    cur_map_data[(x >> 3) + (y >> 3) * MAP_W] = t;

    // erase on the screen
    ubox_put_tile(x >> 3, y >> 3, t);
    ubox_put_tile(x >> 3, (y >> 3) - 1, t);
}

// x and y in pixels
uint8_t is_map_blocked(uint8_t x, uint8_t y)
{
    return cur_map_data[(x >> 3) + (y >> 3) * MAP_W] < LAST_SOLID_TILE + 1;
}

// x and y in pixels
uint8_t is_map_battery(uint8_t x, uint8_t y)
{
    return cur_map_data[(x >> 3) + (y >> 3) * MAP_W] == BATTERY_TILE;
}

// x and y in pixels; always check the bottom tile!
uint8_t is_map_elevator_down(uint8_t x, uint8_t y)
{
    uint8_t t = cur_map_data[(x >> 3) + (y >> 3) * MAP_W];

    // first check the elevator platform comparing tiles
    if (t != 9 && t != 10)
        return 0;

    // then check the elevator tube comparing tiles
    t = cur_map_data[(x >> 3) + ((y >> 3) - 1) * MAP_W];
    return (t != 14 && t != 15);
}

// x and y in pixels; always check the bottom tile!
uint8_t is_map_elevator_up(uint8_t x, uint8_t y)
{
    uint8_t t = cur_map_data[(x >> 3) + (y >> 3) * MAP_W];

    // first check the elevator platform comparing tiles
    if (t != 9 && t != 10)
        return 0;

    // then check the elevator tube comparing tiles
    t = cur_map_data[(x >> 3) + ((y >> 3) - 1) * MAP_W];
    return (t == 14 || t == 15);
}

void update_enemy()
{
    // check for the player; if alive and not invulnerable!
    // we use small hit boxes
    if (lives && !invuln
            && entities[0].x + 6 < self->x + 10 && self->x + 6 < entities[0].x + 10
            && self->y == entities[0].y)
    {
        // change direction
        self->dir ^= 1;

        // remove one life (is more like "hits")
        lives--;
        draw_hud();
        invuln = INVUL_TIME;

        if (!lives)
        {
            // different sound effects if is game over
            mplayer_init(SONG, SONG_SILENCE);
            mplayer_play_effect_p(EFX_DEAD, EFX_CHAN_NO, 0);
            gameover_delay = GAMEOVER_DELAY;
        }
        else
            mplayer_play_effect_p(EFX_HIT, EFX_CHAN_NO, 0);
    }

    // left or right?
    if (self->dir)
    {
        // change direction
        if (self->x == 2 || is_map_blocked(self->x, self->y + 15))
            self->dir ^= 1;
        else
            self->x -= 1;
    }
    else
    {
        // change direction
        if (self->x == 255 - 16 || is_map_blocked(self->x + 15, self->y + 15))
            self->dir ^= 1;
        else
            self->x += 1;
    }

    // update the walking animation
    if (self->delay++ == FRAME_WAIT)
    {
        self->delay = 0;
        if (++self->frame == WALK_CYCLE)
            self->frame = 0;
    }

    // allocate the sprites
    sp.x = self->x;
    // y on the screen starts in 255
    sp.y = self->y - 1;
    // find which pattern to show
    sp.pattern = self->pat + (walk_frames[self->frame] + self->dir * 3) * 4;
    // red
    sp.attr = 9;
    spman_alloc_sprite(&sp);
}

void update_player()
{
    // to know if we need to update the walk animation
    uint8_t moved = 0;

    // player is dead
    if (!lives)
        return;

    // decrease counter if set
    if (invuln)
        invuln--;

    if (control & UBOX_MSX_CTL_RIGHT)
    {
        self->dir = DIR_RIGHT;
        moved = 1;

        // wrap horizontally
        if (self->x == 255 - 16)
            self->x = 0;
        // check if not solid, using bottom right
        else if (!is_map_blocked(self->x + 15, self->y + 15))
            self->x += 2;
    }

    if (control & UBOX_MSX_CTL_LEFT)
    {
        self->dir = DIR_LEFT;
        moved = 1;

        // wrap horizontally
        if (self->x == 2)
            self->x = (uint8_t)(255 - 16);
        // check if not solid, using bottom left
        else if (!is_map_blocked(self->x, self->y + 15))
            self->x -= 2;
    }

    // are we touching a battery?
    // use bottom center
    if (is_map_battery(self->x + 8, self->y + 15))
    {
        mplayer_play_effect_p(EFX_BATTERY, EFX_CHAN_NO, 0);
        batteries--;
        erase_battery(self->x + 8, self->y + 15);
    }

    if (control & UBOX_MSX_CTL_FIRE1)
    {
        // use flags to prevent repeat: the player will
        // have to release fire to use the elevator again
        if (!self->flags)
        {
            self->flags = 1;

            // check elevator down; using bottom middle
            if (is_map_elevator_down(self->x + 8, self->y + 16))
            {
                mplayer_play_effect_p(EFX_ELEVATOR, EFX_CHAN_NO, 0);
                self->y += 8 * 4;
            }
            // then elevator up; using bottom middle
            else if (is_map_elevator_up(self->x + 8, self->y + 16))
            {
                mplayer_play_effect_p(EFX_ELEVATOR, EFX_CHAN_NO, 0);
                self->y -= 8 * 4;
            }
        }
    }
    else
    {
        if (self->flags)
            self->flags = 0;
    }

    // it moved, or at least pushed against a wall
    if (moved)
    {
        // update the walking animation
        if (self->delay++ == FRAME_WAIT)
        {
            self->delay = 0;
            if (++self->frame == WALK_CYCLE)
                self->frame = 0;
        }
    }
    else
    {
        // just stand
        if (self->frame)
        {
            self->frame = 0;
            self->delay = 0;
        }
    }

    // if we are invulnerable, don't draw odd frames
    // and we get a nice blinking effect
    if (invuln & 1)
        return;

    // allocate the player sprites; fixed so they never flicker
    sp.x = self->x;
    // y on the screen starts in 255
    sp.y = self->y - 1;
    // find which pattern to show
    sp.pattern = self->pat + (walk_frames[self->frame] + self->dir * 3) * 8;
    // green
    sp.attr = 12;
    spman_alloc_fixed_sprite(&sp);
    // second one is 4 patterns away (16x16 sprites)
    sp.pattern += 4;
    // white
    sp.attr = 15;
    spman_alloc_fixed_sprite(&sp);
}

void run_game()
{
    uint8_t i;

    // init some variables; look at game.h for description
    lives = MAX_LIVES;
    invuln = 0;
    gameover_delay = 0;

    ubox_disable_screen();

    ubox_fill_screen(WHITESPACE_TILE);

    // we only have one map, select it
    cur_map = map[0];
    // uncompress map data into RAM, we will modify it
    // map data starts on byte 3 (skip map data size and entities size)
    ap_uncompress(cur_map_data, cur_map + 3);

    // init entities before drawing
    init_map_entities();
    draw_map();

    draw_hud();

    ubox_enable_screen();

    mplayer_init(SONG, SONG_IN_GAME);

    // our game loop
    while (1)
    {
        // exit the game
        if (ubox_read_keys(7) == UBOX_MSX_KEY_ESC)
            break;

        // game completed!
        if (!batteries)
            break;

        // we are in the gameover delay
        if (gameover_delay)
        {
            // if finished, exit
            if (--gameover_delay == 0)
                break;
        }

        // read the selected control
        control = ubox_read_ctl(ctl);

        // update all the entities:
        // - self is a pointer to THIS entity
        // - because we don't create/destroy entities dynamically
        //   when we found one that is unused we are done
        for (i = 0, self = entities; i < MAX_ENTITIES && self->type; i++, self++)
            self->update();

        // ensure we wait to our desired update rate
        ubox_wait();
        // update sprites on screen
        spman_update();
    }

    // stop the in game music
    mplayer_init(SONG, SONG_SILENCE);
    // hide all the sprites before going back to the menu
    spman_hide_all_sprites();
}