summaryrefslogtreecommitdiff
path: root/newgrf_engine.c
blob: a07e69d760479597143cf3719f5db020f0b276b0 (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
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
/* $Id$ */

#include "stdafx.h"
#include "openttd.h"
#include "debug.h"
#include "functions.h"
#include "string.h"
#include "strings.h"
#include "engine.h"
#include "newgrf_callbacks.h"
#include "newgrf_engine.h"
#include "sprite.h"
#include "variables.h"
#include "train.h"

// TODO: We don't support cargo-specific wagon overrides. Pretty exotic... ;-) --pasky

typedef struct WagonOverride {
	byte *train_id;
	int trains;
	SpriteGroup *group;
} WagonOverride;

typedef struct WagonOverrides {
	int overrides_count;
	WagonOverride *overrides;
} WagonOverrides;

static WagonOverrides _engine_wagon_overrides[TOTAL_NUM_ENGINES];

void SetWagonOverrideSprites(EngineID engine, SpriteGroup *group, byte *train_id,
	int trains)
{
	WagonOverrides *wos;
	WagonOverride *wo;

	wos = &_engine_wagon_overrides[engine];
	wos->overrides_count++;
	wos->overrides = realloc(wos->overrides,
		wos->overrides_count * sizeof(*wos->overrides));

	wo = &wos->overrides[wos->overrides_count - 1];
	/* FIXME: If we are replacing an override, release original SpriteGroup
	 * to prevent leaks. But first we need to refcount the SpriteGroup.
	 * --pasky */
	wo->group = group;
	wo->trains = trains;
	wo->train_id = malloc(trains);
	memcpy(wo->train_id, train_id, trains);
}

static const SpriteGroup *GetWagonOverrideSpriteSet(EngineID engine, byte overriding_engine)
{
	const WagonOverrides *wos = &_engine_wagon_overrides[engine];
	int i;

	// XXX: This could turn out to be a timesink on profiles. We could
	// always just dedicate 65535 bytes for an [engine][train] trampoline
	// for O(1). Or O(logMlogN) and searching binary tree or smt. like
	// that. --pasky

	for (i = 0; i < wos->overrides_count; i++) {
		const WagonOverride *wo = &wos->overrides[i];
		int j;

		for (j = 0; j < wo->trains; j++) {
			if (wo->train_id[j] == overriding_engine)
				return wo->group;
		}
	}
	return NULL;
}

/**
 * Unload all wagon override sprite groups.
 */
void UnloadWagonOverrides(void)
{
	WagonOverrides *wos;
	WagonOverride *wo;
	EngineID engine;
	int i;

	for (engine = 0; engine < TOTAL_NUM_ENGINES; engine++) {
		wos = &_engine_wagon_overrides[engine];
		for (i = 0; i < wos->overrides_count; i++) {
			wo = &wos->overrides[i];
			wo->group = NULL;
			free(wo->train_id);
		}
		free(wos->overrides);
		wos->overrides_count = 0;
		wos->overrides = NULL;
	}
}

// 0 - 28 are cargos, 29 is default, 30 is the advert (purchase list)
// (It isn't and shouldn't be like this in the GRF files since new cargo types
// may appear in future - however it's more convenient to store it like this in
// memory. --pasky)
static SpriteGroup *engine_custom_sprites[TOTAL_NUM_ENGINES][NUM_GLOBAL_CID];
static uint32 _engine_grf[TOTAL_NUM_ENGINES];

void SetCustomEngineSprites(EngineID engine, byte cargo, SpriteGroup *group)
{
	assert(engine < TOTAL_NUM_ENGINES);
	if (engine_custom_sprites[engine][cargo] != NULL) {
		DEBUG(grf, 6)("SetCustomEngineSprites: engine `%d' cargo `%d' already has group -- replacing.", engine, cargo);
	}
	engine_custom_sprites[engine][cargo] = group;
}

/**
 * Unload all engine sprite groups.
 */
void UnloadCustomEngineSprites(void)
{
	EngineID engine;
	CargoID cargo;

	for (engine = 0; engine < TOTAL_NUM_ENGINES; engine++) {
		for (cargo = 0; cargo < NUM_GLOBAL_CID; cargo++) {
			engine_custom_sprites[engine][cargo] = NULL;
		}
		_engine_grf[engine] = 0;
	}
}

void SetEngineGRF(EngineID engine, uint32 grfid)
{
	assert(engine < TOTAL_NUM_ENGINES);
	_engine_grf[engine] = grfid;
}

uint32 GetEngineGRFID(EngineID engine)
{
	assert(engine < TOTAL_NUM_ENGINES);
	return _engine_grf[engine];
}


static int MapOldSubType(const Vehicle *v)
{
	if (v->type != VEH_Train) return v->subtype;
	if (IsTrainEngine(v)) return 0;
	if (IsFreeWagon(v)) return 4;
	return 2;
}

static int VehicleSpecificProperty(const Vehicle *v, byte var) {
	switch (v->type) {
		case VEH_Train:
			switch (var) {
				case 0x62: return v->u.rail.track;
				case 0x66: return v->u.rail.railtype;
				case 0x73: return v->u.rail.cached_veh_length;
				case 0x74: return v->u.rail.cached_power;
				case 0x75: return v->u.rail.cached_power & 0xFFFFFF;
				case 0x76: return v->u.rail.cached_power & 0xFFFF;
				case 0x77: return v->u.rail.cached_power & 0xFF;
				case 0x7C: return v->first->index;
				case 0x7D: return v->first->index & 0xFF;
			}
			break;

		case VEH_Road:
			switch (var) {
				case 0x62: return v->u.road.state;
				case 0x64: return v->u.road.blocked_ctr;
				case 0x65: return v->u.road.blocked_ctr & 0xFF;
				case 0x66: return v->u.road.overtaking;
				case 0x67: return v->u.road.overtaking_ctr;
				case 0x68: return v->u.road.crashed_ctr;
				case 0x69: return v->u.road.crashed_ctr & 0xFF;
			}
			break;

		case VEH_Aircraft:
			switch (var) {
				// case 0x62: XXX Need to convert from ottd to ttdp state
				case 0x63: return v->u.air.targetairport;
				// case 0x66: XXX
			}
			break;
	}

	DEBUG(grf, 1)("Unhandled vehicle property 0x%02X (var 0x%02X), type 0x%02X", var, var + 0x80, v->type);

	return -1;
}

typedef SpriteGroup *(*resolve_callback)(const SpriteGroup *spritegroup,
	const Vehicle *veh, uint16 callback_info, void *resolve_func); /* XXX data pointer used as function pointer */

static const SpriteGroup* ResolveVehicleSpriteGroup(const SpriteGroup *spritegroup,
	const Vehicle *veh, uint16 callback_info, resolve_callback resolve_func)
{
	if (spritegroup == NULL)
		return NULL;

	//debug("spgt %d", spritegroup->type);
	switch (spritegroup->type) {
		case SGT_REAL:
		case SGT_CALLBACK:
			return spritegroup;

		case SGT_DETERMINISTIC: {
			const DeterministicSpriteGroup *dsg = &spritegroup->g.determ;
			const SpriteGroup *target;
			int value = -1;
			// XXX Temporary support
			byte variable = dsg->adjusts[0].variable;

			//debug("[%p] Having fun resolving variable %x", veh, variable);
			if (variable == 0x0C) {
				/* Callback ID */
				value = callback_info & 0xFF;
			} else if (variable == 0x10) {
				value = (callback_info >> 8) & 0xFF;
			} else if ((variable >> 6) == 0) {
				/* General property */
				value = GetDeterministicSpriteValue(variable);
			} else {
				/* Vehicle-specific property. */

				if (veh == NULL) {
					/* We are in a purchase list of something,
					 * and we are checking for something undefined.
					 * That means we should get the first target
					 * (NOT the default one). */
					if (dsg->num_ranges > 0) {
						target = dsg->ranges[0].group;
					} else {
						target = dsg->default_group;
					}
					return resolve_func(target, NULL, callback_info, resolve_func);
				}

				if (dsg->var_scope == VSG_SCOPE_PARENT) {
					/* First engine in the vehicle chain */
					if (veh->type == VEH_Train)
						veh = GetFirstVehicleInChain(veh);
				}

				if (variable == 0x40 || variable == 0x41) {
					if (veh->type == VEH_Train) {
						const Vehicle *u = GetFirstVehicleInChain(veh);
						byte chain_before = 0, chain_after = 0;

						while (u != veh) {
							chain_before++;
							if (variable == 0x41 && u->engine_type != veh->engine_type)
								chain_before = 0;
							u = u->next;
						}
						while (u->next != NULL && (variable == 0x40 || u->next->engine_type == veh->engine_type)) {
							chain_after++;
							u = u->next;
						};

						value = chain_before | chain_after << 8
						        | (chain_before + chain_after) << 16;
					} else {
						value = 1; /* 1 vehicle in the chain */
					}

				} else {
					// TTDPatch runs on little-endian arch;
					// Variable is 0x80 + offset in TTD's vehicle structure
					switch (variable - 0x80) {
#define veh_prop(id_, value_) case (id_): value = (value_); break
						veh_prop(0x00, veh->type);
						veh_prop(0x01, MapOldSubType(veh));
						veh_prop(0x04, veh->index);
						veh_prop(0x05, veh->index & 0xFF);
						/* XXX? Is THIS right? */
						veh_prop(0x0A, PackOrder(&veh->current_order));
						veh_prop(0x0B, PackOrder(&veh->current_order) & 0xff);
						veh_prop(0x0C, veh->num_orders);
						veh_prop(0x0D, veh->cur_order_index);
						veh_prop(0x10, veh->load_unload_time_rem);
						veh_prop(0x11, veh->load_unload_time_rem & 0xFF);
						veh_prop(0x12, veh->date_of_last_service);
						veh_prop(0x13, veh->date_of_last_service & 0xFF);
						veh_prop(0x14, veh->service_interval);
						veh_prop(0x15, veh->service_interval & 0xFF);
						veh_prop(0x16, veh->last_station_visited);
						veh_prop(0x17, veh->tick_counter);
						veh_prop(0x18, veh->max_speed);
						veh_prop(0x19, veh->max_speed & 0xFF);
						veh_prop(0x1A, veh->x_pos);
						veh_prop(0x1B, veh->x_pos & 0xFF);
						veh_prop(0x1C, veh->y_pos);
						veh_prop(0x1D, veh->y_pos & 0xFF);
						veh_prop(0x1E, veh->z_pos);
						veh_prop(0x1F, veh->direction);
						veh_prop(0x28, veh->cur_image);
						veh_prop(0x29, veh->cur_image & 0xFF);
						veh_prop(0x32, veh->vehstatus);
						veh_prop(0x33, veh->vehstatus);
						veh_prop(0x34, veh->cur_speed);
						veh_prop(0x35, veh->cur_speed & 0xFF);
						veh_prop(0x36, veh->subspeed);
						veh_prop(0x37, veh->acceleration);
						veh_prop(0x39, veh->cargo_type);
						veh_prop(0x3A, veh->cargo_cap);
						veh_prop(0x3B, veh->cargo_cap & 0xFF);
						veh_prop(0x3C, veh->cargo_count);
						veh_prop(0x3D, veh->cargo_count & 0xFF);
						veh_prop(0x3E, veh->cargo_source); // Probably useless; so what
						veh_prop(0x3F, veh->cargo_days);
						veh_prop(0x40, veh->age);
						veh_prop(0x41, veh->age & 0xFF);
						veh_prop(0x42, veh->max_age);
						veh_prop(0x43, veh->max_age & 0xFF);
						veh_prop(0x44, veh->build_year);
						veh_prop(0x45, veh->unitnumber);
						veh_prop(0x46, veh->engine_type);
						veh_prop(0x47, veh->engine_type & 0xFF);
						veh_prop(0x48, veh->spritenum);
						veh_prop(0x49, veh->day_counter);
						veh_prop(0x4A, veh->breakdowns_since_last_service);
						veh_prop(0x4B, veh->breakdown_ctr);
						veh_prop(0x4C, veh->breakdown_delay);
						veh_prop(0x4D, veh->breakdown_chance);
						veh_prop(0x4E, veh->reliability);
						veh_prop(0x4F, veh->reliability & 0xFF);
						veh_prop(0x50, veh->reliability_spd_dec);
						veh_prop(0x51, veh->reliability_spd_dec & 0xFF);
						veh_prop(0x52, veh->profit_this_year);
						veh_prop(0x53, veh->profit_this_year & 0xFFFFFF);
						veh_prop(0x54, veh->profit_this_year & 0xFFFF);
						veh_prop(0x55, veh->profit_this_year & 0xFF);
						veh_prop(0x56, veh->profit_last_year);
						veh_prop(0x57, veh->profit_last_year & 0xFF);
						veh_prop(0x58, veh->profit_last_year);
						veh_prop(0x59, veh->profit_last_year & 0xFF);
						veh_prop(0x5A, veh->next == NULL ? INVALID_VEHICLE : veh->next->index);
						veh_prop(0x5C, veh->value);
						veh_prop(0x5D, veh->value & 0xFFFFFF);
						veh_prop(0x5E, veh->value & 0xFFFF);
						veh_prop(0x5F, veh->value & 0xFF);
						veh_prop(0x60, veh->string_id);
						veh_prop(0x61, veh->string_id & 0xFF);

						veh_prop(0x72, 0); // XXX Refit cycle currently unsupported
						veh_prop(0x7A, veh->random_bits);
						veh_prop(0x7B, veh->waiting_triggers);
#undef veh_prop

						// Handle vehicle specific properties.
						default: value = VehicleSpecificProperty(veh, variable - 0x80); break;
					}
				}
			}

			target = value != -1 ? EvalDeterministicSpriteGroup(dsg, value) : dsg->default_group;
			//debug("Resolved variable %x: %d, %p", dsg->variable, value, callback);
			return resolve_func(target, veh, callback_info, resolve_func);
		}

		case SGT_RANDOMIZED: {
			const RandomizedSpriteGroup *rsg = &spritegroup->g.random;

			if (veh == NULL) {
				/* Purchase list of something. Show the first one. */
				assert(rsg->num_groups > 0);
				//debug("going for %p: %d", rsg->groups[0], rsg->groups[0].type);
				return resolve_func(rsg->groups[0], NULL, callback_info, resolve_func);
			}

			if (rsg->var_scope == VSG_SCOPE_PARENT) {
				/* First engine in the vehicle chain */
				if (veh->type == VEH_Train)
					veh = GetFirstVehicleInChain(veh);
			}

			return resolve_func(EvalRandomizedSpriteGroup(rsg, veh->random_bits), veh, callback_info, resolve_func);
		}

		default:
			error("I don't know how to handle such a spritegroup %d!", spritegroup->type);
			return NULL;
	}
}

static const SpriteGroup *GetVehicleSpriteGroup(EngineID engine, const Vehicle *v)
{
	const SpriteGroup *group;
	CargoID cargo = GC_PURCHASE;

	if (v != NULL) {
		cargo = _global_cargo_id[_opt.landscape][v->cargo_type];
		assert(cargo != GC_INVALID);
	}

	group = engine_custom_sprites[engine][cargo];

	if (v != NULL && v->type == VEH_Train) {
		const SpriteGroup *overset = GetWagonOverrideSpriteSet(engine, v->u.rail.first_engine);

		if (overset != NULL) group = overset;
	}

	return group;
}

int GetCustomEngineSprite(EngineID engine, const Vehicle* v, Direction direction)
{
	const SpriteGroup *group;
	const RealSpriteGroup *rsg;
	CargoID cargo = GC_PURCHASE;
	byte loaded = 0;
	bool in_motion = 0;
	int totalsets, spriteset;

	if (v != NULL) {
		int capacity = v->cargo_cap;

		cargo = _global_cargo_id[_opt.landscape][v->cargo_type];
		assert(cargo != GC_INVALID);

		if (capacity == 0) capacity = 1;
		loaded = (v->cargo_count * 100) / capacity;

		if (v->type == VEH_Train) {
			in_motion = GetFirstVehicleInChain(v)->current_order.type != OT_LOADING;
		} else {
			in_motion = v->current_order.type != OT_LOADING;
		}
	}

	group = GetVehicleSpriteGroup(engine, v);
	group = ResolveVehicleSpriteGroup(group, v, 0, (resolve_callback) ResolveVehicleSpriteGroup);

	if (group == NULL && cargo != GC_DEFAULT) {
		// This group is empty but perhaps there'll be a default one.
		group = ResolveVehicleSpriteGroup(engine_custom_sprites[engine][GC_DEFAULT], v, 0,
		                                (resolve_callback) ResolveVehicleSpriteGroup);
	}

	if (group == NULL)
		return 0;

	assert(group->type == SGT_REAL);
	rsg = &group->g.real;

	// This group is empty. This function users should therefore
	// look up the sprite number in _engine_original_sprites.
	if (rsg->num_loaded == 0 || rsg->num_loading == 0) return 0;

	totalsets = in_motion ? rsg->num_loaded : rsg->num_loading;

	// My aim here is to make it possible to visually determine absolutely
	// empty and totally full vehicles. --pasky
	if (loaded == 100 || totalsets == 1) { // full
		spriteset = totalsets - 1;
	} else if (loaded == 0 || totalsets == 2) { // empty
		spriteset = 0;
	} else { // something inbetween
		spriteset = loaded * (totalsets - 2) / 100 + 1;
		// correct possible rounding errors
		if (!spriteset)
			spriteset = 1;
		else if (spriteset == totalsets - 1)
			spriteset--;
	}

	group = in_motion ? rsg->loaded[spriteset] : rsg->loading[spriteset];
	if (group->type != SGT_RESULT) return 0;

	return group->g.result.sprite + (direction % group->g.result.num_sprites);
}

/**
 * Check if a wagon is currently using a wagon override
 * @param v The wagon to check
 * @return true if it is using an override, false otherwise
 */
bool UsesWagonOverride(const Vehicle* v)
{
	assert(v->type == VEH_Train);
	return GetWagonOverrideSpriteSet(v->engine_type, v->u.rail.first_engine) != NULL;
}

/**
 * Evaluate a newgrf callback for vehicles
 * @param callback The callback to evalute
 * @param param1   First parameter of the callback
 * @param param2   Second parameter of the callback
 * @param engine   Engine type of the vehicle to evaluate the callback for
 * @param vehicle  The vehicle to evaluate the callback for, or NULL if it doesnt exist yet
 * @return The value the callback returned, or CALLBACK_FAILED if it failed
 */
uint16 GetVehicleCallback(byte callback, uint32 param1, uint32 param2, EngineID engine, const Vehicle *v)
{
	const SpriteGroup *group;
	CargoID cargo;
	uint16 callback_info = callback | (param1 << 8); // XXX Temporary conversion between new and old format.

	cargo = (v == NULL) ? GC_PURCHASE : _global_cargo_id[_opt.landscape][v->cargo_type];

	group = engine_custom_sprites[engine][cargo];

	if (v != NULL && v->type == VEH_Train) {
		const SpriteGroup *overset = GetWagonOverrideSpriteSet(engine, v->u.rail.first_engine);

		if (overset != NULL) group = overset;
	}

	group = ResolveVehicleSpriteGroup(group, v, callback_info, (resolve_callback) ResolveVehicleSpriteGroup);

	if ((group == NULL || group->type != SGT_CALLBACK) && cargo != GC_DEFAULT) {
		// This group is empty but perhaps there'll be a default one.
		group = ResolveVehicleSpriteGroup(engine_custom_sprites[engine][GC_DEFAULT], v, callback_info,
		                                (resolve_callback) ResolveVehicleSpriteGroup);
	}

	if (group == NULL || group->type != SGT_CALLBACK)
		return CALLBACK_FAILED;

	return group->g.callback.result;
}



// Global variables are evil, yes, but we would end up with horribly overblown
// calling convention otherwise and this should be 100% reentrant.
static byte _vsg_random_triggers;
static byte _vsg_bits_to_reseed;

static const SpriteGroup *TriggerVehicleSpriteGroup(const SpriteGroup *spritegroup,
	Vehicle *veh, uint16 callback_info, resolve_callback resolve_func)
{
	if (spritegroup == NULL)
		return NULL;

	if (spritegroup->type == SGT_RANDOMIZED) {
		_vsg_bits_to_reseed |= RandomizedSpriteGroupTriggeredBits(
			&spritegroup->g.random,
			_vsg_random_triggers,
			&veh->waiting_triggers
		);
	}

	return ResolveVehicleSpriteGroup(spritegroup, veh, callback_info, resolve_func);
}

static void DoTriggerVehicle(Vehicle *veh, VehicleTrigger trigger, byte base_random_bits, bool first)
{
	const SpriteGroup *group;
	const RealSpriteGroup *rsg;
	byte new_random_bits;

	_vsg_random_triggers = trigger;
	_vsg_bits_to_reseed = 0;
	group = TriggerVehicleSpriteGroup(GetVehicleSpriteGroup(veh->engine_type, veh), veh, 0,
	                                  (resolve_callback) TriggerVehicleSpriteGroup);

	if (group == NULL && veh->cargo_type != GC_DEFAULT) {
		// This group turned out to be empty but perhaps there'll be a default one.
		group = TriggerVehicleSpriteGroup(engine_custom_sprites[veh->engine_type][GC_DEFAULT], veh, 0,
		                                  (resolve_callback) TriggerVehicleSpriteGroup);
	}

	if (group == NULL)
		return;

	assert(group->type == SGT_REAL);
	rsg = &group->g.real;

	new_random_bits = Random();
	veh->random_bits &= ~_vsg_bits_to_reseed;
	veh->random_bits |= (first ? new_random_bits : base_random_bits) & _vsg_bits_to_reseed;

	switch (trigger) {
		case VEHICLE_TRIGGER_NEW_CARGO:
			/* All vehicles in chain get ANY_NEW_CARGO trigger now.
			 * So we call it for the first one and they will recurse. */
			/* Indexing part of vehicle random bits needs to be
			 * same for all triggered vehicles in the chain (to get
			 * all the random-cargo wagons carry the same cargo,
			 * i.e.), so we give them all the NEW_CARGO triggered
			 * vehicle's portion of random bits. */
			assert(first);
			DoTriggerVehicle(GetFirstVehicleInChain(veh), VEHICLE_TRIGGER_ANY_NEW_CARGO, new_random_bits, false);
			break;
		case VEHICLE_TRIGGER_DEPOT:
			/* We now trigger the next vehicle in chain recursively.
			 * The random bits portions may be different for each
			 * vehicle in chain. */
			if (veh->next != NULL)
				DoTriggerVehicle(veh->next, trigger, 0, true);
			break;
		case VEHICLE_TRIGGER_EMPTY:
			/* We now trigger the next vehicle in chain
			 * recursively.  The random bits portions must be same
			 * for each vehicle in chain, so we give them all
			 * first chained vehicle's portion of random bits. */
			if (veh->next != NULL)
				DoTriggerVehicle(veh->next, trigger, first ? new_random_bits : base_random_bits, false);
			break;
		case VEHICLE_TRIGGER_ANY_NEW_CARGO:
			/* Now pass the trigger recursively to the next vehicle
			 * in chain. */
			assert(!first);
			if (veh->next != NULL)
				DoTriggerVehicle(veh->next, VEHICLE_TRIGGER_ANY_NEW_CARGO, base_random_bits, false);
			break;
	}
}

void TriggerVehicle(Vehicle *veh, VehicleTrigger trigger)
{
	if (trigger == VEHICLE_TRIGGER_DEPOT) {
		// store that the vehicle entered a depot this tick
		VehicleEnteredDepotThisTick(veh);
	}

	DoTriggerVehicle(veh, trigger, 0, true);
}

StringID _engine_custom_names[TOTAL_NUM_ENGINES];

void SetCustomEngineName(EngineID engine, StringID name)
{
	assert(engine < lengthof(_engine_custom_names));
	_engine_custom_names[engine] = name;
}

void UnloadCustomEngineNames(void)
{
	EngineID i;
	for (i = 0; i < TOTAL_NUM_ENGINES; i++) {
		_engine_custom_names[i] = 0;
	}
}

StringID GetCustomEngineName(EngineID engine)
{
	return _engine_custom_names[engine] == 0 ? _engine_name_strings[engine] : _engine_custom_names[engine];
}

// Functions for changing the order of vehicle purchase lists
// This is currently only implemented for rail vehicles.
static EngineID engine_list_order[NUM_TRAIN_ENGINES];

void ResetEngineListOrder(void)
{
	EngineID i;

	for (i = 0; i < NUM_TRAIN_ENGINES; i++)
		engine_list_order[i] = i;
}

EngineID GetRailVehAtPosition(EngineID pos)
{
	return engine_list_order[pos];
}

void AlterRailVehListOrder(EngineID engine, EngineID target)
{
	EngineID i;
	bool moving = false;

	if (engine == target) return;

	// First, remove our ID from the list.
	for (i = 0; i < NUM_TRAIN_ENGINES - 1; i++) {
		if (engine_list_order[i] == engine)
			moving = true;
		if (moving)
			engine_list_order[i] = engine_list_order[i + 1];
	}

	// Now, insert it again, before the target engine.
	for (i = NUM_TRAIN_ENGINES - 1; i > 0; i--) {
		engine_list_order[i] = engine_list_order[i - 1];
		if (engine_list_order[i] == target) {
			engine_list_order[i - 1] = engine;
			break;
		}
	}
}