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[nageru] / nageru / scene.cpp
1 #include <assert.h>
2 extern "C" {
3 #include <lauxlib.h>
4 #include <lua.hpp>
5 }
6
7 #ifdef HAVE_CEF
8 #include "cef_capture.h"
9 #endif
10 #include "ffmpeg_capture.h"
11 #include "flags.h"
12 #include "image_input.h"
13 #include "input_state.h"
14 #include "lua_utils.h"
15 #include "scene.h"
16 #include "theme.h"
17
18 using namespace movit;
19 using namespace std;
20
21 bool display(Block *block, lua_State *L, int idx);
22
23 EffectType current_type(const Block *block)
24 {
25         return block->alternatives[block->currently_chosen_alternative]->effect_type;
26 }
27
28 int find_index_of(const Block *block, EffectType val)
29 {
30         for (size_t idx = 0; idx < block->alternatives.size(); ++idx) {
31                 if (block->alternatives[idx]->effect_type == val) {
32                         return idx;
33                 }
34         }
35         return -1;
36 }
37
38 string get_declaration_point(lua_State *L)
39 {
40         lua_Debug ar;
41         lua_getstack(L, 1, &ar);
42         lua_getinfo(L, "nSl", &ar);
43         char buf[256];
44         snprintf(buf, sizeof(buf), "%s:%d", ar.source, ar.currentline);
45         return buf;
46 }
47
48 Scene::Scene(Theme *theme, float aspect_nom, float aspect_denom)
49         : theme(theme), aspect_nom(aspect_nom), aspect_denom(aspect_denom), resource_pool(theme->get_resource_pool()) {}
50
51 size_t Scene::compute_chain_number(bool is_main_chain) const
52 {
53         assert(chains.size() > 0);
54         assert(chains.size() % 2 == 0);
55         bitset<256> disabled = find_disabled_blocks(size_t(-1));
56
57         size_t chain_number = compute_chain_number_for_block(blocks.size() - 1, disabled);
58         assert(chain_number < chains.size() / 2);
59         if (is_main_chain) {
60                 chain_number += chains.size() / 2;
61         }
62         return chain_number;
63 }
64
65 size_t Scene::compute_chain_number_for_block(size_t block_idx, const bitset<256> &disabled) const
66 {
67         Block *block = blocks[block_idx];
68         size_t chain_number;
69
70         size_t currently_chosen_alternative;
71         if (disabled.test(block_idx)) {
72                 // It doesn't matter, so pick the canonical choice
73                 // (this is the only one that is actually instantiated).
74                 currently_chosen_alternative = block->canonical_alternative;
75         } else {
76                 currently_chosen_alternative = block->currently_chosen_alternative;
77         }
78         assert(currently_chosen_alternative < block->alternatives.size());
79
80         if (block_idx == 0) {
81                 assert(block->cardinality_base == 1);
82                 chain_number = currently_chosen_alternative;
83         } else {
84                 chain_number = compute_chain_number_for_block(block_idx - 1, disabled) + block->cardinality_base * currently_chosen_alternative;
85         }
86         return chain_number;
87 }
88
89 bitset<256> Scene::find_disabled_blocks(size_t chain_idx) const
90 {
91         assert(blocks.size() < 256);
92
93         // The find_disabled_blocks() recursion logic needs only one pass by itself,
94         // but the disabler logic is not so smart, so we just run multiple times
95         // until it converges.
96         bitset<256> prev, ret;
97         do {
98                 find_disabled_blocks(chain_idx, blocks.size() - 1, /*currently_disabled=*/false, &ret);
99                 prev = ret;
100
101                 // Propagate DISABLE_IF_OTHER_DISABLED constraints (we can always do this).
102                 for (Block *block : blocks) {
103                         if (ret.test(block->idx)) continue;  // Already disabled.
104
105                         EffectType chosen_type = block->alternatives[block->chosen_alternative(chain_idx)]->effect_type;
106                         if (chosen_type == IDENTITY_EFFECT) {
107                                 ret.set(block->idx);
108                                 continue;
109                         }
110
111                         for (const Block::Disabler &disabler : block->disablers) {
112                                 Block *other = blocks[disabler.block_idx];
113                                 EffectType chosen_type = other->alternatives[other->chosen_alternative(chain_idx)]->effect_type;
114                                 bool other_disabled = ret.test(disabler.block_idx) || chosen_type == IDENTITY_EFFECT;
115                                 if (other_disabled && disabler.condition == Block::Disabler::DISABLE_IF_OTHER_DISABLED) {
116                                         ret.set(block->idx);
117                                         break;
118                                 }
119                         }
120                 }
121
122                 // We cannot propagate DISABLE_IF_OTHER_ENABLED in all cases;
123                 // the problem is that if A is disabled if B is enabled,
124                 // then we cannot disable A unless we actually know for sure
125                 // that B _is_ enabled. (E.g., imagine that B is disabled
126                 // if C is enabled -- we couldn't disable A before we knew if
127                 // C was enabled or not!)
128                 //
129                 // We could probably fix a fair amount of these, but the
130                 // primary use case for DISABLE_IF_OTHER_ENABLED is really
131                 // mutual exclusion; A must be disabled if B is enabled
132                 // _and_ vice versa. These loops cannot be automatically
133                 // resolved; it would depend on what A and B is. Thus,
134                 // we simply declare this kind of constraint to be a promise
135                 // from the user, not something that we'll solve for them.
136         } while (prev != ret);
137         return ret;
138 }
139
140 void Scene::find_disabled_blocks(size_t chain_idx, size_t block_idx, bool currently_disabled, bitset<256> *disabled) const
141 {
142         if (currently_disabled) {
143                 disabled->set(block_idx);
144         }
145         Block *block = blocks[block_idx];
146         EffectType chosen_type = block->alternatives[block->chosen_alternative(chain_idx)]->effect_type;
147         for (size_t input_idx = 0; input_idx < block->inputs.size(); ++input_idx) {
148                 if (chosen_type == IDENTITY_EFFECT && input_idx > 0) {
149                         // Multi-input effect that has been replaced by
150                         // IdentityEffect, so every effect but the first are
151                         // disabled and will not participate in the chain.
152                         find_disabled_blocks(chain_idx, block->inputs[input_idx], /*currently_disabled=*/true, disabled);
153                 } else {
154                         // Just keep on recursing down.
155                         find_disabled_blocks(chain_idx, block->inputs[input_idx], currently_disabled, disabled);
156                 }
157         }
158 }
159
160 bool Scene::is_noncanonical_chain(size_t chain_idx) const
161 {
162         bitset<256> disabled = find_disabled_blocks(chain_idx);
163         assert(blocks.size() < 256);
164         for (size_t block_idx = 0; block_idx < blocks.size(); ++block_idx) {
165                 Block *block = blocks[block_idx];
166                 if (disabled.test(block_idx) && block->chosen_alternative(chain_idx) != block->canonical_alternative) {
167                         return true;
168                 }
169
170                 // Test if we're supposed to be disabled by some other block being enabled;
171                 // the disabled bit mask does not fully capture this.
172                 if (!disabled.test(block_idx)) {
173                         for (const Block::Disabler &disabler : block->disablers) {
174                                 if (disabler.condition == Block::Disabler::DISABLE_IF_OTHER_ENABLED &&
175                                     !disabled.test(disabler.block_idx)) {
176                                         return true;
177                                 }
178                         }
179                 }
180         }
181         return false;
182 }
183
184 int Scene::add_input(lua_State* L)
185 {
186         assert(lua_gettop(L) == 1 || lua_gettop(L) == 2);
187         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
188
189         Block *block = new Block;
190         block->declaration_point = get_declaration_point(L);
191         block->idx = scene->blocks.size();
192         if (lua_gettop(L) == 1) {
193                 // No parameter given, so a flexible input.
194                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR));
195                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR_WITH_DEINTERLACE));
196                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR_PLANAR));
197                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_BGRA));
198                 block->alternatives.emplace_back(new EffectBlueprint(IMAGE_INPUT));
199         } else {
200                 // Input of a given type. We'll specialize it here, plus connect the input as given.
201                 if (lua_isnumber(L, 2)) {
202                         block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR));
203                         block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR_WITH_DEINTERLACE));
204 #ifdef HAVE_CEF
205                 } else if (luaL_testudata(L, 2, "HTMLInput")) {
206                         block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_BGRA));
207 #endif
208                 } else if (luaL_testudata(L, 2, "VideoInput")) {
209                         FFmpegCapture *capture = *(FFmpegCapture **)luaL_checkudata(L, 2, "VideoInput");
210                         if (capture->get_current_pixel_format() == bmusb::PixelFormat_8BitYCbCrPlanar) {
211                                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR_PLANAR));
212                         } else {
213                                 assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
214                                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_BGRA));
215                         }
216                 } else if (luaL_testudata(L, 2, "ImageInput")) {
217                         block->alternatives.emplace_back(new EffectBlueprint(IMAGE_INPUT));
218                 } else {
219                         luaL_error(L, "add_input() called with something that's not a signal (a signal number, a HTML input, or a VideoInput)");
220                 }
221                 bool ok = display(block, L, 2);
222                 assert(ok);
223         }
224         block->is_input = true;
225         scene->blocks.push_back(block);
226
227         return wrap_lua_existing_object_nonowned<Block>(L, "Block", block);
228 }
229
230 void Scene::find_inputs_for_block(lua_State *L, Scene *scene, Block *block)
231 {
232         if (lua_gettop(L) == 2) {
233                 // Implicitly the last added effect.
234                 assert(!scene->blocks.empty());
235                 block->inputs.push_back(scene->blocks.size() - 1);
236                 return;
237         }
238
239         for (int idx = 3; idx <= lua_gettop(L); ++idx) {
240                 Block *input_block = nullptr;
241                 if (luaL_testudata(L, idx, "Block")) {
242                         input_block = *(Block **)luaL_checkudata(L, idx, "Block");
243                 } else {
244                         EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, idx, "EffectBlueprint");
245
246                         // Search through all the blocks to figure out which one contains this effect.
247                         for (Block *block : scene->blocks) {
248                                 if (find(block->alternatives.begin(), block->alternatives.end(), blueprint) != block->alternatives.end()) {
249                                         input_block = block;
250                                         break;
251                                 }
252                         }
253                         if (input_block == nullptr) {
254                                 luaL_error(L, "Input effect in parameter #%d has not been added to this scene", idx - 1);
255                         }
256                 }
257                 block->inputs.push_back(input_block->idx);
258         }
259 }
260
261 int Scene::add_effect(lua_State* L)
262 {
263         assert(lua_gettop(L) >= 2);
264         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
265
266         Block *block = new Block;
267         block->declaration_point = get_declaration_point(L);
268         block->idx = scene->blocks.size();
269
270         if (lua_istable(L, 2)) {
271                 size_t len = lua_objlen(L, 2);
272                 for (size_t i = 0; i < len; ++i) {
273                         lua_rawgeti(L, 2, i + 1);
274                         EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, -1, "EffectBlueprint");
275                         block->alternatives.push_back(blueprint);
276                         lua_settop(L, -2);
277                 }
278         } else {
279                 EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, 2, "EffectBlueprint");
280                 block->alternatives.push_back(blueprint);
281         }
282
283         int identity_index = find_index_of(block, IDENTITY_EFFECT);
284         if (identity_index == -1) {
285                 block->canonical_alternative = 0;
286         } else {
287                 // Pick the IdentityEffect as the canonical alternative, in case it
288                 // helps us disable more stuff.
289                 block->canonical_alternative = identity_index;
290         }
291
292         find_inputs_for_block(L, scene, block);
293         scene->blocks.push_back(block);
294
295         return wrap_lua_existing_object_nonowned<Block>(L, "Block", block);
296 }
297
298 int Scene::add_optional_effect(lua_State* L)
299 {
300         assert(lua_gettop(L) >= 2);
301         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
302
303         Block *block = new Block;
304         block->declaration_point = get_declaration_point(L);
305         block->idx = scene->blocks.size();
306
307         EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, 2, "EffectBlueprint");
308         block->alternatives.push_back(blueprint);
309
310         // An IdentityEffect will be the alternative for when the effect is disabled.
311         block->alternatives.push_back(new EffectBlueprint(IDENTITY_EFFECT));
312
313         block->canonical_alternative = 1;
314
315         find_inputs_for_block(L, scene, block);
316         scene->blocks.push_back(block);
317
318         return wrap_lua_existing_object_nonowned<Block>(L, "Block", block);
319 }
320
321 Effect *Scene::instantiate_effects(const Block *block, size_t chain_idx, Scene::Instantiation *instantiation)
322 {
323         // Find the chosen alternative for this block in this instance.
324         EffectType chosen_type = block->alternatives[block->chosen_alternative(chain_idx)]->effect_type;
325
326         vector<Effect *> inputs;
327         for (size_t input_idx : block->inputs) {
328                 inputs.push_back(instantiate_effects(blocks[input_idx], chain_idx, instantiation));
329
330                 // As a special case, we allow IdentityEffect to take only one input
331                 // even if the other alternative (or alternatives) is multi-input.
332                 // Thus, even if there are more than one inputs, instantiate only
333                 // the first one.
334                 if (chosen_type == IDENTITY_EFFECT) {
335                         break;
336                 }
337         }
338
339         Effect *effect;
340         switch (chosen_type) {
341         case LIVE_INPUT_YCBCR:
342         case LIVE_INPUT_YCBCR_WITH_DEINTERLACE:
343         case LIVE_INPUT_YCBCR_PLANAR:
344         case LIVE_INPUT_BGRA: {
345                 bool deinterlace = (chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
346                 bool override_bounce = !deinterlace;  // For most chains, this will be fine. Reconsider if we see real problems somewhere; it's better than having the user try to understand it.
347                 bmusb::PixelFormat pixel_format;
348                 if (chosen_type == LIVE_INPUT_BGRA) {
349                         pixel_format = bmusb::PixelFormat_8BitBGRA;
350                 } else if (chosen_type == LIVE_INPUT_YCBCR_PLANAR) {
351                         pixel_format = bmusb::PixelFormat_8BitYCbCrPlanar;
352                 } else if (global_flags.ten_bit_input) {
353                         pixel_format = bmusb::PixelFormat_10BitYCbCr;
354                 } else {
355                         pixel_format = bmusb::PixelFormat_8BitYCbCr;
356                 }
357                 LiveInputWrapper *input = new LiveInputWrapper(theme, instantiation->chain.get(), pixel_format, override_bounce, deinterlace, /*user_connectable=*/true);
358                 effect = input->get_effect();  // Adds itself to the chain, so no need to call add_effect().
359                 instantiation->inputs.emplace(block->idx, input);
360                 break;
361         }
362         case IMAGE_INPUT: {
363                 ImageInput *input = new ImageInput;
364                 instantiation->chain->add_input(input);
365                 instantiation->image_inputs.emplace(block->idx, input);
366                 effect = input;
367                 break;
368         }
369         default:
370                 effect = instantiate_effect(instantiation->chain.get(), chosen_type);
371                 instantiation->chain->add_effect(effect, inputs);
372                 break;
373         }
374         instantiation->effects.emplace(block->idx, effect);
375         return effect;
376 }
377
378 int Scene::finalize(lua_State* L)
379 {
380         bool only_one_mode = false;
381         bool chosen_mode = false;
382         if (lua_gettop(L) == 2) {
383                 only_one_mode = true;
384                 chosen_mode = checkbool(L, 2);
385         } else {
386                 assert(lua_gettop(L) == 1);
387         }
388         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
389         Theme *theme = get_theme_updata(L);
390
391         size_t base = 1;
392         for (Block *block : scene->blocks) {
393                 block->cardinality_base = base;
394                 base *= block->alternatives.size();
395         }
396
397         const size_t cardinality = base;
398         size_t real_cardinality = 0;
399         for (size_t chain_idx = 0; chain_idx < cardinality; ++chain_idx) {
400                 if (!scene->is_noncanonical_chain(chain_idx)) {
401                         ++real_cardinality;
402                 }
403         }
404         const size_t total_cardinality = real_cardinality * (only_one_mode ? 1 : 2);
405         if (total_cardinality > 200) {
406                 print_warning(L, "The given Scene will instantiate %zu different versions. This will take a lot of time and RAM to compile; see if you could limit some options by e.g. locking the input type in some cases (by giving a fixed input to add_input()).\n",
407                         total_cardinality);
408         }
409
410         Block *output_block = scene->blocks.back();
411         for (bool is_main_chain : { false, true }) {
412                 for (size_t chain_idx = 0; chain_idx < cardinality; ++chain_idx) {
413                         if ((only_one_mode && is_main_chain != chosen_mode) ||
414                             scene->is_noncanonical_chain(chain_idx)) {
415                                 scene->chains.emplace_back();
416                                 continue;
417                         }
418
419                         Scene::Instantiation instantiation;
420                         instantiation.chain.reset(new EffectChain(scene->aspect_nom, scene->aspect_denom, theme->get_resource_pool()));
421                         scene->instantiate_effects(output_block, chain_idx, &instantiation);
422
423                         add_outputs_and_finalize(instantiation.chain.get(), is_main_chain);
424                         scene->chains.emplace_back(move(instantiation));
425                 }
426         }
427         return 0;
428 }
429
430 std::pair<movit::EffectChain *, std::function<void()>>
431 Scene::get_chain(Theme *theme, lua_State *L, unsigned num, const InputState &input_state)
432 {
433         // For video inputs, pick the right interlaced/progressive version
434         // based on the current state of the signals.
435         InputStateInfo info(input_state);
436         for (Block *block : blocks) {
437                 if (block->is_input && block->signal_type_to_connect == Block::CONNECT_SIGNAL) {
438                         EffectType chosen_type = current_type(block);
439                         assert(chosen_type == LIVE_INPUT_YCBCR || chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
440                         if (info.last_interlaced[block->signal_to_connect]) {
441                                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
442                         } else {
443                                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR);
444                         }
445                 }
446         }
447
448         // Pick out the right chain based on the current selections,
449         // and snapshot all the set variables so that we can set them
450         // in the prepare function even if they're being changed by
451         // the Lua code later.
452         bool is_main_chain = (num == 0);
453         size_t chain_idx = compute_chain_number(is_main_chain);
454         if (is_noncanonical_chain(chain_idx)) {
455                 // This should be due to promise_to_disable_if_enabled(). Find out what
456                 // happened, to give the user some help.
457                 bitset<256> disabled = find_disabled_blocks(chain_idx);
458                 for (size_t block_idx = 0; block_idx < blocks.size(); ++block_idx) {
459                         Block *block = blocks[block_idx];
460                         if (disabled.test(block_idx)) continue;
461                         for (const Block::Disabler &disabler : block->disablers) {
462                                 if (disabler.condition == Block::Disabler::DISABLE_IF_OTHER_ENABLED &&
463                                     !disabled.test(disabler.block_idx)) {
464                                         fprintf(stderr, "Promise declared at %s violated.\n", disabler.declaration_point.c_str());
465                                         abort();
466                                 }
467                         }
468                 }
469                 assert(false);  // Something else happened, seemingly.
470         }
471         const Scene::Instantiation &instantiation = chains[chain_idx];
472         EffectChain *effect_chain = instantiation.chain.get();
473
474         map<LiveInputWrapper *, int> signals_to_connect;
475         map<ImageInput *, string> images_to_select;
476         map<pair<Effect *, string>, int> int_to_set;
477         map<pair<Effect *, string>, float> float_to_set;
478         map<pair<Effect *, string>, array<float, 3>> vec3_to_set;
479         map<pair<Effect *, string>, array<float, 4>> vec4_to_set;
480         for (const auto &index_and_input : instantiation.inputs) {
481                 Block *block = blocks[index_and_input.first];
482                 EffectType chosen_type = current_type(block);
483                 LiveInputWrapper *input = index_and_input.second;
484                 if (chosen_type == LIVE_INPUT_YCBCR ||
485                     chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE ||
486                     chosen_type == LIVE_INPUT_YCBCR_PLANAR ||
487                     chosen_type == LIVE_INPUT_BGRA) {
488                         if (block->signal_type_to_connect == Block::CONNECT_SIGNAL) {
489                                 signals_to_connect.emplace(input, block->signal_to_connect);
490 #ifdef HAVE_CEF
491                         } else if (block->signal_type_to_connect == Block::CONNECT_CEF) {
492                                 signals_to_connect.emplace(input, block->cef_to_connect->get_card_index());
493 #endif
494                         } else if (block->signal_type_to_connect == Block::CONNECT_VIDEO) {
495                                 signals_to_connect.emplace(input, block->video_to_connect->get_card_index());
496                         } else if (block->signal_type_to_connect == Block::CONNECT_NONE) {
497                                 luaL_error(L, "An input in a scene was not connected to anything (forgot to call display())");
498                         } else {
499                                 assert(false);
500                         }
501                 }
502         }
503         for (const auto &index_and_input : instantiation.image_inputs) {
504                 Block *block = blocks[index_and_input.first];
505                 ImageInput *input = index_and_input.second;
506                 if (current_type(block) == IMAGE_INPUT) {
507                         images_to_select.emplace(input, block->pathname);
508                 }
509         }
510         for (const auto &index_and_effect : instantiation.effects) {
511                 Block *block = blocks[index_and_effect.first];
512                 Effect *effect = index_and_effect.second;
513
514                 bool missing_width = (current_type(block) == RESIZE_EFFECT ||
515                         current_type(block) == RESAMPLE_EFFECT ||
516                         current_type(block) == PADDING_EFFECT);
517                 bool missing_height = missing_width;
518
519                 // Get the effects currently set on the block.
520                 if (current_type(block) != IDENTITY_EFFECT) {  // Ignore settings on optional effects.
521                         if (block->int_parameters.count("width") && block->int_parameters["width"] > 0) {
522                                 missing_width = false;
523                         }
524                         if (block->int_parameters.count("height") && block->int_parameters["height"] > 0) {
525                                 missing_height = false;
526                         }
527                         for (const auto &key_and_tuple : block->int_parameters) {
528                                 int_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
529                         }
530                         for (const auto &key_and_tuple : block->float_parameters) {
531                                 float_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
532                         }
533                         for (const auto &key_and_tuple : block->vec3_parameters) {
534                                 vec3_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
535                         }
536                         for (const auto &key_and_tuple : block->vec4_parameters) {
537                                 vec4_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
538                         }
539                 }
540
541                 // Parameters set on the blueprint itself override those that are set for the block,
542                 // so they are set afterwards.
543                 if (!block->alternatives.empty()) {
544                         EffectBlueprint *blueprint = block->alternatives[block->currently_chosen_alternative];
545                         if (blueprint->int_parameters.count("width") && blueprint->int_parameters["width"] > 0) {
546                                 missing_width = false;
547                         }
548                         if (blueprint->int_parameters.count("height") && blueprint->int_parameters["height"] > 0) {
549                                 missing_height = false;
550                         }
551                         for (const auto &key_and_tuple : blueprint->int_parameters) {
552                                 int_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
553                         }
554                         for (const auto &key_and_tuple : blueprint->float_parameters) {
555                                 float_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
556                         }
557                         for (const auto &key_and_tuple : blueprint->vec3_parameters) {
558                                 vec3_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
559                         }
560                         for (const auto &key_and_tuple : blueprint->vec4_parameters) {
561                                 vec4_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
562                         }
563                 }
564
565                 if (missing_width || missing_height) {
566                         fprintf(stderr, "WARNING: Unset or nonpositive width/height for effect declared at %s "
567                                 "when getting scene for signal %u; setting to 1x1 to avoid crash.\n",
568                                 block->declaration_point.c_str(), num);
569                         int_to_set[make_pair(effect, "width")] = 1;
570                         int_to_set[make_pair(effect, "height")] = 1;
571                 }
572         }
573
574         lua_pop(L, 1);
575
576         auto setup_chain = [L, theme, signals_to_connect, images_to_select, int_to_set, float_to_set, vec3_to_set, vec4_to_set, input_state]{
577                 lock_guard<mutex> lock(theme->m);
578
579                 // Set up state, including connecting signals.
580                 for (const auto &input_and_signal : signals_to_connect) {
581                         LiveInputWrapper *input = input_and_signal.first;
582                         input->connect_signal_raw(input_and_signal.second, input_state);
583                 }
584                 for (const auto &input_and_filename : images_to_select) {
585                         input_and_filename.first->switch_image(input_and_filename.second);
586                 }
587                 for (const auto &effect_and_key_and_value : int_to_set) {
588                         Effect *effect = effect_and_key_and_value.first.first;
589                         const string &key = effect_and_key_and_value.first.second;
590                         const int value = effect_and_key_and_value.second;
591                         if (!effect->set_int(key, value)) {
592                                 luaL_error(L, "Effect refused set_int(\"%s\", %d) (invalid key?)", key.c_str(), value);
593                         }
594                 }
595                 for (const auto &effect_and_key_and_value : float_to_set) {
596                         Effect *effect = effect_and_key_and_value.first.first;
597                         const string &key = effect_and_key_and_value.first.second;
598                         const float value = effect_and_key_and_value.second;
599                         if (!effect->set_float(key, value)) {
600                                 luaL_error(L, "Effect refused set_float(\"%s\", %f) (invalid key?)", key.c_str(), value);
601                         }
602                 }
603                 for (const auto &effect_and_key_and_value : vec3_to_set) {
604                         Effect *effect = effect_and_key_and_value.first.first;
605                         const string &key = effect_and_key_and_value.first.second;
606                         const float *value = effect_and_key_and_value.second.data();
607                         if (!effect->set_vec3(key, value)) {
608                                 luaL_error(L, "Effect refused set_vec3(\"%s\", %f, %f, %f) (invalid key?)", key.c_str(),
609                                                 value[0], value[1], value[2]);
610                         }
611                 }
612                 for (const auto &effect_and_key_and_value : vec4_to_set) {
613                         Effect *effect = effect_and_key_and_value.first.first;
614                         const string &key = effect_and_key_and_value.first.second;
615                         const float *value = effect_and_key_and_value.second.data();
616                         if (!effect->set_vec4(key, value)) {
617                                 luaL_error(L, "Effect refused set_vec4(\"%s\", %f, %f, %f, %f) (invalid key?)", key.c_str(),
618                                                 value[0], value[1], value[2], value[3]);
619                         }
620                 }
621         };
622         return make_pair(effect_chain, move(setup_chain));
623 }
624
625 bool display(Block *block, lua_State *L, int idx)
626 {
627         if (lua_isnumber(L, idx)) {
628                 Theme *theme = get_theme_updata(L);
629                 int signal_idx = luaL_checknumber(L, idx);
630                 block->signal_type_to_connect = Block::CONNECT_SIGNAL;
631                 block->signal_to_connect = theme->map_signal(signal_idx);
632                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR);  // Will be changed to deinterlaced at get_chain() time if needed.
633                 return true;
634 #ifdef HAVE_CEF
635         } else if (luaL_testudata(L, idx, "HTMLInput")) {
636                 CEFCapture *capture = *(CEFCapture **)luaL_checkudata(L, idx, "HTMLInput");
637                 block->signal_type_to_connect = Block::CONNECT_CEF;
638                 block->cef_to_connect = capture;
639                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_BGRA);
640                 assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
641                 return true;
642 #endif
643         } else if (luaL_testudata(L, idx, "VideoInput")) {
644                 FFmpegCapture *capture = *(FFmpegCapture **)luaL_checkudata(L, idx, "VideoInput");
645                 block->signal_type_to_connect = Block::CONNECT_VIDEO;
646                 block->video_to_connect = capture;
647                 if (capture->get_current_pixel_format() == bmusb::PixelFormat_8BitYCbCrPlanar) {
648                         block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR_PLANAR);
649                 } else {
650                         assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
651                         block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_BGRA);
652                 }
653                 return true;
654         } else if (luaL_testudata(L, idx, "ImageInput")) {
655                 ImageInput *image = *(ImageInput **)luaL_checkudata(L, idx, "ImageInput");
656                 block->signal_type_to_connect = Block::CONNECT_NONE;
657                 block->currently_chosen_alternative = find_index_of(block, IMAGE_INPUT);
658                 block->pathname = image->get_pathname();
659                 return true;
660         } else {
661                 return false;
662         }
663 }
664
665 int Block_display(lua_State* L)
666 {
667         assert(lua_gettop(L) == 2);
668         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
669         if (!block->is_input) {
670                 luaL_error(L, "display() called on something that isn't an input");
671         }
672
673         bool ok = display(block, L, 2);
674         if (!ok) {
675                 luaL_error(L, "display() called with something that's not a signal (a signal number, a HTML input, or a VideoInput)");
676         }
677
678         if (block->currently_chosen_alternative == -1) {
679                 luaL_error(L, "display() called on an input whose type was fixed at construction time, with a signal of different type");
680         }
681
682         return 0;
683 }
684
685 int Block_choose(lua_State* L)
686 {
687         assert(lua_gettop(L) == 2);
688         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
689         int alternative_idx = -1;
690         if (lua_isnumber(L, 2)) {
691                 alternative_idx = luaL_checknumber(L, 2);
692         } else if (lua_istable(L, 2)) {
693                 // See if it's an Effect metatable (e.g. foo:choose(ResampleEffect))
694                 lua_getfield(L, 2, "__effect_type_id");
695                 if (lua_isnumber(L, -1)) {
696                         EffectType effect_type = EffectType(luaL_checknumber(L, -1));
697                         alternative_idx = find_index_of(block, effect_type);
698                 }
699                 lua_pop(L, 1);
700         }
701
702         if (alternative_idx == -1) {
703                 luaL_error(L, "choose() called with something that was not an index or an effect type (e.g. ResampleEffect) that was part of the alternatives");
704         }
705
706         assert(alternative_idx >= 0);
707         assert(size_t(alternative_idx) < block->alternatives.size());
708         block->currently_chosen_alternative = alternative_idx;
709
710         return wrap_lua_existing_object_nonowned<EffectBlueprint>(L, "EffectBlueprint", block->alternatives[alternative_idx]);
711 }
712
713 int Block_enable(lua_State *L)
714 {
715         assert(lua_gettop(L) == 1);
716         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
717
718         if (block->alternatives.size() != 2 ||
719             block->alternatives[1]->effect_type != IDENTITY_EFFECT) {
720                 luaL_error(L, "enable() called on something that wasn't added with add_optional_effect()");
721         }
722         block->currently_chosen_alternative = 0;  // The actual effect.
723         return 0;
724 }
725
726 int Block_enable_if(lua_State *L)
727 {
728         assert(lua_gettop(L) == 2);
729         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
730
731         if (block->alternatives.size() != 2 ||
732             block->alternatives[1]->effect_type != IDENTITY_EFFECT) {
733                 luaL_error(L, "enable_if() called on something that wasn't added with add_optional_effect()");
734         }
735         bool enabled = checkbool(L, 2);
736         block->currently_chosen_alternative = enabled ? 0 : 1;
737         return 0;
738 }
739
740 int Block_disable(lua_State *L)
741 {
742         assert(lua_gettop(L) == 1);
743         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
744
745         block->currently_chosen_alternative = find_index_of(block, IDENTITY_EFFECT);
746         if (block->currently_chosen_alternative == -1) {
747                 luaL_error(L, "disable() called on something that didn't have an IdentityEffect fallback (try add_optional_effect())");
748         }
749         assert(block->currently_chosen_alternative != -1);
750         return 0;
751 }
752
753 int Block_always_disable_if_disabled(lua_State *L)
754 {
755         assert(lua_gettop(L) == 2);
756         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
757         Block *disabler_block = *(Block **)luaL_checkudata(L, 2, "Block");
758
759         int my_alternative = find_index_of(block, IDENTITY_EFFECT);
760         int their_alternative = find_index_of(disabler_block, IDENTITY_EFFECT);
761         if (my_alternative == -1) {
762                 luaL_error(L, "always_disable_if_disabled() called on something that didn't have an IdentityEffect fallback (try add_optional_effect())");
763         }
764         if (their_alternative == -1) {
765                 luaL_error(L, "always_disable_if_disabled() with an argument that didn't have an IdentityEffect fallback (try add_optional_effect())");
766         }
767
768         // The declaration point isn't actually used, but it's nice for completeness.
769         block->disablers.push_back(Block::Disabler{ disabler_block->idx, Block::Disabler::DISABLE_IF_OTHER_DISABLED, get_declaration_point(L) });
770
771         lua_pop(L, 2);
772         return 0;
773 }
774
775 int Block_promise_to_disable_if_enabled(lua_State *L)
776 {
777         assert(lua_gettop(L) == 2);
778         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
779         Block *disabler_block = *(Block **)luaL_checkudata(L, 2, "Block");
780
781         int my_alternative = find_index_of(block, IDENTITY_EFFECT);
782         int their_alternative = find_index_of(disabler_block, IDENTITY_EFFECT);
783         if (my_alternative == -1) {
784                 luaL_error(L, "promise_to_disable_if_enabled() called on something that didn't have an IdentityEffect fallback (try add_optional_effect())");
785         }
786         if (their_alternative == -1) {
787                 luaL_error(L, "promise_to_disable_if_enabled() with an argument that didn't have an IdentityEffect fallback (try add_optional_effect())");
788         }
789
790         block->disablers.push_back(Block::Disabler{ disabler_block->idx, Block::Disabler::DISABLE_IF_OTHER_ENABLED, get_declaration_point(L) });
791
792         lua_pop(L, 2);
793         return 0;
794 }
795
796 int Block_set_int(lua_State *L)
797 {
798         assert(lua_gettop(L) == 3);
799         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
800         string key = checkstdstring(L, 2);
801         float value = luaL_checknumber(L, 3);
802
803         // TODO: check validity already here, if possible?
804         block->int_parameters[key] = value;
805
806         return 0;
807 }
808
809 int Block_set_float(lua_State *L)
810 {
811         assert(lua_gettop(L) == 3);
812         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
813         string key = checkstdstring(L, 2);
814         float value = luaL_checknumber(L, 3);
815
816         // TODO: check validity already here, if possible?
817         block->float_parameters[key] = value;
818
819         return 0;
820 }
821
822 int Block_set_vec3(lua_State *L)
823 {
824         assert(lua_gettop(L) == 5);
825         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
826         string key = checkstdstring(L, 2);
827         array<float, 3> v;
828         v[0] = luaL_checknumber(L, 3);
829         v[1] = luaL_checknumber(L, 4);
830         v[2] = luaL_checknumber(L, 5);
831
832         // TODO: check validity already here, if possible?
833         block->vec3_parameters[key] = v;
834
835         return 0;
836 }
837
838 int Block_set_vec4(lua_State *L)
839 {
840         assert(lua_gettop(L) == 6);
841         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
842         string key = checkstdstring(L, 2);
843         array<float, 4> v;
844         v[0] = luaL_checknumber(L, 3);
845         v[1] = luaL_checknumber(L, 4);
846         v[2] = luaL_checknumber(L, 5);
847         v[3] = luaL_checknumber(L, 6);
848
849         // TODO: check validity already here, if possible?
850         block->vec4_parameters[key] = v;
851
852         return 0;
853 }
854