git.sesse.net Git - nageru/blob - 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                         // Auto white balance is always disabled for image inputs.
 181                         if (block->root_input_block != nullptr) {
 182                                 const Block *input = block->root_input_block;
 183                                 if (input->alternatives[input->chosen_alternative(chain_idx)]->effect_type == IMAGE_INPUT) {
 184                                         return true;
 185                                 }
 186                         }
 187                 }
 188         }
 189         return false;
 190 }
 191
 192 int Scene::add_input(lua_State* L)
 193 {
 194         assert(lua_gettop(L) == 1 || lua_gettop(L) == 2);
 195         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
 196
 197         Block *block = new Block;
 198         block->declaration_point = get_declaration_point(L);
 199         block->idx = scene->blocks.size();
 200         if (lua_gettop(L) == 1) {
 201                 // No parameter given, so a flexible input.
 202                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR));
 203                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR_WITH_DEINTERLACE));
 204                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR_PLANAR));
 205                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_BGRA));
 206                 block->alternatives.emplace_back(new EffectBlueprint(IMAGE_INPUT));
 207         } else {
 208                 // Input of a given type. We'll specialize it here, plus connect the input as given.
 209                 if (lua_isnumber(L, 2)) {
 210                         block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR));
 211                         block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR_WITH_DEINTERLACE));
 212 #ifdef HAVE_CEF
 213                 } else if (luaL_testudata(L, 2, "HTMLInput")) {
 214                         block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_BGRA));
 215 #endif
 216                 } else if (luaL_testudata(L, 2, "VideoInput")) {
 217                         FFmpegCapture *capture = *(FFmpegCapture **)luaL_checkudata(L, 2, "VideoInput");
 218                         if (capture->get_current_pixel_format() == bmusb::PixelFormat_8BitYCbCrPlanar) {
 219                                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR_PLANAR));
 220                         } else {
 221                                 assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
 222                                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_BGRA));
 223                         }
 224                 } else if (luaL_testudata(L, 2, "ImageInput")) {
 225                         block->alternatives.emplace_back(new EffectBlueprint(IMAGE_INPUT));
 226                 } else {
 227                         luaL_error(L, "add_input() called with something that's not a signal (a signal number, a HTML input, or a VideoInput)");
 228                 }
 229                 bool ok = display(block, L, 2);
 230                 assert(ok);
 231         }
 232         block->is_input = true;
 233         scene->blocks.push_back(block);
 234
 235         return wrap_lua_existing_object_nonowned<Block>(L, "Block", block);
 236 }
 237
 238 void Scene::find_inputs_for_block(lua_State *L, Scene *scene, Block *block, int first_input_idx)
 239 {
 240         if (lua_gettop(L) == first_input_idx - 1) {
 241                 // Implicitly the last added effect.
 242                 assert(!scene->blocks.empty());
 243                 block->inputs.push_back(scene->blocks.size() - 1);
 244                 return;
 245         }
 246
 247         for (int idx = first_input_idx; idx <= lua_gettop(L); ++idx) {
 248                 Block *input_block = nullptr;
 249                 if (luaL_testudata(L, idx, "Block")) {
 250                         input_block = *(Block **)luaL_checkudata(L, idx, "Block");
 251                 } else {
 252                         EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, idx, "EffectBlueprint");
 253
 254                         // Search through all the blocks to figure out which one contains this effect.
 255                         for (Block *block : scene->blocks) {
 256                                 if (find(block->alternatives.begin(), block->alternatives.end(), blueprint) != block->alternatives.end()) {
 257                                         input_block = block;
 258                                         break;
 259                                 }
 260                         }
 261                         if (input_block == nullptr) {
 262                                 luaL_error(L, "Input effect in parameter #%d has not been added to this scene", idx - 1);
 263                         }
 264                 }
 265                 block->inputs.push_back(input_block->idx);
 266         }
 267 }
 268
 269 int Scene::add_effect(lua_State* L)
 270 {
 271         assert(lua_gettop(L) >= 2);
 272         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
 273
 274         Block *block = new Block;
 275         block->declaration_point = get_declaration_point(L);
 276         block->idx = scene->blocks.size();
 277
 278         if (lua_istable(L, 2)) {
 279                 size_t len = lua_objlen(L, 2);
 280                 for (size_t i = 0; i < len; ++i) {
 281                         lua_rawgeti(L, 2, i + 1);
 282                         EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, -1, "EffectBlueprint");
 283                         block->alternatives.push_back(blueprint);
 284                         lua_settop(L, -2);
 285                 }
 286         } else {
 287                 EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, 2, "EffectBlueprint");
 288                 block->alternatives.push_back(blueprint);
 289         }
 290
 291         int identity_index = find_index_of(block, IDENTITY_EFFECT);
 292         if (identity_index == -1) {
 293                 block->canonical_alternative = 0;
 294         } else {
 295                 // Pick the IdentityEffect as the canonical alternative, in case it
 296                 // helps us disable more stuff.
 297                 block->canonical_alternative = identity_index;
 298         }
 299
 300         find_inputs_for_block(L, scene, block);
 301         scene->blocks.push_back(block);
 302
 303         return wrap_lua_existing_object_nonowned<Block>(L, "Block", block);
 304 }
 305
 306 int Scene::add_optional_effect(lua_State* L)
 307 {
 308         assert(lua_gettop(L) >= 2);
 309         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
 310
 311         Block *block = new Block;
 312         block->declaration_point = get_declaration_point(L);
 313         block->idx = scene->blocks.size();
 314
 315         EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, 2, "EffectBlueprint");
 316         block->alternatives.push_back(blueprint);
 317
 318         // An IdentityEffect will be the alternative for when the effect is disabled.
 319         block->alternatives.push_back(new EffectBlueprint(IDENTITY_EFFECT));
 320
 321         block->canonical_alternative = 1;
 322
 323         find_inputs_for_block(L, scene, block);
 324         scene->blocks.push_back(block);
 325
 326         return wrap_lua_existing_object_nonowned<Block>(L, "Block", block);
 327 }
 328
 329 const Block *Scene::find_root_input_block(lua_State *L, const Block *block)
 330 {
 331         if (block->is_input) {
 332                 assert(block->inputs.size() == 0);
 333                 return block;
 334         }
 335
 336         const Block *ret = nullptr;
 337         for (size_t input_idx : block->inputs) {
 338                 const Block *parent = find_root_input_block(L, blocks[input_idx]);
 339                 if (parent != nullptr) {
 340                         if (ret != nullptr) {
 341                                 luaL_error(L, "add_auto_white_balance() was connected to more than one input");
 342                         }
 343                         ret = parent;
 344                 }
 345         }
 346         return ret;
 347 }
 348
 349 int Scene::add_auto_white_balance(lua_State* L)
 350 {
 351         assert(lua_gettop(L) >= 1);
 352         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
 353
 354         Block *block = new Block;
 355         block->declaration_point = get_declaration_point(L);
 356         block->idx = scene->blocks.size();
 357
 358         block->alternatives.push_back(new EffectBlueprint(WHITE_BALANCE_EFFECT));
 359         block->alternatives.push_back(new EffectBlueprint(IDENTITY_EFFECT));
 360
 361         block->canonical_alternative = 1;
 362
 363         find_inputs_for_block(L, scene, block, /*first_input_idx=*/2);
 364
 365         if (block->inputs.size() != 1) {
 366                 luaL_error(L, "add_auto_white_balance() needs exactly one input");
 367         }
 368         block->root_input_block = scene->find_root_input_block(L, block);
 369         if (block->root_input_block == nullptr) {
 370                 luaL_error(L, "add_auto_white_balance() was not connected to an input");
 371         }
 372
 373         scene->blocks.push_back(block);
 374
 375         return wrap_lua_existing_object_nonowned<Block>(L, "Block", block);
 376 }
 377
 378 Effect *Scene::instantiate_effects(const Block *block, size_t chain_idx, Scene::Instantiation *instantiation)
 379 {
 380         // Find the chosen alternative for this block in this instance.
 381         EffectType chosen_type = block->alternatives[block->chosen_alternative(chain_idx)]->effect_type;
 382
 383         vector<Effect *> inputs;
 384         for (size_t input_idx : block->inputs) {
 385                 inputs.push_back(instantiate_effects(blocks[input_idx], chain_idx, instantiation));
 386
 387                 // As a special case, we allow IdentityEffect to take only one input
 388                 // even if the other alternative (or alternatives) is multi-input.
 389                 // Thus, even if there are more than one inputs, instantiate only
 390                 // the first one.
 391                 if (chosen_type == IDENTITY_EFFECT) {
 392                         break;
 393                 }
 394         }
 395
 396         Effect *effect;
 397         switch (chosen_type) {
 398         case LIVE_INPUT_YCBCR:
 399         case LIVE_INPUT_YCBCR_WITH_DEINTERLACE:
 400         case LIVE_INPUT_YCBCR_PLANAR:
 401         case LIVE_INPUT_BGRA: {
 402                 bool deinterlace = (chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
 403                 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.
 404                 bmusb::PixelFormat pixel_format;
 405                 if (chosen_type == LIVE_INPUT_BGRA) {
 406                         pixel_format = bmusb::PixelFormat_8BitBGRA;
 407                 } else if (chosen_type == LIVE_INPUT_YCBCR_PLANAR) {
 408                         pixel_format = bmusb::PixelFormat_8BitYCbCrPlanar;
 409                 } else if (global_flags.ten_bit_input) {
 410                         pixel_format = bmusb::PixelFormat_10BitYCbCr;
 411                 } else {
 412                         pixel_format = bmusb::PixelFormat_8BitYCbCr;
 413                 }
 414                 LiveInputWrapper *input = new LiveInputWrapper(theme, instantiation->chain.get(), pixel_format, override_bounce, deinterlace, /*user_connectable=*/true);
 415                 effect = input->get_effect();  // Adds itself to the chain, so no need to call add_effect().
 416                 instantiation->inputs.emplace(block->idx, input);
 417                 break;
 418         }
 419         case IMAGE_INPUT: {
 420                 ImageInput *input = new ImageInput;
 421                 instantiation->chain->add_input(input);
 422                 instantiation->image_inputs.emplace(block->idx, input);
 423                 effect = input;
 424                 break;
 425         }
 426         default:
 427                 effect = instantiate_effect(instantiation->chain.get(), chosen_type);
 428                 instantiation->chain->add_effect(effect, inputs);
 429                 break;
 430         }
 431         instantiation->effects.emplace(block->idx, effect);
 432         return effect;
 433 }
 434
 435 int Scene::finalize(lua_State* L)
 436 {
 437         bool only_one_mode = false;
 438         bool chosen_mode = false;
 439         if (lua_gettop(L) == 2) {
 440                 only_one_mode = true;
 441                 chosen_mode = checkbool(L, 2);
 442         } else {
 443                 assert(lua_gettop(L) == 1);
 444         }
 445         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
 446         Theme *theme = get_theme_updata(L);
 447
 448         size_t base = 1;
 449         for (Block *block : scene->blocks) {
 450                 block->cardinality_base = base;
 451                 base *= block->alternatives.size();
 452         }
 453
 454         const size_t cardinality = base;
 455         size_t real_cardinality = 0;
 456         for (size_t chain_idx = 0; chain_idx < cardinality; ++chain_idx) {
 457                 if (!scene->is_noncanonical_chain(chain_idx)) {
 458                         ++real_cardinality;
 459                 }
 460         }
 461         const size_t total_cardinality = real_cardinality * (only_one_mode ? 1 : 2);
 462         if (total_cardinality > 200) {
 463                 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",
 464                         total_cardinality);
 465         }
 466
 467         Block *output_block = scene->blocks.back();
 468         for (bool is_main_chain : { false, true }) {
 469                 for (size_t chain_idx = 0; chain_idx < cardinality; ++chain_idx) {
 470                         if ((only_one_mode && is_main_chain != chosen_mode) ||
 471                             scene->is_noncanonical_chain(chain_idx)) {
 472                                 scene->chains.emplace_back();
 473                                 continue;
 474                         }
 475
 476                         Scene::Instantiation instantiation;
 477                         instantiation.chain.reset(new EffectChain(scene->aspect_nom, scene->aspect_denom, theme->get_resource_pool()));
 478                         scene->instantiate_effects(output_block, chain_idx, &instantiation);
 479
 480                         add_outputs_and_finalize(instantiation.chain.get(), is_main_chain);
 481                         scene->chains.emplace_back(move(instantiation));
 482                 }
 483         }
 484         return 0;
 485 }
 486
 487 int find_signal_to_connect(lua_State *L, const Block *block)
 488 {
 489         if (block->signal_type_to_connect == Block::CONNECT_SIGNAL) {
 490                 return block->signal_to_connect;
 491 #ifdef HAVE_CEF
 492         } else if (block->signal_type_to_connect == Block::CONNECT_CEF) {
 493                 return block->cef_to_connect->get_card_index();
 494 #endif
 495         } else if (block->signal_type_to_connect == Block::CONNECT_VIDEO) {
 496                 return block->video_to_connect->get_card_index();
 497         } else if (block->signal_type_to_connect == Block::CONNECT_NONE) {
 498                 luaL_error(L, "An input in a scene was not connected to anything (forgot to call display())");
 499         } else {
 500                 assert(false);
 501         }
 502         return -1;
 503 }
 504
 505 std::pair<movit::EffectChain *, std::function<void()>>
 506 Scene::get_chain(Theme *theme, lua_State *L, unsigned num, const InputState &input_state)
 507 {
 508         // For video inputs, pick the right interlaced/progressive version
 509         // based on the current state of the signals.
 510         InputStateInfo info(input_state);
 511         for (Block *block : blocks) {
 512                 if (block->is_input && block->signal_type_to_connect == Block::CONNECT_SIGNAL) {
 513                         EffectType chosen_type = current_type(block);
 514                         assert(chosen_type == LIVE_INPUT_YCBCR || chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
 515                         if (info.last_interlaced[block->signal_to_connect]) {
 516                                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
 517                         } else {
 518                                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR);
 519                         }
 520                 }
 521         }
 522
 523         // Find all auto white balance blocks, turn on and off the effect as needed,
 524         // and fetch the actual white balance set (it is stored in Theme).
 525         map<Block *, array<float, 3>> white_balance;
 526         for (size_t block_idx = 0; block_idx < blocks.size(); ++block_idx) {
 527                 Block *block = blocks[block_idx];
 528                 const Block *input = block->root_input_block;
 529                 if (input == nullptr) {
 530                         continue;  // Not an auto white balance block.
 531                 }
 532
 533                 EffectType chosen_type = current_type(input);
 534                 if (chosen_type == IMAGE_INPUT) {
 535                         // Image inputs never get white balance applied.
 536                         block->currently_chosen_alternative = find_index_of(block, IDENTITY_EFFECT);
 537                         continue;
 538                 }
 539
 540                 assert(chosen_type == LIVE_INPUT_YCBCR ||
 541                        chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE ||
 542                        chosen_type == LIVE_INPUT_YCBCR_PLANAR ||
 543                        chosen_type == LIVE_INPUT_BGRA);
 544                 int signal = find_signal_to_connect(L, input);
 545                 Theme::WhiteBalance wb = theme->get_white_balance_for_signal(signal);
 546                 if (fabs(wb.r - 1.0) < 1e-3 && fabs(wb.g - 1.0) < 1e-3 && fabs(wb.b - 1.0) < 1e-3) {
 547                         // Neutral white balance.
 548                         block->currently_chosen_alternative = find_index_of(block, IDENTITY_EFFECT);
 549                 } else {
 550                         block->currently_chosen_alternative = find_index_of(block, WHITE_BALANCE_EFFECT);
 551                         white_balance.emplace(block, array<float, 3>{ wb.r, wb.g, wb.b });
 552                 }
 553         }
 554
 555         // Pick out the right chain based on the current selections,
 556         // and snapshot all the set variables so that we can set them
 557         // in the prepare function even if they're being changed by
 558         // the Lua code later.
 559         bool is_main_chain = (num == 0);
 560         size_t chain_idx = compute_chain_number(is_main_chain);
 561         if (is_noncanonical_chain(chain_idx)) {
 562                 // This should be due to promise_to_disable_if_enabled(). Find out what
 563                 // happened, to give the user some help.
 564                 bitset<256> disabled = find_disabled_blocks(chain_idx);
 565                 for (size_t block_idx = 0; block_idx < blocks.size(); ++block_idx) {
 566                         Block *block = blocks[block_idx];
 567                         if (disabled.test(block_idx)) continue;
 568                         for (const Block::Disabler &disabler : block->disablers) {
 569                                 if (disabler.condition == Block::Disabler::DISABLE_IF_OTHER_ENABLED &&
 570                                     !disabled.test(disabler.block_idx)) {
 571                                         fprintf(stderr, "Promise declared at %s violated.\n", disabler.declaration_point.c_str());
 572                                         abort();
 573                                 }
 574                         }
 575                 }
 576                 assert(false);  // Something else happened, seemingly.
 577         }
 578         const Scene::Instantiation &instantiation = chains[chain_idx];
 579         EffectChain *effect_chain = instantiation.chain.get();
 580
 581         map<LiveInputWrapper *, int> signals_to_connect;
 582         map<ImageInput *, string> images_to_select;
 583         map<pair<Effect *, string>, int> int_to_set;
 584         map<pair<Effect *, string>, float> float_to_set;
 585         map<pair<Effect *, string>, array<float, 3>> vec3_to_set;
 586         map<pair<Effect *, string>, array<float, 4>> vec4_to_set;
 587         for (const auto &index_and_input : instantiation.inputs) {
 588                 Block *block = blocks[index_and_input.first];
 589                 EffectType chosen_type = current_type(block);
 590                 if (chosen_type == LIVE_INPUT_YCBCR ||
 591                     chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE ||
 592                     chosen_type == LIVE_INPUT_YCBCR_PLANAR ||
 593                     chosen_type == LIVE_INPUT_BGRA) {
 594                         LiveInputWrapper *input = index_and_input.second;
 595                         signals_to_connect.emplace(input, find_signal_to_connect(L, block));
 596                 }
 597         }
 598         for (const auto &index_and_input : instantiation.image_inputs) {
 599                 Block *block = blocks[index_and_input.first];
 600                 ImageInput *input = index_and_input.second;
 601                 if (current_type(block) == IMAGE_INPUT) {
 602                         images_to_select.emplace(input, block->pathname);
 603                 }
 604         }
 605         for (const auto &index_and_effect : instantiation.effects) {
 606                 Block *block = blocks[index_and_effect.first];
 607                 Effect *effect = index_and_effect.second;
 608
 609                 bool missing_width = (current_type(block) == RESIZE_EFFECT ||
 610                         current_type(block) == RESAMPLE_EFFECT ||
 611                         current_type(block) == PADDING_EFFECT);
 612                 bool missing_height = missing_width;
 613
 614                 // Get the effects currently set on the block.
 615                 if (current_type(block) != IDENTITY_EFFECT) {  // Ignore settings on optional effects.
 616                         if (block->int_parameters.count("width") && block->int_parameters["width"] > 0) {
 617                                 missing_width = false;
 618                         }
 619                         if (block->int_parameters.count("height") && block->int_parameters["height"] > 0) {
 620                                 missing_height = false;
 621                         }
 622                         for (const auto &key_and_tuple : block->int_parameters) {
 623                                 int_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 624                         }
 625                         for (const auto &key_and_tuple : block->float_parameters) {
 626                                 float_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 627                         }
 628                         if (white_balance.count(block)) {
 629                                 vec3_to_set.emplace(make_pair(effect, "neutral_color"), white_balance[block]);
 630                         }
 631                         for (const auto &key_and_tuple : block->vec3_parameters) {
 632                                 vec3_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 633                         }
 634                         for (const auto &key_and_tuple : block->vec4_parameters) {
 635                                 vec4_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 636                         }
 637                 }
 638
 639                 // Parameters set on the blueprint itself override those that are set for the block,
 640                 // so they are set afterwards.
 641                 if (!block->alternatives.empty()) {
 642                         EffectBlueprint *blueprint = block->alternatives[block->currently_chosen_alternative];
 643                         if (blueprint->int_parameters.count("width") && blueprint->int_parameters["width"] > 0) {
 644                                 missing_width = false;
 645                         }
 646                         if (blueprint->int_parameters.count("height") && blueprint->int_parameters["height"] > 0) {
 647                                 missing_height = false;
 648                         }
 649                         for (const auto &key_and_tuple : blueprint->int_parameters) {
 650                                 int_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 651                         }
 652                         for (const auto &key_and_tuple : blueprint->float_parameters) {
 653                                 float_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 654                         }
 655                         for (const auto &key_and_tuple : blueprint->vec3_parameters) {
 656                                 vec3_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 657                         }
 658                         for (const auto &key_and_tuple : blueprint->vec4_parameters) {
 659                                 vec4_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 660                         }
 661                 }
 662
 663                 if (missing_width || missing_height) {
 664                         fprintf(stderr, "WARNING: Unset or nonpositive width/height for effect declared at %s "
 665                                 "when getting scene for signal %u; setting to 1x1 to avoid crash.\n",
 666                                 block->declaration_point.c_str(), num);
 667                         int_to_set[make_pair(effect, "width")] = 1;
 668                         int_to_set[make_pair(effect, "height")] = 1;
 669                 }
 670         }
 671
 672         lua_pop(L, 1);
 673
 674         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]{
 675                 lock_guard<mutex> lock(theme->m);
 676
 677                 // Set up state, including connecting signals.
 678                 for (const auto &input_and_signal : signals_to_connect) {
 679                         LiveInputWrapper *input = input_and_signal.first;
 680                         input->connect_signal_raw(input_and_signal.second, input_state);
 681                 }
 682                 for (const auto &input_and_filename : images_to_select) {
 683                         input_and_filename.first->switch_image(input_and_filename.second);
 684                 }
 685                 for (const auto &effect_and_key_and_value : int_to_set) {
 686                         Effect *effect = effect_and_key_and_value.first.first;
 687                         const string &key = effect_and_key_and_value.first.second;
 688                         const int value = effect_and_key_and_value.second;
 689                         if (!effect->set_int(key, value)) {
 690                                 luaL_error(L, "Effect refused set_int(\"%s\", %d) (invalid key?)", key.c_str(), value);
 691                         }
 692                 }
 693                 for (const auto &effect_and_key_and_value : float_to_set) {
 694                         Effect *effect = effect_and_key_and_value.first.first;
 695                         const string &key = effect_and_key_and_value.first.second;
 696                         const float value = effect_and_key_and_value.second;
 697                         if (!effect->set_float(key, value)) {
 698                                 luaL_error(L, "Effect refused set_float(\"%s\", %f) (invalid key?)", key.c_str(), value);
 699                         }
 700                 }
 701                 for (const auto &effect_and_key_and_value : vec3_to_set) {
 702                         Effect *effect = effect_and_key_and_value.first.first;
 703                         const string &key = effect_and_key_and_value.first.second;
 704                         const float *value = effect_and_key_and_value.second.data();
 705                         if (!effect->set_vec3(key, value)) {
 706                                 luaL_error(L, "Effect refused set_vec3(\"%s\", %f, %f, %f) (invalid key?)", key.c_str(),
 707                                                 value[0], value[1], value[2]);
 708                         }
 709                 }
 710                 for (const auto &effect_and_key_and_value : vec4_to_set) {
 711                         Effect *effect = effect_and_key_and_value.first.first;
 712                         const string &key = effect_and_key_and_value.first.second;
 713                         const float *value = effect_and_key_and_value.second.data();
 714                         if (!effect->set_vec4(key, value)) {
 715                                 luaL_error(L, "Effect refused set_vec4(\"%s\", %f, %f, %f, %f) (invalid key?)", key.c_str(),
 716                                                 value[0], value[1], value[2], value[3]);
 717                         }
 718                 }
 719         };
 720         return make_pair(effect_chain, move(setup_chain));
 721 }
 722
 723 bool display(Block *block, lua_State *L, int idx)
 724 {
 725         if (lua_isnumber(L, idx)) {
 726                 Theme *theme = get_theme_updata(L);
 727                 int signal_idx = luaL_checknumber(L, idx);
 728                 block->signal_type_to_connect = Block::CONNECT_SIGNAL;
 729                 block->signal_to_connect = theme->map_signal(signal_idx);
 730                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR);  // Will be changed to deinterlaced at get_chain() time if needed.
 731                 return true;
 732 #ifdef HAVE_CEF
 733         } else if (luaL_testudata(L, idx, "HTMLInput")) {
 734                 CEFCapture *capture = *(CEFCapture **)luaL_checkudata(L, idx, "HTMLInput");
 735                 block->signal_type_to_connect = Block::CONNECT_CEF;
 736                 block->cef_to_connect = capture;
 737                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_BGRA);
 738                 assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
 739                 return true;
 740 #endif
 741         } else if (luaL_testudata(L, idx, "VideoInput")) {
 742                 FFmpegCapture *capture = *(FFmpegCapture **)luaL_checkudata(L, idx, "VideoInput");
 743                 block->signal_type_to_connect = Block::CONNECT_VIDEO;
 744                 block->video_to_connect = capture;
 745                 if (capture->get_current_pixel_format() == bmusb::PixelFormat_8BitYCbCrPlanar) {
 746                         block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR_PLANAR);
 747                 } else {
 748                         assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
 749                         block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_BGRA);
 750                 }
 751                 return true;
 752         } else if (luaL_testudata(L, idx, "ImageInput")) {
 753                 ImageInput *image = *(ImageInput **)luaL_checkudata(L, idx, "ImageInput");
 754                 block->signal_type_to_connect = Block::CONNECT_NONE;
 755                 block->currently_chosen_alternative = find_index_of(block, IMAGE_INPUT);
 756                 block->pathname = image->get_pathname();
 757                 return true;
 758         } else {
 759                 return false;
 760         }
 761 }
 762
 763 int Block_display(lua_State* L)
 764 {
 765         assert(lua_gettop(L) == 2);
 766         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 767         if (!block->is_input) {
 768                 luaL_error(L, "display() called on something that isn't an input");
 769         }
 770
 771         bool ok = display(block, L, 2);
 772         if (!ok) {
 773                 luaL_error(L, "display() called with something that's not a signal (a signal number, a HTML input, or a VideoInput)");
 774         }
 775
 776         if (block->currently_chosen_alternative == -1) {
 777                 luaL_error(L, "display() called on an input whose type was fixed at construction time, with a signal of different type");
 778         }
 779
 780         return 0;
 781 }
 782
 783 int Block_choose(lua_State* L)
 784 {
 785         assert(lua_gettop(L) == 2);
 786         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 787         int alternative_idx = -1;
 788         if (lua_isnumber(L, 2)) {
 789                 alternative_idx = luaL_checknumber(L, 2);
 790         } else if (lua_istable(L, 2)) {
 791                 // See if it's an Effect metatable (e.g. foo:choose(ResampleEffect))
 792                 lua_getfield(L, 2, "__effect_type_id");
 793                 if (lua_isnumber(L, -1)) {
 794                         EffectType effect_type = EffectType(luaL_checknumber(L, -1));
 795                         alternative_idx = find_index_of(block, effect_type);
 796                 }
 797                 lua_pop(L, 1);
 798         }
 799
 800         if (alternative_idx == -1) {
 801                 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");
 802         }
 803
 804         assert(alternative_idx >= 0);
 805         assert(size_t(alternative_idx) < block->alternatives.size());
 806         block->currently_chosen_alternative = alternative_idx;
 807
 808         return wrap_lua_existing_object_nonowned<EffectBlueprint>(L, "EffectBlueprint", block->alternatives[alternative_idx]);
 809 }
 810
 811 int Block_enable(lua_State *L)
 812 {
 813         assert(lua_gettop(L) == 1);
 814         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 815
 816         if (block->alternatives.size() != 2 ||
 817             block->alternatives[1]->effect_type != IDENTITY_EFFECT) {
 818                 luaL_error(L, "enable() called on something that wasn't added with add_optional_effect()");
 819         }
 820         block->currently_chosen_alternative = 0;  // The actual effect.
 821         return 0;
 822 }
 823
 824 int Block_enable_if(lua_State *L)
 825 {
 826         assert(lua_gettop(L) == 2);
 827         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 828
 829         if (block->alternatives.size() != 2 ||
 830             block->alternatives[1]->effect_type != IDENTITY_EFFECT) {
 831                 luaL_error(L, "enable_if() called on something that wasn't added with add_optional_effect()");
 832         }
 833         bool enabled = checkbool(L, 2);
 834         block->currently_chosen_alternative = enabled ? 0 : 1;
 835         return 0;
 836 }
 837
 838 int Block_disable(lua_State *L)
 839 {
 840         assert(lua_gettop(L) == 1);
 841         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 842
 843         block->currently_chosen_alternative = find_index_of(block, IDENTITY_EFFECT);
 844         if (block->currently_chosen_alternative == -1) {
 845                 luaL_error(L, "disable() called on something that didn't have an IdentityEffect fallback (try add_optional_effect())");
 846         }
 847         assert(block->currently_chosen_alternative != -1);
 848         return 0;
 849 }
 850
 851 int Block_always_disable_if_disabled(lua_State *L)
 852 {
 853         assert(lua_gettop(L) == 2);
 854         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 855         Block *disabler_block = *(Block **)luaL_checkudata(L, 2, "Block");
 856
 857         int my_alternative = find_index_of(block, IDENTITY_EFFECT);
 858         int their_alternative = find_index_of(disabler_block, IDENTITY_EFFECT);
 859         if (my_alternative == -1) {
 860                 luaL_error(L, "always_disable_if_disabled() called on something that didn't have an IdentityEffect fallback (try add_optional_effect())");
 861         }
 862         if (their_alternative == -1) {
 863                 luaL_error(L, "always_disable_if_disabled() with an argument that didn't have an IdentityEffect fallback (try add_optional_effect())");
 864         }
 865
 866         // The declaration point isn't actually used, but it's nice for completeness.
 867         block->disablers.push_back(Block::Disabler{ disabler_block->idx, Block::Disabler::DISABLE_IF_OTHER_DISABLED, get_declaration_point(L) });
 868
 869         lua_pop(L, 2);
 870         return 0;
 871 }
 872
 873 int Block_promise_to_disable_if_enabled(lua_State *L)
 874 {
 875         assert(lua_gettop(L) == 2);
 876         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 877         Block *disabler_block = *(Block **)luaL_checkudata(L, 2, "Block");
 878
 879         int my_alternative = find_index_of(block, IDENTITY_EFFECT);
 880         int their_alternative = find_index_of(disabler_block, IDENTITY_EFFECT);
 881         if (my_alternative == -1) {
 882                 luaL_error(L, "promise_to_disable_if_enabled() called on something that didn't have an IdentityEffect fallback (try add_optional_effect())");
 883         }
 884         if (their_alternative == -1) {
 885                 luaL_error(L, "promise_to_disable_if_enabled() with an argument that didn't have an IdentityEffect fallback (try add_optional_effect())");
 886         }
 887
 888         block->disablers.push_back(Block::Disabler{ disabler_block->idx, Block::Disabler::DISABLE_IF_OTHER_ENABLED, get_declaration_point(L) });
 889
 890         lua_pop(L, 2);
 891         return 0;
 892 }
 893
 894 int Block_set_int(lua_State *L)
 895 {
 896         assert(lua_gettop(L) == 3);
 897         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 898         string key = checkstdstring(L, 2);
 899         float value = luaL_checknumber(L, 3);
 900
 901         // TODO: check validity already here, if possible?
 902         block->int_parameters[key] = value;
 903
 904         return 0;
 905 }
 906
 907 int Block_set_float(lua_State *L)
 908 {
 909         assert(lua_gettop(L) == 3);
 910         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 911         string key = checkstdstring(L, 2);
 912         float value = luaL_checknumber(L, 3);
 913
 914         // TODO: check validity already here, if possible?
 915         block->float_parameters[key] = value;
 916
 917         return 0;
 918 }
 919
 920 int Block_set_vec3(lua_State *L)
 921 {
 922         assert(lua_gettop(L) == 5);
 923         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 924         string key = checkstdstring(L, 2);
 925         array<float, 3> v;
 926         v[0] = luaL_checknumber(L, 3);
 927         v[1] = luaL_checknumber(L, 4);
 928         v[2] = luaL_checknumber(L, 5);
 929
 930         // TODO: check validity already here, if possible?
 931         block->vec3_parameters[key] = v;
 932
 933         return 0;
 934 }
 935
 936 int Block_set_vec4(lua_State *L)
 937 {
 938         assert(lua_gettop(L) == 6);
 939         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 940         string key = checkstdstring(L, 2);
 941         array<float, 4> v;
 942         v[0] = luaL_checknumber(L, 3);
 943         v[1] = luaL_checknumber(L, 4);
 944         v[2] = luaL_checknumber(L, 5);
 945         v[3] = luaL_checknumber(L, 6);
 946
 947         // TODO: check validity already here, if possible?
 948         block->vec4_parameters[key] = v;
 949
 950         return 0;
 951 }
 952