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->white_balance_controller_block != nullptr) {
 182                                 const Block *input = block->white_balance_controller_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 Block *Scene::find_block_from_arg(lua_State *L, Scene *scene, int idx)
 239 {
 240         if (luaL_testudata(L, idx, "Block")) {
 241                 return *(Block **)luaL_checkudata(L, idx, "Block");
 242         } else {
 243                 EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, idx, "EffectBlueprint");
 244
 245                 // Search through all the blocks to figure out which one contains this effect.
 246                 for (Block *block : scene->blocks) {
 247                         if (find(block->alternatives.begin(), block->alternatives.end(), blueprint) != block->alternatives.end()) {
 248                                 return block;
 249                         }
 250                 }
 251                 luaL_error(L, "Input effect in parameter #%d has not been added to this scene", idx - 1);
 252                 return nullptr;  // Dead code.
 253         }
 254 }
 255
 256 void Scene::find_inputs_for_block(lua_State *L, Scene *scene, Block *block, int first_input_idx)
 257 {
 258         if (lua_gettop(L) == first_input_idx - 1) {
 259                 // Implicitly the last added effect.
 260                 assert(!scene->blocks.empty());
 261                 block->inputs.push_back(scene->blocks.size() - 1);
 262                 return;
 263         }
 264
 265         for (int idx = first_input_idx; idx <= lua_gettop(L); ++idx) {
 266                 block->inputs.push_back(find_block_from_arg(L, scene, idx)->idx);
 267         }
 268 }
 269
 270 int Scene::add_effect(lua_State* L)
 271 {
 272         assert(lua_gettop(L) >= 2);
 273         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
 274
 275         Block *block = new Block;
 276         block->declaration_point = get_declaration_point(L);
 277         block->idx = scene->blocks.size();
 278
 279         if (lua_istable(L, 2)) {
 280                 size_t len = lua_objlen(L, 2);
 281                 for (size_t i = 0; i < len; ++i) {
 282                         lua_rawgeti(L, 2, i + 1);
 283                         EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, -1, "EffectBlueprint");
 284                         block->alternatives.push_back(blueprint);
 285                         lua_settop(L, -2);
 286                 }
 287         } else {
 288                 EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, 2, "EffectBlueprint");
 289                 block->alternatives.push_back(blueprint);
 290         }
 291
 292         int identity_index = find_index_of(block, IDENTITY_EFFECT);
 293         if (identity_index == -1) {
 294                 block->canonical_alternative = 0;
 295         } else {
 296                 // Pick the IdentityEffect as the canonical alternative, in case it
 297                 // helps us disable more stuff.
 298                 block->canonical_alternative = identity_index;
 299         }
 300
 301         find_inputs_for_block(L, scene, block);
 302         scene->blocks.push_back(block);
 303
 304         return wrap_lua_existing_object_nonowned<Block>(L, "Block", block);
 305 }
 306
 307 int Scene::add_optional_effect(lua_State* L)
 308 {
 309         assert(lua_gettop(L) >= 2);
 310         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
 311
 312         Block *block = new Block;
 313         block->declaration_point = get_declaration_point(L);
 314         block->idx = scene->blocks.size();
 315
 316         EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, 2, "EffectBlueprint");
 317         block->alternatives.push_back(blueprint);
 318
 319         // An IdentityEffect will be the alternative for when the effect is disabled.
 320         block->alternatives.push_back(new EffectBlueprint(IDENTITY_EFFECT));
 321
 322         block->canonical_alternative = 1;
 323
 324         find_inputs_for_block(L, scene, block);
 325         scene->blocks.push_back(block);
 326
 327         return wrap_lua_existing_object_nonowned<Block>(L, "Block", block);
 328 }
 329
 330 const Block *Scene::find_root_input_block(lua_State *L, const Block *block)
 331 {
 332         if (block->is_input) {
 333                 assert(block->inputs.size() == 0);
 334                 return block;
 335         }
 336
 337         const Block *ret = nullptr;
 338         for (size_t input_idx : block->inputs) {
 339                 const Block *parent = find_root_input_block(L, blocks[input_idx]);
 340                 if (parent != nullptr) {
 341                         if (ret != nullptr) {
 342                                 luaL_error(L, "add_auto_white_balance() was connected to more than one input");
 343                         }
 344                         ret = parent;
 345                 }
 346         }
 347         return ret;
 348 }
 349
 350 int Scene::add_auto_white_balance(lua_State* L)
 351 {
 352         assert(lua_gettop(L) >= 1);
 353         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
 354
 355         Block *block = new Block;
 356         block->declaration_point = get_declaration_point(L);
 357         block->idx = scene->blocks.size();
 358
 359         block->alternatives.push_back(new EffectBlueprint(WHITE_BALANCE_EFFECT));
 360         block->alternatives.push_back(new EffectBlueprint(IDENTITY_EFFECT));
 361
 362         block->canonical_alternative = 1;
 363
 364         if (lua_gettop(L) == 1) {
 365                 // The last added effect is implicitly both the input and gives the white balance controller.
 366                 assert(!scene->blocks.empty());
 367                 block->inputs.push_back(scene->blocks.size() - 1);
 368                 block->white_balance_controller_block = scene->find_root_input_block(L, block);
 369         } else if (lua_gettop(L) == 2) {
 370                 // The given effect is both the input and the white balance controller.
 371                 block->inputs.push_back(find_block_from_arg(L, scene, 2)->idx);
 372                 block->white_balance_controller_block = scene->find_root_input_block(L, block);
 373         } else if (lua_gettop(L) == 3) {
 374                 // We have explicit input and white balance controller.
 375                 block->inputs.push_back(find_block_from_arg(L, scene, 2)->idx);
 376                 block->white_balance_controller_block = find_block_from_arg(L, scene, 3);
 377         } else {
 378                 luaL_error(L, "add_auto_white_balance([input], [white_balance_controller]) takes zero, one or two arguments");
 379         }
 380         if (block->white_balance_controller_block == nullptr || !block->white_balance_controller_block->is_input) {
 381                 luaL_error(L, "add_auto_white_balance() does not get its white balance from an input");
 382         }
 383
 384         scene->blocks.push_back(block);
 385
 386         return wrap_lua_existing_object_nonowned<Block>(L, "Block", block);
 387 }
 388
 389 Effect *Scene::instantiate_effects(const Block *block, size_t chain_idx, Scene::Instantiation *instantiation)
 390 {
 391         // Find the chosen alternative for this block in this instance.
 392         EffectType chosen_type = block->alternatives[block->chosen_alternative(chain_idx)]->effect_type;
 393
 394         vector<Effect *> inputs;
 395         for (size_t input_idx : block->inputs) {
 396                 inputs.push_back(instantiate_effects(blocks[input_idx], chain_idx, instantiation));
 397
 398                 // As a special case, we allow IdentityEffect to take only one input
 399                 // even if the other alternative (or alternatives) is multi-input.
 400                 // Thus, even if there are more than one inputs, instantiate only
 401                 // the first one.
 402                 if (chosen_type == IDENTITY_EFFECT) {
 403                         break;
 404                 }
 405         }
 406
 407         Effect *effect;
 408         switch (chosen_type) {
 409         case LIVE_INPUT_YCBCR:
 410         case LIVE_INPUT_YCBCR_WITH_DEINTERLACE:
 411         case LIVE_INPUT_YCBCR_PLANAR:
 412         case LIVE_INPUT_BGRA: {
 413                 bool deinterlace = (chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
 414                 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.
 415                 bmusb::PixelFormat pixel_format;
 416                 if (chosen_type == LIVE_INPUT_BGRA) {
 417                         pixel_format = bmusb::PixelFormat_8BitBGRA;
 418                 } else if (chosen_type == LIVE_INPUT_YCBCR_PLANAR) {
 419                         pixel_format = bmusb::PixelFormat_8BitYCbCrPlanar;
 420                 } else if (global_flags.ten_bit_input) {
 421                         pixel_format = bmusb::PixelFormat_10BitYCbCr;
 422                 } else {
 423                         pixel_format = bmusb::PixelFormat_8BitYCbCr;
 424                 }
 425                 LiveInputWrapper *input = new LiveInputWrapper(theme, instantiation->chain.get(), pixel_format, override_bounce, deinterlace, /*user_connectable=*/true);
 426                 effect = input->get_effect();  // Adds itself to the chain, so no need to call add_effect().
 427                 instantiation->inputs.emplace(block->idx, input);
 428                 break;
 429         }
 430         case IMAGE_INPUT: {
 431                 ImageInput *input = new ImageInput;
 432                 instantiation->chain->add_input(input);
 433                 instantiation->image_inputs.emplace(block->idx, input);
 434                 effect = input;
 435                 break;
 436         }
 437         default:
 438                 effect = instantiate_effect(instantiation->chain.get(), chosen_type);
 439                 instantiation->chain->add_effect(effect, inputs);
 440                 break;
 441         }
 442         instantiation->effects.emplace(block->idx, effect);
 443         return effect;
 444 }
 445
 446 int Scene::finalize(lua_State* L)
 447 {
 448         bool only_one_mode = false;
 449         bool chosen_mode = false;
 450         if (lua_gettop(L) == 2) {
 451                 only_one_mode = true;
 452                 chosen_mode = checkbool(L, 2);
 453         } else {
 454                 assert(lua_gettop(L) == 1);
 455         }
 456         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
 457         Theme *theme = get_theme_updata(L);
 458
 459         size_t base = 1;
 460         for (Block *block : scene->blocks) {
 461                 block->cardinality_base = base;
 462                 base *= block->alternatives.size();
 463         }
 464
 465         const size_t cardinality = base;
 466         size_t real_cardinality = 0;
 467         for (size_t chain_idx = 0; chain_idx < cardinality; ++chain_idx) {
 468                 if (!scene->is_noncanonical_chain(chain_idx)) {
 469                         ++real_cardinality;
 470                 }
 471         }
 472         const size_t total_cardinality = real_cardinality * (only_one_mode ? 1 : 2);
 473         if (total_cardinality > 200) {
 474                 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",
 475                         total_cardinality);
 476         }
 477
 478         Block *output_block = scene->blocks.back();
 479         for (bool is_main_chain : { false, true }) {
 480                 for (size_t chain_idx = 0; chain_idx < cardinality; ++chain_idx) {
 481                         if ((only_one_mode && is_main_chain != chosen_mode) ||
 482                             scene->is_noncanonical_chain(chain_idx)) {
 483                                 scene->chains.emplace_back();
 484                                 continue;
 485                         }
 486
 487                         Scene::Instantiation instantiation;
 488                         instantiation.chain.reset(new EffectChain(scene->aspect_nom, scene->aspect_denom, theme->get_resource_pool()));
 489                         scene->instantiate_effects(output_block, chain_idx, &instantiation);
 490
 491                         add_outputs_and_finalize(instantiation.chain.get(), is_main_chain);
 492                         scene->chains.emplace_back(move(instantiation));
 493                 }
 494         }
 495         return 0;
 496 }
 497
 498 int find_signal_to_connect(lua_State *L, const Block *block)
 499 {
 500         if (block->signal_type_to_connect == Block::CONNECT_SIGNAL) {
 501                 return block->signal_to_connect;
 502 #ifdef HAVE_CEF
 503         } else if (block->signal_type_to_connect == Block::CONNECT_CEF) {
 504                 return block->cef_to_connect->get_card_index();
 505 #endif
 506         } else if (block->signal_type_to_connect == Block::CONNECT_VIDEO) {
 507                 return block->video_to_connect->get_card_index();
 508         } else if (block->signal_type_to_connect == Block::CONNECT_NONE) {
 509                 luaL_error(L, "An input in a scene was not connected to anything (forgot to call display())");
 510         } else {
 511                 assert(false);
 512         }
 513         return -1;
 514 }
 515
 516 std::pair<movit::EffectChain *, std::function<void()>>
 517 Scene::get_chain(Theme *theme, lua_State *L, unsigned num, const InputState &input_state)
 518 {
 519         // For video inputs, pick the right interlaced/progressive version
 520         // based on the current state of the signals.
 521         InputStateInfo info(input_state);
 522         for (Block *block : blocks) {
 523                 if (block->is_input && block->signal_type_to_connect == Block::CONNECT_SIGNAL) {
 524                         EffectType chosen_type = current_type(block);
 525                         assert(chosen_type == LIVE_INPUT_YCBCR || chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
 526                         if (info.last_interlaced[block->signal_to_connect]) {
 527                                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
 528                         } else {
 529                                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR);
 530                         }
 531                 }
 532         }
 533
 534         // Find all auto white balance blocks, turn on and off the effect as needed,
 535         // and fetch the actual white balance set (it is stored in Theme).
 536         map<Block *, array<float, 3>> white_balance;
 537         for (size_t block_idx = 0; block_idx < blocks.size(); ++block_idx) {
 538                 Block *block = blocks[block_idx];
 539                 const Block *input = block->white_balance_controller_block;
 540                 if (input == nullptr) {
 541                         continue;  // Not an auto white balance block.
 542                 }
 543
 544                 EffectType chosen_type = current_type(input);
 545                 if (chosen_type == IMAGE_INPUT) {
 546                         // Image inputs never get white balance applied.
 547                         block->currently_chosen_alternative = find_index_of(block, IDENTITY_EFFECT);
 548                         continue;
 549                 }
 550
 551                 assert(chosen_type == LIVE_INPUT_YCBCR ||
 552                        chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE ||
 553                        chosen_type == LIVE_INPUT_YCBCR_PLANAR ||
 554                        chosen_type == LIVE_INPUT_BGRA);
 555                 int signal = find_signal_to_connect(L, input);
 556                 RGBTriplet wb = theme->get_white_balance_for_signal(signal);
 557                 if (fabs(wb.r - 1.0) < 1e-3 && fabs(wb.g - 1.0) < 1e-3 && fabs(wb.b - 1.0) < 1e-3) {
 558                         // Neutral white balance.
 559                         block->currently_chosen_alternative = find_index_of(block, IDENTITY_EFFECT);
 560                 } else {
 561                         block->currently_chosen_alternative = find_index_of(block, WHITE_BALANCE_EFFECT);
 562                         white_balance.emplace(block, array<float, 3>{ wb.r, wb.g, wb.b });
 563                 }
 564         }
 565
 566         // Pick out the right chain based on the current selections,
 567         // and snapshot all the set variables so that we can set them
 568         // in the prepare function even if they're being changed by
 569         // the Lua code later.
 570         bool is_main_chain = (num == 0);
 571         size_t chain_idx = compute_chain_number(is_main_chain);
 572         if (is_noncanonical_chain(chain_idx)) {
 573                 // This should be due to promise_to_disable_if_enabled(). Find out what
 574                 // happened, to give the user some help.
 575                 bitset<256> disabled = find_disabled_blocks(chain_idx);
 576                 for (size_t block_idx = 0; block_idx < blocks.size(); ++block_idx) {
 577                         Block *block = blocks[block_idx];
 578                         if (disabled.test(block_idx)) continue;
 579                         for (const Block::Disabler &disabler : block->disablers) {
 580                                 if (disabler.condition == Block::Disabler::DISABLE_IF_OTHER_ENABLED &&
 581                                     !disabled.test(disabler.block_idx)) {
 582                                         fprintf(stderr, "Promise declared at %s violated.\n", disabler.declaration_point.c_str());
 583                                         abort();
 584                                 }
 585                         }
 586                 }
 587                 assert(false);  // Something else happened, seemingly.
 588         }
 589         const Scene::Instantiation &instantiation = chains[chain_idx];
 590         EffectChain *effect_chain = instantiation.chain.get();
 591
 592         map<LiveInputWrapper *, int> signals_to_connect;
 593         map<ImageInput *, string> images_to_select;
 594         map<pair<Effect *, string>, int> int_to_set;
 595         map<pair<Effect *, string>, float> float_to_set;
 596         map<pair<Effect *, string>, array<float, 3>> vec3_to_set;
 597         map<pair<Effect *, string>, array<float, 4>> vec4_to_set;
 598         for (const auto &index_and_input : instantiation.inputs) {
 599                 Block *block = blocks[index_and_input.first];
 600                 EffectType chosen_type = current_type(block);
 601                 if (chosen_type == LIVE_INPUT_YCBCR ||
 602                     chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE ||
 603                     chosen_type == LIVE_INPUT_YCBCR_PLANAR ||
 604                     chosen_type == LIVE_INPUT_BGRA) {
 605                         LiveInputWrapper *input = index_and_input.second;
 606                         signals_to_connect.emplace(input, find_signal_to_connect(L, block));
 607                 }
 608         }
 609         for (const auto &index_and_input : instantiation.image_inputs) {
 610                 Block *block = blocks[index_and_input.first];
 611                 ImageInput *input = index_and_input.second;
 612                 if (current_type(block) == IMAGE_INPUT) {
 613                         images_to_select.emplace(input, block->pathname);
 614                 }
 615         }
 616         for (const auto &index_and_effect : instantiation.effects) {
 617                 Block *block = blocks[index_and_effect.first];
 618                 Effect *effect = index_and_effect.second;
 619
 620                 bool missing_width = (current_type(block) == RESIZE_EFFECT ||
 621                         current_type(block) == RESAMPLE_EFFECT ||
 622                         current_type(block) == PADDING_EFFECT);
 623                 bool missing_height = missing_width;
 624
 625                 // Get the effects currently set on the block.
 626                 if (current_type(block) != IDENTITY_EFFECT) {  // Ignore settings on optional effects.
 627                         if (block->int_parameters.count("width") && block->int_parameters["width"] > 0) {
 628                                 missing_width = false;
 629                         }
 630                         if (block->int_parameters.count("height") && block->int_parameters["height"] > 0) {
 631                                 missing_height = false;
 632                         }
 633                         for (const auto &key_and_tuple : block->int_parameters) {
 634                                 int_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 635                         }
 636                         for (const auto &key_and_tuple : block->float_parameters) {
 637                                 float_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 638                         }
 639                         if (white_balance.count(block)) {
 640                                 vec3_to_set.emplace(make_pair(effect, "neutral_color"), white_balance[block]);
 641                         }
 642                         for (const auto &key_and_tuple : block->vec3_parameters) {
 643                                 vec3_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 644                         }
 645                         for (const auto &key_and_tuple : block->vec4_parameters) {
 646                                 vec4_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 647                         }
 648                 }
 649
 650                 // Parameters set on the blueprint itself override those that are set for the block,
 651                 // so they are set afterwards.
 652                 if (!block->alternatives.empty()) {
 653                         EffectBlueprint *blueprint = block->alternatives[block->currently_chosen_alternative];
 654                         if (blueprint->int_parameters.count("width") && blueprint->int_parameters["width"] > 0) {
 655                                 missing_width = false;
 656                         }
 657                         if (blueprint->int_parameters.count("height") && blueprint->int_parameters["height"] > 0) {
 658                                 missing_height = false;
 659                         }
 660                         for (const auto &key_and_tuple : blueprint->int_parameters) {
 661                                 int_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 662                         }
 663                         for (const auto &key_and_tuple : blueprint->float_parameters) {
 664                                 float_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 665                         }
 666                         for (const auto &key_and_tuple : blueprint->vec3_parameters) {
 667                                 vec3_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 668                         }
 669                         for (const auto &key_and_tuple : blueprint->vec4_parameters) {
 670                                 vec4_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 671                         }
 672                 }
 673
 674                 if (missing_width || missing_height) {
 675                         fprintf(stderr, "WARNING: Unset or nonpositive width/height for effect declared at %s "
 676                                 "when getting scene for signal %u; setting to 1x1 to avoid crash.\n",
 677                                 block->declaration_point.c_str(), num);
 678                         int_to_set[make_pair(effect, "width")] = 1;
 679                         int_to_set[make_pair(effect, "height")] = 1;
 680                 }
 681         }
 682
 683         lua_pop(L, 1);
 684
 685         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]{
 686                 lock_guard<mutex> lock(theme->m);
 687
 688                 // Set up state, including connecting signals.
 689                 for (const auto &input_and_signal : signals_to_connect) {
 690                         LiveInputWrapper *input = input_and_signal.first;
 691                         input->connect_signal_raw(input_and_signal.second, input_state);
 692                 }
 693                 for (const auto &input_and_filename : images_to_select) {
 694                         input_and_filename.first->switch_image(input_and_filename.second);
 695                 }
 696                 for (const auto &effect_and_key_and_value : int_to_set) {
 697                         Effect *effect = effect_and_key_and_value.first.first;
 698                         const string &key = effect_and_key_and_value.first.second;
 699                         const int value = effect_and_key_and_value.second;
 700                         if (!effect->set_int(key, value)) {
 701                                 luaL_error(L, "Effect refused set_int(\"%s\", %d) (invalid key?)", key.c_str(), value);
 702                         }
 703                 }
 704                 for (const auto &effect_and_key_and_value : float_to_set) {
 705                         Effect *effect = effect_and_key_and_value.first.first;
 706                         const string &key = effect_and_key_and_value.first.second;
 707                         const float value = effect_and_key_and_value.second;
 708                         if (!effect->set_float(key, value)) {
 709                                 luaL_error(L, "Effect refused set_float(\"%s\", %f) (invalid key?)", key.c_str(), value);
 710                         }
 711                 }
 712                 for (const auto &effect_and_key_and_value : vec3_to_set) {
 713                         Effect *effect = effect_and_key_and_value.first.first;
 714                         const string &key = effect_and_key_and_value.first.second;
 715                         const float *value = effect_and_key_and_value.second.data();
 716                         if (!effect->set_vec3(key, value)) {
 717                                 luaL_error(L, "Effect refused set_vec3(\"%s\", %f, %f, %f) (invalid key?)", key.c_str(),
 718                                                 value[0], value[1], value[2]);
 719                         }
 720                 }
 721                 for (const auto &effect_and_key_and_value : vec4_to_set) {
 722                         Effect *effect = effect_and_key_and_value.first.first;
 723                         const string &key = effect_and_key_and_value.first.second;
 724                         const float *value = effect_and_key_and_value.second.data();
 725                         if (!effect->set_vec4(key, value)) {
 726                                 luaL_error(L, "Effect refused set_vec4(\"%s\", %f, %f, %f, %f) (invalid key?)", key.c_str(),
 727                                                 value[0], value[1], value[2], value[3]);
 728                         }
 729                 }
 730         };
 731         return make_pair(effect_chain, move(setup_chain));
 732 }
 733
 734 bool display(Block *block, lua_State *L, int idx)
 735 {
 736         if (lua_isnumber(L, idx)) {
 737                 Theme *theme = get_theme_updata(L);
 738                 int signal_idx = luaL_checknumber(L, idx);
 739                 block->signal_type_to_connect = Block::CONNECT_SIGNAL;
 740                 block->signal_to_connect = theme->map_signal(signal_idx);
 741                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR);  // Will be changed to deinterlaced at get_chain() time if needed.
 742                 return true;
 743 #ifdef HAVE_CEF
 744         } else if (luaL_testudata(L, idx, "HTMLInput")) {
 745                 CEFCapture *capture = *(CEFCapture **)luaL_checkudata(L, idx, "HTMLInput");
 746                 block->signal_type_to_connect = Block::CONNECT_CEF;
 747                 block->cef_to_connect = capture;
 748                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_BGRA);
 749                 assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
 750                 return true;
 751 #endif
 752         } else if (luaL_testudata(L, idx, "VideoInput")) {
 753                 FFmpegCapture *capture = *(FFmpegCapture **)luaL_checkudata(L, idx, "VideoInput");
 754                 block->signal_type_to_connect = Block::CONNECT_VIDEO;
 755                 block->video_to_connect = capture;
 756                 if (capture->get_current_pixel_format() == bmusb::PixelFormat_8BitYCbCrPlanar) {
 757                         block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR_PLANAR);
 758                 } else {
 759                         assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
 760                         block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_BGRA);
 761                 }
 762                 return true;
 763         } else if (luaL_testudata(L, idx, "ImageInput")) {
 764                 ImageInput *image = *(ImageInput **)luaL_checkudata(L, idx, "ImageInput");
 765                 block->signal_type_to_connect = Block::CONNECT_NONE;
 766                 block->currently_chosen_alternative = find_index_of(block, IMAGE_INPUT);
 767                 block->pathname = image->get_pathname();
 768                 return true;
 769         } else {
 770                 return false;
 771         }
 772 }
 773
 774 int Block_display(lua_State* L)
 775 {
 776         assert(lua_gettop(L) == 2);
 777         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 778         if (!block->is_input) {
 779                 luaL_error(L, "display() called on something that isn't an input");
 780         }
 781
 782         bool ok = display(block, L, 2);
 783         if (!ok) {
 784                 luaL_error(L, "display() called with something that's not a signal (a signal number, a HTML input, or a VideoInput)");
 785         }
 786
 787         if (block->currently_chosen_alternative == -1) {
 788                 luaL_error(L, "display() called on an input whose type was fixed at construction time, with a signal of different type");
 789         }
 790
 791         return 0;
 792 }
 793
 794 int Block_choose(lua_State* L)
 795 {
 796         assert(lua_gettop(L) == 2);
 797         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 798         int alternative_idx = -1;
 799         if (lua_isnumber(L, 2)) {
 800                 alternative_idx = luaL_checknumber(L, 2);
 801         } else if (lua_istable(L, 2)) {
 802                 // See if it's an Effect metatable (e.g. foo:choose(ResampleEffect))
 803                 lua_getfield(L, 2, "__effect_type_id");
 804                 if (lua_isnumber(L, -1)) {
 805                         EffectType effect_type = EffectType(luaL_checknumber(L, -1));
 806                         alternative_idx = find_index_of(block, effect_type);
 807                 }
 808                 lua_pop(L, 1);
 809         }
 810
 811         if (alternative_idx == -1) {
 812                 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");
 813         }
 814
 815         assert(alternative_idx >= 0);
 816         assert(size_t(alternative_idx) < block->alternatives.size());
 817         block->currently_chosen_alternative = alternative_idx;
 818
 819         return wrap_lua_existing_object_nonowned<EffectBlueprint>(L, "EffectBlueprint", block->alternatives[alternative_idx]);
 820 }
 821
 822 int Block_enable(lua_State *L)
 823 {
 824         assert(lua_gettop(L) == 1);
 825         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 826
 827         if (block->alternatives.size() != 2 ||
 828             block->alternatives[1]->effect_type != IDENTITY_EFFECT) {
 829                 luaL_error(L, "enable() called on something that wasn't added with add_optional_effect()");
 830         }
 831         block->currently_chosen_alternative = 0;  // The actual effect.
 832         return 0;
 833 }
 834
 835 int Block_enable_if(lua_State *L)
 836 {
 837         assert(lua_gettop(L) == 2);
 838         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 839
 840         if (block->alternatives.size() != 2 ||
 841             block->alternatives[1]->effect_type != IDENTITY_EFFECT) {
 842                 luaL_error(L, "enable_if() called on something that wasn't added with add_optional_effect()");
 843         }
 844         bool enabled = checkbool(L, 2);
 845         block->currently_chosen_alternative = enabled ? 0 : 1;
 846         return 0;
 847 }
 848
 849 int Block_disable(lua_State *L)
 850 {
 851         assert(lua_gettop(L) == 1);
 852         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 853
 854         block->currently_chosen_alternative = find_index_of(block, IDENTITY_EFFECT);
 855         if (block->currently_chosen_alternative == -1) {
 856                 luaL_error(L, "disable() called on something that didn't have an IdentityEffect fallback (try add_optional_effect())");
 857         }
 858         assert(block->currently_chosen_alternative != -1);
 859         return 0;
 860 }
 861
 862 int Block_always_disable_if_disabled(lua_State *L)
 863 {
 864         assert(lua_gettop(L) == 2);
 865         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 866         Block *disabler_block = *(Block **)luaL_checkudata(L, 2, "Block");
 867
 868         int my_alternative = find_index_of(block, IDENTITY_EFFECT);
 869         int their_alternative = find_index_of(disabler_block, IDENTITY_EFFECT);
 870         if (my_alternative == -1) {
 871                 luaL_error(L, "always_disable_if_disabled() called on something that didn't have an IdentityEffect fallback (try add_optional_effect())");
 872         }
 873         if (their_alternative == -1) {
 874                 luaL_error(L, "always_disable_if_disabled() with an argument that didn't have an IdentityEffect fallback (try add_optional_effect())");
 875         }
 876
 877         // The declaration point isn't actually used, but it's nice for completeness.
 878         block->disablers.push_back(Block::Disabler{ disabler_block->idx, Block::Disabler::DISABLE_IF_OTHER_DISABLED, get_declaration_point(L) });
 879
 880         lua_pop(L, 2);
 881         return 0;
 882 }
 883
 884 int Block_promise_to_disable_if_enabled(lua_State *L)
 885 {
 886         assert(lua_gettop(L) == 2);
 887         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 888         Block *disabler_block = *(Block **)luaL_checkudata(L, 2, "Block");
 889
 890         int my_alternative = find_index_of(block, IDENTITY_EFFECT);
 891         int their_alternative = find_index_of(disabler_block, IDENTITY_EFFECT);
 892         if (my_alternative == -1) {
 893                 luaL_error(L, "promise_to_disable_if_enabled() called on something that didn't have an IdentityEffect fallback (try add_optional_effect())");
 894         }
 895         if (their_alternative == -1) {
 896                 luaL_error(L, "promise_to_disable_if_enabled() with an argument that didn't have an IdentityEffect fallback (try add_optional_effect())");
 897         }
 898
 899         block->disablers.push_back(Block::Disabler{ disabler_block->idx, Block::Disabler::DISABLE_IF_OTHER_ENABLED, get_declaration_point(L) });
 900
 901         lua_pop(L, 2);
 902         return 0;
 903 }
 904
 905 int Block_set_int(lua_State *L)
 906 {
 907         assert(lua_gettop(L) == 3);
 908         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 909         string key = checkstdstring(L, 2);
 910         float value = luaL_checknumber(L, 3);
 911
 912         // TODO: check validity already here, if possible?
 913         block->int_parameters[key] = value;
 914
 915         return 0;
 916 }
 917
 918 int Block_set_float(lua_State *L)
 919 {
 920         assert(lua_gettop(L) == 3);
 921         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 922         string key = checkstdstring(L, 2);
 923         float value = luaL_checknumber(L, 3);
 924
 925         // TODO: check validity already here, if possible?
 926         block->float_parameters[key] = value;
 927
 928         return 0;
 929 }
 930
 931 int Block_set_vec3(lua_State *L)
 932 {
 933         assert(lua_gettop(L) == 5);
 934         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 935         string key = checkstdstring(L, 2);
 936         array<float, 3> v;
 937         v[0] = luaL_checknumber(L, 3);
 938         v[1] = luaL_checknumber(L, 4);
 939         v[2] = luaL_checknumber(L, 5);
 940
 941         // TODO: check validity already here, if possible?
 942         block->vec3_parameters[key] = v;
 943
 944         return 0;
 945 }
 946
 947 int Block_set_vec4(lua_State *L)
 948 {
 949         assert(lua_gettop(L) == 6);
 950         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 951         string key = checkstdstring(L, 2);
 952         array<float, 4> v;
 953         v[0] = luaL_checknumber(L, 3);
 954         v[1] = luaL_checknumber(L, 4);
 955         v[2] = luaL_checknumber(L, 5);
 956         v[3] = luaL_checknumber(L, 6);
 957
 958         // TODO: check validity already here, if possible?
 959         block->vec4_parameters[key] = v;
 960
 961         return 0;
 962 }
 963