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 Scene::Scene(Theme *theme, float aspect_nom, float aspect_denom)
  39         : theme(theme), aspect_nom(aspect_nom), aspect_denom(aspect_denom), resource_pool(theme->get_resource_pool()) {}
  40
  41 size_t Scene::compute_chain_number(bool is_main_chain) const
  42 {
  43         assert(chains.size() > 0);
  44         assert(chains.size() % 2 == 0);
  45         size_t chain_number = compute_chain_number_for_block(blocks.size() - 1);
  46         assert(chain_number < chains.size() / 2);
  47         if (is_main_chain) {
  48                 chain_number += chains.size() / 2;
  49         }
  50         return chain_number;
  51 }
  52
  53 size_t Scene::compute_chain_number_for_block(size_t block_idx) const
  54 {
  55         Block *block = blocks[block_idx];
  56         size_t chain_number;
  57         if (block_idx == 0) {
  58                 assert(block->cardinality_base == 1);
  59                 chain_number = block->currently_chosen_alternative;
  60         } else {
  61                 chain_number = compute_chain_number_for_block(block_idx - 1) + block->cardinality_base * block->currently_chosen_alternative;
  62         }
  63         assert(block->currently_chosen_alternative < int(block->alternatives.size()));
  64         return chain_number;
  65 }
  66
  67 int Scene::add_input(lua_State* L)
  68 {
  69         assert(lua_gettop(L) == 1 || lua_gettop(L) == 2);
  70         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
  71
  72         Block *block = new Block;
  73         block->idx = scene->blocks.size();
  74         if (lua_gettop(L) == 1) {
  75                 // No parameter given, so a flexible input.
  76                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR));
  77                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR_WITH_DEINTERLACE));
  78                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR_PLANAR));
  79                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_BGRA));
  80                 block->alternatives.emplace_back(new EffectBlueprint(IMAGE_INPUT));
  81         } else {
  82                 // Input of a given type. We'll specialize it here, plus connect the input as given.
  83                 if (lua_isnumber(L, 2)) {
  84                         block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR));
  85                         block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR_WITH_DEINTERLACE));
  86 #ifdef HAVE_CEF
  87                 } else if (luaL_testudata(L, 2, "HTMLInput")) {
  88                         block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_BGRA));
  89 #endif
  90                 } else if (luaL_testudata(L, 2, "VideoInput")) {
  91                         FFmpegCapture *capture = *(FFmpegCapture **)luaL_checkudata(L, 2, "VideoInput");
  92                         if (capture->get_current_pixel_format() == bmusb::PixelFormat_8BitYCbCrPlanar) {
  93                                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_YCBCR_PLANAR));
  94                         } else {
  95                                 assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
  96                                 block->alternatives.emplace_back(new EffectBlueprint(LIVE_INPUT_BGRA));
  97                         }
  98                 } else if (luaL_testudata(L, 2, "ImageInput")) {
  99                         block->alternatives.emplace_back(new EffectBlueprint(IMAGE_INPUT));
 100                 } else {
 101                         luaL_error(L, "add_input() called with something that's not a signal (a signal number, a HTML input, or a VideoInput)");
 102                 }
 103                 bool ok = display(block, L, 2);
 104                 assert(ok);
 105         }
 106         block->is_input = true;
 107         scene->blocks.push_back(block);
 108
 109         return wrap_lua_existing_object_nonowned<Block>(L, "Block", block);
 110 }
 111
 112 int Scene::add_effect(lua_State* L)
 113 {
 114         assert(lua_gettop(L) >= 2);
 115         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
 116
 117         Block *block = new Block;
 118         block->idx = scene->blocks.size();
 119
 120         if (lua_istable(L, 2)) {
 121                 size_t len = lua_objlen(L, 2);
 122                 for (size_t i = 0; i < len; ++i) {
 123                         lua_rawgeti(L, 2, i + 1);
 124                         EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, -1, "EffectBlueprint");
 125                         block->alternatives.push_back(blueprint);
 126                         lua_settop(L, -2);
 127                 }
 128         } else {
 129                 EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, 2, "EffectBlueprint");
 130                 block->alternatives.push_back(blueprint);
 131         }
 132
 133         // Find the inputs.
 134         if (lua_gettop(L) == 2) {
 135                 assert(!scene->blocks.empty());
 136                 block->inputs.push_back(scene->blocks.size() - 1);
 137         } else {
 138                 for (int idx = 3; idx <= lua_gettop(L); ++idx) {
 139                         Block *input_block = nullptr;
 140                         if (luaL_testudata(L, idx, "Block")) {
 141                                 input_block = *(Block **)luaL_checkudata(L, idx, "Block");
 142                         } else {
 143                                 EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, idx, "EffectBlueprint");
 144
 145                                 // Search through all the blocks to figure out which one contains this effect.
 146                                 for (Block *block : scene->blocks) {
 147                                         if (find(block->alternatives.begin(), block->alternatives.end(), blueprint) != block->alternatives.end()) {
 148                                                 input_block = block;
 149                                                 break;
 150                                         }
 151                                 }
 152                                 if (input_block == nullptr) {
 153                                         luaL_error(L, "Input effect in parameter #%d has not been added to this scene", idx - 1);
 154                                 }
 155                         }
 156                         block->inputs.push_back(input_block->idx);
 157                 }
 158         }
 159
 160         scene->blocks.push_back(block);
 161
 162         return wrap_lua_existing_object_nonowned<Block>(L, "Block", block);
 163 }
 164
 165 int Scene::add_optional_effect(lua_State* L)
 166 {
 167         assert(lua_gettop(L) >= 2);
 168         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
 169
 170         // NOTE: We only support effects with a single parent, since that's what IdentityEffect does.
 171         Block *block = new Block;
 172         block->idx = scene->blocks.size();
 173
 174         EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, 2, "EffectBlueprint");
 175         block->alternatives.push_back(blueprint);
 176
 177         // An IdentityEffect will be the alternative for when the effect is disabled.
 178         block->alternatives.push_back(new EffectBlueprint(IDENTITY_EFFECT));
 179
 180         block->inputs.push_back(scene->blocks.size() - 1);
 181         scene->blocks.push_back(block);
 182
 183         return wrap_lua_existing_object_nonowned<Block>(L, "Block", block);
 184 }
 185
 186 Effect *Scene::instantiate_effects(const Block *block, size_t chain_idx, Scene::Instantiation *instantiation)
 187 {
 188         vector<Effect *> inputs;
 189         for (size_t input_idx : block->inputs) {
 190                 inputs.push_back(instantiate_effects(blocks[input_idx], chain_idx, instantiation));
 191         }
 192
 193         // Find the chosen alternative for this block in this instance.
 194         size_t chosen_alternative = (chain_idx / block->cardinality_base) % block->alternatives.size();
 195         EffectType chosen_type = block->alternatives[chosen_alternative]->effect_type;
 196
 197         Effect *effect;
 198         switch (chosen_type) {
 199         case LIVE_INPUT_YCBCR:
 200         case LIVE_INPUT_YCBCR_WITH_DEINTERLACE:
 201         case LIVE_INPUT_YCBCR_PLANAR:
 202         case LIVE_INPUT_BGRA: {
 203                 bool deinterlace = (chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
 204                 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.
 205                 bmusb::PixelFormat pixel_format;
 206                 if (chosen_type == LIVE_INPUT_BGRA) {
 207                         pixel_format = bmusb::PixelFormat_8BitBGRA;
 208                 } else if (chosen_type == LIVE_INPUT_YCBCR_PLANAR) {
 209                         pixel_format = bmusb::PixelFormat_8BitYCbCrPlanar;
 210                 } else if (global_flags.ten_bit_input) {
 211                         pixel_format = bmusb::PixelFormat_10BitYCbCr;
 212                 } else {
 213                         pixel_format = bmusb::PixelFormat_8BitYCbCr;
 214                 }
 215                 LiveInputWrapper *input = new LiveInputWrapper(theme, instantiation->chain.get(), pixel_format, override_bounce, deinterlace, /*user_connectable=*/true);
 216                 effect = input->get_effect();  // Adds itself to the chain, so no need to call add_effect().
 217                 instantiation->inputs.emplace(block->idx, input);
 218                 break;
 219         }
 220         case IMAGE_INPUT: {
 221                 ImageInput *input = new ImageInput;
 222                 instantiation->chain->add_input(input);
 223                 instantiation->image_inputs.emplace(block->idx, input);
 224                 effect = input;
 225                 break;
 226         }
 227         default:
 228                 effect = instantiate_effect(instantiation->chain.get(), block->alternatives[chosen_alternative]->effect_type);
 229                 instantiation->chain->add_effect(effect, inputs);
 230                 break;
 231         }
 232         instantiation->effects.emplace(block->idx, effect);
 233         return effect;
 234 }
 235
 236 int Scene::finalize(lua_State* L)
 237 {
 238         bool only_one_mode = false;
 239         bool chosen_mode = false;
 240         if (lua_gettop(L) == 2) {
 241                 only_one_mode = true;
 242                 chosen_mode = checkbool(L, 2);
 243         } else {
 244                 assert(lua_gettop(L) == 1);
 245         }
 246         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
 247         Theme *theme = get_theme_updata(L);
 248
 249         size_t base = 1;
 250         for (Block *block : scene->blocks) {
 251                 block->cardinality_base = base;
 252                 base *= block->alternatives.size();
 253         }
 254
 255         const size_t cardinality = base;
 256         const size_t total_cardinality = cardinality * (only_one_mode ? 1 : 2);
 257         if (total_cardinality > 200) {
 258                 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",
 259                         total_cardinality);
 260         }
 261
 262         Block *output_block = scene->blocks.back();
 263         for (bool is_main_chain : { false, true }) {
 264                 for (size_t chain_idx = 0; chain_idx < cardinality; ++chain_idx) {
 265                         if (only_one_mode && is_main_chain != chosen_mode) {
 266                                 scene->chains.emplace_back();
 267                                 continue;
 268                         }
 269
 270                         Scene::Instantiation instantiation;
 271                         instantiation.chain.reset(new EffectChain(scene->aspect_nom, scene->aspect_denom, theme->get_resource_pool()));
 272                         scene->instantiate_effects(output_block, chain_idx, &instantiation);
 273
 274                         add_outputs_and_finalize(instantiation.chain.get(), is_main_chain);
 275                         scene->chains.emplace_back(move(instantiation));
 276                 }
 277         }
 278         return 0;
 279 }
 280
 281 std::pair<movit::EffectChain *, std::function<void()>>
 282 Scene::get_chain(Theme *theme, lua_State *L, unsigned num, const InputState &input_state)
 283 {
 284         // For video inputs, pick the right interlaced/progressive version
 285         // based on the current state of the signals.
 286         InputStateInfo info(input_state);
 287         for (Block *block : blocks) {
 288                 if (block->is_input && block->signal_type_to_connect == Block::CONNECT_SIGNAL) {
 289                         EffectType chosen_type = current_type(block);
 290                         assert(chosen_type == LIVE_INPUT_YCBCR || chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
 291                         if (info.last_interlaced[block->signal_to_connect]) {
 292                                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
 293                         } else {
 294                                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR);
 295                         }
 296                 }
 297         }
 298
 299         // Pick out the right chain based on the current selections,
 300         // and snapshot all the set variables so that we can set them
 301         // in the prepare function even if they're being changed by
 302         // the Lua code later.
 303         bool is_main_chain = (num == 0);
 304         size_t chain_idx = compute_chain_number(is_main_chain);
 305         const Scene::Instantiation &instantiation = chains[chain_idx];
 306         EffectChain *effect_chain = instantiation.chain.get();
 307
 308         map<LiveInputWrapper *, int> signals_to_connect;
 309         map<ImageInput *, string> images_to_select;
 310         map<pair<Effect *, string>, int> int_to_set;
 311         map<pair<Effect *, string>, float> float_to_set;
 312         map<pair<Effect *, string>, array<float, 3>> vec3_to_set;
 313         map<pair<Effect *, string>, array<float, 4>> vec4_to_set;
 314         for (const auto &index_and_input : instantiation.inputs) {
 315                 Block *block = blocks[index_and_input.first];
 316                 EffectType chosen_type = current_type(block);
 317                 LiveInputWrapper *input = index_and_input.second;
 318                 if (chosen_type == LIVE_INPUT_YCBCR ||
 319                     chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE ||
 320                     chosen_type == LIVE_INPUT_YCBCR_PLANAR ||
 321                     chosen_type == LIVE_INPUT_BGRA) {
 322                         if (block->signal_type_to_connect == Block::CONNECT_SIGNAL) {
 323                                 signals_to_connect.emplace(input, block->signal_to_connect);
 324 #ifdef HAVE_CEF
 325                         } else if (block->signal_type_to_connect == Block::CONNECT_CEF) {
 326                                 signals_to_connect.emplace(input, block->cef_to_connect->get_card_index());
 327 #endif
 328                         } else if (block->signal_type_to_connect == Block::CONNECT_VIDEO) {
 329                                 signals_to_connect.emplace(input, block->video_to_connect->get_card_index());
 330                         } else if (block->signal_type_to_connect == Block::CONNECT_NONE) {
 331                                 luaL_error(L, "An input in a scene was not connected to anything (forgot to call display())");
 332                         } else {
 333                                 assert(false);
 334                         }
 335                 }
 336         }
 337         for (const auto &index_and_input : instantiation.image_inputs) {
 338                 Block *block = blocks[index_and_input.first];
 339                 ImageInput *input = index_and_input.second;
 340                 if (current_type(block) == IMAGE_INPUT) {
 341                         images_to_select.emplace(input, block->pathname);
 342                 }
 343         }
 344         for (const auto &index_and_effect : instantiation.effects) {
 345                 Block *block = blocks[index_and_effect.first];
 346                 Effect *effect = index_and_effect.second;
 347
 348                 // Get the effects currently set on the block.
 349                 if (current_type(block) != IDENTITY_EFFECT) {  // Ignore settings on optional effects.
 350                         for (const auto &key_and_tuple : block->int_parameters) {
 351                                 int_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 352                         }
 353                         for (const auto &key_and_tuple : block->float_parameters) {
 354                                 float_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 355                         }
 356                         for (const auto &key_and_tuple : block->vec3_parameters) {
 357                                 vec3_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 358                         }
 359                         for (const auto &key_and_tuple : block->vec4_parameters) {
 360                                 vec4_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 361                         }
 362                 }
 363
 364                 // Parameters set on the blueprint itself override those that are set for the block,
 365                 // so they are set afterwards.
 366                 if (!block->alternatives.empty()) {
 367                         EffectBlueprint *blueprint = block->alternatives[block->currently_chosen_alternative];
 368                         for (const auto &key_and_tuple : blueprint->int_parameters) {
 369                                 int_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 370                         }
 371                         for (const auto &key_and_tuple : blueprint->float_parameters) {
 372                                 float_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 373                         }
 374                         for (const auto &key_and_tuple : blueprint->vec3_parameters) {
 375                                 vec3_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 376                         }
 377                         for (const auto &key_and_tuple : blueprint->vec4_parameters) {
 378                                 vec4_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 379                         }
 380                 }
 381         }
 382
 383         lua_pop(L, 1);
 384
 385         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]{
 386                 lock_guard<mutex> lock(theme->m);
 387
 388                 // Set up state, including connecting signals.
 389                 for (const auto &input_and_signal : signals_to_connect) {
 390                         LiveInputWrapper *input = input_and_signal.first;
 391                         input->connect_signal_raw(input_and_signal.second, input_state);
 392                 }
 393                 for (const auto &input_and_filename : images_to_select) {
 394                         input_and_filename.first->switch_image(input_and_filename.second);
 395                 }
 396                 for (const auto &effect_and_key_and_value : int_to_set) {
 397                         Effect *effect = effect_and_key_and_value.first.first;
 398                         const string &key = effect_and_key_and_value.first.second;
 399                         const int value = effect_and_key_and_value.second;
 400                         if (!effect->set_int(key, value)) {
 401                                 luaL_error(L, "Effect refused set_int(\"%s\", %d) (invalid key?)", key.c_str(), value);
 402                         }
 403                 }
 404                 for (const auto &effect_and_key_and_value : float_to_set) {
 405                         Effect *effect = effect_and_key_and_value.first.first;
 406                         const string &key = effect_and_key_and_value.first.second;
 407                         const float value = effect_and_key_and_value.second;
 408                         if (!effect->set_float(key, value)) {
 409                                 luaL_error(L, "Effect refused set_float(\"%s\", %f) (invalid key?)", key.c_str(), value);
 410                         }
 411                 }
 412                 for (const auto &effect_and_key_and_value : vec3_to_set) {
 413                         Effect *effect = effect_and_key_and_value.first.first;
 414                         const string &key = effect_and_key_and_value.first.second;
 415                         const float *value = effect_and_key_and_value.second.data();
 416                         if (!effect->set_vec3(key, value)) {
 417                                 luaL_error(L, "Effect refused set_vec3(\"%s\", %f, %f, %f) (invalid key?)", key.c_str(),
 418                                                 value[0], value[1], value[2]);
 419                         }
 420                 }
 421                 for (const auto &effect_and_key_and_value : vec4_to_set) {
 422                         Effect *effect = effect_and_key_and_value.first.first;
 423                         const string &key = effect_and_key_and_value.first.second;
 424                         const float *value = effect_and_key_and_value.second.data();
 425                         if (!effect->set_vec4(key, value)) {
 426                                 luaL_error(L, "Effect refused set_vec4(\"%s\", %f, %f, %f, %f) (invalid key?)", key.c_str(),
 427                                                 value[0], value[1], value[2], value[3]);
 428                         }
 429                 }
 430         };
 431         return make_pair(effect_chain, move(setup_chain));
 432 }
 433
 434 bool display(Block *block, lua_State *L, int idx)
 435 {
 436         if (lua_isnumber(L, idx)) {
 437                 Theme *theme = get_theme_updata(L);
 438                 int signal_idx = luaL_checknumber(L, idx);
 439                 block->signal_type_to_connect = Block::CONNECT_SIGNAL;
 440                 block->signal_to_connect = theme->map_signal(signal_idx);
 441                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR);  // Will be changed to deinterlaced at get_chain() time if needed.
 442                 return true;
 443 #ifdef HAVE_CEF
 444         } else if (luaL_testudata(L, idx, "HTMLInput")) {
 445                 CEFCapture *capture = *(CEFCapture **)luaL_checkudata(L, idx, "HTMLInput");
 446                 block->signal_type_to_connect = Block::CONNECT_CEF;
 447                 block->cef_to_connect = capture;
 448                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_BGRA);
 449                 assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
 450                 return true;
 451 #endif
 452         } else if (luaL_testudata(L, idx, "VideoInput")) {
 453                 FFmpegCapture *capture = *(FFmpegCapture **)luaL_checkudata(L, idx, "VideoInput");
 454                 block->signal_type_to_connect = Block::CONNECT_VIDEO;
 455                 block->video_to_connect = capture;
 456                 if (capture->get_current_pixel_format() == bmusb::PixelFormat_8BitYCbCrPlanar) {
 457                         block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR_PLANAR);
 458                 } else {
 459                         assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
 460                         block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_BGRA);
 461                 }
 462                 return true;
 463         } else if (luaL_testudata(L, idx, "ImageInput")) {
 464                 ImageInput *image = *(ImageInput **)luaL_checkudata(L, idx, "ImageInput");
 465                 block->signal_type_to_connect = Block::CONNECT_NONE;
 466                 block->currently_chosen_alternative = find_index_of(block, IMAGE_INPUT);
 467                 block->pathname = image->get_pathname();
 468                 return true;
 469         } else {
 470                 return false;
 471         }
 472 }
 473
 474 int Block_display(lua_State* L)
 475 {
 476         assert(lua_gettop(L) == 2);
 477         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 478         if (!block->is_input) {
 479                 luaL_error(L, "display() called on something that isn't an input");
 480         }
 481
 482         bool ok = display(block, L, 2);
 483         if (!ok) {
 484                 luaL_error(L, "display() called with something that's not a signal (a signal number, a HTML input, or a VideoInput)");
 485         }
 486
 487         if (block->currently_chosen_alternative == -1) {
 488                 luaL_error(L, "display() called on an input whose type was fixed at construction time, with a signal of different type");
 489         }
 490
 491         return 0;
 492 }
 493
 494 int Block_choose(lua_State* L)
 495 {
 496         assert(lua_gettop(L) == 2);
 497         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 498         int alternative_idx = -1;
 499         if (lua_isnumber(L, 2)) {
 500                 alternative_idx = luaL_checknumber(L, 2);
 501         } else if (lua_istable(L, 2)) {
 502                 // See if it's an Effect metatable (e.g. foo:choose(ResampleEffect))
 503                 lua_getfield(L, 2, "__effect_type_id");
 504                 if (lua_isnumber(L, -1)) {
 505                         EffectType effect_type = EffectType(luaL_checknumber(L, -1));
 506                         alternative_idx = find_index_of(block, effect_type);
 507                 }
 508                 lua_pop(L, 1);
 509         }
 510
 511         if (alternative_idx == -1) {
 512                 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");
 513         }
 514
 515         assert(alternative_idx >= 0);
 516         assert(size_t(alternative_idx) < block->alternatives.size());
 517         block->currently_chosen_alternative = alternative_idx;
 518
 519         return wrap_lua_existing_object_nonowned<EffectBlueprint>(L, "EffectBlueprint", block->alternatives[alternative_idx]);
 520 }
 521
 522 int Block_enable(lua_State *L)
 523 {
 524         assert(lua_gettop(L) == 1);
 525         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 526
 527         if (block->alternatives.size() != 2 ||
 528             block->alternatives[1]->effect_type != IDENTITY_EFFECT) {
 529                 luaL_error(L, "enable() called on something that wasn't added with add_optional_effect()");
 530         }
 531         block->currently_chosen_alternative = 0;  // The actual effect.
 532         return 0;
 533 }
 534
 535 int Block_disable(lua_State *L)
 536 {
 537         assert(lua_gettop(L) == 1);
 538         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 539
 540         block->currently_chosen_alternative = find_index_of(block, IDENTITY_EFFECT);
 541         if (block->currently_chosen_alternative == -1) {
 542                 luaL_error(L, "disable() called on something that didn't have an IdentityEffect fallback (try add_optional_effect())");
 543         }
 544         assert(block->currently_chosen_alternative != -1);
 545         return 0;
 546 }
 547
 548 int Block_set_int(lua_State *L)
 549 {
 550         assert(lua_gettop(L) == 3);
 551         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 552         string key = checkstdstring(L, 2);
 553         float value = luaL_checknumber(L, 3);
 554
 555         // TODO: check validity already here, if possible?
 556         block->int_parameters[key] = value;
 557
 558         return 0;
 559 }
 560
 561 int Block_set_float(lua_State *L)
 562 {
 563         assert(lua_gettop(L) == 3);
 564         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 565         string key = checkstdstring(L, 2);
 566         float value = luaL_checknumber(L, 3);
 567
 568         // TODO: check validity already here, if possible?
 569         block->float_parameters[key] = value;
 570
 571         return 0;
 572 }
 573
 574 int Block_set_vec3(lua_State *L)
 575 {
 576         assert(lua_gettop(L) == 5);
 577         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 578         string key = checkstdstring(L, 2);
 579         array<float, 3> v;
 580         v[0] = luaL_checknumber(L, 3);
 581         v[1] = luaL_checknumber(L, 4);
 582         v[2] = luaL_checknumber(L, 5);
 583
 584         // TODO: check validity already here, if possible?
 585         block->vec3_parameters[key] = v;
 586
 587         return 0;
 588 }
 589
 590 int Block_set_vec4(lua_State *L)
 591 {
 592         assert(lua_gettop(L) == 6);
 593         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 594         string key = checkstdstring(L, 2);
 595         array<float, 4> v;
 596         v[0] = luaL_checknumber(L, 3);
 597         v[1] = luaL_checknumber(L, 4);
 598         v[2] = luaL_checknumber(L, 5);
 599         v[3] = luaL_checknumber(L, 6);
 600
 601         // TODO: check validity already here, if possible?
 602         block->vec4_parameters[key] = v;
 603
 604         return 0;
 605 }
 606