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 *chain = (Scene *)luaL_checkudata(L, 1, "Scene");
  71
  72         Block *block = new Block;
  73         block->idx = chain->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         chain->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 *chain = (Scene *)luaL_checkudata(L, 1, "Scene");
 116
 117         Block *block = new Block;
 118         block->idx = chain->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(!chain->blocks.empty());
 136                 block->inputs.push_back(chain->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 : chain->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 chain", idx - 1);
 154                                 }
 155                         }
 156                         block->inputs.push_back(input_block->idx);
 157                 }
 158         }
 159
 160         chain->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 *chain = (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 = chain->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(chain->blocks.size() - 1);
 181         chain->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 *chain = (Scene *)luaL_checkudata(L, 1, "Scene");
 247         Theme *theme = get_theme_updata(L);
 248
 249         size_t base = 1;
 250         for (Block *block : chain->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 = chain->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                                 chain->chains.emplace_back();
 267                                 continue;
 268                         }
 269
 270                         Scene::Instantiation instantiation;
 271                         instantiation.chain.reset(new EffectChain(chain->aspect_nom, chain->aspect_denom, theme->get_resource_pool()));
 272                         chain->instantiate_effects(output_block, chain_idx, &instantiation);
 273
 274                         add_outputs_and_finalize(instantiation.chain.get(), is_main_chain);
 275                         chain->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 chain 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.emplace(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.emplace(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.emplace(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.emplace(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                 assert(theme->input_state == nullptr);
 389                 theme->input_state = &input_state;
 390
 391                 // Set up state, including connecting signals.
 392                 for (const auto &input_and_signal : signals_to_connect) {
 393                         LiveInputWrapper *input = input_and_signal.first;
 394                         input->connect_signal_raw(input_and_signal.second, input_state);
 395                 }
 396                 for (const auto &input_and_filename : images_to_select) {
 397                         input_and_filename.first->switch_image(input_and_filename.second);
 398                 }
 399                 for (const auto &effect_and_key_and_value : int_to_set) {
 400                         Effect *effect = effect_and_key_and_value.first.first;
 401                         const string &key = effect_and_key_and_value.first.second;
 402                         const int value = effect_and_key_and_value.second;
 403                         if (!effect->set_int(key, value)) {
 404                                 luaL_error(L, "Effect refused set_int(\"%s\", %d) (invalid key?)", key.c_str(), value);
 405                         }
 406                 }
 407                 for (const auto &effect_and_key_and_value : float_to_set) {
 408                         Effect *effect = effect_and_key_and_value.first.first;
 409                         const string &key = effect_and_key_and_value.first.second;
 410                         const float value = effect_and_key_and_value.second;
 411                         if (!effect->set_float(key, value)) {
 412                                 luaL_error(L, "Effect refused set_float(\"%s\", %f) (invalid key?)", key.c_str(), value);
 413                         }
 414                 }
 415                 for (const auto &effect_and_key_and_value : vec3_to_set) {
 416                         Effect *effect = effect_and_key_and_value.first.first;
 417                         const string &key = effect_and_key_and_value.first.second;
 418                         const float *value = effect_and_key_and_value.second.data();
 419                         if (!effect->set_vec3(key, value)) {
 420                                 luaL_error(L, "Effect refused set_vec3(\"%s\", %f, %f, %f) (invalid key?)", key.c_str(),
 421                                                 value[0], value[1], value[2]);
 422                         }
 423                 }
 424                 for (const auto &effect_and_key_and_value : vec4_to_set) {
 425                         Effect *effect = effect_and_key_and_value.first.first;
 426                         const string &key = effect_and_key_and_value.first.second;
 427                         const float *value = effect_and_key_and_value.second.data();
 428                         if (!effect->set_vec4(key, value)) {
 429                                 luaL_error(L, "Effect refused set_vec4(\"%s\", %f, %f, %f, %f) (invalid key?)", key.c_str(),
 430                                                 value[0], value[1], value[2], value[3]);
 431                         }
 432                 }
 433
 434                 theme->input_state = nullptr;
 435         };
 436         return make_pair(effect_chain, move(setup_chain));
 437 }
 438
 439 bool display(Block *block, lua_State *L, int idx)
 440 {
 441         if (lua_isnumber(L, idx)) {
 442                 Theme *theme = get_theme_updata(L);
 443                 int signal_idx = luaL_checknumber(L, idx);
 444                 block->signal_type_to_connect = Block::CONNECT_SIGNAL;
 445                 block->signal_to_connect = theme->map_signal(signal_idx);
 446                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR);  // Will be changed to deinterlaced at get_chain() time if needed.
 447                 return true;
 448 #ifdef HAVE_CEF
 449         } else if (luaL_testudata(L, idx, "HTMLInput")) {
 450                 CEFCapture *capture = *(CEFCapture **)luaL_checkudata(L, idx, "HTMLInput");
 451                 block->signal_type_to_connect = Block::CONNECT_CEF;
 452                 block->cef_to_connect = capture;
 453                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_BGRA);
 454                 assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
 455                 return true;
 456 #endif
 457         } else if (luaL_testudata(L, idx, "VideoInput")) {
 458                 FFmpegCapture *capture = *(FFmpegCapture **)luaL_checkudata(L, idx, "VideoInput");
 459                 block->signal_type_to_connect = Block::CONNECT_VIDEO;
 460                 block->video_to_connect = capture;
 461                 if (capture->get_current_pixel_format() == bmusb::PixelFormat_8BitYCbCrPlanar) {
 462                         block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR_PLANAR);
 463                 } else {
 464                         assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
 465                         block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_BGRA);
 466                 }
 467                 return true;
 468         } else if (luaL_testudata(L, idx, "ImageInput")) {
 469                 ImageInput *image = *(ImageInput **)luaL_checkudata(L, idx, "ImageInput");
 470                 block->signal_type_to_connect = Block::CONNECT_NONE;
 471                 block->currently_chosen_alternative = find_index_of(block, IMAGE_INPUT);
 472                 block->pathname = image->get_pathname();
 473                 return true;
 474         } else {
 475                 return false;
 476         }
 477 }
 478
 479 int Block_display(lua_State* L)
 480 {
 481         assert(lua_gettop(L) == 2);
 482         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 483         if (!block->is_input) {
 484                 luaL_error(L, "display() called on something that isn't an input");
 485         }
 486
 487         bool ok = display(block, L, 2);
 488         if (!ok) {
 489                 luaL_error(L, "display() called with something that's not a signal (a signal number, a HTML input, or a VideoInput)");
 490         }
 491
 492         if (block->currently_chosen_alternative == -1) {
 493                 luaL_error(L, "display() called on an input whose type was fixed at construction time, with a signal of different type");
 494         }
 495
 496         return 0;
 497 }
 498
 499 int Block_choose_alternative(lua_State* L)
 500 {
 501         assert(lua_gettop(L) == 2);
 502         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 503         int alternative_idx = luaL_checknumber(L, 2);
 504
 505         assert(alternative_idx >= 0);
 506         assert(size_t(alternative_idx) < block->alternatives.size());
 507         block->currently_chosen_alternative = alternative_idx;
 508
 509         return 0;
 510 }
 511
 512 int Block_enable(lua_State *L)
 513 {
 514         assert(lua_gettop(L) == 1);
 515         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 516
 517         if (block->alternatives.size() != 2 ||
 518             block->alternatives[1]->effect_type != IDENTITY_EFFECT) {
 519                 luaL_error(L, "enable() called on something that wasn't added with add_optional_effect()");
 520         }
 521         block->currently_chosen_alternative = 0;  // The actual effect.
 522         return 0;
 523 }
 524
 525 int Block_disable(lua_State *L)
 526 {
 527         assert(lua_gettop(L) == 1);
 528         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 529
 530         if (block->alternatives.size() != 2 ||
 531             block->alternatives[1]->effect_type != IDENTITY_EFFECT) {
 532                 luaL_error(L, "disable() called on something that wasn't added with add_optional_effect()");
 533         }
 534         block->currently_chosen_alternative = find_index_of(block, IDENTITY_EFFECT);
 535         assert(block->currently_chosen_alternative != -1);
 536         return 0;
 537 }
 538
 539 int Block_set_int(lua_State *L)
 540 {
 541         assert(lua_gettop(L) == 3);
 542         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 543         string key = checkstdstring(L, 2);
 544         float value = luaL_checknumber(L, 3);
 545
 546         // TODO: check validity already here, if possible?
 547         block->int_parameters[key] = value;
 548
 549         return 0;
 550 }
 551
 552 int Block_set_float(lua_State *L)
 553 {
 554         assert(lua_gettop(L) == 3);
 555         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 556         string key = checkstdstring(L, 2);
 557         float value = luaL_checknumber(L, 3);
 558
 559         // TODO: check validity already here, if possible?
 560         block->float_parameters[key] = value;
 561
 562         return 0;
 563 }
 564
 565 int Block_set_vec3(lua_State *L)
 566 {
 567         assert(lua_gettop(L) == 5);
 568         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 569         string key = checkstdstring(L, 2);
 570         array<float, 3> v;
 571         v[0] = luaL_checknumber(L, 3);
 572         v[1] = luaL_checknumber(L, 4);
 573         v[2] = luaL_checknumber(L, 5);
 574
 575         // TODO: check validity already here, if possible?
 576         block->vec3_parameters[key] = v;
 577
 578         return 0;
 579 }
 580
 581 int Block_set_vec4(lua_State *L)
 582 {
 583         assert(lua_gettop(L) == 6);
 584         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 585         string key = checkstdstring(L, 2);
 586         array<float, 4> v;
 587         v[0] = luaL_checknumber(L, 3);
 588         v[1] = luaL_checknumber(L, 4);
 589         v[2] = luaL_checknumber(L, 5);
 590         v[3] = luaL_checknumber(L, 6);
 591
 592         // TODO: check validity already here, if possible?
 593         block->vec4_parameters[key] = v;
 594
 595         return 0;
 596 }
 597