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         EffectType chosen_type = block->alternatives[block->chosen_alternative(chain_idx)]->effect_type;
 195
 196         Effect *effect;
 197         switch (chosen_type) {
 198         case LIVE_INPUT_YCBCR:
 199         case LIVE_INPUT_YCBCR_WITH_DEINTERLACE:
 200         case LIVE_INPUT_YCBCR_PLANAR:
 201         case LIVE_INPUT_BGRA: {
 202                 bool deinterlace = (chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
 203                 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.
 204                 bmusb::PixelFormat pixel_format;
 205                 if (chosen_type == LIVE_INPUT_BGRA) {
 206                         pixel_format = bmusb::PixelFormat_8BitBGRA;
 207                 } else if (chosen_type == LIVE_INPUT_YCBCR_PLANAR) {
 208                         pixel_format = bmusb::PixelFormat_8BitYCbCrPlanar;
 209                 } else if (global_flags.ten_bit_input) {
 210                         pixel_format = bmusb::PixelFormat_10BitYCbCr;
 211                 } else {
 212                         pixel_format = bmusb::PixelFormat_8BitYCbCr;
 213                 }
 214                 LiveInputWrapper *input = new LiveInputWrapper(theme, instantiation->chain.get(), pixel_format, override_bounce, deinterlace, /*user_connectable=*/true);
 215                 effect = input->get_effect();  // Adds itself to the chain, so no need to call add_effect().
 216                 instantiation->inputs.emplace(block->idx, input);
 217                 break;
 218         }
 219         case IMAGE_INPUT: {
 220                 ImageInput *input = new ImageInput;
 221                 instantiation->chain->add_input(input);
 222                 instantiation->image_inputs.emplace(block->idx, input);
 223                 effect = input;
 224                 break;
 225         }
 226         default:
 227                 effect = instantiate_effect(instantiation->chain.get(), chosen_type);
 228                 instantiation->chain->add_effect(effect, inputs);
 229                 break;
 230         }
 231         instantiation->effects.emplace(block->idx, effect);
 232         return effect;
 233 }
 234
 235 int Scene::finalize(lua_State* L)
 236 {
 237         bool only_one_mode = false;
 238         bool chosen_mode = false;
 239         if (lua_gettop(L) == 2) {
 240                 only_one_mode = true;
 241                 chosen_mode = checkbool(L, 2);
 242         } else {
 243                 assert(lua_gettop(L) == 1);
 244         }
 245         Scene *scene = (Scene *)luaL_checkudata(L, 1, "Scene");
 246         Theme *theme = get_theme_updata(L);
 247
 248         size_t base = 1;
 249         for (Block *block : scene->blocks) {
 250                 block->cardinality_base = base;
 251                 base *= block->alternatives.size();
 252         }
 253
 254         const size_t cardinality = base;
 255         const size_t total_cardinality = cardinality * (only_one_mode ? 1 : 2);
 256         if (total_cardinality > 200) {
 257                 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",
 258                         total_cardinality);
 259         }
 260
 261         Block *output_block = scene->blocks.back();
 262         for (bool is_main_chain : { false, true }) {
 263                 for (size_t chain_idx = 0; chain_idx < cardinality; ++chain_idx) {
 264                         if (only_one_mode && is_main_chain != chosen_mode) {
 265                                 scene->chains.emplace_back();
 266                                 continue;
 267                         }
 268
 269                         Scene::Instantiation instantiation;
 270                         instantiation.chain.reset(new EffectChain(scene->aspect_nom, scene->aspect_denom, theme->get_resource_pool()));
 271                         scene->instantiate_effects(output_block, chain_idx, &instantiation);
 272
 273                         add_outputs_and_finalize(instantiation.chain.get(), is_main_chain);
 274                         scene->chains.emplace_back(move(instantiation));
 275                 }
 276         }
 277         return 0;
 278 }
 279
 280 std::pair<movit::EffectChain *, std::function<void()>>
 281 Scene::get_chain(Theme *theme, lua_State *L, unsigned num, const InputState &input_state)
 282 {
 283         // For video inputs, pick the right interlaced/progressive version
 284         // based on the current state of the signals.
 285         InputStateInfo info(input_state);
 286         for (Block *block : blocks) {
 287                 if (block->is_input && block->signal_type_to_connect == Block::CONNECT_SIGNAL) {
 288                         EffectType chosen_type = current_type(block);
 289                         assert(chosen_type == LIVE_INPUT_YCBCR || chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
 290                         if (info.last_interlaced[block->signal_to_connect]) {
 291                                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR_WITH_DEINTERLACE);
 292                         } else {
 293                                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR);
 294                         }
 295                 }
 296         }
 297
 298         // Pick out the right chain based on the current selections,
 299         // and snapshot all the set variables so that we can set them
 300         // in the prepare function even if they're being changed by
 301         // the Lua code later.
 302         bool is_main_chain = (num == 0);
 303         size_t chain_idx = compute_chain_number(is_main_chain);
 304         const Scene::Instantiation &instantiation = chains[chain_idx];
 305         EffectChain *effect_chain = instantiation.chain.get();
 306
 307         map<LiveInputWrapper *, int> signals_to_connect;
 308         map<ImageInput *, string> images_to_select;
 309         map<pair<Effect *, string>, int> int_to_set;
 310         map<pair<Effect *, string>, float> float_to_set;
 311         map<pair<Effect *, string>, array<float, 3>> vec3_to_set;
 312         map<pair<Effect *, string>, array<float, 4>> vec4_to_set;
 313         for (const auto &index_and_input : instantiation.inputs) {
 314                 Block *block = blocks[index_and_input.first];
 315                 EffectType chosen_type = current_type(block);
 316                 LiveInputWrapper *input = index_and_input.second;
 317                 if (chosen_type == LIVE_INPUT_YCBCR ||
 318                     chosen_type == LIVE_INPUT_YCBCR_WITH_DEINTERLACE ||
 319                     chosen_type == LIVE_INPUT_YCBCR_PLANAR ||
 320                     chosen_type == LIVE_INPUT_BGRA) {
 321                         if (block->signal_type_to_connect == Block::CONNECT_SIGNAL) {
 322                                 signals_to_connect.emplace(input, block->signal_to_connect);
 323 #ifdef HAVE_CEF
 324                         } else if (block->signal_type_to_connect == Block::CONNECT_CEF) {
 325                                 signals_to_connect.emplace(input, block->cef_to_connect->get_card_index());
 326 #endif
 327                         } else if (block->signal_type_to_connect == Block::CONNECT_VIDEO) {
 328                                 signals_to_connect.emplace(input, block->video_to_connect->get_card_index());
 329                         } else if (block->signal_type_to_connect == Block::CONNECT_NONE) {
 330                                 luaL_error(L, "An input in a scene was not connected to anything (forgot to call display())");
 331                         } else {
 332                                 assert(false);
 333                         }
 334                 }
 335         }
 336         for (const auto &index_and_input : instantiation.image_inputs) {
 337                 Block *block = blocks[index_and_input.first];
 338                 ImageInput *input = index_and_input.second;
 339                 if (current_type(block) == IMAGE_INPUT) {
 340                         images_to_select.emplace(input, block->pathname);
 341                 }
 342         }
 343         for (const auto &index_and_effect : instantiation.effects) {
 344                 Block *block = blocks[index_and_effect.first];
 345                 Effect *effect = index_and_effect.second;
 346
 347                 // Get the effects currently set on the block.
 348                 if (current_type(block) != IDENTITY_EFFECT) {  // Ignore settings on optional effects.
 349                         for (const auto &key_and_tuple : block->int_parameters) {
 350                                 int_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 351                         }
 352                         for (const auto &key_and_tuple : block->float_parameters) {
 353                                 float_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 354                         }
 355                         for (const auto &key_and_tuple : block->vec3_parameters) {
 356                                 vec3_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 357                         }
 358                         for (const auto &key_and_tuple : block->vec4_parameters) {
 359                                 vec4_to_set.emplace(make_pair(effect, key_and_tuple.first), key_and_tuple.second);
 360                         }
 361                 }
 362
 363                 // Parameters set on the blueprint itself override those that are set for the block,
 364                 // so they are set afterwards.
 365                 if (!block->alternatives.empty()) {
 366                         EffectBlueprint *blueprint = block->alternatives[block->currently_chosen_alternative];
 367                         for (const auto &key_and_tuple : blueprint->int_parameters) {
 368                                 int_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 369                         }
 370                         for (const auto &key_and_tuple : blueprint->float_parameters) {
 371                                 float_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 372                         }
 373                         for (const auto &key_and_tuple : blueprint->vec3_parameters) {
 374                                 vec3_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 375                         }
 376                         for (const auto &key_and_tuple : blueprint->vec4_parameters) {
 377                                 vec4_to_set[make_pair(effect, key_and_tuple.first)] = key_and_tuple.second;
 378                         }
 379                 }
 380         }
 381
 382         lua_pop(L, 1);
 383
 384         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]{
 385                 lock_guard<mutex> lock(theme->m);
 386
 387                 // Set up state, including connecting signals.
 388                 for (const auto &input_and_signal : signals_to_connect) {
 389                         LiveInputWrapper *input = input_and_signal.first;
 390                         input->connect_signal_raw(input_and_signal.second, input_state);
 391                 }
 392                 for (const auto &input_and_filename : images_to_select) {
 393                         input_and_filename.first->switch_image(input_and_filename.second);
 394                 }
 395                 for (const auto &effect_and_key_and_value : int_to_set) {
 396                         Effect *effect = effect_and_key_and_value.first.first;
 397                         const string &key = effect_and_key_and_value.first.second;
 398                         const int value = effect_and_key_and_value.second;
 399                         if (!effect->set_int(key, value)) {
 400                                 luaL_error(L, "Effect refused set_int(\"%s\", %d) (invalid key?)", key.c_str(), value);
 401                         }
 402                 }
 403                 for (const auto &effect_and_key_and_value : float_to_set) {
 404                         Effect *effect = effect_and_key_and_value.first.first;
 405                         const string &key = effect_and_key_and_value.first.second;
 406                         const float value = effect_and_key_and_value.second;
 407                         if (!effect->set_float(key, value)) {
 408                                 luaL_error(L, "Effect refused set_float(\"%s\", %f) (invalid key?)", key.c_str(), value);
 409                         }
 410                 }
 411                 for (const auto &effect_and_key_and_value : vec3_to_set) {
 412                         Effect *effect = effect_and_key_and_value.first.first;
 413                         const string &key = effect_and_key_and_value.first.second;
 414                         const float *value = effect_and_key_and_value.second.data();
 415                         if (!effect->set_vec3(key, value)) {
 416                                 luaL_error(L, "Effect refused set_vec3(\"%s\", %f, %f, %f) (invalid key?)", key.c_str(),
 417                                                 value[0], value[1], value[2]);
 418                         }
 419                 }
 420                 for (const auto &effect_and_key_and_value : vec4_to_set) {
 421                         Effect *effect = effect_and_key_and_value.first.first;
 422                         const string &key = effect_and_key_and_value.first.second;
 423                         const float *value = effect_and_key_and_value.second.data();
 424                         if (!effect->set_vec4(key, value)) {
 425                                 luaL_error(L, "Effect refused set_vec4(\"%s\", %f, %f, %f, %f) (invalid key?)", key.c_str(),
 426                                                 value[0], value[1], value[2], value[3]);
 427                         }
 428                 }
 429         };
 430         return make_pair(effect_chain, move(setup_chain));
 431 }
 432
 433 bool display(Block *block, lua_State *L, int idx)
 434 {
 435         if (lua_isnumber(L, idx)) {
 436                 Theme *theme = get_theme_updata(L);
 437                 int signal_idx = luaL_checknumber(L, idx);
 438                 block->signal_type_to_connect = Block::CONNECT_SIGNAL;
 439                 block->signal_to_connect = theme->map_signal(signal_idx);
 440                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR);  // Will be changed to deinterlaced at get_chain() time if needed.
 441                 return true;
 442 #ifdef HAVE_CEF
 443         } else if (luaL_testudata(L, idx, "HTMLInput")) {
 444                 CEFCapture *capture = *(CEFCapture **)luaL_checkudata(L, idx, "HTMLInput");
 445                 block->signal_type_to_connect = Block::CONNECT_CEF;
 446                 block->cef_to_connect = capture;
 447                 block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_BGRA);
 448                 assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
 449                 return true;
 450 #endif
 451         } else if (luaL_testudata(L, idx, "VideoInput")) {
 452                 FFmpegCapture *capture = *(FFmpegCapture **)luaL_checkudata(L, idx, "VideoInput");
 453                 block->signal_type_to_connect = Block::CONNECT_VIDEO;
 454                 block->video_to_connect = capture;
 455                 if (capture->get_current_pixel_format() == bmusb::PixelFormat_8BitYCbCrPlanar) {
 456                         block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_YCBCR_PLANAR);
 457                 } else {
 458                         assert(capture->get_current_pixel_format() == bmusb::PixelFormat_8BitBGRA);
 459                         block->currently_chosen_alternative = find_index_of(block, LIVE_INPUT_BGRA);
 460                 }
 461                 return true;
 462         } else if (luaL_testudata(L, idx, "ImageInput")) {
 463                 ImageInput *image = *(ImageInput **)luaL_checkudata(L, idx, "ImageInput");
 464                 block->signal_type_to_connect = Block::CONNECT_NONE;
 465                 block->currently_chosen_alternative = find_index_of(block, IMAGE_INPUT);
 466                 block->pathname = image->get_pathname();
 467                 return true;
 468         } else {
 469                 return false;
 470         }
 471 }
 472
 473 int Block_display(lua_State* L)
 474 {
 475         assert(lua_gettop(L) == 2);
 476         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 477         if (!block->is_input) {
 478                 luaL_error(L, "display() called on something that isn't an input");
 479         }
 480
 481         bool ok = display(block, L, 2);
 482         if (!ok) {
 483                 luaL_error(L, "display() called with something that's not a signal (a signal number, a HTML input, or a VideoInput)");
 484         }
 485
 486         if (block->currently_chosen_alternative == -1) {
 487                 luaL_error(L, "display() called on an input whose type was fixed at construction time, with a signal of different type");
 488         }
 489
 490         return 0;
 491 }
 492
 493 int Block_choose(lua_State* L)
 494 {
 495         assert(lua_gettop(L) == 2);
 496         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 497         int alternative_idx = -1;
 498         if (lua_isnumber(L, 2)) {
 499                 alternative_idx = luaL_checknumber(L, 2);
 500         } else if (lua_istable(L, 2)) {
 501                 // See if it's an Effect metatable (e.g. foo:choose(ResampleEffect))
 502                 lua_getfield(L, 2, "__effect_type_id");
 503                 if (lua_isnumber(L, -1)) {
 504                         EffectType effect_type = EffectType(luaL_checknumber(L, -1));
 505                         alternative_idx = find_index_of(block, effect_type);
 506                 }
 507                 lua_pop(L, 1);
 508         }
 509
 510         if (alternative_idx == -1) {
 511                 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");
 512         }
 513
 514         assert(alternative_idx >= 0);
 515         assert(size_t(alternative_idx) < block->alternatives.size());
 516         block->currently_chosen_alternative = alternative_idx;
 517
 518         return wrap_lua_existing_object_nonowned<EffectBlueprint>(L, "EffectBlueprint", block->alternatives[alternative_idx]);
 519 }
 520
 521 int Block_enable(lua_State *L)
 522 {
 523         assert(lua_gettop(L) == 1);
 524         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 525
 526         if (block->alternatives.size() != 2 ||
 527             block->alternatives[1]->effect_type != IDENTITY_EFFECT) {
 528                 luaL_error(L, "enable() called on something that wasn't added with add_optional_effect()");
 529         }
 530         block->currently_chosen_alternative = 0;  // The actual effect.
 531         return 0;
 532 }
 533
 534 int Block_disable(lua_State *L)
 535 {
 536         assert(lua_gettop(L) == 1);
 537         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 538
 539         block->currently_chosen_alternative = find_index_of(block, IDENTITY_EFFECT);
 540         if (block->currently_chosen_alternative == -1) {
 541                 luaL_error(L, "disable() called on something that didn't have an IdentityEffect fallback (try add_optional_effect())");
 542         }
 543         assert(block->currently_chosen_alternative != -1);
 544         return 0;
 545 }
 546
 547 int Block_set_int(lua_State *L)
 548 {
 549         assert(lua_gettop(L) == 3);
 550         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 551         string key = checkstdstring(L, 2);
 552         float value = luaL_checknumber(L, 3);
 553
 554         // TODO: check validity already here, if possible?
 555         block->int_parameters[key] = value;
 556
 557         return 0;
 558 }
 559
 560 int Block_set_float(lua_State *L)
 561 {
 562         assert(lua_gettop(L) == 3);
 563         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 564         string key = checkstdstring(L, 2);
 565         float value = luaL_checknumber(L, 3);
 566
 567         // TODO: check validity already here, if possible?
 568         block->float_parameters[key] = value;
 569
 570         return 0;
 571 }
 572
 573 int Block_set_vec3(lua_State *L)
 574 {
 575         assert(lua_gettop(L) == 5);
 576         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 577         string key = checkstdstring(L, 2);
 578         array<float, 3> v;
 579         v[0] = luaL_checknumber(L, 3);
 580         v[1] = luaL_checknumber(L, 4);
 581         v[2] = luaL_checknumber(L, 5);
 582
 583         // TODO: check validity already here, if possible?
 584         block->vec3_parameters[key] = v;
 585
 586         return 0;
 587 }
 588
 589 int Block_set_vec4(lua_State *L)
 590 {
 591         assert(lua_gettop(L) == 6);
 592         Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
 593         string key = checkstdstring(L, 2);
 594         array<float, 4> v;
 595         v[0] = luaL_checknumber(L, 3);
 596         v[1] = luaL_checknumber(L, 4);
 597         v[2] = luaL_checknumber(L, 5);
 598         v[3] = luaL_checknumber(L, 6);
 599
 600         // TODO: check validity already here, if possible?
 601         block->vec4_parameters[key] = v;
 602
 603         return 0;
 604 }
 605