Added background scripts

Background scripts are scripts that are launched when a map is loaded. They differ in use from a map's init script in that they are expected to contain an infinite loop. These scripts are linked to a sprite and will be killed when that sprite is destroyed (usually when the map is unloaded, but if the sprite is made persistent then it may last longer). The thread running the script is given no warning that it is being killed; the coroutine is simply never called again, and the thread is disposed of. Because of this, background scripts MUST ensure the game is in a consistent state before coroutine yielding, because it is not guaranteed that the coroutine will ever be called again.

1 files changed, 9 insertions, 0 deletions

@@ -52,6 +52,7 @@ void Game::loadMap(std::string filename) {
   // Load the new map.
   map_ = std::make_unique<Map>(filename);
 
+  std::vector<std::tuple<int, std::string>> backgroundScripts;
   for (const Prototype& p : map_->getPrototypes()) {
     if (spritesByAlias_.count(p.name)) continue;
 
@@ -84,6 +85,9 @@ void Game::loadMap(std::string filename) {
       getSprite(spriteId).mirrorAxis = p.mirrorAxis;
       getSprite(spriteId).mirroredSpriteId = getSpriteByAlias(p.spriteToMirror);
     }
+    if (!p.backgroundScript.empty()) {
+      backgroundScripts.push_back({spriteId, p.backgroundScript});
+    }
   }
 
   for (const Trigger& t : map_->getTriggers()) {
@@ -99,4 +103,9 @@ void Game::loadMap(std::string filename) {
   if (getSystem<ScriptSystem>().mapHasScript(map_->getName(), "init")) {
     getSystem<ScriptSystem>().runScript(map_->getName(), "init");
   }
+
+  // Run any background scripts associated with new sprites.
+  for (auto& [spriteId, scriptName] : backgroundScripts) {
+    getSystem<ScriptSystem>().runScript(map_->getName(), scriptName, spriteId);
+  }
 }