+}
+
+// An EffectBlueprint refers to an Effect before it's being added to the graph.
+// It contains enough information to instantiate the effect, including any
+// parameters that were set before it was added to the graph. Once it is
+// instantiated, it forwards its calls on to the real Effect instead.
+struct EffectBlueprint {
+ EffectBlueprint(EffectType effect_type) : effect_type(effect_type) {}
+
+ EffectType effect_type;
+ map<string, int> int_parameters;
+ map<string, float> float_parameters;
+ map<string, array<float, 3>> vec3_parameters;
+ map<string, array<float, 4>> vec4_parameters;
+
+ Effect *effect = nullptr; // Gets filled out when it's instantiated.
+};
+
+Effect *get_effect_from_blueprint(EffectChain *chain, lua_State *L, int idx)
+{
+ EffectBlueprint *blueprint = *(EffectBlueprint **)luaL_checkudata(L, idx, "EffectBlueprint");
+ if (blueprint->effect != nullptr) {
+ // NOTE: This will change in the future.
+ luaL_error(L, "An effect can currently only be added to one chain.\n");
+ }
+
+ Effect *effect = instantiate_effect(chain, blueprint->effect_type);
+
+ // Set the parameters that were deferred earlier.
+ for (const auto &kv : blueprint->int_parameters) {
+ if (!effect->set_int(kv.first, kv.second)) {
+ luaL_error(L, "Effect refused set_int(\"%s\", %d) (invalid key?)", kv.first.c_str(), kv.second);
+ }
+ }
+ for (const auto &kv : blueprint->float_parameters) {
+ if (!effect->set_float(kv.first, kv.second)) {
+ luaL_error(L, "Effect refused set_float(\"%s\", %f) (invalid key?)", kv.first.c_str(), kv.second);
+ }
+ }
+ for (const auto &kv : blueprint->vec3_parameters) {
+ if (!effect->set_vec3(kv.first, kv.second.data())) {
+ luaL_error(L, "Effect refused set_vec3(\"%s\", %f, %f, %f) (invalid key?)", kv.first.c_str(),
+ kv.second[0], kv.second[1], kv.second[2]);
+ }
+ }
+ for (const auto &kv : blueprint->vec4_parameters) {
+ if (!effect->set_vec4(kv.first, kv.second.data())) {
+ luaL_error(L, "Effect refused set_vec4(\"%s\", %f, %f, %f, %f) (invalid key?)", kv.first.c_str(),
+ kv.second[0], kv.second[1], kv.second[2], kv.second[3]);
+ }
+ }
+ blueprint->effect = effect;
+ return effect;