Support enable/disable of voices in GME backend

backends/playback/gme/gme_backend.cpp

@@ -12,6 +12,70 @@
 #include <assets/assets.h>
 #include <limits.h>
 #include <gme/gme.h>
+std::vector<Property> GmeBackend::get_property_list() {
+    std::vector<Property> output;
+    for (auto &kv : voices) {
+        Property prop;
+        prop.set_id(PropertyId::BackendSpecific);
+        prop.set_name(fmt::format("gme/voice/{}/enable", kv.first));
+        prop.set_type(PropertyType::Boolean);
+        prop.set_path(prop.name());
+        output.push_back(prop);
+    }
+    return output;
+}
+std::optional<int> GmeBackend::get_voice_id(std::string path) {
+    std::string prefix = "gme/voice/";
+    std::string suffix = "/enable";
+    if (path.substr(0, prefix.length()) != prefix) {
+        return {};
+    }
+    if (path.substr(path.length() - suffix.length()) != suffix) {
+        return {};
+    }
+    path = path.substr(prefix.length());
+    path = path.substr(0, path.length() - suffix.length());
+    if (!voices.contains(path)) {
+        return {};
+    }
+    return voices[path];
+}
+bool GmeBackend::set(std::string path, google::protobuf::Any value) {
+    auto maybe_voice_id = get_voice_id(path);
+    if (maybe_voice_id.has_value()) {
+        bool enable = resolve_any<bool>(value);
+        gme_mute_voice(gme_backend, maybe_voice_id.value(), !enable);
+        properties[path] = value;
+        return true;
+    }
+    return false;
+}
+std::optional<google::protobuf::Any> GmeBackend::get(std::string path) {
+    auto maybe_voice_id = get_voice_id(path);
+    if (maybe_voice_id.has_value()) {
+        if (properties.contains(path)) {
+            return properties[path];
+        } else {
+            return reset(path);
+        }
+    } else {
+        return {};
+    }
+}
+std::optional<google::protobuf::Any> GmeBackend::reset(std::string path) {
+    auto maybe_voice_id = get_voice_id(path);
+    if (maybe_voice_id.has_value()) {
+        google::protobuf::Any prop;
+        BooleanProperty bool_prop;
+        bool_prop.set_value(true);
+        prop.PackFrom(bool_prop);
+        properties[path] = prop;
+        gme_mute_voice(gme_backend, maybe_voice_id.value(), false);
+        return prop;
+    } else {
+        return {};
+    }
+}
 void GmeBackend::load(const char *filename) {
     memset(&spec, 0, sizeof(spec));
     current_file = filename;
@@ -58,16 +122,22 @@ void GmeBackend::switch_stream(int idx) {
         info->length = 0;
     }
     uint64_t tmp = info->length;
+    this->loop_len = info->loop_length;
+    this->loop_start = info->intro_length;
+    if (tmp == 0) tmp = this->loop_len + this->loop_start;
     tmp *= spec.freq;
     tmp /= 1000;
     this->length = tmp;
-    this->loop_len = info->loop_length;
-    this->loop_start = info->intro_length;
     if (info->song[0] == '\0') {
         this->current_title = {};
     } else {
         this->current_title = info->song;
     }
+    int voice_count = gme_voice_count(gme_backend);
+    for (int i = 0; i < voice_count; i++) {
+        const char *voice_name = gme_voice_name(gme_backend, i);
+        voices[voice_name] = i;
+    }
     gme_free_info(info);
     gme_ignore_silence(gme_backend, true);
     open = true;

backends/playback/gme/gme_backend.hpp

@@ -29,7 +29,7 @@ class GmeBackend : public PlaybackBackend {
         return "Game Music Emu";
     }
     void add_licenses() override;
-    //std::vector<Property> get_property_list() override;
+    std::vector<Property> get_property_list() override;
     void seek_samples(uint64_t position) override;
     void load(const char *filename) override;
     void switch_stream(int idx) override;

backends/playback/gme/properties.inc

@@ -3,7 +3,7 @@
 BOOL_PROPERTY(pcm_enable, true)
 BOOL_PROPERTY(psg_enable, true)
 BOOL_PROPERTY(fm_enable, true)
-DOUBLE_PROPERTY(pcm_volume, 1.0)
+DOUBLE_PROPERTY(tempo, 1.0)
 DOUBLE_PROPERTY(psg_volume, 1.0)
 DOUBLE_PROPERTY(fm_volume, 1.0)
 #undef BOOL_PROPERTY