add way to change audio volume (#330)

* add way to change audio volume

* more

parallel-rdp/interface.cpp

@@ -195,6 +195,12 @@ bool sdl_event_filter(void *userdata, SDL_Event *event)
 		case SDL_SCANCODE_F7:
 			callback.load_state = true;
 			break;
+		case SDL_SCANCODE_LEFTBRACKET:
+			callback.lower_volume = true;
+			break;
+		case SDL_SCANCODE_RIGHTBRACKET:
+			callback.raise_volume = true;
+			break;
 		default:
 			break;
 		}
@@ -449,6 +455,8 @@ CALL_BACK rdp_check_callback()
 	CALL_BACK return_value = callback;
 	callback.save_state = false;
 	callback.load_state = false;
+	callback.lower_volume = false;
+	callback.raise_volume = false;
 	return return_value;
 }
 

parallel-rdp/interface.hpp

@@ -30,6 +30,8 @@ extern "C"
 		bool save_state;
 		bool load_state;
 		bool enable_speedlimiter;
+		bool lower_volume;
+		bool raise_volume;
 	} CALL_BACK;
 
 	void rdp_init(void *_window, GFX_INFO _gfx_info);

src/ui/audio.rs

@@ -86,6 +86,28 @@ pub fn close(ui: &mut ui::Ui) {
     }
 }
 
+pub fn lower_audio_volume(ui: &ui::Ui) {
+    unsafe {
+        let mut gain = sdl3_sys::audio::SDL_GetAudioStreamGain(ui.audio.audio_stream) - 0.05;
+        if gain < 0.0 {
+            gain = 0.0;
+        }
+        sdl3_sys::audio::SDL_SetAudioStreamGain(ui.audio.audio_stream, gain);
+        sdl3_sys::audio::SDL_SetAudioStreamGain(ui.audio.event_audio_stream, gain);
+    }
+}
+
+pub fn raise_audio_volume(ui: &ui::Ui) {
+    unsafe {
+        let mut gain = sdl3_sys::audio::SDL_GetAudioStreamGain(ui.audio.audio_stream) + 0.05;
+        if gain > 1.0 {
+            gain = 1.0;
+        }
+        sdl3_sys::audio::SDL_SetAudioStreamGain(ui.audio.audio_stream, gain);
+        sdl3_sys::audio::SDL_SetAudioStreamGain(ui.audio.event_audio_stream, gain);
+    }
+}
+
 pub fn play_netplay_audio(ui: &mut ui::Ui, error: u32) {
     if ui.audio.event_audio_stream.is_null() {
         return;

src/ui/video.rs

@@ -114,6 +114,12 @@ pub fn check_callback(device: &mut device::Device) {
         }
         device.vi.enable_speed_limiter = callback.enable_speedlimiter;
     }
+
+    if callback.lower_volume {
+        ui::audio::lower_audio_volume(&device.ui);
+    } else if callback.raise_volume {
+        ui::audio::raise_audio_volume(&device.ui);
+    }
 }
 
 pub fn set_register(reg: u32, value: u32) {