Start engine sound

game.h

@@ -42,6 +42,11 @@
   - Implement the below described functions according to their description.
   - Implement the main program and game loop.
   - Call the below described functions as described.
+  - If you want to support music, make your frontend play music from the "music"
+    file in assets. It is in raw format, storing 8bit unsigned samples at 8000
+    Hz. Use the LCR_gameGetMusicVolume to check what the music volume is. If you
+    don't support music, set LCR_SETTING_MUSIC to 0 in your frontend code so
+    that the game knows music is disabled.
 */
 
 /**
@@ -93,6 +98,16 @@ void LCR_gameEnd(void);
 */
 uint8_t LCR_gameStep(uint32_t timeMs);
 
+/**
+  Gets the current music volume;
+*/
+uint8_t LCR_gameGetMusicVolume(void);
+
+/**
+  Gets next audio sample (unsigned 8bit samples, 8 KHz).
+*/
+uint8_t LCR_gameGetNextAudioSample(void);
+
 //------------------------------------------------------------------------------
 
 #define LCR_LOG0(s) ;
@@ -133,8 +148,19 @@ struct
   uint8_t debugDraw;
   uint8_t checkpointsTaken;
   uint32_t runTime;
+
+  uint8_t musicVolume;
 } LCR_game;
 
+uint8_t LCR_gameGetMusicVolume(void)
+{
+#if LCR_SETTING_MUSIC
+  return LCR_game.musicVolume;
+#else
+  return 0;
+#endif
+}
+
 void LCR_drawPixelXYUnsafe(unsigned int x, unsigned int y,
   uint16_t color);
 
@@ -149,6 +175,7 @@ static inline void LCR_drawPixelXYSafe(unsigned int x, unsigned int y,
 #include "racing.h"
 #include "assets.h"
 #include "renderer.h"
+#include "audio.h"
 
 uint8_t LCR_keyStates[LCR_KEYS_TOTAL]; /**< Assures unchanging key states
                                             during a single frame, holds
@@ -219,12 +246,12 @@ void LCR_gameInit(void)
 
   LCR_rendererInit();
   LCR_racingInit();
+  LCR_audioInit();
 
+  LCR_game.musicVolume = 255;
   LCR_game.nextRenderFrameTime = 0;
   LCR_game.nextRacingTickTime = 0;
-
   LCR_game.controlMode = LCR_CONTROL_MODE_FREECAM;
-
   LCR_gameStartRun(LCR_maps[0]);
 }
 
@@ -369,6 +396,8 @@ LCR_GameUnit physicsInterpolationParam = LCR_GAME_UNIT -
 
     int val = LCR_carSpeedKMH();
 
+LCR_audioSetEngineIntensity(val < 256 ? val : 255);
+
     if (val < 5) // don't show tiny oscillations when still
       val = 0;
 
@@ -424,4 +453,9 @@ LCR_GameUnit physicsInterpolationParam = LCR_GAME_UNIT -
   return 1;
 }
 
+uint8_t LCR_gameGetNextAudioSample(void)
+{
+  return LCR_audioGetNextSample();
+}
+
 #endif // guard