From d9d0b7d59bf303b21745bdb756248205da300a65 Mon Sep 17 00:00:00 2001
From: Mark Street <22226349+mkst@users.noreply.github.com>
Date: Thu, 17 Sep 2020 22:07:14 +0100
Subject: [PATCH] Pushing audio to 2nd CPU (OS Core) (#31)

---
 README.md                          |   7 ++
 enhancements/60fps.patch           |  16 +--
 enhancements/fps.patch             |  17 ++--
 enhancements/puppycam.patch        | 156 ++++++++++++++---------------
 src/game/game_init.c               |   7 ++
 src/pc/audio/audio_3ds.c           | 129 ++++++++++++++++++------
 src/pc/audio/audio_3ds_threading.h |  34 +++++++
 src/pc/audio/audio_api.h           |   3 +
 src/pc/audio/audio_null.c          |  10 +-
 src/pc/gfx/gfx_3ds.c               |  14 +--
 src/pc/pc_main.c                   |   9 +-
 11 files changed, 264 insertions(+), 138 deletions(-)
 create mode 100644 src/pc/audio/audio_3ds_threading.h

diff --git a/README.md b/README.md
index c2f9d40865..13bc4dc3fc 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,9 @@ A prior copy of the game is required to extract the assets.
 ## Changes vs. Vanilla 3DS Port
 
  - Based off [Refresh 11](https://github.com/sm64-port/sm64-port/commit/9214dddabcce4723d9b6cda2ebccbac209f6447d)
+ - Audio running on 2nd CPU core; better performance on O3DS
+ - Naive frame-skip if frame takes longer than 33.3ms (1 / 30 FPS) to render
+     - Disable by building with `DISABLE_N3DS_FRAMESKIP=1`
  - Configurable controls via `sm64config.txt`
      - Use [this](https://codepen.io/benoitcaron/full/abNZrbP) online editor from [BenoitCaron](https://github.com/BenoitCaron).
  - GFX_POOL_SIZE [fix](https://github.com/aboood40091/sm64-port/commit/6ae4f4687ed234291ac1e572b75d65191ca9f364) (support 60 FPS on 32bit platforms)
@@ -16,6 +19,10 @@ A prior copy of the game is required to extract the assets.
  - Experimental Stereo 3D support; add build flag `ENABLE_N3DS_3D_MODE=1` to try it out
  - Support injection of [SMDH](https://www.3dbrew.org/wiki/SMDH) file into the .3dsx
      - Change the `icon.png` in the base of this repository before building.
+ - Patches updated for 3DS:
+     - [60 FPS](enhancements/60fps.patch)
+     - [Puppycam](enhancements/puppycam.patch)
+     - [Show FPS](enhancements/fps.patch)
 
 ## Building
 
diff --git a/enhancements/60fps.patch b/enhancements/60fps.patch
index 8a3d52a2c7..d76967b35c 100644
--- a/enhancements/60fps.patch
+++ b/enhancements/60fps.patch
@@ -1857,7 +1857,7 @@ index 2d49d06..31cb72f 100644
          gSPDisplayList(displayListIter++, &intro_seg7_dl_0700B3A0);
          gSPPopMatrix(displayListIter++, G_MTX_MODELVIEW);
 diff --git a/src/pc/gfx/gfx_citro3d.c b/src/pc/gfx/gfx_citro3d.c
-index affdf08..42e86b8 100644
+index fbad0f6..0d1d6c1 100644
 --- a/src/pc/gfx/gfx_citro3d.c
 +++ b/src/pc/gfx/gfx_citro3d.c
 @@ -810,7 +810,7 @@ static void gfx_citro3d_init(void)
@@ -1942,10 +1942,10 @@ index 4fd5c43..7897c6b 100644
      Uint32 elapsed = SDL_GetTicks() - last_time;
  
 diff --git a/src/pc/pc_main.c b/src/pc/pc_main.c
-index fba2ba0..0c92f3d 100644
+index 43bedb4..b3224b6 100644
 --- a/src/pc/pc_main.c
 +++ b/src/pc/pc_main.c
-@@ -80,6 +80,25 @@ void send_display_list(struct SPTask *spTask) {
+@@ -81,6 +81,25 @@ void send_display_list(struct SPTask *spTask) {
  #define SAMPLES_LOW 528
  #endif
  
@@ -1971,15 +1971,15 @@ index fba2ba0..0c92f3d 100644
  void produce_one_frame(void) {
      gfx_start_frame();
      game_loop_one_iteration();
-@@ -93,6 +112,11 @@ void produce_one_frame(void) {
+@@ -94,6 +113,11 @@ void produce_one_frame(void) {
      audio_api->play((u8 *)audio_buffer, 2 * num_audio_samples * 4);
- 
+ #endif
      gfx_end_frame();
 +
 +    gfx_start_frame();
 +    patch_interpolations();
 +    send_display_list(gGfxSPTask);
 +    gfx_end_frame();
- }
- 
- #ifdef TARGET_WEB
+ #ifdef TARGET_N3DS
+     LightEvent_Wait(&s_event_main);
+ #endif
diff --git a/enhancements/fps.patch b/enhancements/fps.patch
index 60e04d3e29..a1a37174ce 100644
--- a/enhancements/fps.patch
+++ b/enhancements/fps.patch
@@ -1,8 +1,8 @@
 diff --git a/src/game/game_init.c b/src/game/game_init.c
-index 3ce5f2d..a102e6f 100644
+index 0e1d914..fbfa95e 100644
 --- a/src/game/game_init.c
 +++ b/src/game/game_init.c
-@@ -59,6 +59,24 @@ struct DemoInput *gCurrDemoInput = NULL; // demo input sequence
+@@ -63,6 +63,24 @@ struct DemoInput *gCurrDemoInput = NULL; // demo input sequence
  u16 gDemoInputListID = 0;
  struct DemoInput gRecordedDemoInput = { 0 }; // possibly removed in EU. TODO: Check
  
@@ -27,20 +27,15 @@ index 3ce5f2d..a102e6f 100644
  /**
   * Initializes the Reality Display Processor (RDP).
   * This function initializes settings such as texture filtering mode,
-@@ -639,12 +657,12 @@ void game_loop_one_iteration(void) {
+@@ -652,7 +670,7 @@ void game_loop_one_iteration(void) {
+         LightEvent_Signal(&s_event_audio);
  #endif
-             osContStartReadData(&gSIEventMesgQueue);
-         }
--
-         audio_game_loop_tick();
-         config_gfx_pool();
-         read_controller_inputs();
-         levelCommandAddr = level_script_execute(levelCommandAddr);
          display_and_vsync();
+-
 +        render_fps();
- 
          // when debug info is enabled, print the "BUF %d" information.
          if (gShowDebugText) {
+             // subtract the end of the gfx pool with the display list to obtain the
 diff --git a/src/pc/ultra_reimplementation.c b/src/pc/ultra_reimplementation.c
 index 2b28ea8..541b419 100644
 --- a/src/pc/ultra_reimplementation.c
diff --git a/enhancements/puppycam.patch b/enhancements/puppycam.patch
index 3d45a4bb21..06a737b5e1 100644
--- a/enhancements/puppycam.patch
+++ b/enhancements/puppycam.patch
@@ -1,5 +1,5 @@
 diff --git a/Makefile b/Makefile
-index db5b620..52177e0 100644
+index 723512b..4bc4c51 100644
 --- a/Makefile
 +++ b/Makefile
 @@ -264,7 +264,7 @@ else
@@ -10,14 +10,14 @@ index db5b620..52177e0 100644
 +  OPT_FLAGS := -O2
  endif
  endif
-
+ 
 @@ -668,6 +668,8 @@ $(BUILD_DIR)/include/text_strings.h: $(BUILD_DIR)/include/text_menu_strings.h
  $(BUILD_DIR)/src/menu/file_select.o: $(BUILD_DIR)/include/text_strings.h
  $(BUILD_DIR)/src/menu/star_select.o: $(BUILD_DIR)/include/text_strings.h
  $(BUILD_DIR)/src/game/ingame_menu.o: $(BUILD_DIR)/include/text_strings.h
 +$(BUILD_DIR)/src/game/camera.o: $(BUILD_DIR)/include/text_strings.h
 +
-
+ 
  ################################################################
  # TEXTURE GENERATION                                           #
 diff --git a/enhancements/puppycam.h b/enhancements/puppycam.h
@@ -92,7 +92,7 @@ index 0000000..dc4481e
 +#endif // TARGET_N64
 diff --git a/enhancements/puppycam.inc.c b/enhancements/puppycam.inc.c
 new file mode 100644
-index 0000000..eedb206
+index 0000000..f75b329
 --- /dev/null
 +++ b/enhancements/puppycam.inc.c
 @@ -0,0 +1,1058 @@
@@ -1396,12 +1396,12 @@ index 8963446..f6bfa63 100644
 +#define _SEGMENTS_H
 +
 +#define USE_EXT_RAM
-
+ 
  /*
   * Memory addresses for segments. Ideally, this header file would not be
 @@ -44,13 +46,13 @@
   */
-
+ 
  #define SEG_BUFFERS      0x8005C000 // 0x0085000 in size
 -#define SEG_MAIN         0x800E1000 // 0x1328000 in size
 -#define SEG_ENGINE       0x80213800 // 0x0017000 in size
@@ -1415,17 +1415,17 @@ index 8963446..f6bfa63 100644
  #define SEG_POOL_END_4MB 0x80400000 // For the error message screen enhancement.
  #define SEG_GODDARD      SEG_POOL_START + 0x113000
  #endif
-
+ 
 -#endif // SEGMENTS_H
 +#endif // _SEGMENTS_H
 diff --git a/include/text_strings.h.in b/include/text_strings.h.in
-index 749179b..f0deb0f 100644
+index 749179b..18d3803 100644
 --- a/include/text_strings.h.in
 +++ b/include/text_strings.h.in
 @@ -3,6 +3,75 @@
-
+ 
  #include "text_menu_strings.h"
-
+ 
 +#if defined(VERSION_JP)
 +	#define NC_CAMX 				_("Camera X Sensitivity")
 +    #define NC_CAMY 				_("Camera Y Sensitivity")
@@ -1505,7 +1505,7 @@ index 58c5e3f..488f67d 100644
 @@ -49,6 +49,35 @@ void *vec3f_sum(Vec3f dest, Vec3f a, Vec3f b) {
      return &dest; //! warning: function returns address of local variable
  }
-
+ 
 +/// Multiply vector 'dest' by a
 +void *vec3f_mul(Vec3f dest, f32 a)
 +{
@@ -1543,9 +1543,9 @@ index cb37d52..2013402 100644
 --- a/src/engine/math_util.h
 +++ b/src/engine/math_util.h
 @@ -32,15 +32,21 @@ extern f32 gCosineTable[];
-
+ 
  #define sqr(x) ((x) * (x))
-
+ 
 +#define abs(x) ((x) < 0 ? -(x) : (x))
 +
  void *vec3f_copy(Vec3f dest, Vec3f src);
@@ -1574,7 +1574,7 @@ index 9aff62f..822d30a 100644
  #include "surface_load.h"
 +#include "math_util.h"
 +#include "game/game_init.h"
-
+ 
  /**************************************************
   *                      WALLS                     *
 diff --git a/src/game/camera.c b/src/game/camera.c
@@ -1587,13 +1587,13 @@ index 60bfb86..2e1f23f 100644
  }
 +//Compiler gets mad if I put this any further above. thanks refresh 7
 +#include "../../enhancements/puppycam.inc.c"
-
+ 
  void focus_on_mario(Vec3f focus, Vec3f pos, f32 posYOff, f32 focYOff, f32 dist, s16 pitch, s16 yaw) {
      Vec3f marioPos;
 @@ -2852,6 +2854,8 @@ void set_camera_mode(struct Camera *c, s16 mode, s16 frames) {
      struct LinearTransitionPoint *start = &sModeInfo.transitionStart;
      struct LinearTransitionPoint *end = &sModeInfo.transitionEnd;
-
+ 
 +    if (mode != CAM_MODE_NEWCAM && gLakituState.mode != CAM_MODE_NEWCAM)
 +    {
      if (mode == CAMERA_MODE_WATER_SURFACE && gCurrLevelArea == AREA_TTM_OUTSIDE) {
@@ -1605,12 +1605,12 @@ index 60bfb86..2e1f23f 100644
      }
 +    }
  }
-
+ 
  /**
 @@ -2979,7 +2984,7 @@ void update_lakitu(struct Camera *c) {
          gLakituState.roll += sHandheldShakeRoll;
          gLakituState.roll += gLakituState.keyDanceRoll;
-
+ 
 -        if (c->mode != CAMERA_MODE_C_UP && c->cutscene == 0) {
 +        if (c->mode != CAMERA_MODE_C_UP && c->cutscene == 0 && c->mode != CAM_MODE_NEWCAM) {
              gCheckingSurfaceCollisionsForCamera = TRUE;
@@ -1628,7 +1628,7 @@ index 60bfb86..2e1f23f 100644
 @@ -3050,10 +3055,18 @@ void update_camera(struct Camera *c) {
      c->mode = gLakituState.mode;
      c->defMode = gLakituState.defMode;
-
+ 
 +    if (c->mode != CAM_MODE_NEWCAM)
 +    {
      camera_course_processing(c);
@@ -1643,13 +1643,13 @@ index 60bfb86..2e1f23f 100644
 +        gMarioState->area->camera->mode = CAM_MODE_NEWCAM;
 +        gLakituState.mode = CAM_MODE_NEWCAM;
 +    }
-
+ 
      if (c->cutscene != 0) {
          sYawSpeed = 0;
 @@ -3091,6 +3104,10 @@ void update_camera(struct Camera *c) {
                      mode_cannon_camera(c);
                      break;
-
+ 
 +                case CAM_MODE_NEWCAM:
 +                    newcam_loop(c);
 +                    break;
@@ -1680,7 +1680,7 @@ index 60bfb86..2e1f23f 100644
 +        newcam_init(c, 0);
 +    }
  }
-
+ 
  /**
 @@ -5513,6 +5541,9 @@ void set_camera_mode_8_directions(struct Camera *c) {
          s8DirModeBaseYaw = 0;
@@ -1690,7 +1690,7 @@ index 60bfb86..2e1f23f 100644
 +    if (newcam_active == 1)
 +        c->mode = CAM_MODE_NEWCAM;
  }
-
+ 
  /**
 @@ -5524,6 +5555,9 @@ void set_camera_mode_boss_fight(struct Camera *c) {
          transition_to_camera_mode(c, CAMERA_MODE_BOSS_FIGHT, 15);
@@ -1700,7 +1700,7 @@ index 60bfb86..2e1f23f 100644
 +    if (newcam_active == 1)
 +        c->mode = CAM_MODE_NEWCAM;
  }
-
+ 
  void set_camera_mode_close_cam(u8 *mode) {
 @@ -5531,6 +5565,9 @@ void set_camera_mode_close_cam(u8 *mode) {
          sStatusFlags &= ~CAM_FLAG_SMOOTH_MOVEMENT;
@@ -1710,7 +1710,7 @@ index 60bfb86..2e1f23f 100644
 +    if (newcam_active == 1)
 +        *mode = CAM_MODE_NEWCAM;
  }
-
+ 
  /**
 @@ -5555,6 +5592,9 @@ void set_camera_mode_radial(struct Camera *c, s16 transitionTime) {
          }
@@ -1720,7 +1720,7 @@ index 60bfb86..2e1f23f 100644
 +    if (newcam_active == 1)
 +        c->mode = CAM_MODE_NEWCAM;
  }
-
+ 
  /**
 @@ -6933,6 +6973,7 @@ s16 cutscene_object(u8 cutscene, struct Object *o) {
  void update_camera_yaw(struct Camera *c) {
@@ -1728,10 +1728,10 @@ index 60bfb86..2e1f23f 100644
      c->yaw = c->nextYaw;
 +    newcam_apply_outside_values(c,0);
  }
-
+ 
  void cutscene_reset_spline(void) {
 @@ -9201,7 +9242,12 @@ BAD_RETURN(s32) cutscene_non_painting_end(struct Camera *c) {
-
+ 
      if (c->defMode == CAMERA_MODE_CLOSE) {
          c->mode = CAMERA_MODE_CLOSE;
 -    } else {
@@ -1743,11 +1743,11 @@ index 60bfb86..2e1f23f 100644
 +    {
          c->mode = CAMERA_MODE_FREE_ROAM;
      }
-
+ 
 @@ -9957,6 +10003,7 @@ BAD_RETURN(s32) cutscene_sliding_doors_follow_mario(struct Camera *c) {
  BAD_RETURN(s32) cutscene_sliding_doors_open(struct Camera *c) {
      UNUSED u32 pad[2];
-
+ 
 +    newcam_apply_outside_values(c,1);
      reset_pan_distance(c);
      cutscene_event(cutscene_sliding_doors_open_start, c, 0, 8);
@@ -1781,7 +1781,7 @@ index 60bfb86..2e1f23f 100644
 +    {
 +        c->mode = CAMERA_MODE_FREE_ROAM;
      }
-
+ 
      c->cutscene = 0;
 diff --git a/src/game/camera.h b/src/game/camera.h
 index f56ed02..36bb6d9 100644
@@ -1792,13 +1792,13 @@ index f56ed02..36bb6d9 100644
  #define CAMERA_MODE_FREE_ROAM         0x10
  #define CAMERA_MODE_SPIRAL_STAIRS     0x11
 +#define CAM_MODE_NEWCAM 0x12
-
+ 
  #define CAM_MOVE_RETURN_TO_MIDDLE       0x0001
  #define CAM_MOVE_ZOOMED_OUT             0x0002
 @@ -656,8 +657,6 @@ struct LakituState
      /*0xBC*/ s16 unused;
  };
-
+ 
 -// bss order hack to not affect BSS order. if possible, remove me, but it will be hard to match otherwise
 -#ifndef INCLUDED_FROM_CAMERA_C
  // BSS
@@ -1809,11 +1809,11 @@ index f56ed02..36bb6d9 100644
  extern s32 gObjCutsceneDone;
  extern struct Camera *gCamera;
 -#endif
-
+ 
  extern struct Object *gCutsceneFocus;
  extern struct Object *gSecondCameraFocus;
 diff --git a/src/game/game_init.c b/src/game/game_init.c
-index 3ce5f2d..856388b 100644
+index 0e1d914..f7a2b68 100644
 --- a/src/game/game_init.c
 +++ b/src/game/game_init.c
 @@ -20,6 +20,8 @@
@@ -1822,19 +1822,19 @@ index 3ce5f2d..856388b 100644
  #include <prevent_bss_reordering.h>
 +#include "../../enhancements/puppycam.h"
 +#include "pc/controller/controller_3ds.h"
-
- // FIXME: I'm not sure all of these variables belong in this file, but I don't
- // know of a good way to split them
-@@ -609,6 +611,7 @@ void thread5_game_loop(UNUSED void *arg) {
-
+ 
+ #ifdef TARGET_N3DS
+ #include "pc/audio/audio_3ds_threading.h"
+@@ -613,6 +615,7 @@ void thread5_game_loop(UNUSED void *arg) {
+ 
      play_music(SEQ_PLAYER_SFX, SEQUENCE_ARGS(0, SEQ_SOUND_PLAYER), 0);
      set_sound_mode(save_file_get_sound_mode());
 +    newcam_init_settings();
-
+ 
  #ifdef TARGET_N64
      rendering_init();
 diff --git a/src/game/hud.c b/src/game/hud.c
-index 5d78cfc..2a9b874 100644
+index 8d4daa5..c1f2099 100644
 --- a/src/game/hud.c
 +++ b/src/game/hud.c
 @@ -13,6 +13,7 @@
@@ -1842,21 +1842,21 @@ index 5d78cfc..2a9b874 100644
  #include "save_file.h"
  #include "print.h"
 +#include "../../enhancements/puppycam.h"
-
+ 
  /* @file hud.c
   * This file implements HUD rendering and power meter animations.
 @@ -469,7 +470,8 @@ void render_hud(void) {
-
+ 
          if (hudDisplayFlags & HUD_DISPLAY_FLAG_CAMERA_AND_POWER) {
              render_hud_power_meter();
 -            render_hud_camera_status();
 +            if (!newcam_active)
 +                render_hud_camera_status();
          }
-
+ 
          if (hudDisplayFlags & HUD_DISPLAY_FLAG_TIMER) {
 diff --git a/src/game/ingame_menu.c b/src/game/ingame_menu.c
-index 04047a1..dee4fb9 100644
+index b9a43df..f6f2d7f 100644
 --- a/src/game/ingame_menu.c
 +++ b/src/game/ingame_menu.c
 @@ -22,6 +22,7 @@
@@ -1864,7 +1864,7 @@ index 04047a1..dee4fb9 100644
  #include "text_strings.h"
  #include "types.h"
 +#include "../../enhancements/puppycam.h"
-
+ 
  u16 gDialogColorFadeTimer;
  s8 gLastDialogLineNum;
 @@ -2603,7 +2604,10 @@ s16 render_pause_courses_and_castle(void) {
@@ -1893,7 +1893,7 @@ index 04047a1..dee4fb9 100644
 +    newcam_check_pause_buttons();
 +    newcam_render_option_text();
 +    #endif
-
+ 
      return 0;
  }
 diff --git a/src/game/mario.c b/src/game/mario.c
@@ -1905,12 +1905,12 @@ index 5b103fa..3e55490 100644
  #include "sound_init.h"
  #include "thread6.h"
 +#include "../../enhancements/puppycam.h"
-
+ 
  u32 unused80339F10;
  s8 filler80339F1C[20];
 @@ -1306,7 +1307,10 @@ void update_mario_joystick_inputs(struct MarioState *m) {
      }
-
+ 
      if (m->intendedMag > 0.0f) {
 -        m->intendedYaw = atan2s(-controller->stickY, controller->stickX) + m->area->camera->yaw;
 +        if (gLakituState.mode != CAM_MODE_NEWCAM)
@@ -1923,12 +1923,12 @@ index 5b103fa..3e55490 100644
 @@ -1616,7 +1620,7 @@ void mario_update_hitbox_and_cap_model(struct MarioState *m) {
      struct MarioBodyState *bodyState = m->marioBodyState;
      s32 flags = update_and_return_cap_flags(m);
-
+ 
 -    if (flags & MARIO_VANISH_CAP) {
 +    if (flags & MARIO_VANISH_CAP || newcam_xlu < 255) {
          bodyState->modelState = MODEL_STATE_NOISE_ALPHA;
      }
-
+ 
 diff --git a/src/game/mario_misc.c b/src/game/mario_misc.c
 index e6354e8..393d8bb 100644
 --- a/src/game/mario_misc.c
@@ -1938,13 +1938,13 @@ index e6354e8..393d8bb 100644
  #include "skybox.h"
  #include "sound_init.h"
 +#include "../../enhancements/puppycam.h"
-
+ 
  #define TOAD_STAR_1_REQUIREMENT 12
  #define TOAD_STAR_2_REQUIREMENT 25
 @@ -296,12 +297,45 @@ void bhv_unlock_door_star_loop(void) {
      }
  }
-
+ 
 +static u32 find_capflag(struct MarioState *m) {
 +    u32 flags = m->flags;
 +    u64 sCapFlickerFrames = 0x4444449249255555;
@@ -1984,7 +1984,7 @@ index e6354e8..393d8bb 100644
      Gfx *gfxHead = NULL;
 +    u8 alphaBias;
 +    s32 flags = find_capflag(gMarioState);
-
+ 
      if (alpha == 255) {
          node->fnNode.node.flags = (node->fnNode.node.flags & 0xFF) | (LAYER_OPAQUE << 8);
 @@ -311,9 +345,17 @@ static Gfx *make_gfx_mario_alpha(struct GraphNodeGenerated *node, s16 alpha) {
@@ -2016,20 +2016,20 @@ index 4748b99..bb9f149 100644
  #include "course_table.h"
  #include "thread6.h"
 +#include "../../enhancements/puppycam.h"
-
+ 
  #define MENU_DATA_MAGIC 0x4849
  #define SAVE_FILE_MAGIC 0x4441
-
+ 
 -STATIC_ASSERT(sizeof(struct SaveBuffer) == EEPROM_SIZE, "eeprom buffer size must match");
 +STATIC_ASSERT(sizeof(struct SaveBuffer) <= EEPROM_SIZE, "eeprom buffer size higher than intended");
 +STATIC_ASSERT(sizeof(struct SaveBuffer) >= EEPROM_SIZE, "eeprom buffer size lower than intended");
-
+ 
  extern struct SaveBuffer gSaveBuffer;
-
+ 
 @@ -565,6 +567,51 @@ u16 save_file_get_sound_mode(void) {
      return gSaveBuffer.menuData[0].soundMode;
  }
-
+ 
 +#ifndef NC_CODE_NOSAVE
 +void save_file_set_setting(void) {
 +
@@ -2083,9 +2083,9 @@ index 3ee5a19..824ee79 100644
 --- a/src/game/save_file.h
 +++ b/src/game/save_file.h
 @@ -8,7 +8,12 @@
-
+ 
  #include "course_table.h"
-
+ 
 -#define EEPROM_SIZE 0x200
 +#ifndef NC_CODE_NOSAVE
 +    #define EEPROM_SIZE 0x800
@@ -2094,7 +2094,7 @@ index 3ee5a19..824ee79 100644
 +#endif
 +
  #define NUM_SAVE_FILES 4
-
+ 
  struct SaveBlockSignature
 @@ -52,16 +57,28 @@ struct MainMenuSaveData
      // on the high score screen.
@@ -2119,12 +2119,12 @@ index 3ee5a19..824ee79 100644
 -#define SUBTRAHEND 6
 +#define SUBTRAHEND 15
  #endif
-
+ 
 +    #ifdef NC_CODE_NOSAVE
      // Pad to match the EEPROM size of 0x200 (10 bytes on JP/US, 8 bytes on EU)
      u8 filler[EEPROM_SIZE / 2 - SUBTRAHEND - NUM_SAVE_FILES * (4 + sizeof(struct SaveFile))];
 +    #endif
-
+ 
      struct SaveBlockSignature signature;
  };
 @@ -72,6 +89,11 @@ struct SaveBuffer
@@ -2137,7 +2137,7 @@ index 3ee5a19..824ee79 100644
 +    u8 filler[EEPROM_SIZE - ((NUM_SAVE_FILES*(sizeof(struct SaveFile))+sizeof(struct MainMenuSaveData))*2)];
 +    #endif
  };
-
+ 
  extern u8 gLastCompletedCourseNum;
 @@ -144,6 +166,12 @@ s32 save_file_get_cap_pos(Vec3s capPos);
  void save_file_set_sound_mode(u16 mode);
@@ -2149,7 +2149,7 @@ index 3ee5a19..824ee79 100644
 +void save_file_get_setting(void);
 +void save_file_set_setting(void);
 +#endif
-
+ 
  void disable_warp_checkpoint(void);
  void check_if_should_set_warp_checkpoint(struct WarpNode *warpNode);
 diff --git a/src/pc/configfile.c b/src/pc/configfile.c
@@ -2159,7 +2159,7 @@ index 7bbdcef..43d7f01 100644
 @@ -68,6 +68,15 @@ unsigned int configKeyStickLeft  = 0;
  unsigned int configKeyStickRight = 0;
  #endif
-
+ 
 +unsigned int puppycam_sensitivityX = 75;
 +unsigned int puppycam_sensitivityY = 75;
 +unsigned int puppycam_invertX = 0;
@@ -2169,7 +2169,7 @@ index 7bbdcef..43d7f01 100644
 +unsigned int puppycam_panlevel = 75;
 +
 +
-
+ 
  static const struct ConfigOption options[] = {
      {.name = "fullscreen",     .type = CONFIG_TYPE_BOOL, .boolValue = &configFullscreen},
 @@ -81,6 +90,13 @@ static const struct ConfigOption options[] = {
@@ -2193,7 +2193,7 @@ index 7128aaa..eaa85da 100644
 @@ -17,6 +17,14 @@ extern unsigned int configKeyStickDown;
  extern unsigned int configKeyStickLeft;
  extern unsigned int configKeyStickRight;
-
+ 
 +extern unsigned int puppycam_sensitivityX;
 +extern unsigned int puppycam_sensitivityY;
 +extern unsigned int puppycam_invertX;
@@ -2204,27 +2204,27 @@ index 7128aaa..eaa85da 100644
 +
  void configfile_load(const char *filename);
  void configfile_save(const char *filename);
-
+ 
 diff --git a/src/pc/controller/controller_3ds.c b/src/pc/controller/controller_3ds.c
 index aeb80d8..5d449fd 100644
 --- a/src/pc/controller/controller_3ds.c
 +++ b/src/pc/controller/controller_3ds.c
 @@ -36,6 +36,11 @@
-
+ 
  #include "../configfile.h"
-
+ 
 +#include <include/types.h>
 +#include <enhancements/puppycam.h>
 +
 +s16 rightstick[2];
 +
  static int button_mapping[10][2];
-
+ 
  static void set_button_mapping(int index, int mask_n64, int mask_3ds)
 @@ -77,10 +82,21 @@ static void controller_3ds_read(OSContPad *pad)
  {
      pad->button = controller_3ds_get_held();
-
+ 
 -    circlePosition pos;
 -    hidCircleRead(&pos);
 -    pad->stick_x = pos.dx / 2;
@@ -2245,7 +2245,7 @@ index aeb80d8..5d449fd 100644
 +        newcam_analogue = 1;
 +    }
  }
-
+ 
  struct ControllerAPI controller_3ds = {
 diff --git a/src/pc/controller/controller_3ds.h b/src/pc/controller/controller_3ds.h
 index 00f3fae..038216d 100644
@@ -2253,8 +2253,8 @@ index 00f3fae..038216d 100644
 +++ b/src/pc/controller/controller_3ds.h
 @@ -4,5 +4,6 @@
  #include "controller_api.h"
-
+ 
  extern struct ControllerAPI controller_3ds;
 +extern s16 rightstick[2];
-
+ 
  #endif
diff --git a/src/game/game_init.c b/src/game/game_init.c
index 3ce5f2d620..0e1d9149f4 100644
--- a/src/game/game_init.c
+++ b/src/game/game_init.c
@@ -21,6 +21,10 @@
 #include "thread6.h"
 #include <prevent_bss_reordering.h>
 
+#ifdef TARGET_N3DS
+#include "pc/audio/audio_3ds_threading.h"
+#endif
+
 // FIXME: I'm not sure all of these variables belong in this file, but I don't
 // know of a good way to split them
 struct Controller gControllers[3];
@@ -644,6 +648,9 @@ void game_loop_one_iteration(void) {
         config_gfx_pool();
         read_controller_inputs();
         levelCommandAddr = level_script_execute(levelCommandAddr);
+#ifdef TARGET_N3DS
+        LightEvent_Signal(&s_event_audio);
+#endif
         display_and_vsync();
 
         // when debug info is enabled, print the "BUF %d" information.
diff --git a/src/pc/audio/audio_3ds.c b/src/pc/audio/audio_3ds.c
index ae8f9f84a9..d6e93d5c85 100644
--- a/src/pc/audio/audio_3ds.c
+++ b/src/pc/audio/audio_3ds.c
@@ -1,16 +1,85 @@
 #ifdef TARGET_N3DS
 
+#include <stdio.h>
 #include <string.h>
 #include <3ds.h>
 #include "macros.h"
-#include "audio_api.h"
+#include "audio_3ds.h"
+#include "audio_3ds_threading.h"
+
+#ifdef VERSION_EU
+#define SAMPLES_HIGH 656
+#define SAMPLES_LOW 640
+#else
+#define SAMPLES_HIGH 544
+#define SAMPLES_LOW 528
+#endif
 
 #define N3DS_DSP_DMA_BUFFER_COUNT   4
 
+extern void create_next_audio_buffer(s16 *samples, u32 num_samples);
+
 static int sNextBuffer;
 static ndspWaveBuf sDspBuffers[N3DS_DSP_DMA_BUFFER_COUNT];
 
-static bool audio_3ds_init(void)
+static int audio_3ds_buffered(void)
+{
+    int total = 0;
+    for (int i = 0; i < N3DS_DSP_DMA_BUFFER_COUNT; i++)
+    {
+        if (sDspBuffers[i].status == NDSP_WBUF_QUEUED ||
+            sDspBuffers[i].status == NDSP_WBUF_PLAYING)
+            total += sDspBuffers[i].nsamples;
+    }
+    return total;
+}
+
+static int audio_3ds_get_desired_buffered(void)
+{
+    return 1100;
+}
+
+static void audio_3ds_play(const uint8_t *buf, size_t len)
+{
+    if (len > 4096 * 4)
+        return;
+    if (sDspBuffers[sNextBuffer].status != NDSP_WBUF_FREE &&
+        sDspBuffers[sNextBuffer].status != NDSP_WBUF_DONE)
+        return;
+    sDspBuffers[sNextBuffer].nsamples = len / 4;
+    sDspBuffers[sNextBuffer].status = NDSP_WBUF_FREE;
+    ndspChnWaveBufAdd(0, &sDspBuffers[sNextBuffer]);
+
+    s16* dst = (s16*)sDspBuffers[sNextBuffer].data_vaddr;
+    memcpy(dst, buf, len);
+    DSP_FlushDataCache(dst, len);
+
+    sNextBuffer = (sNextBuffer + 1) % N3DS_DSP_DMA_BUFFER_COUNT;
+}
+
+static bool running = true;
+LightEvent s_event_audio, s_event_main;
+
+static void audio_3ds_loop()
+{
+    while (running)
+    {
+        LightEvent_Wait(&s_event_audio);
+        if (!running)
+            break;
+        u32 num_audio_samples = audio_3ds_buffered() < audio_3ds_get_desired_buffered() ? SAMPLES_HIGH : SAMPLES_LOW;
+        s16 audio_buffer[SAMPLES_HIGH * 2 * 2];
+        for (int i = 0; i < 2; i++) {
+            create_next_audio_buffer(audio_buffer + i * (num_audio_samples * 2), num_audio_samples);
+        }
+        audio_3ds_play((u8 *)audio_buffer, 2 * num_audio_samples * 4);
+        LightEvent_Signal(&s_event_main);
+    }
+}
+
+Thread threadId;
+
+static bool audio_3ds_init()
 {
     ndspInit();
 
@@ -36,40 +105,35 @@ static bool audio_3ds_init(void)
     }
 
     sNextBuffer = 0;
-    return true;
-}
 
-static int audio_3ds_buffered(void)
-{
-    int total = 0;
-    for (int i = 0; i < N3DS_DSP_DMA_BUFFER_COUNT; i++)
-    {
-        if (sDspBuffers[i].status == NDSP_WBUF_QUEUED ||
-            sDspBuffers[i].status == NDSP_WBUF_PLAYING)
-            total += sDspBuffers[i].nsamples;
-    }
-    return total;
-}
+    LightEvent_Init(&s_event_audio, RESET_ONESHOT);
+    LightEvent_Init(&s_event_main, RESET_ONESHOT);
 
-static int audio_3ds_get_desired_buffered(void)
-{
-    return 1100;
+    s32 prio = 0;
+    svcGetThreadPriority(&prio, CUR_THREAD_HANDLE);
+
+    int cpu = 0; // application core
+    if (R_SUCCEEDED(APT_SetAppCpuTimeLimit(80)))
+        cpu = 1; // system core
+
+    threadId = threadCreate(audio_3ds_loop, 0, 128 * 1024, prio - 1, cpu, true);
+
+    if (threadId)
+        printf("Created audio thread on %s core\n", cpu ? "os" : "application");
+    else
+        printf("Failed to create audio thread\n");
+
+    return threadId != NULL;
 }
 
-static void audio_3ds_play(const uint8_t *buf, size_t len)
+static void audio_3ds_stop(void)
 {
-    if (len > 4096 * 4)
-        return;
-    if (sDspBuffers[sNextBuffer].status != NDSP_WBUF_FREE &&
-        sDspBuffers[sNextBuffer].status != NDSP_WBUF_DONE)
-        return;
-    s16* dst = (s16*)sDspBuffers[sNextBuffer].data_vaddr;
-    memcpy(dst, buf, len);
-    DSP_FlushDataCache(dst, len);
-    sDspBuffers[sNextBuffer].nsamples = len / 4;
-    sDspBuffers[sNextBuffer].status = NDSP_WBUF_FREE;
-    ndspChnWaveBufAdd(0, &sDspBuffers[sNextBuffer]);
-    sNextBuffer = (sNextBuffer + 1) % N3DS_DSP_DMA_BUFFER_COUNT;
+    running = false;
+    LightEvent_Signal(&s_event_audio);
+
+    if (threadId)
+        threadJoin(threadId, U64_MAX);
+    ndspExit();
 }
 
 struct AudioAPI audio_3ds =
@@ -77,7 +141,8 @@ struct AudioAPI audio_3ds =
     audio_3ds_init,
     audio_3ds_buffered,
     audio_3ds_get_desired_buffered,
-    audio_3ds_play
+    audio_3ds_play,
+    audio_3ds_stop
 };
 
 #endif
diff --git a/src/pc/audio/audio_3ds_threading.h b/src/pc/audio/audio_3ds_threading.h
new file mode 100644
index 0000000000..3b24366179
--- /dev/null
+++ b/src/pc/audio/audio_3ds_threading.h
@@ -0,0 +1,34 @@
+#ifdef TARGET_N3DS
+
+#ifndef GFX_3DS_AUDIO_THREADING_H
+#define GFX_3DS_AUDIO_THREADING_H
+
+#define u64 __u64
+#define s64 __s64
+#define u32 __u32
+#define vu32 __vu32
+#define vs32 __vs32
+#define s32 __s32
+#define u16 __u16
+#define s16 __s16
+#define u8 __u8
+#define s8 __s8
+#include <3ds/types.h>
+#undef u64
+#undef s64
+#undef u32
+#undef vu32
+#undef vs32
+#undef s32
+#undef u16
+#undef s16
+#undef u8
+#undef s8
+
+#include <3ds.h>
+
+extern LightEvent s_event_audio;
+extern LightEvent s_event_main;
+
+#endif
+#endif
diff --git a/src/pc/audio/audio_api.h b/src/pc/audio/audio_api.h
index 26794dd6f9..08b13b2f51 100644
--- a/src/pc/audio/audio_api.h
+++ b/src/pc/audio/audio_api.h
@@ -10,6 +10,9 @@ struct AudioAPI {
     int (*buffered)(void);
     int (*get_desired_buffered)(void);
     void (*play)(const uint8_t *buf, size_t len);
+#ifdef TARGET_N3DS
+    void (*stop)(void);
+#endif
 };
 
 #endif
diff --git a/src/pc/audio/audio_null.c b/src/pc/audio/audio_null.c
index 88b7a42bf3..e940ab6562 100644
--- a/src/pc/audio/audio_null.c
+++ b/src/pc/audio/audio_null.c
@@ -16,9 +16,17 @@ static int audio_null_get_desired_buffered(void) {
 static void audio_null_play(UNUSED const uint8_t *buf, UNUSED size_t len) {
 }
 
+#ifdef TARGET_N3DS
+static void audio_null_stop(void) {
+}
+#endif
+
 struct AudioAPI audio_null = {
     audio_null_init,
     audio_null_buffered,
     audio_null_get_desired_buffered,
-    audio_null_play
+    audio_null_play,
+#ifdef TARGET_N3DS
+    audio_null_stop
+#endif
 };
diff --git a/src/pc/gfx/gfx_3ds.c b/src/pc/gfx/gfx_3ds.c
index fb7fcf1f26..dc0d1aecbe 100644
--- a/src/pc/gfx/gfx_3ds.c
+++ b/src/pc/gfx/gfx_3ds.c
@@ -156,7 +156,6 @@ static void gfx_3ds_main_loop(void (*run_one_game_iter)(void))
         run_one_game_iter();
     }
 
-    ndspExit();
     C3D_Fini();
     gfxExit();
 }
@@ -206,23 +205,25 @@ static void gfx_3ds_handle_events(void)
     }
 }
 
-float cpu_time;
+float cpu_time, gpu_time;
 uint8_t skip_debounce;
 
 static bool gfx_3ds_start_frame(void)
 {
+#ifndef DISABLE_N3DS_FRAMESKIP
     if (skip_debounce)
     {
         skip_debounce--;
         return true;
     }
-    // we only want 30FPS... but 16.6 ~ 60FPS?
-    if (cpu_time > 16.6f)
+    // skip if frame took longer than 1 / 30 = 33.3 ms
+    if (cpu_time + gpu_time > 33.3f)
     {
-        skip_debounce = 3;
-        cpu_time = 0;
+        skip_debounce = 3; // skip a max of once every 4 frames
+        cpu_time, gpu_time = 0;
         return false;
     }
+#endif
     return true;
 }
 
@@ -233,6 +234,7 @@ static void gfx_3ds_swap_buffers_begin(void)
 static void gfx_3ds_swap_buffers_end(void)
 {
     cpu_time = C3D_GetProcessingTime();
+    gpu_time = C3D_GetDrawingTime();
 }
 
 static double gfx_3ds_get_time(void)
diff --git a/src/pc/pc_main.c b/src/pc/pc_main.c
index fba2ba04e7..43bedb4698 100644
--- a/src/pc/pc_main.c
+++ b/src/pc/pc_main.c
@@ -27,6 +27,7 @@
 #include "audio/audio_sdl.h"
 #include "audio/audio_null.h"
 #include "audio/audio_3ds.h"
+#include "audio/audio_3ds_threading.h"
 
 #include "controller/controller_keyboard.h"
 
@@ -83,7 +84,7 @@ void send_display_list(struct SPTask *spTask) {
 void produce_one_frame(void) {
     gfx_start_frame();
     game_loop_one_iteration();
-
+#ifndef TARGET_N3DS
     int samples_left = audio_api->buffered();
     u32 num_audio_samples = samples_left < audio_api->get_desired_buffered() ? SAMPLES_HIGH : SAMPLES_LOW;
     s16 audio_buffer[SAMPLES_HIGH * 2 * 2];
@@ -91,8 +92,11 @@ void produce_one_frame(void) {
         create_next_audio_buffer(audio_buffer + i * (num_audio_samples * 2), num_audio_samples);
     }
     audio_api->play((u8 *)audio_buffer, 2 * num_audio_samples * 4);
-
+#endif
     gfx_end_frame();
+#ifdef TARGET_N3DS
+    LightEvent_Wait(&s_event_main);
+#endif
 }
 
 #ifdef TARGET_WEB
@@ -211,6 +215,7 @@ void main_func(void) {
     inited = 1;
     //the 3ds version has its own main loop
     wm_api->main_loop(produce_one_frame);
+    audio_api->stop();
 #else
     inited = 1;
     while (1) {