From 572a4b698b524e58fb2e8d7dd44a49e861135cfa Mon Sep 17 00:00:00 2001
From: fgsfds <pvt.fgsfds@gmail.com>
Date: Thu, 9 Jul 2020 17:02:43 +0300
Subject: [PATCH] do vsync exactly like sm64-port does it

maybe this will finally work better
---
 src/game/options_menu.c |  2 +-
 src/pc/configfile.c     |  4 ++--
 src/pc/configfile.h     |  2 +-
 src/pc/gfx/gfx_sdl2.c   | 19 +++++++++----------
 4 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/src/game/options_menu.c b/src/game/options_menu.c
index 8ce169f0..56dba619 100644
--- a/src/game/options_menu.c
+++ b/src/game/options_menu.c
@@ -255,7 +255,7 @@ static struct Option optsControls[] = {
 
 static struct Option optsVideo[] = {
     DEF_OPT_TOGGLE( optsVideoStr[0], &configWindow.fullscreen ),
-    DEF_OPT_CHOICE( optsVideoStr[5], &configWindow.vsync, vsyncChoices ),
+    DEF_OPT_TOGGLE( optsVideoStr[5], &configWindow.vsync ),
     DEF_OPT_CHOICE( optsVideoStr[1], &configFiltering, filterChoices ),
     DEF_OPT_TOGGLE( optsVideoStr[7], &configHUD ),
     DEF_OPT_BUTTON( optsVideoStr[4], optvideo_reset_window ),
diff --git a/src/pc/configfile.c b/src/pc/configfile.c
index f55334f4..7411d4f8 100644
--- a/src/pc/configfile.c
+++ b/src/pc/configfile.c
@@ -100,7 +100,7 @@ static const struct ConfigOption options[] = {
     {.name = "window_y",             .type = CONFIG_TYPE_UINT, .uintValue = &configWindow.y},
     {.name = "window_w",             .type = CONFIG_TYPE_UINT, .uintValue = &configWindow.w},
     {.name = "window_h",             .type = CONFIG_TYPE_UINT, .uintValue = &configWindow.h},
-    {.name = "vsync",                .type = CONFIG_TYPE_UINT, .uintValue = &configWindow.vsync},
+    {.name = "vsync",                .type = CONFIG_TYPE_BOOL, .boolValue = &configWindow.vsync},
     {.name = "texture_filtering",    .type = CONFIG_TYPE_UINT, .uintValue = &configFiltering},
     {.name = "master_volume",        .type = CONFIG_TYPE_UINT, .uintValue = &configMasterVolume},
     {.name = "music_volume",         .type = CONFIG_TYPE_UINT, .uintValue = &configMusicVolume},
@@ -268,7 +268,7 @@ void configfile_load(const char *filename) {
                         case CONFIG_TYPE_BOOL:
                             if (strcmp(tokens[1], "true") == 0)
                                 *option->boolValue = true;
-                            else if (strcmp(tokens[1], "false") == 0)
+                            else
                                 *option->boolValue = false;
                             break;
                         case CONFIG_TYPE_UINT:
diff --git a/src/pc/configfile.h b/src/pc/configfile.h
index 848a3494..b92ae7be 100644
--- a/src/pc/configfile.h
+++ b/src/pc/configfile.h
@@ -10,7 +10,7 @@
 
 typedef struct {
     unsigned int x, y, w, h;
-    unsigned int vsync;
+    bool vsync;
     bool reset;
     bool fullscreen;
     bool exiting_fullscreen;
diff --git a/src/pc/gfx/gfx_sdl2.c b/src/pc/gfx/gfx_sdl2.c
index aef29780..8729e07d 100644
--- a/src/pc/gfx/gfx_sdl2.c
+++ b/src/pc/gfx/gfx_sdl2.c
@@ -53,8 +53,7 @@ static void (*kb_all_keys_up)(void) = NULL;
 // whether to use timer for frame control
 static bool use_timer = true;
 // time between consequtive game frames
-static const Uint32 frame_time = 1000 / FRAMERATE;
-static Uint32 frame_start = 0;
+static const int frame_time = 1000 / FRAMERATE;
 
 const SDL_Scancode windows_scancode_table[] = {
   /*  0                        1                            2                         3                            4                     5                            6                            7  */
@@ -138,8 +137,8 @@ int test_vsync(void) {
     return 0;
 }
 
-static inline void gfx_sdl_set_vsync(int mode) {
-    if (mode > 1) {
+static inline void gfx_sdl_set_vsync(const bool enabled) {
+    if (enabled) {
         // try to detect refresh rate
         SDL_GL_SetSwapInterval(1);
         const int vblanks = test_vsync();
@@ -149,13 +148,12 @@ static inline void gfx_sdl_set_vsync(int mode) {
             use_timer = false;
             return;
         } else {
-            printf("could not determine swap interval, falling back to one vblank + timer sync\n");
-            mode = 1;
+            printf("could not determine swap interval, falling back to timer sync\n");
         }
     }
 
-    SDL_GL_SetSwapInterval(mode);
-    use_timer = (mode <= 1);
+    use_timer = true;
+    SDL_GL_SetSwapInterval(0);
 }
 
 static void gfx_sdl_set_fullscreen(void) {
@@ -324,14 +322,15 @@ static void gfx_sdl_set_keyboard_callbacks(kb_callback_t on_key_down, kb_callbac
 }
 
 static bool gfx_sdl_start_frame(void) {
-    frame_start = SDL_GetTicks();
     return true;
 }
 
 static inline void sync_framerate_with_timer(void) {
-    const Uint32 elapsed = SDL_GetTicks() - frame_start;
+    static Uint32 last_time = 0;
+    const int elapsed = SDL_GetTicks() - last_time;
     if (elapsed < frame_time)
         SDL_Delay(frame_time - elapsed);
+    last_time += frame_time;
 }
 
 static void gfx_sdl_swap_buffers_begin(void) {