Revert "(hopefully) fix the timing crap; add vsync option"

This reverts commit 2bd840a299.

include/text_strings.h.in

@@ -27,8 +27,6 @@
 #define TEXT_OPT_NEAREST   _("Nearest")
 #define TEXT_OPT_LINEAR    _("Linear")
 #define TEXT_OPT_MVOLUME   _("Master Volume")
-#define TEXT_OPT_VSYNC     _("Vertical Sync")
-#define TEXT_OPT_DOUBLE    _("Double")
 #define TEXT_RESET_WINDOW  _("Reset Window")
 
 #define TEXT_OPT_UNBOUND   _("NONE")

src/game/options_menu.c

@@ -72,9 +72,7 @@ static const u8 optsVideoStr[][32] = {
     { TEXT_OPT_TEXFILTER },
     { TEXT_OPT_NEAREST },
     { TEXT_OPT_LINEAR },
-    { TEXT_RESET_WINDOW },
-    { TEXT_OPT_VSYNC },
-    { TEXT_OPT_DOUBLE },
+    { TEXT_RESET_WINDOW }
 };
 
 static const u8 optsAudioStr[][32] = {
@@ -114,12 +112,6 @@ static const u8 *filterChoices[] = {
     optsVideoStr[3],
 };
 
-static const u8 *vsyncChoices[] = {
-    toggleStr[0],
-    toggleStr[1],
-    optsVideoStr[6],
-};
-
 enum OptType {
     OPT_INVALID = 0,
     OPT_TOGGLE,
@@ -186,12 +178,8 @@ static void optmenu_act_exit(UNUSED struct Option *self, s32 arg) {
     if (!arg) game_exit(); // only exit on A press and not directions
 }
 
-static void optvideo_reset_window(UNUSED struct Option *self, s32 arg) {
-    if (!arg) {
-        // Restrict reset to A press and not directions
-        configWindow.reset = true;
-        configWindow.settings_changed = true;
-    }
+static void optvide_reset_window(UNUSED struct Option *self, s32 arg) {
+    if (!arg) configWindow.reset = true;; // Restrict reset to A press and not directions
 }
 
 /* submenu option lists */
@@ -229,9 +217,8 @@ 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_CHOICE( optsVideoStr[1], &configFiltering, filterChoices ),
-    DEF_OPT_BUTTON( optsVideoStr[4], optvideo_reset_window ),
+    DEF_OPT_BUTTON( optsVideoStr[4], optvide_reset_window ),
 };
 
 static struct Option optsAudio[] = {

src/pc/configfile.c

@@ -40,11 +40,10 @@ ConfigWindow configWindow       = {
     .y = SDL_WINDOWPOS_CENTERED,
     .w = DESIRED_SCREEN_WIDTH,
     .h = DESIRED_SCREEN_HEIGHT,
-    .vsync = 1,
     .reset = false,
+    .vsync = false,
     .fullscreen = false,
     .exiting_fullscreen = false,
-    .settings_changed = false,
 };
 unsigned int configFiltering    = 1;          // 0=force nearest, 1=linear, (TODO) 2=three-point
 unsigned int configMasterVolume = MAX_VOLUME; // 0 - MAX_VOLUME
@@ -85,7 +84,6 @@ 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 = "texture_filtering",    .type = CONFIG_TYPE_UINT, .uintValue = &configFiltering},
     {.name = "master_volume",        .type = CONFIG_TYPE_UINT, .uintValue = &configMasterVolume},
     {.name = "key_a",                .type = CONFIG_TYPE_BIND, .uintValue = configKeyA},

src/pc/configfile.h

@@ -11,11 +11,10 @@
 
 typedef struct {
     unsigned int x, y, w, h;
-    unsigned int vsync;
     bool reset;
+    bool vsync;
     bool fullscreen;
     bool exiting_fullscreen;
-    bool settings_changed;
 } ConfigWindow;
 
 extern ConfigWindow configWindow;

src/pc/gfx/gfx_sdl2.c

@@ -39,12 +39,9 @@
 # define FRAMERATE 30
 #endif
 
-static const Uint32 FRAME_TIME = 1000 / FRAMERATE;
-
 static SDL_Window *wnd;
 static SDL_GLContext ctx = NULL;
 static int inverted_scancode_table[512];
-static Uint32 frame_start = 0;
 
 const SDL_Scancode windows_scancode_table[] =
 {
@@ -113,9 +110,9 @@ static void gfx_sdl_set_fullscreen() {
 }
 
 static void gfx_sdl_reset_dimension_and_pos() {
-    if (configWindow.exiting_fullscreen) {
+    if (configWindow.exiting_fullscreen)
         configWindow.exiting_fullscreen = false;
-    } else if (configWindow.reset) {
+    else if (configWindow.reset) {
         configWindow.x = SDL_WINDOWPOS_CENTERED;
         configWindow.y = SDL_WINDOWPOS_CENTERED;
         configWindow.w = DESIRED_SCREEN_WIDTH;
@@ -126,14 +123,29 @@ static void gfx_sdl_reset_dimension_and_pos() {
             configWindow.fullscreen = false;
             return;
         }
-    } else if (!configWindow.settings_changed) {
+    } else
         return;
-    }
 
-    configWindow.settings_changed = false;
     SDL_SetWindowSize(wnd, configWindow.w, configWindow.h);
     SDL_SetWindowPosition(wnd, configWindow.x, configWindow.y);
-    SDL_GL_SetSwapInterval(configWindow.vsync); // in case vsync changed
+}
+
+static bool test_vsync(void) {
+    // Even if SDL_GL_SetSwapInterval succeeds, it doesn't mean that VSync actually works.
+    // A 60 Hz monitor should have a swap interval of 16.67 milliseconds.
+    // If it takes less than 12 milliseconds, assume that VSync is not working.
+    // SDL_GetTicks() probably does not offer enough precision for this kind of shit.
+    Uint32 start, end;
+
+    // do an extra swap, sometimes the first one takes longer (maybe creates buffers?)
+    SDL_GL_SwapWindow(wnd);
+
+    SDL_GL_SwapWindow(wnd);
+    start = SDL_GetTicks();
+    SDL_GL_SwapWindow(wnd);
+    end = SDL_GetTicks();
+
+    return (end - start >= 12);
 }
 
 static void gfx_sdl_init(void) {
@@ -153,9 +165,11 @@ static void gfx_sdl_init(void) {
 
     if (gCLIOpts.FullScreen == 1)
         configWindow.fullscreen = true;
-    else if (gCLIOpts.FullScreen == 2)
+
+    if (gCLIOpts.FullScreen == 2)
         configWindow.fullscreen = false;
 
+
     const char* window_title = 
     #ifndef USE_GLES
     "Super Mario 64 PC port (OpenGL)";
@@ -169,11 +183,14 @@ static void gfx_sdl_init(void) {
         SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE
     );
     ctx = SDL_GL_CreateContext(wnd);
-
-    SDL_GL_SetSwapInterval(configWindow.vsync);
+    SDL_GL_SetSwapInterval(2);
 
     gfx_sdl_set_fullscreen();
 
+    configWindow.vsync = test_vsync();
+    if (!configWindow.vsync)
+        printf("Warning: VSync is not enabled or not working. Falling back to timer for synchronization\n");
+
     for (size_t i = 0; i < sizeof(windows_scancode_table) / sizeof(SDL_Scancode); i++) {
         inverted_scancode_table[windows_scancode_table[i]] = i;
     }
@@ -258,19 +275,23 @@ static void gfx_sdl_handle_events(void) {
 }
 
 static bool gfx_sdl_start_frame(void) {
-    frame_start = SDL_GetTicks();
     return true;
 }
 
 static void sync_framerate_with_timer(void) {
-    Uint32 elapsed = SDL_GetTicks() - frame_start;
+    // Number of milliseconds a frame should take (30 fps)
+    const Uint32 FRAME_TIME = 1000 / FRAMERATE;
+    static Uint32 last_time;
+
+    Uint32 elapsed = SDL_GetTicks() - last_time;
     if (elapsed < FRAME_TIME)
         SDL_Delay(FRAME_TIME - elapsed);
+
+    last_time = SDL_GetTicks();
 }
 
 static void gfx_sdl_swap_buffers_begin(void) {
-    // if vsync is set to 2, depend only on SwapInterval to sync
-    if (configWindow.vsync <= 1)
+    if (!configWindow.vsync)
         sync_framerate_with_timer();
     SDL_GL_SwapWindow(wnd);
 }