Revert "much better frame pacing"

- No one complained about framerate since several updates now; don't fix what isn't broken
- Too much frames are drawn at low framerates when Vsync is enabled
- FPS and delay calculation are wrong with Vsync: 60 FPS looks like 30 with a 120+Hz monitor
- Fixed Auto mode that was broken
- Kept precise_delay_f64 as I have observed no noticeable impact on CPU

src/pc/gfx/gfx_pc.c

@@ -1970,26 +1970,18 @@ void gfx_run(Gfx *commands) {
     //double t0 = gfx_wapi->get_time();
     gfx_rapi->start_frame();
     gfx_run_dl(commands);
-}
-
-void gfx_end_frame_render(void) {
     gfx_flush();
     gfx_rapi->end_frame();
+    gfx_wapi->swap_buffers_begin();
 }
 
-void gfx_display_frame(void) {
+void gfx_end_frame(void) {
-    gfx_wapi->swap_buffers_begin();
     if (!dropped_frame) {
         gfx_rapi->finish_render();
         gfx_wapi->swap_buffers_end();
     }
 }
 
-void gfx_end_frame(void) {
-    gfx_end_frame_render();
-    gfx_display_frame();
-}
-
 void gfx_shutdown(void) {
     if (gfx_rapi) {
         if (gfx_rapi->shutdown) gfx_rapi->shutdown();

src/pc/gfx/gfx_pc.h

@@ -21,8 +21,6 @@ void gfx_init(struct GfxWindowManagerAPI *wapi, struct GfxRenderingAPI *rapi, co
 struct GfxRenderingAPI *gfx_get_current_rendering_api(void);
 void gfx_start_frame(void);
 void gfx_run(Gfx *commands);
-void gfx_end_frame_render(void);
-void gfx_display_frame(void);
 void gfx_end_frame(void);
 void gfx_shutdown(void);
 void gfx_pc_precomp_shader(uint32_t rgb1, uint32_t alpha1, uint32_t rgb2, uint32_t alpha2, uint32_t flags);

src/pc/pc_main.c

@@ -205,16 +205,20 @@ static s32 get_num_frames_to_draw(f64 t, u32 frameLimit) {
 static u32 get_refresh_rate() {
     if (configFramerateMode == RRM_MANUAL) { return configFrameLimit; }
     if (configFramerateMode == RRM_UNLIMITED) { return 3000; } // Has no effect
-    static u32 refreshRate = 60;
+    static u32 refreshRate = 0;
 #ifdef HAVE_SDL2
     if (!refreshRate) {
         SDL_DisplayMode mode;
         if (SDL_GetCurrentDisplayMode(0, &mode) == 0) {
             refreshRate = (u32) mode.refresh_rate;
+        } else {
+            refreshRate = 60;
         }
     }
-#endif
     return refreshRate;
+#else
+    return 60;
+#endif
 }
 
 void produce_interpolation_frames_and_delay(void) {
@@ -223,53 +227,42 @@ void produce_interpolation_frames_and_delay(void) {
 
     gRenderingInterpolated = true;
 
+    f64 curTime = clock_elapsed_f64();
     f64 targetTime = sFrameTimeStart + sFrameTime;
     s32 numFramesToDraw = get_num_frames_to_draw(sFrameTimeStart, refreshRate);
 
-    f64 curTime = clock_elapsed_f64();
     f64 loopStartTime = curTime;
     f64 expectedTime = 0;
-    u16 frames = 0;
-    const f64 interpFrameTime = sFrameTime / (f64) numFramesToDraw;
 
     // interpolate and render
     // make sure to draw at least one frame to prevent the game from freezing completely
     // (including inputs and window events) if the game update duration is greater than 33ms
     do {
-        ++frames;
-
-        // when we know how many frames to draw, use a precise delta
-        f64 idealTime = configFramerateMode != RRM_UNLIMITED ? (sFrameTimeStart + interpFrameTime * frames) : curTime;
         f32 delta = (
             is30Fps ?
             1.0f :
-            clamp((idealTime - sFrameTimeStart) / sFrameTime, 0.f, 1.f)
+            clamp((curTime - sFrameTimeStart) / sFrameTime, 0.f, 1.f)
         );
         gRenderingDelta = delta;
 
-        // prepare interpolated frame
         gfx_start_frame();
         if (!gSkipInterpolationTitleScreen) { patch_interpolations(delta); }
         send_display_list(gGfxSPTask);
-        gfx_end_frame_render();
+        gfx_end_frame();
-
-        // delay if our framerate is capped
-        if (configFramerateMode != RRM_UNLIMITED && !configWindow.vsync) {
-            f64 now = clock_elapsed_f64();
-            f64 elapsedTime = now - loopStartTime;
-            expectedTime += (targetTime - curTime) / (f64) numFramesToDraw;
-            f64 delay = (expectedTime - elapsedTime);
-
-            numFramesToDraw--;
-            if (delay > 0.0) {
-                precise_delay_f64(delay);
-            }
-        }
-
-        // send the frame to the screen (should be directly after the delay for good frame pacing)
-        gfx_display_frame();
 
         sDrawnFrames++;
+
+        if (!is30Fps && configFramerateMode == RRM_UNLIMITED) { continue; }
+
+        // delay if our framerate is capped
+        f64 now = clock_elapsed_f64();
+        f64 elapsedTime = now - loopStartTime;
+        expectedTime += (targetTime - curTime) / (f64) numFramesToDraw;
+        f64 delay = (expectedTime - elapsedTime);
+        if (delay > 0.0) {
+            precise_delay_f64(delay);
+        }
+        numFramesToDraw--;
     } while ((curTime = clock_elapsed_f64()) < targetTime && numFramesToDraw > 0);
 
     // compute and update the frame rate every second