From 06c1d1c42eeba1c418f3d2789f26d68cf09cdd5a Mon Sep 17 00:00:00 2001
From: Miloslav Ciz <drummyfish@disroot.org>
Date: Sun, 20 Apr 2025 14:18:57 +0200
Subject: [PATCH] Add FPS measure

---
 TODO.txt       |  2 +-
 frontend_sdl.c |  3 +++
 game.h         | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/TODO.txt b/TODO.txt
index be0ba06..e413072 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -14,7 +14,6 @@
   inbetween world space and model space.
 - Consider better input handling in SDL? Currently it just detects presses on
   the exact frame, so a press can be missed. But how tho?
-- FPS logging for optim
 - try to add distance fog?
 - use 332 in SDL with potato?
 - option to turn on simple 332 colors?
@@ -79,6 +78,7 @@
 =========== HANDLED ==============
 
 - MAP4: one triangle in top section is missing!
+- FPS logging for optim
 - the pinch collision test seems to sometimes stop the car e.g. after falling
   from bigger height or when running into ramp at high speed (or not?) - FIX
 - sometimes during long loading the screen goes black, seems to have appeared
diff --git a/frontend_sdl.c b/frontend_sdl.c
index e6abfeb..2b91c7c 100644
--- a/frontend_sdl.c
+++ b/frontend_sdl.c
@@ -8,6 +8,9 @@
 #define LCR_SETTING_LOG_LEVEL 2
 #define DATA_FILE_NAME "data"
 #define LCR_LOADING_COMMAND SDL_PumpEvents();
+
+// #define LCR_FPS_GET_MS SDL_GetTicks() // uncomment for FPS measuring
+
 #include "game.h"
 
 SDL_Window *window;
diff --git a/game.h b/game.h
index e91cdea..b875875 100644
--- a/game.h
+++ b/game.h
@@ -176,6 +176,12 @@ uint8_t LCR_gameGetNextAudioSample(void);
   #define LCR_LOADING_COMMAND ;
 #endif
 
+/*
+  To make the game log FPS define a macro named LCR_FPS_GET_MS to a command that
+  evaluates to the current number of milliseconds since some given time. It
+  will be used to measure frame duration and average values will be logged.
+*/
+
 //------------------------------------------------------------------------------
 
 #define LCR_LOG0(s) ;
@@ -357,6 +363,13 @@ struct
                            is to allow ghosts for even long replays. */
   } ghost;
 #endif
+
+#ifdef LCR_FPS_GET_MS
+  uint16_t renderFrameMS;
+  uint16_t physicsFrameMS;
+  uint8_t  renderFramesMeasured;
+  uint8_t  physicsFramesMeasured;
+#endif
 } LCR_game;
 
 uint8_t LCR_gameMusicOn(void)
@@ -1039,6 +1052,11 @@ void LCR_gameInit(int argc, const char **argv)
   LCR_game.cameraMode = LCR_CAMERA_MODE_DRIVE;
   LCR_currentMap.blockCount = 0; // means no map loaded
 
+#ifdef LCR_FPS_GET_MS
+  LCR_game.renderFrameMS = 0;
+  LCR_game.physicsFrameMS = 0;
+#endif
+
   LCR_LOG2("parsing arguments");
 
   uint8_t quickLoad = 0;
@@ -1550,6 +1568,10 @@ uint8_t LCR_gameStep(uint32_t time)
 {
   LCR_LOG2("game step (start)");
 
+#ifdef LCR_FPS_GET_MS
+  uint32_t frameTime;
+#endif
+
   uint32_t sleep = 0;
   int paused = LCR_game.state == LCR_GAME_STATE_MENU ||
     LCR_game.state == LCR_GAME_STATE_RUN_STARTING;
@@ -1593,8 +1615,17 @@ uint8_t LCR_gameStep(uint32_t time)
        (LCR_game.keyStates[LCR_KEY_DOWN]  ? LCR_RACING_INPUT_BACK  : 0) |
        (LCR_game.keyStates[LCR_KEY_LEFT]  ? LCR_RACING_INPUT_LEFT  : 0));
 
+#ifdef LCR_FPS_GET_MS
+    frameTime = LCR_FPS_GET_MS;
+#endif
+
     uint32_t events = paused ? 0 : LCR_racingStep(input);
 
+#ifdef LCR_FPS_GET_MS
+    LCR_game.physicsFrameMS += LCR_FPS_GET_MS - frameTime;
+    LCR_game.physicsFramesMeasured++;
+#endif
+
     if (events & LCR_RACING_EVENT_CP_TAKEN)
     {
       int carBlock[3];
@@ -1680,6 +1711,10 @@ uint8_t LCR_gameStep(uint32_t time)
     while (time >= LCR_game.nextRenderFrameTime)
       LCR_game.nextRenderFrameTime += 1000 / LCR_SETTING_FPS;
 
+#ifdef LCR_FPS_GET_MS
+    frameTime = LCR_FPS_GET_MS;
+#endif
+
     if ((LCR_game.state == LCR_GAME_STATE_MENU) || 
       LCR_game.state == LCR_GAME_STATE_LOADING)
       LCR_rendererDrawMenu(LCR_texts[LCR_TEXTS_TABS
@@ -1696,6 +1731,11 @@ uint8_t LCR_gameStep(uint32_t time)
       LCR_gameDrawPopupMessage();
       LCR_game.popupCountdown--;
     }
+
+#ifdef LCR_FPS_GET_MS
+    LCR_game.renderFrameMS += LCR_FPS_GET_MS - frameTime;
+    LCR_game.renderFramesMeasured++;
+#endif
   }
   else
   {
@@ -1722,6 +1762,24 @@ uint8_t LCR_gameStep(uint32_t time)
   LCR_game.frame++;
   LCR_LOG2("game step (end)");
 
+#ifdef LCR_FPS_GET_MS
+  if (LCR_game.renderFramesMeasured >= 64)
+  {
+    LCR_LOG0("us/frame (render):");
+    LCR_LOG0_NUM((LCR_game.renderFrameMS * 1000) / 64);
+    LCR_game.renderFramesMeasured = 0;
+    LCR_game.renderFrameMS = 0;
+  }
+
+  if (LCR_game.physicsFramesMeasured >= 64)
+  {
+    LCR_LOG0("us/frame (physics):");
+    LCR_LOG0_NUM((LCR_game.physicsFrameMS * 1000) / 64);
+    LCR_game.physicsFramesMeasured = 0;
+    LCR_game.physicsFrameMS = 0;
+  }
+#endif
+
   return 1;
 }