Record and replay input on a world clock: game seconds stepped since the player first stands away from the title screen's origin

With the real-time frame step, a frame advances the game by its own length, so a recording keyed by presents replayed at another frame rate pressed at other game times, and every load of another length shifted the rest. Lines after the first save load are now written as "@<ms> <what> <hold ms>" and replayed on that clock; menu input before it stays in presents. Two replays of one recording whose loads ended at presents 1887 and 2094 kept the player within 2 m for 15 game seconds, until the fight's own nondeterminism took over.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

runtime/frame_rate.c

@@ -22,6 +22,11 @@
 // One 64-bit and one 32-bit store per present; the guest reads the floats on its own threads, and each stays finite
 // and in range whichever store it sees.
 //
+// The world clock (frame_step_world_us) sums the steps from the first present that finds the player actor away from
+// the origin, where the title screen keeps it: the end of the first save load. Recorded and scripted input
+// (input_win.c) runs on it, so a replay presses at the same game time at any frame rate and after a first load of any
+// length; a later load (fast travel) still shifts what follows by its length.
+//
 // TOTK_TRACE=perf adds a line per 120 presents: fps, the game seconds stepped against wall seconds, and with
 // TOTK_SPEED_PROBE=1 the player's position and ground speed (an independent check: Link runs at the same speed at
 // any frame rate when game time follows wall time).
@@ -201,11 +206,30 @@ static void speed_report(uint64_t now, double step, int interval) {
     memset(win_hist, 0, sizeof win_hist);
 }
 
+static _Atomic int64_t world_us = -1;
+static uint64_t presents;
+
+int64_t frame_step_world_us(void) { return atomic_load_explicit(&world_us, memory_order_relaxed); }
+
+static void world_clock(double dt, double step) {
+    presents++;
+    int64_t w = atomic_load_explicit(&world_us, memory_order_relaxed);
+    if (w < 0) {
+        float p[3];
+        if (!player_pos(p) || fabsf(p[0]) + fabsf(p[2]) < 1.0f) return;   // a few guest reads, until the load ends
+        rt_log("frame step: world clock starts at present %llu (the player at %.1f %.1f %.1f)",
+               (unsigned long long)presents, p[0], p[1], p[2]);
+        atomic_store_explicit(&world_us, 0, memory_order_relaxed);
+        return;
+    }
+    if (!step_word) step = dt > STEP_MAX_S ? STEP_MAX_S : dt;   // whole-vsync steps: the display time stands in
+    atomic_store_explicit(&world_us, w + (int64_t)(step * 1e6 + 0.5), memory_order_relaxed);
+}
+
 void frame_step_present(uint64_t display_ns, int interval) {
     frame_limit_live();
-    double step = 0;
+    double step = 0, dt = last_ns ? (double)(display_ns - last_ns) * 1e-9 : 0;
     if (step_word && last_ns) {
-        double dt = (double)(display_ns - last_ns) * 1e-9;
         if (dt > STEP_RESET_S || dt < 0.001) {
             sample_count = sample_next = 0;
         } else {
@@ -219,5 +243,6 @@ void frame_step_present(uint64_t display_ns, int interval) {
         }
     }
     last_ns = display_ns;
+    world_clock(dt, step);
     if (rt_trace & RT_TRACE_PERF) speed_report(display_ns, step, interval);
 }

runtime/host.h

@@ -237,6 +237,7 @@ void *rt_patch_page(void);                                 // the page the patch
 void frame_step_init(void);                                // after rt_patches_init: the real-time step's first value
 int frame_step_realtime(void);                             // the real-time step is on: presents ignore the interval
 uint64_t frame_step_cap_ns(void);                          // with the real-time step: the shortest frame in ns
+int64_t frame_step_world_us(void);                         // game time since the loaded save's first frame, -1 before
                                                            // (TOTK_FPS_LIMIT, live)
 void frame_step_present(uint64_t display_ns, int interval); // nvnQueuePresentTexture: the frame's display time and
                                                            // present interval (60 Hz ticks)

runtime/input_win.c

@@ -41,7 +41,11 @@ static const SDL_GamepadButton pad_sdl[PAD_COUNT] = {
 };
 
 // TOTK_INPUT_SCRIPT=<file>: lines "<frame> <button> [hold]" or "<frame> LSTICK|RSTICK <x> <y> [hold]", ORed into the real input.
-typedef struct { uint64_t frame, hold; int bit, stick; int32_t x, y; int logged; char text[48]; } ScriptEv;
+// A line "@<ms> ..." is timed instead: <ms> and its hold are milliseconds of the world clock (frame_step_world_us, game
+// time since the loaded save's first frame), so it lands at the same game time at any frame rate and load length. A
+// timed event shorter than a frame is applied once.
+// at, hold: presents, or microseconds of the world clock when timed.
+typedef struct { uint64_t at, hold; int bit, stick, timed; int32_t x, y; int logged; char text[48]; } ScriptEv;
 static const struct { const char *name; int bit; } script_buttons[] = {
     {"A", B_A}, {"B", B_B}, {"X", B_X}, {"Y", B_Y}, {"LCLICK", B_STICK_L}, {"RCLICK", B_STICK_R}, {"L", B_L}, {"R", B_R},
     {"ZL", B_ZL}, {"ZR", B_ZR}, {"PLUS", B_PLUS}, {"MINUS", B_MINUS}, {"LEFT", B_LEFT}, {"UP", B_UP}, {"RIGHT", B_RIGHT}, {"DOWN", B_DOWN},
@@ -62,22 +66,25 @@ static void script_load(void) {
         char *h = strchr(line, '#');
         if (h) *h = 0;
         char name[32];
-        unsigned long long fr;
-        int off = 0;
-        if (sscanf(line, "%llu %31s%n", &fr, name, &off) < 2) continue;
-        ScriptEv e = {.frame = fr, .hold = 4, .bit = -1};
-        long a, b, c;
+        double at;
+        int off = 0, timed = line[0] == '@';
+        if (sscanf(line + timed, "%lf %31s%n", &at, name, &off) < 2 || at < 0) continue;
+        off += timed;
+        double unit = timed ? 1000.0 : 1.0;   // ms to us, or presents
+        ScriptEv e = {.at = (uint64_t)(at * unit + 0.5), .hold = timed ? 66667 : 4, .bit = -1, .timed = timed};
+        long a, b;
+        double c;
         if (!strcmp(name, "LSTICK") || !strcmp(name, "RSTICK")) {
-            int n = sscanf(line + off, "%ld %ld %ld", &a, &b, &c);
+            int n = sscanf(line + off, "%ld %ld %lf", &a, &b, &c);
             if (n < 2) { rt_log("input: script line %d: %s needs x y [hold]", ln, name); continue; }
             e.stick = name[0] == 'L' ? 1 : 2; e.x = (int32_t)a; e.y = (int32_t)b;
-            if (n >= 3) e.hold = (uint64_t)c;
+            if (n >= 3 && c > 0) e.hold = (uint64_t)(c * unit + 0.5);
             snprintf(e.text, sizeof e.text, "%s %d %d", name, e.x, e.y);
         } else {
             for (size_t i = 0; i < sizeof script_buttons / sizeof *script_buttons; i++)
                 if (!strcmp(name, script_buttons[i].name)) e.bit = script_buttons[i].bit;
             if (e.bit < 0) { rt_log("input: script line %d: unknown button %s", ln, name); continue; }
-            if (sscanf(line + off, "%ld", &a) == 1) e.hold = (uint64_t)a;
+            if (sscanf(line + off, "%lf", &c) == 1 && c > 0) e.hold = (uint64_t)(c * unit + 0.5);
             snprintf(e.text, sizeof e.text, "%s", name);
         }
         if (script_n == cap) {
@@ -95,10 +102,17 @@ static void script_apply(uint64_t *b, int32_t sl[2], int32_t sr[2]) {
     if (!script_state) script_load();
     if (!script_n) return;
     uint64_t fr = __atomic_load_n(&gfx_counters.frames, __ATOMIC_RELAXED);
+    int64_t w = frame_step_world_us();
     for (int i = 0; i < script_n; i++) {
         ScriptEv *e = &script_ev[i];
-        if (fr < e->frame || fr >= e->frame + e->hold) continue;
-        if (!e->logged) { e->logged = 1; rt_log("input: script frame %llu: %s", (unsigned long long)fr, e->text); }
+        if (e->timed && w < 0) continue;
+        uint64_t now = e->timed ? (uint64_t)w : fr;
+        if (now < e->at || (now >= e->at + e->hold && (e->logged || !e->timed))) continue;
+        if (!e->logged) {
+            e->logged = 1;
+            if (e->timed) rt_log("input: script frame %llu at %.1f ms: %s", (unsigned long long)fr, w / 1000.0, e->text);
+            else rt_log("input: script frame %llu: %s", (unsigned long long)fr, e->text);
+        }
         if (e->stick) { int32_t *s = e->stick == 1 ? sl : sr; s[0] = e->x; s[1] = e->y; }
         else *b |= 1ull << e->bit;
     }
@@ -106,29 +120,40 @@ static void script_apply(uint64_t *b, int32_t sl[2], int32_t sr[2]) {
 
 // TOTK_INPUT_RECORD=<file>: writes the merged input as TOTK_INPUT_SCRIPT lines, one per button press and per stick
 // segment, so a played session replays as a script. A stick segment ends when an axis moves by more than REC_STICK_STEP.
+// An event that begins on the world clock is written timed ("@<ms>", hold in ms), one before it in presents.
 enum { REC_STICK_STEP = 2048 };
 static FILE *rec;
 static int rec_state;                // 0 not opened, 1 recording, -1 off
 static uint64_t rec_down[16];        // frame + 1 at which each button went down, 0 while up
+static int64_t rec_down_w[16];       // the world clock then, -1 before it started
 static uint64_t rec_stick_from[2];   // frame + 1 at which the current non-zero stick segment began
+static int64_t rec_stick_w[2];
 static int32_t rec_stick[2][2];
 
-static void rec_close_stick(int s, uint64_t fr) {
+// "<frame> <what> <hold>" or "@<ms> <what> <hold ms>": from frame from and world clock from_w to now.
+static void rec_line(uint64_t from, int64_t from_w, uint64_t fr, int64_t w, const char *what) {
+    if (from_w >= 0 && w >= from_w)
+        fprintf(rec, "@%.1f %s %.1f\n", from_w / 1000.0, what, (w > from_w ? w - from_w : 1000) / 1000.0);
+    else
+        fprintf(rec, "%llu %s %llu\n", (unsigned long long)from, what, (unsigned long long)(fr > from ? fr - from : 1));
+}
+
+static void rec_close_stick(int s, uint64_t fr, int64_t w) {
     if (!rec_stick_from[s]) return;
-    uint64_t from = rec_stick_from[s] - 1;
-    fprintf(rec, "%llu %s %d %d %llu\n", (unsigned long long)from, s ? "RSTICK" : "LSTICK", rec_stick[s][0],
-            rec_stick[s][1], (unsigned long long)(fr > from ? fr - from : 1));
+    char what[48];
+    snprintf(what, sizeof what, "%s %d %d", s ? "RSTICK" : "LSTICK", rec_stick[s][0], rec_stick[s][1]);
+    rec_line(rec_stick_from[s] - 1, rec_stick_w[s], fr, w, what);
     rec_stick_from[s] = 0;
 }
 
 static void rec_flush_all(void) {
     if (rec_state != 1) return;
-    uint64_t fr = __atomic_load_n(&gfx_counters.frames, __ATOMIC_RELAXED);
+    uint64_t fr = __atomic_load_n(&gfx_counters.frames, __ATOMIC_RELAXED) + 1;
+    int64_t w = frame_step_world_us();
     for (int i = 0; i < 16; i++)
-        if (rec_down[i]) { fprintf(rec, "%llu %s %llu\n", (unsigned long long)(rec_down[i] - 1), script_buttons[i].name,
-                                   (unsigned long long)(fr - (rec_down[i] - 1) + 1)); rec_down[i] = 0; }
-    rec_close_stick(0, fr);
-    rec_close_stick(1, fr);
+        if (rec_down[i]) { rec_line(rec_down[i] - 1, rec_down_w[i], fr, w, script_buttons[i].name); rec_down[i] = 0; }
+    rec_close_stick(0, fr, w);
+    rec_close_stick(1, fr, w);
     fflush(rec);
 }
 
@@ -138,19 +163,18 @@ static void rec_apply(uint64_t b, const int32_t sl[2], const int32_t sr[2]) {
         rec = path && *path ? fopen(path, "w") : NULL;
         rec_state = rec ? 1 : -1;
         if (path && *path && !rec) rt_log("input: cannot open TOTK_INPUT_RECORD %s", path);
-        if (rec) { fprintf(rec, "# Recorded input (TOTK_INPUT_RECORD); frame = presents.\n"); atexit(rec_flush_all);
+        if (rec) { fprintf(rec, "# Recorded input (TOTK_INPUT_RECORD); frame = presents, @ms = world clock.\n"); atexit(rec_flush_all);
                    rt_log("input: recording to %s", path); }
     }
     if (rec_state != 1) return;
     uint64_t fr = __atomic_load_n(&gfx_counters.frames, __ATOMIC_RELAXED);
+    int64_t w = frame_step_world_us();
     int wrote = 0;
     for (int i = 0; i < 16; i++) {
         int bit = script_buttons[i].bit, down = (b >> bit & 1) != 0;
-        if (down && !rec_down[i]) rec_down[i] = fr + 1;
+        if (down && !rec_down[i]) rec_down[i] = fr + 1, rec_down_w[i] = w;
         else if (!down && rec_down[i]) {
-            uint64_t from = rec_down[i] - 1;
-            fprintf(rec, "%llu %s %llu\n", (unsigned long long)from, script_buttons[i].name,
-                    (unsigned long long)(fr > from ? fr - from : 1));
+            rec_line(rec_down[i] - 1, rec_down_w[i], fr, w, script_buttons[i].name);
             rec_down[i] = 0;
             wrote = 1;
         }
@@ -160,9 +184,9 @@ static void rec_apply(uint64_t b, const int32_t sl[2], const int32_t sr[2]) {
         int moved = abs(st[s][0] - rec_stick[s][0]) > REC_STICK_STEP || abs(st[s][1] - rec_stick[s][1]) > REC_STICK_STEP ||
                     ((st[s][0] || st[s][1]) != (rec_stick[s][0] || rec_stick[s][1]));
         if (!moved) continue;
-        if (rec_stick_from[s]) { rec_close_stick(s, fr); wrote = 1; }
+        if (rec_stick_from[s]) { rec_close_stick(s, fr, w); wrote = 1; }
         rec_stick[s][0] = st[s][0]; rec_stick[s][1] = st[s][1];
-        if (st[s][0] || st[s][1]) rec_stick_from[s] = fr + 1;
+        if (st[s][0] || st[s][1]) rec_stick_from[s] = fr + 1, rec_stick_w[s] = w;
     }
     if (wrote) fflush(rec);
 }