1 files changed, 17 insertions, 19 deletions
diff --git a/src/web.zig b/src/web.zig
index b77d07a6..532e3794 100644
--- a/src/web.zig
+++ b/src/web.zig
@@ -1,7 +1,7 @@
 //! Freestanding WebAssembly boundary for the DOM backend.
 //!
 //! JavaScript owns the clock and nothing else: it calls `pardes_tick` (one
-//! `Pardes.pump`) and reads the packed cell buffer `present` left behind. The
+//! `Pardes.pump`, at requestAnimationFrame's timestamp) and reads the packed cell buffer `present` left behind. The
 //! host vtable below is only what a page genuinely has — pixels, the
 //! clipboard, links, downloads. Processes, a real filesystem, a language
 //! backend and subprocess pipes are left null, so the core answers them itself
@@ -106,6 +106,9 @@ const State = struct {
     frame_len: usize = 0,
     frame_cols: u16 = 0,
     frame_rows: u16 = 0,
+    /// requestAnimationFrame's timestamp as the last tick gave it, in ns:
+    /// the core's clock (`Host.now`).
+    now_ns: u64 = 0,
 
     fn init(cols: u16, rows: u16) !State {
         const allocs = pardes.memory.init(gpa);
@@ -276,30 +279,19 @@ export fn pardes_pointer_leave() void {
     s.core.update(.pointer_leave);
 }
 
-/// One iteration of the core's own loop: queued input, effects, render,
-/// present. JS calls it once per animation frame, after spending that frame's
-/// animation ticks.
-export fn pardes_tick() void {
+/// One iteration of the core's own loop: queued input, effects, the frames
+/// of animation `timestamp_ms` (requestAnimationFrame's clock) has brought,
+/// render, present. JS calls it once per display frame; a call with no
+/// timestamp (NaN) leaves the clock where it was.
+export fn pardes_tick(timestamp_ms: f64) void {
     const s = &(state orelse return);
+    if (std.math.isFinite(timestamp_ms) and timestamp_ms >= 0)
+        s.now_ns = @intFromFloat(timestamp_ms * std.time.ns_per_ms);
     s.core.pump(host(s)) catch |err| {
         last_error = @intFromError(err);
     };
 }
 
-/// Spend one fixed 60 Hz animation step, the only writer of animated time in
-/// this host. Separate from the pump for the reason the AppKit shell keeps them
-/// separate: if every input pump also advanced the transition, a burst of keys
-/// would collapse a ten-frame fade into one display frame.
-export fn pardes_animation_tick() void {
-    const s = &(state orelse return);
-    s.core.update(.tick);
-}
-
-export fn pardes_animating() u32 {
-    const s = &(state orelse return 0);
-    return @intFromBool(s.core.animationActive());
-}
-
 /// The Exit builtin, or the last pane closing. JS stops its frame loop.
 export fn pardes_should_quit() u32 {
     const s = &(state orelse return 0);
@@ -462,7 +454,13 @@ extern "pardes" fn host_download(
     bytes_len: usize,
 ) callconv(.c) void;
 
+fn now(ctx: ?*anyopaque) u64 {
+    const s: *State = @ptrCast(@alignCast(ctx.?));
+    return s.now_ns;
+}
+
 const vtable: pardes.Host.VTable = .{
+    .now = now,
     .present = present,
     .write_file = writeFile,
     .write_dump = writeDump,