P11.1: juicier match pops & brighter bursts (sx / iOS)

Visual-juice vibe-pass, FX-only — no logic/state changes, input gating
still owned by BoardAnim.active.

- board_fx.sx: bigger, punchier match bursts — peak size 1.95->2.50 cells,
  combo bonus 0.55->0.72, and the per-gem fx tints saturated a touch (low
  channel trimmed, dominant/mid lifted) so every burst pops as a brighter,
  more vivid candy colour. The hot per-pixel tint loop's hoisted locals are
  preserved (issue 0001).
- gem_anim.sx: snappier clear pop — faster rise (0.30->0.18 of the window)
  to a bigger overshoot (CLEAR_POP_A 0.22->0.34) so the matched-gem clear
  reads as a candy snap. gem_pose's clear-pop invariants still hold.
- main.sx: M3TE_FX=<n> deterministic match-FX capture hook, mirroring the
  M3TE_SELECT pattern. Commits the n-th currently-legal swap at startup via
  the normal plan_and_commit path and begins the move timeline + burst/popup
  FX; M3TE_ANIM_TIME pins the phase and the frame loop holds the move/FX
  frozen while pinned, so the burst + "+points" screenshot identically every
  run. A larger M3TE_ANIM_TIME captures the settled, FX-gone board. Startup-
  only and guarded, so normal play is untouched.
- README.md: document the new M3TE_FX pin alongside the other capture hooks.
- goldens/p6_fx_match.png: updated deterministic golden (iOS 26 sim,
  SIMCTL_CHILD_M3TE_FX=3 SIMCTL_CHILD_M3TE_ANIM_TIME=0.22) — the vertical
  red 3-match, burst region +1.4% mean luminance / 3.2:1 brighter:dimmer vs
  the same scene on the pre-juice constants.

Gate: ios-sim build links, 19/19 logic tests green (incl. gem_pose t=0 rest).

README.md

@@ -115,3 +115,32 @@ env SIMCTL_CHILD_M3TE_TARGET=0 SIMCTL_CHILD_M3TE_RESTART=1 SIMCTL_CHILD_M3TE_ANI
 While a banner is up the board freezes (only the restart button is live, per
 P7.1's finished-level rule); `tests/banner_layout.sx` locks the restart button's
 rect ↔ hit-test round-trip headlessly.
+
+### Match-FX capture (P11.1)
+
+The match bursts + score popup (`board_fx.sx`) only spawn off a *committed* move,
+which the simulator can't script (there is no public touch injection). One more
+env hook forces a representative match at startup so the FX can be screenshot
+deterministically — combine it with `M3TE_ANIM_TIME` to freeze the phase:
+
+- `M3TE_FX=<n>` commits the **n-th currently-legal swap** (1-based, clamped; `=1`
+  is the first) through the normal `plan_and_commit` path, then begins the move
+  timeline + its burst/popup FX. While `M3TE_ANIM_TIME` is set the move/FX
+  timelines are pinned at that phase (the frame loop holds them frozen), so the
+  burst and floating `+points` render identically every run. A larger
+  `M3TE_ANIM_TIME` lands past the timeline, capturing the settled board with the
+  FX fully pruned. Startup-only and guarded by the var, so normal play is
+  untouched.
+
+The legal-swap order is the fixed enumeration in `tests/expected/swap_legality.stdout`
+(row-major, right-before-down). For seed 1337, `M3TE_FX=3` is the vertical red
+3-match used by the golden.
+
+```bash
+# Punchy match burst + "+30" popup, pinned mid-clear: goldens/p6_fx_match.png
+env SIMCTL_CHILD_M3TE_FX=3 SIMCTL_CHILD_M3TE_ANIM_TIME=0.22 \
+    xcrun simctl launch booted co.swipelab.m3te
+# Same match, later phase — FX fully gone over the settled board (no golden):
+env SIMCTL_CHILD_M3TE_FX=3 SIMCTL_CHILD_M3TE_ANIM_TIME=2.0 \
+    xcrun simctl launch booted co.swipelab.m3te
+```

board_fx.sx

@@ -25,8 +25,8 @@
 // lingers a touch into the fall; combos (cascade rounds past the first) burst
 // bigger. Sizes are in CELL units (1.0 == one grid cell).
 FX_BURST_LIFE   :f32: 0.70;
-FX_BURST_BASE   :f32: 1.95;
+FX_BURST_BASE   :f32: 2.50;
-FX_BURST_COMBO  :f32: 0.55;   // extra peak size per cascade depth (capped)
+FX_BURST_COMBO  :f32: 0.72;   // extra peak size per cascade depth (capped)
 
 // Popup timing/motion. Rises ~1.2 cells over its life and fades out; a combo
 // (depth > 1) popup is larger and gold.
@@ -35,15 +35,17 @@ FX_POPUP_RISE   :f32: 1.2;
 FX_POPUP_FONT   :f32: 34.0;
 FX_POPUP_COMBO_FONT :f32: 48.0;
 
-// Bright, slightly pastel tints so a soft glow reads over the dark board, in gem
+// Vivid candy tints so a soft glow reads brightly over the dark board, in gem
-// order (red, orange, yellow, green, blue, purple).
+// order (red, orange, yellow, green, blue, purple). Saturated a touch past the
+// pastel — the low channel is trimmed while the dominant/mid channel is lifted —
+// so every burst pops as a punchier colour without losing luminance.
 fx_tint :: (i: s64) -> Color {
-    if i == 0 { return Color.{ r = 255, g = 86,  b = 86,  a = 255 }; }
+    if i == 0 { return Color.{ r = 255, g = 92,  b = 62,  a = 255 }; }
-    if i == 1 { return Color.{ r = 255, g = 158, b = 64,  a = 255 }; }
+    if i == 1 { return Color.{ r = 255, g = 164, b = 44,  a = 255 }; }
-    if i == 2 { return Color.{ r = 255, g = 234, b = 96,  a = 255 }; }
+    if i == 2 { return Color.{ r = 255, g = 240, b = 72,  a = 255 }; }
-    if i == 3 { return Color.{ r = 120, g = 240, b = 120, a = 255 }; }
+    if i == 3 { return Color.{ r = 112, g = 250, b = 112, a = 255 }; }
-    if i == 4 { return Color.{ r = 110, g = 184, b = 255, a = 255 }; }
+    if i == 4 { return Color.{ r = 96,  g = 192, b = 255, a = 255 }; }
-    Color.{ r = 206, g = 132, b = 255, a = 255 }
+    Color.{ r = 224, g = 124, b = 255, a = 255 }
 }
 
 FX_POPUP_COLOR       :: Color.{ r = 255, g = 255, b = 255, a = 255 };

gem_anim.sx

@@ -74,19 +74,21 @@ land_squash :: (tl: f32) -> f32 {
 }
 
 // --- Clear pop ---------------------------------------------------------------
-// The matched-gem clear: a brief outward pop then a collapse to nothing over its
+// The matched-gem clear: a snappy outward pop then a collapse to nothing over its
-// local 0..1, so the clear reads as a satisfying pop rather than a plain shrink.
+// local 0..1, so the clear reads as a satisfying candy pop rather than a plain
-// Composes with the existing particle burst / score popup (board_fx.sx).
+// shrink. A fast rise to a bigger overshoot makes the snap read; the soft
-CLEAR_POP_A :f32: 0.22;
+// particle burst / score popup (board_fx.sx) compose on top.
+CLEAR_POP_A    :f32: 0.34;   // overshoot height above resting scale
+CLEAR_POP_RISE :f32: 0.18;   // fraction of the window spent rising to the peak
 
 clear_pop_scale :: (t: f32) -> f32 {
     if t <= 0.0 { return 1.0; }
     if t >= 1.0 { return 0.0; }
-    if t < 0.30 {
+    if t < CLEAR_POP_RISE {
-        return 1.0 + CLEAR_POP_A * (t / 0.30);
+        return 1.0 + CLEAR_POP_A * (t / CLEAR_POP_RISE);
     }
     peak := 1.0 + CLEAR_POP_A;
-    u := (t - 0.30) / 0.70;
+    u := (t - CLEAR_POP_RISE) / (1.0 - CLEAR_POP_RISE);
     peak * (1.0 - u * u)
 }
 

main.sx

@@ -180,10 +180,15 @@ frame :: () {
         g_pipeline.dispatch_event(ev);
     }
 
-    // Advance the in-flight move animation by this frame's delta before rendering,
+    // Advance the in-flight move animation + its match FX by this frame's delta
-    // so the board view draws the timeline slice for the current wall-clock time.
+    // before rendering, so the board view draws the timeline slice for the current
-    if g_anim != null { g_anim.tick(g_delta_time); }
+    // wall-clock time. Capture mode pins the animation clock (M3TE_ANIM_TIME);
-    if g_fx != null { g_fx.tick(g_delta_time); }
+    // while pinned the move/FX timelines stay frozen at the phase the startup
+    // hooks set, so the FX-match scene (M3TE_FX) screenshots identically each run.
+    if g_motion == null or !g_motion.pinned {
+        if g_anim != null { g_anim.tick(g_delta_time); }
+        if g_fx != null { g_fx.tick(g_delta_time); }
+    }
 
     // Advance the always-on per-gem animation clock (idle/select/land). Capture
     // mode pins the clock, so it only moves when not pinned. On the exact frame a
@@ -326,6 +331,30 @@ main :: () -> void {
         }
     }
 
+    // Match-FX capture hook (P11.1). The bursts/popups spawn off a committed move,
+    // which the sim can't script (no public touch injection), so M3TE_FX forces a
+    // representative match at startup the same way a swipe would: it commits the
+    // n-th currently-legal swap (1-based, clamped; =1 is the first) via the normal
+    // plan_and_commit path, then begins the move timeline + its FX. M3TE_ANIM_TIME
+    // pins the phase — advancing both to that time, after which the frozen frame
+    // loop holds them there — so the burst + "+points" popup screenshot identically
+    // every run. A larger M3TE_ANIM_TIME lands past the timeline, capturing the
+    // settled board with the FX fully pruned. Startup-only and unset → fully live.
+    if fx := read_env("M3TE_FX") {
+        swaps := legal_swaps(g_board);
+        if swaps.len > 0 {
+            n := parse_s64(fx);
+            if n < 1 { n = 1; }
+            if n > swaps.len { n = swaps.len; }
+            sw := swaps.items[n - 1];
+            mv := plan_and_commit(g_board, sw.a, sw.b);
+            g_anim.begin(mv);
+            g_fx.begin(@mv);
+            g_anim.tick(g_motion.clock);
+            g_fx.tick(g_motion.clock);
+        }
+    }
+
     // Level-state capture hooks (P7.2): override the goal / move budget so a
     // terminal status can be screenshot without scripting a swipe. M3TE_TARGET=0
     // makes the fresh board read WON immediately (score 0 ≥ goal 0);