From f2744b5b17385edcd79286174224830997bd796e Mon Sep 17 00:00:00 2001
From: chazmm <balloverwatchh@gmail.com>
Date: Tue, 8 Sep 2026 21:20:15 +0100
Subject: [PATCH] Restore takeoff heading isolation from authored board spin

---
 .../src/physics/ground_animation.rs           |  4 ++-
 .../skate-game/src/physics/riding_outputs.rs  | 29 ++++++++++++++-----
 docs/archive-crates-5-integration.md          | 11 +++++++
 3 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/crates/skate-game/src/physics/ground_animation.rs b/crates/skate-game/src/physics/ground_animation.rs
index b2c42e4e..6177434b 100644
--- a/crates/skate-game/src/physics/ground_animation.rs
+++ b/crates/skate-game/src/physics/ground_animation.rs
@@ -50,7 +50,8 @@ pub(crate) fn advance(physics: &mut GamePhysics, skater: &mut SkaterRuntime) ->
     skater.ground_animation.launched = false;
     let p = &skater.player_input.processed;
     let com = p.animation_com_to_deck_752.map(f32::from_bits);
-    physics.riding.update_ground_reckoning(
+    let heading = physics.riding.reckoning_frames.heading;
+    physics.riding.update_ground_reckoning_with_heading(
         &physics.board,
         super::riding_outputs::RidingPoseInputs {
             com_to_deck: Vector3::new(com[0], com[1], com[2]),
@@ -60,6 +61,7 @@ pub(crate) fn advance(physics: &mut GamePhysics, skater: &mut SkaterRuntime) ->
         skater.animation_input.fields.balance,
         p.flags_2476 & 0x4000_0000 != 0,
         p,
+        heading,
     );
     skeleton::advance(physics, skater)?;
     skater.skeleton_output.correction.pending = true;
diff --git a/crates/skate-game/src/physics/riding_outputs.rs b/crates/skate-game/src/physics/riding_outputs.rs
index dd26e482..ac8d1443 100644
--- a/crates/skate-game/src/physics/riding_outputs.rs
+++ b/crates/skate-game/src/physics/riding_outputs.rs
@@ -155,18 +155,33 @@ impl RidingOutputs {
         animation_balance: f32,
         coffin: bool,
         processed: &skate_core::player::input_phase::ProcessedPhysicsInput,
+    ) {
+        let deck = board.part_transforms()[BodyId::Deck.index()];
+        // Ordinary ground riding follows the physical deck (82D4E250).
+        self.update_ground_reckoning_with_heading(
+            board, pose, processed_flags_2468, animation_balance, coffin, processed,
+            [deck.basis.columns[2][0], deck.basis.columns[2][1], deck.basis.columns[2][2], 0.0],
+        );
+    }
+
+    /// Animated takeoff retains the rider's heading while the deck begins its
+    /// authored spin. Feeding the driven deck axis back into this frame would
+    /// apply that spin to the whole skater again on each ground-animation tick.
+    pub fn update_ground_reckoning_with_heading(
+        &mut self,
+        board: &BoardRuntime,
+        pose: RidingPoseInputs,
+        processed_flags_2468: u32,
+        animation_balance: f32,
+        coffin: bool,
+        processed: &skate_core::player::input_phase::ProcessedPhysicsInput,
+        heading: [f32; 4],
     ) {
         let observations = ground_input::GroundPacketInputs::from_processed(processed);
         let deck = board.part_transforms()[BodyId::Deck.index()];
-        //82D4E250 overrides heading1200 from input752 (raw board Z).
         //The source takes the previous final frame X for the damping step.
         let previous_right = self.reckoning_frames.system[0];
-        self.reckoning_frames.heading = [
-            deck.basis.columns[2][0],
-            deck.basis.columns[2][1],
-            deck.basis.columns[2][2],
-            0.0,
-        ];
+        self.reckoning_frames.heading = heading;
         body_spin::update_ground(&mut self.body_spin, pose.body_spin);
         let effective = BoardMotionOutput::from_board(
             board,
diff --git a/docs/archive-crates-5-integration.md b/docs/archive-crates-5-integration.md
index 5c599524..e42fb0cc 100644
--- a/docs/archive-crates-5-integration.md
+++ b/docs/archive-crates-5-integration.md
@@ -95,3 +95,14 @@ push, merge into the main branch, or release is performed by this task.
 
 Report failures with the diagnostic report, map/difficulty and last controller
 action. Compile and source-preservation checks do not establish gameplay parity.
+
+## Takeoff heading regression
+
+Restored the `c70726d` takeoff-heading separation removed by the re-merge.
+GroundAnimation retains the rider heading while the authored deck begins to
+spin; ordinary ground riding still follows the physical deck. The imported
+processed ground-input observations remain in use. The existing
+`nollie_inward_heel_keeps_body_heading_at_pop` regression compiles but was not
+executed (private gameplay assets required). Check nollie inward heels and
+other flip tricks, stationary and rolling, for an abrupt sideways body turn
+at takeoff while ensuring the board still spins and intentional body spins work.