GUI: Insert-only close, freeze mouse look at the source

Feedback pass:

- Insert now toggles the GUI; the old text tree moved to F1.
- Remove the title-bar X. Insert is the only close path; Esc only cancels
  bind capture.
- Discard accumulated mouse deltas in CInput::CreateMove before the game can
  apply them (CInput::ClearStates), so the camera no longer moves for a frame
  and snaps back. Also skip ExtraMouseSample and zero relative mouse state
  while the GUI is open.
- Strip attack/use/impulse/weapon selection from the command while open;
  keep jump, duck and walk. Skip combat command edits (spread seed) too.
- Widen System page buttons so "Reload config" and "Reset defaults" fit.
- Update CONTEXT/ADR for the Insert-only close behavior.

1 files changed, 37 insertions, 1 deletions

diff --git a/src/cinput.cpp b/src/cinput.cpp
index a75cc4f..ad7face 100644
--- a/src/cinput.cpp
+++ b/src/cinput.cpp
@@ -85,12 +85,42 @@ void fix_verified_crc(int seq, uint32_t crc) {
 
 using InputCreateMoveFn = void (*)(void *, int, float, bool);
 static InputCreateMoveFn oInputCreateMove = nullptr;
+using InputExtraMouseFn = void (*)(void *, float, bool);
+static InputExtraMouseFn oInputExtraMouseSample = nullptr;
+
+// ExtraMouseSample runs AdjustAngles at render-frame rate, between movement
+// commands. While the GUI is open it must not touch the view; movement still
+// comes through CreateMove.
+static void hkdInputExtraMouseSample(void *self, float frametime, bool active) {
+  if (gui_is_open())
+    return;
+  if (oInputExtraMouseSample)
+    oInputExtraMouseSample(self, frametime, active);
+}
+
+void input_clear_mouse_states() {
+  if (!g_input)
+    return;
+  // CInput::ClearStates (IInput slot 20): zeros both the software mouse
+  // accumulator and the engine raw-input accumulator.
+  using Fn = void (*)(void *);
+  vfunc<Fn>((void *)g_input, 20)((void *)g_input);
+}
 
 static void hkdInputCreateMove(void *self, int seq, float frametime,
                                bool active) {
+  // Mouse deltas are accumulated between ticks. With the custom GUI open we
+  // must discard them before CInput::CreateMove applies mouse look, otherwise
+  // the view moves for one frame and snaps back when do_move freezes it.
+  if (gui_is_open())
+    input_clear_mouse_states();
   if (oInputCreateMove)
     oInputCreateMove(self, seq, frametime, active);
 
+  // No combat features may modify the command while the GUI is open.
+  if (gui_is_open())
+    return;
+
   CUserCmd *cmd = get_usercmd(seq);
   if (!cmd)
     return;
@@ -125,8 +155,14 @@ static bool install_input_hook() {
   memcpy(nvt, vt, N * sizeof(void *));
   oInputCreateMove = (InputCreateMoveFn)vt[3];
   nvt[3] = (void *)&hkdInputCreateMove;
+  if (N > 4) {
+    oInputExtraMouseSample = (InputExtraMouseFn)vt[4];
+    nvt[4] = (void *)&hkdInputExtraMouseSample;
+  }
   VTABLE((void *)g_input) = nvt;
-  logf("CInput CreateMove hooked: slot 3 orig=%p", (void *)oInputCreateMove);
+  logf("CInput CreateMove hooked: slot 3 orig=%p; ExtraMouseSample slot 4 "
+       "orig=%p",
+       (void *)oInputCreateMove, (void *)oInputExtraMouseSample);
   return true;
 }