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.

7 files changed, 110 insertions, 37 deletions

diff --git a/CONTEXT.md b/CONTEXT.md
index 53c662e..6f6e59e 100644
--- a/CONTEXT.md
+++ b/CONTEXT.md
@@ -94,14 +94,14 @@ Relevant vtable slots (this build):
 
 ## Menu
 
-Starts fully collapsed on first open. `Insert` toggles; `Up`/`Down` navigate;
+Preview key: `F1` (the final GUI will replace this tree). Starts fully collapsed on first open. `F1` toggles; `Up`/`Down` navigate;
 `Enter` expands/toggles; `Left`/`Right` edit values; `Escape` closes.
 Bind rows enter bind-select mode: press a key/button to assign, `Escape` sets
 None (always-on), `Enter` cancels.
 
 > The text menu below is being replaced by the GUI described in the next
-> section. The old tree is kept only until the GUI reaches parity. The current
-> preview shell opens with F2; Insert still opens the text tree.
+> section. The old tree is kept only until the GUI reaches parity. During the
+> preview, **Insert** toggles the GUI and the old text tree is on **F1**.
 
 ```
 HL2hake
@@ -149,10 +149,11 @@ Binds use SDL scancodes; mouse buttons are pseudo-scancodes 600..604.
 - **Card**: per-feature panel. Header always shows Active + Bind; body is a
   collapsible set of settings.
 - **Freeze**: while the GUI is open, look/attack/use/impulse/weapon selection
-  are blocked and combat features are skipped, but normal WASD/jump/duck
-  movement is allowed. Bind capture blocks all game input until it ends. The
-  game keeps simulating and ESP/FOV circle/speed graph keep drawing. No
-  invulnerability.
+  are blocked and combat features are skipped, but normal WASD/jump/duck/walk
+  movement is allowed. Mouse deltas are discarded before `CInput::CreateMove`
+  can apply them (`CInput::ClearStates`), so the view cannot drift for a frame.
+  Bind capture blocks all game input until it ends. The game keeps simulating
+  and ESP/FOV circle/speed graph keep drawing. No invulnerability.
 - **Native cursor**: on open, leave SDL relative-mouse mode and show the OS
   cursor; restore on close. Absolute mouse coordinates are used.
 - **Bind capture**: click Bind, press a key/button; Esc cancels capture but
@@ -165,7 +166,7 @@ Binds use SDL scancodes; mouse buttons are pseudo-scancodes 600..604.
   that restores feature settings/binds but keeps GUI layout.
 - Window: fixed-size, draggable by title bar, clamped to screen, position,
   category and expanded cards persisted under `[gui]`. Esc does not close the
-  GUI; the toggle key or title-bar X does.
+  GUI; the toggle key (Insert) is the only close path. There is no title-bar X.
 
 
 ## Bones / ESP
diff --git a/docs/adr/0001-custom-isurface-gui.md b/docs/adr/0001-custom-isurface-gui.md
index 9595ca8..5525844 100644
--- a/docs/adr/0001-custom-isurface-gui.md
+++ b/docs/adr/0001-custom-isurface-gui.md
@@ -54,6 +54,6 @@ path.
 - The GUI remains inside the engine's VGUI paint path, so it inherits the
   existing font registration and in-game overlay behavior.
 - The old text menu is removed once the GUI reaches feature parity. During
-  development the GUI is built alongside the text menu and opened with a
-  temporary F2 key; the replacement is complete only when the old tree is
-  deleted.
+  development the GUI is built alongside the text menu; Insert toggles the
+  GUI and F1 keeps the old tree accessible. The replacement is complete only
+  when the old tree is deleted.
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;
 }
 
diff --git a/src/gui.cpp b/src/gui.cpp
index 923cd4d..eb9062e 100644
--- a/src/gui.cpp
+++ b/src/gui.cpp
@@ -1,4 +1,4 @@
-// gui.cpp — custom immediate-mode GUI shell (temporary F2 preview)
+// gui.cpp — custom immediate-mode GUI shell (temporary Insert preview)
 //
 // This is the first vertical slice: the visual shell, categories, cards,
 // dummy controls, cursor handling and input freeze. It does not read or write
@@ -575,6 +575,7 @@ static void close_gui() {
   g_dragging = false;
   g_scroll_drag = false;
   g_slider_drag = -1;
+  input_clear_mouse_states();
   if (g_sdl_ready) {
     if (sd_set_relative)
       sd_set_relative(g_prev_relative ? 1 : 0);
@@ -611,6 +612,7 @@ static void open_gui() {
     if (sd_show_cursor)
       sd_show_cursor(1);
   }
+  input_clear_mouse_states();
   g_open = true;
   g_capture_card = -1;
   g_wheel.exchange(0);
@@ -659,7 +661,7 @@ static void handle_capture(const unsigned char *keys) {
   for (int k = 0; k < 512; k++) {
     if (!keys[k] || g_prev_keys[k])
       continue;
-    if (k == 73 || k == 59) // Insert reserved; F2 closes the preview
+    if (k == 73) // Insert is reserved for opening/closing the GUI
       continue;
     g_cards[g_capture_card].bind = k;
     g_capture_card = -1;
@@ -674,12 +676,7 @@ static void handle_mouse_click() {
 
   // title bar: drag or close
   Rect title{g_win_x, g_win_y, g_win_w, S(38.0f)};
-  Rect close{g_win_x + g_win_w - S(38.0f), g_win_y, S(38.0f), S(38.0f)};
   if (title.has(mx, my)) {
-    if (close.has(mx, my)) {
-      close_gui();
-      return;
-    }
     g_dragging = true;
     g_drag_dx = mx - g_win_x;
     g_drag_dy = my - g_win_y;
@@ -787,7 +784,7 @@ static void handle_mouse_click() {
           return;
         }
         if (ct.kind == CK_BUTTON) {
-          Rect b{cr.x + cr.w - S(130.0f), by + S(3.0f), S(114.0f),
+          Rect b{cr.x + cr.w - S(176.0f), by + S(3.0f), S(160.0f),
                  S(26.0f)};
           if (b.has(mx, my)) {
             logf("gui: dummy action %s", ct.label ? ct.label : "?");
@@ -858,8 +855,8 @@ void gui_handle_input() {
   if (nk > 512) nk = 512;
   update_mouse();
 
-  bool f2 = (nk > 59) && keys[59];
-  bool f2_edge = f2 && !g_prev_keys[59];
+  bool toggle_key = (nk > 73) && keys[73];
+  bool toggle_edge = toggle_key && !g_prev_keys[73];
   bool esc = (nk > 41) && keys[41];
   bool esc_edge = esc && !g_prev_keys[41];
   bool left = (nk > 80) && keys[80];
@@ -867,7 +864,7 @@ void gui_handle_input() {
   bool left_edge = left && !g_prev_keys[80];
   bool right_edge = right && !g_prev_keys[79];
 
-  if (f2_edge) {
+  if (toggle_edge) {
     if (g_open)
       close_gui();
     else
@@ -887,6 +884,11 @@ void gui_handle_input() {
     sd_set_relative(0);
   if (sd_show_cursor)
     sd_show_cursor(1);
+  if (g_iface.engine) {
+    QAngle f = g_frozen;
+    using SetViewFn = void (*)(void *, QAngle *);
+    vfunc<SetViewFn>(g_iface.engine, 20)(g_iface.engine, &f);
+  }
 
   handle_capture(keys);
 
@@ -1063,7 +1065,7 @@ static void draw_card(const Rect &clip, int index, int y) {
       text_in(clip, cr.x + S(16.0f), by + S(1.0f), ct.label, g_font_body,
               g_body_h, cr.w - S(24.0f), C_DIM);
     } else if (ct.kind == CK_BUTTON) {
-      Rect b{cr.x + cr.w - S(130.0f), by + S(3.0f), S(114.0f), S(26.0f)};
+      Rect b{cr.x + cr.w - S(176.0f), by + S(3.0f), S(160.0f), S(26.0f)};
       fill(b, Col{45, 50, 60, 255}, &clip);
       outline(b, C_BORDER, &clip);
       text_in(clip, b.x + S(10.0f), b.y + S(4.0f), ct.label, g_font_body,
@@ -1126,12 +1128,6 @@ void gui_draw() {
           g_title_h, win.w - S(80.0f), C_TEXT);
   text_in(win, win.x + S(110.0f), win.y + S(10.0f), "GUI shell preview",
           g_font_body, g_body_h, win.w - S(180.0f), C_DIM);
-  Rect close{win.x + win.w - S(38.0f), win.y, S(38.0f), S(38.0f)};
-  fill(close, Col{45, 48, 56, 255});
-  line(close.x + S(13.0f), close.y + S(12.0f), close.x + S(25.0f),
-       close.y + S(25.0f), C_DIM);
-  line(close.x + S(25.0f), close.y + S(12.0f), close.x + S(13.0f),
-       close.y + S(25.0f), C_DIM);
 
   Rect side{win.x, win.y + S(38.0f), S(190.0f),
             win.h - S(38.0f) - S(30.0f)};
@@ -1185,7 +1181,7 @@ void gui_draw() {
           "config: ~/.config/hl2hake/config", g_font_body, g_body_h,
           foot.w - S(220.0f), C_DIM);
   text_in(foot, foot.x + foot.w - S(200.0f), foot.y + S(6.0f),
-          g_capture_card >= 0 ? "press a key / Esc" : "F2 close  |  Insert text",
+          g_capture_card >= 0 ? "press a key / Esc" : "INS close  |  F1 text menu",
           g_font_body, g_body_h, S(190.0f), C_DIM);
 
   draw_tooltip();
@@ -1281,3 +1277,40 @@ SDL_WarpMouseGlobal(int x, int y) {
   if (real_warp_global)
     real_warp_global(x, y);
 }
+
+static unsigned int (*real_get_rel_mouse)(int *, int *) = nullptr;
+static int (*real_poll_event)(void *) = nullptr;
+
+extern "C" __attribute__((visibility("default"))) unsigned int
+SDL_GetRelativeMouseState(int *x, int *y) {
+  if (!real_get_rel_mouse)
+    real_get_rel_mouse =
+        (unsigned int (*)(int *, int *))dlsym(RTLD_NEXT,
+                                              "SDL_GetRelativeMouseState");
+  unsigned int mask = real_get_rel_mouse ? real_get_rel_mouse(x, y) : 0;
+  if (g_open) {
+    if (x) *x = 0;
+    if (y) *y = 0;
+  }
+  return mask;
+}
+
+extern "C" __attribute__((visibility("default"))) int
+SDL_PollEvent(void *event) {
+  if (!real_poll_event)
+    real_poll_event = (int (*)(void *))dlsym(RTLD_NEXT, "SDL_PollEvent");
+  if (!real_poll_event)
+    return 0;
+  for (;;) {
+    int r = real_poll_event(event);
+    if (!r)
+      return 0;
+    if (!g_open || !event)
+      return r;
+    unsigned int type = *(unsigned int *)event;
+    if (type != 0x400) // SDL_MOUSEMOTION
+      return r;
+    // Drop motion while the GUI is open: the game must not accumulate look
+    // deltas. The GUI uses absolute SDL_GetMouseState polling.
+  }
+}
diff --git a/src/hl2h.cpp b/src/hl2h.cpp
index a0e6b53..1460577 100644
--- a/src/hl2h.cpp
+++ b/src/hl2h.cpp
@@ -561,7 +561,8 @@ static void do_move(int seq, float frametime) {
       cmd->buttons = 0;
     } else {
       // Movement is allowed while the GUI is open, but not look/attack/use.
-      cmd->buttons &= (IN_JUMP | IN_DUCK);
+      // Keep locomotion buttons (jump, duck, walk) only.
+      cmd->buttons &= (IN_JUMP | IN_DUCK | IN_SPEED);
     }
     cmd->impulse = 0;
     cmd->weaponselect = 0;
diff --git a/src/hl2h.h b/src/hl2h.h
index 8a81439..d5a9dc3 100644
--- a/src/hl2h.h
+++ b/src/hl2h.h
@@ -129,7 +129,7 @@ struct CUserCmd {
 // engine constants
 // ---------------------------------------------------------------------------
 
-enum { IN_ATTACK = 1 << 0, IN_JUMP = 1 << 1, IN_DUCK = 1 << 2, IN_USE = 1 << 5, IN_ATTACK2 = 1 << 11 };
+enum { IN_ATTACK = 1 << 0, IN_JUMP = 1 << 1, IN_DUCK = 1 << 2, IN_USE = 1 << 5, IN_ATTACK2 = 1 << 11, IN_SPEED = 1 << 17 };
 enum { FL_ONGROUND = 1 << 0, FL_DUCKING = 1 << 1, FL_INWATER = 1 << 9 };
 enum { MOVETYPE_WALK = 2, MOVETYPE_NOCLIP = 8, MOVETYPE_LADDER = 9 };
 
@@ -180,6 +180,7 @@ enum EspOption {
 // ---------------------------------------------------------------------------
 void note_modified(const CUserCmd *cmd, int flags, const float *vel);
 CUserCmd *get_usercmd(int seq);
+void input_clear_mouse_states();
 void fix_verified_crc(int seq, uint32_t crc);
 uint32_t usercmd_checksum(const CUserCmd *c);
 bool find_input_global();
diff --git a/src/menu.cpp b/src/menu.cpp
index 56fe6fa..a0cf323 100644
--- a/src/menu.cpp
+++ b/src/menu.cpp
@@ -467,7 +467,8 @@ static void config_load() {
 // ---------------------------------------------------------------------------
 
 // SDL scancodes for navigation keys (matches the game's scancode set)
-static constexpr int SCAN_INSERT = 73;
+static constexpr int SCAN_INSERT = 73; // reserved for the GUI
+static constexpr int SCAN_TEXT_MENU = 58; // F1 preview key for the old tree
 static constexpr int SCAN_UP = 82;    // these are SDL scancodes
 static constexpr int SCAN_DOWN = 81;
 static constexpr int SCAN_LEFT = 80;
@@ -637,7 +638,7 @@ static void menu_handle_input() {
   // SDL state can be sampled several times per rendered frame (both ISurface
   // hooks call outer_draw). Use a physical-key latch instead of the one-poll
   // edge so one press cannot open and close the menu in the same frame.
-  bool insert_down = key_held(SCAN_INSERT);
+  bool insert_down = key_held(SCAN_TEXT_MENU);
   bool insert_edge = insert_down && !g_insert_latch;
   if (insert_down)
     g_insert_latch = true;
@@ -662,8 +663,8 @@ static void menu_handle_input() {
     for (int i = 0; i < MOUSE_BASE + 5; i++) {
       if (!g_key_down[i])
         continue;
-      if (i == SCAN_INSERT || i == SCAN_UP || i == SCAN_DOWN ||
-          i == SCAN_LEFT || i == SCAN_RIGHT) {
+      if (i == SCAN_INSERT || i == SCAN_TEXT_MENU || i == SCAN_UP ||
+          i == SCAN_DOWN || i == SCAN_LEFT || i == SCAN_RIGHT) {
         g_bind_mode = false;
         return; // cancel bind select
       }