Bhop: uni-directional auto-strafe for all movement directions

- derive the desired air direction from the raw W/S/A/D input (view-relative)
- pick the velocity perpendicular that rotates toward that target, so S/A/D
  work instead of only forward and A/D no longer spin in circles
- no keys: accelerate along the crosshair
- menu label now "Uni-directional auto-strafe"; state column moved to x=270

3 files changed, 73 insertions, 5 deletions

diff --git a/src/hl2h.cpp b/src/hl2h.cpp
index a451a18..b666585 100644
--- a/src/hl2h.cpp
+++ b/src/hl2h.cpp
@@ -114,6 +114,60 @@ void *entitylist_get(int idx) {
   return vfunc<Fn>(g_iface.entitylist, 3)(g_iface.entitylist, idx);
 }
 
+// Source air-strafe. The movement code caps the *wishspeed* used for the
+// acceleration delta to GetAirSpeedCap() (30) but scales accelspeed by the
+// full wishspeed, then clamps to the delta. Putting wishdir perpendicular to
+// the horizontal velocity makes the delta maximal every tick. We express that
+// world-space direction in the current view basis so the camera is untouched.
+//
+// The perpendicular is chosen so the velocity turns toward the direction the
+// player is actually asking for (W/S/A/D relative to the view), which keeps
+// the feature useful in every direction instead of only forward.
+static void apply_autostrafe(CUserCmd *cmd, const float *vel) {
+  float vx = vel[0], vy = vel[1];
+  float speed = sqrtf(vx * vx + vy * vy);
+  if (speed < 1.0f)
+    return;
+
+  float yaw = cmd->viewangles[1] * PI_F / 180.0f;
+  float cy = cosf(yaw), sy = sinf(yaw);
+  float fx = cy, fy = sy;   // view forward on the XY plane
+  float rx = sy, ry = -cy;  // view right on the XY plane
+
+  // Intended ground-plane direction from the raw movement keys (before we
+  // overwrite them). No keys held -> keep accelerating along current travel.
+  float tx, ty;
+  if (fabsf(cmd->forwardmove) > 0.01f || fabsf(cmd->sidemove) > 0.01f) {
+    tx = fx * cmd->forwardmove + rx * cmd->sidemove;
+    ty = fy * cmd->forwardmove + ry * cmd->sidemove;
+    float tl = sqrtf(tx * tx + ty * ty);
+    tx /= tl;
+    ty /= tl;
+  } else {
+    // No movement keys held: accelerate along the crosshair (a velocity-
+    // relative target would keep rotating with the velocity and circle).
+    tx = fx;
+    ty = fy;
+  }
+
+  // +90 degrees from horizontal velocity ("left" in Source's XY convention);
+  // the other perpendicular is its negation. Pick the side that rotates the
+  // velocity toward the intended direction.
+  float px = -vy / speed, py = vx / speed;
+  float cross = vx * ty - vy * tx; // > 0 => target is left of velocity
+  static int last_side = -1;
+  int side = (cross >= 0.0f) ? -1 : 1;
+  if (fabsf(cross) < 1e-6f) // exactly aligned/opposite: keep previous side
+    side = last_side;
+  last_side = side;
+
+  float dx = (side < 0) ? px : -px;
+  float dy = (side < 0) ? py : -py;
+  // 450 saturates the usercmd move clamps and the engine's air-accel cap.
+  cmd->forwardmove = (dx * fx + dy * fy) * 450.0f;
+  cmd->sidemove = (dx * rx + dy * ry) * 450.0f;
+}
+
 static void do_move(int seq) {
   static bool g_echo_sent = false;
   if (!g_input || !g_net.ok())
@@ -177,6 +231,8 @@ static void do_move(int seq) {
     if (!onground) {
       lastground = false;
       cmd->buttons &= ~IN_JUMP;
+      if (!inwater && bhop_autostrafe_enabled())
+        apply_autostrafe(cmd, vel);
       note_modified(cmd, flags, vel);
     } else if (!lastground) {
       lastground = true;
diff --git a/src/hl2h.h b/src/hl2h.h
index 50b5525..0986017 100644
--- a/src/hl2h.h
+++ b/src/hl2h.h
@@ -161,6 +161,7 @@ void find_modules();
 void init_conmsg();
 bool feature_active(int feature);
 bool esp_option(int opt);
+bool bhop_autostrafe_enabled();
 void *entitylist_get(int idx);
 int engine_get_local_player();
 void draw_text_col(int x, int y, const char *s, int r, int g, int b);
diff --git a/src/menu.cpp b/src/menu.cpp
index 2caf0aa..c8dffc9 100644
--- a/src/menu.cpp
+++ b/src/menu.cpp
@@ -52,6 +52,7 @@ struct FeatureState {
 };
 
 static FeatureState g_bhop{true, 0};
+static bool g_bhop_autostrafe = true;
 
 static FeatureState g_abh{true, 0};
 static FeatureState g_esp{true, 0};
@@ -64,6 +65,7 @@ static bool g_esp_opt[ESP_OPT_COUNT] = {true, true, true, true};
 static MenuNode g_root{NODE_ROOT, "HL2hake", true, 0, {}, nullptr, nullptr, nullptr};
 static MenuNode g_bhop_feat{NODE_FEATURE, "Bunnyhop", true, 1, {}, nullptr, nullptr, nullptr};
 static MenuNode g_bhop_active{NODE_TOGGLE, "Active", false, 0, {}, &g_bhop.active, nullptr, nullptr};
+static MenuNode g_bhop_autostrafe_node{NODE_TOGGLE, "Uni-directional auto-strafe", false, 0, {}, &g_bhop_autostrafe, nullptr, nullptr};
 static MenuNode g_abh_feat{NODE_FEATURE, "ABH", true, 1, {}, nullptr, nullptr, nullptr};
 static MenuNode g_abh_active{NODE_TOGGLE, "Active", false, 0, {}, &g_abh.active, nullptr, nullptr};
 static MenuNode g_esp_feat{NODE_FEATURE, "ESP", true, 1, {}, nullptr, nullptr, nullptr};
@@ -83,6 +85,8 @@ bool g_menu_open = false;
 static bool g_bind_mode = false;
 static void build_tree() {
   g_bhop_feat.children[0] = &g_bhop_active;
+  g_bhop_feat.children[1] = &g_bhop_autostrafe_node;
+  g_bhop_feat.child_count = 2;
   g_abh_feat.children[0] = &g_abh_active;
   g_esp_feat.children[0] = &g_esp_active;
   for (int i = 0; i < ESP_OPT_COUNT; i++)
@@ -151,7 +155,8 @@ static void config_save() {
   FILE *f = fopen(config_path().c_str(), "w");
   if (!f)
     return;
-  fprintf(f, "[bhop]\nactive=%d\nbind=%d\n", g_bhop.active, g_bhop.bind);
+  fprintf(f, "[bhop]\nactive=%d\nbind=%d\nautostrafe=%d\n", g_bhop.active,
+          g_bhop.bind, g_bhop_autostrafe);
   fprintf(f, "[abh]\nactive=%d\nbind=%d\n", g_abh.active, g_abh.bind);
   fprintf(f, "[esp]\nactive=%d\nbind=%d\nneutral=%d\nhealthbar=%d\n"
              "healthnum=%d\nname=%d\n",
@@ -167,7 +172,7 @@ static void config_load() {
     return;
   char line[256];
   FeatureState *cur = nullptr;
-  bool in_esp = false;
+  bool in_esp = false, in_bhop = false;
   while (fgets(line, sizeof(line), f)) {
     line[strcspn(line, "\r\n")] = 0;
     if (line[0] == '[') {
@@ -180,12 +185,16 @@ static void config_load() {
       else
         cur = nullptr;
       in_esp = (cur == &g_esp);
+      in_bhop = (cur == &g_bhop);
     } else if (cur) {
       char *eq = strchr(line, '=');
       if (!eq)
         continue;
       *eq = 0;
       const char *key = line, *val = eq + 1;
+      if (in_bhop && strcmp(key, "autostrafe") == 0) {
+        g_bhop_autostrafe = atoi(val) != 0;
+      }
       if (in_esp) {
         if (strcmp(key, "neutral") == 0)
           g_esp_opt[ESP_OPT_SHOW_NEUTRAL] = atoi(val) != 0;
@@ -319,6 +328,8 @@ bool esp_option(int opt) {
   return opt >= 0 && opt < ESP_OPT_COUNT && g_esp_opt[opt];
 }
 
+bool bhop_autostrafe_enabled() { return g_bhop_autostrafe; }
+
 static void menu_handle_input() {
   poll_keyboard();
 
@@ -557,10 +568,10 @@ void outer_draw() {
     draw_text(x, 10 + i * 20, line);
     // right-aligned state
     if (n->type == NODE_TOGGLE) {
-      draw_text(200, 10 + i * 20, *n->active_ptr ? "[on]" : "[off]");
+      draw_text(270, 10 + i * 20, *n->active_ptr ? "[on]" : "[off]");
     } else if (n->type == NODE_BIND) {
       if (g_bind_mode && i == g_selected)
-        draw_text(200, 10 + i * 20, "[press key]");
+        draw_text(270, 10 + i * 20, "[press key]");
       else {
         /* stable name for current bind */
         static char bn[2][32];
@@ -570,7 +581,7 @@ void outer_draw() {
           if (n->bind_ptr == &feats[k]->bind)
             fi = k;
         snprintf(bn[fi], 32, "[%s]", scancode_name(*n->bind_ptr));
-        draw_text(200, 10 + i * 20, bn[fi]);
+        draw_text(270, 10 + i * 20, bn[fi]);
       }
     }
   }