Items: hide full ammo pickups; robust close-target projection

- Resolve m_iAmmo and m_hMyWeapons arrays from the client recv tables.
- "Only if usable" now compares m_iAmmo[type] against sk_max_* (stock caps as
  fallback: RPG rockets 3, AR2 60, ...). Full ammo hides the pickup, including
  RPG rockets and fallen weapons converted to ammo.
- Inventory now comes from m_hMyWeapons directly, so fallen weapons are ammo
  before the player equips the matching weapon.
- Projection: fall back to local math when ScreenPosition claims "behind" for
  a point with positive view depth, and build NPC boxes from vertical samples
  so feet behind the near plane no longer drop the whole target. Log the first
  8 near-target projection failures for diagnosis.

4 files changed, 233 insertions, 36 deletions

diff --git a/CONTEXT.md b/CONTEXT.md
index acdab2f..839d340 100644
--- a/CONTEXT.md
+++ b/CONTEXT.md
@@ -232,7 +232,11 @@ vocabulary / decisions.
   (>1e7). A point on the view axis (e.g. directly below the player's feet)
   can make `IVDebugOverlay::ScreenPosition` return NaN/huge values; casting
   those to int corrupted the ISurface clip state and made the whole overlay
-  disappear for that frame.
+  disappear for that frame. If the overlay reports "behind" for a point whose
+  view-space depth is actually positive, a local projection is used instead.
+- NPC boxes are built from several vertical samples, so a target whose feet
+  are behind the near plane (standing over it) still gets a box from the
+  visible span instead of being dropped.
 - Projectile radius rings are drawn independently of the centre marker, so a
   grenade behind the camera/off-screen still shows its blast circle when any
   part of the ring projects.
@@ -606,10 +610,14 @@ vocabulary / decisions.
 - A world weapon whose type is already in the local player's inventory is
   reclassified as ammo (`SMG ammo`, `AR2 ammo`, ...). Owner handles are
   unreliable on this client (`m_hOwnerEntity`/`m_hOwner` resolve to -1), so
-  the inventory mask is accumulated from every weapon type the player has
-  held (client `m_hActiveWeapon`, with the server handle as fallback) since
-  the current local entity appeared. NPC-held weapons are therefore ignored.
-  Weapons the player does not own stay under the Weapons category.
+  the inventory is read directly from the local `m_hMyWeapons[48]` handle
+  array (and remembered active types as a fallback). NPC-held weapons are
+  therefore ignored. Weapons the player does not own stay under the Weapons
+  category.
+- Ammo pickups also honour "Only if usable": the reserve count from
+  `m_iAmmo[type]` is compared with the `sk_max_*` cvar (stock caps as fallback,
+  e.g. RPG rockets = 3). Full ammo hides the pickup; if either value cannot
+  be read the item stays visible.
 - Scans the client entity list every 100 ms and tags health, ammo, armor/suit,
   world weapon pickups, the two supply-crate models and generic items.
 - Each tag is a colored marker with a name and optional distance, filtered by
diff --git a/src/esp.cpp b/src/esp.cpp
index 715dbc8..1d4a6a5 100644
--- a/src/esp.cpp
+++ b/src/esp.cpp
@@ -52,27 +52,11 @@ static double esp_now() {
   return (double)ts.tv_sec + (double)ts.tv_nsec * 1e-9;
 }
 
-bool world_to_screen(const Vector &w, float &sx, float &sy) {
-  // Preferred: the engine's own transform. Uses the real view setup (FOV,
-  // aspect, roll), so boxes do not drift at the screen edges.
-  if (g_iface.debugoverlay) {
-    using Fn = int (*)(void *, const Vector *, Vector *);
-    Vector s;
-    int behind =
-        vfunc<Fn>(g_iface.debugoverlay, 9)(g_iface.debugoverlay, &w, &s);
-    if (behind)
-      return false;
-    // A point on the view axis (e.g. directly below the feet) can produce
-    // NaN/inf or enormous coordinates; drawing those as ints corrupts the
-    // surface clip state and hides the rest of the overlay.
-    if (!std::isfinite(s.x) || !std::isfinite(s.y) || fabsf(s.x) > 1e7f ||
-        fabsf(s.y) > 1e7f)
-      return false;
-    sx = s.x;
-    sy = s.y;
-    return true;
-  }
-  // Fallback: local math with the default HL2 FOV.
+// Local perspective projection used when the engine's debug-overlay
+// projection refuses a point that is actually in front of the camera.
+static bool project_manual(const Vector &w, float &sx, float &sy) {
+  if (!g_scr_w || !g_scr_h)
+    return false;
   float pitch = g_cam_view.x * PI_F / 180.0f;
   float yaw = g_cam_view.y * PI_F / 180.0f;
   float sp = sinf(pitch), cp = cosf(pitch);
@@ -82,7 +66,8 @@ bool world_to_screen(const Vector &w, float &sx, float &sy) {
   float up[3] = {sp * cy, sp * syy, cp};
   float dx = w.x - g_cam_eye.x, dy = w.y - g_cam_eye.y, dz = w.z - g_cam_eye.z;
   float z = dx * fwd[0] + dy * fwd[1] + dz * fwd[2];
-  if (z < 1.0f) return false;
+  if (z < 1.0f)
+    return false;
   float x = dx * right[0] + dy * right[1] + dz * right[2];
   float y = dx * up[0] + dy * up[1] + dz * up[2];
   float tanfov = tanf(75.0f * 0.5f * PI_F / 180.0f);
@@ -92,6 +77,42 @@ bool world_to_screen(const Vector &w, float &sx, float &sy) {
          fabsf(sy) < 1e7f;
 }
 
+bool world_to_screen(const Vector &w, float &sx, float &sy) {
+  // Preferred: the engine's own transform. Uses the real view setup (FOV,
+  // aspect, roll), so boxes do not drift at the screen edges.
+  if (g_iface.debugoverlay) {
+    using Fn = int (*)(void *, const Vector *, Vector *);
+    Vector s;
+    int behind =
+        vfunc<Fn>(g_iface.debugoverlay, 9)(g_iface.debugoverlay, &w, &s);
+    if (behind) {
+      // The overlay transform can report "behind" for points that are in
+      // front but near the view axis/extremes (e.g. something directly below
+      // the player). Use the local projection in that case.
+      float pitch = g_cam_view.x * PI_F / 180.0f;
+      float yaw = g_cam_view.y * PI_F / 180.0f;
+      float cp = cosf(pitch), sp = sinf(pitch);
+      float fwd[3] = {cp * cosf(yaw), cp * sinf(yaw), -sp};
+      float z = (w.x - g_cam_eye.x) * fwd[0] +
+                (w.y - g_cam_eye.y) * fwd[1] +
+                (w.z - g_cam_eye.z) * fwd[2];
+      if (z > 4.0f)
+        return project_manual(w, sx, sy);
+      return false;
+    }
+    // A point on the view axis can produce NaN/inf or enormous coordinates;
+    // drawing those as ints corrupts the surface clip state and hides the
+    // rest of the overlay.
+    if (!std::isfinite(s.x) || !std::isfinite(s.y) || fabsf(s.x) > 1e7f ||
+        fabsf(s.y) > 1e7f)
+      return false;
+    sx = s.x;
+    sy = s.y;
+    return true;
+  }
+  return project_manual(w, sx, sy);
+}
+
 // ---------------------------------------------------------------------------
 // entity helpers (IClientEntityList / IClientNetworkable, header-documented)
 // ---------------------------------------------------------------------------
@@ -431,8 +452,6 @@ static void esp_collect(int local_idx) {
     }
     Vector origin{*(float *)(e + g_net.origin), *(float *)(e + g_net.origin + 4),
                   *(float *)(e + g_net.origin + 8)};
-    Vector bottom{origin.x, origin.y, origin.z + minz};
-    Vector top{origin.x, origin.y, origin.z + maxz};
     bool neutral = false;
     bool friendly = npc && npc_is_friendly(idx, model, local_idx, neutral);
     // Arrows are collected before projection: a hostile behind the camera
@@ -443,12 +462,47 @@ static void esp_collect(int local_idx) {
       a.head = Vector{origin.x, origin.y, origin.z + maxz * 0.7f};
       a.neutral = neutral;
     }
-    float sx, sy, tx, ty;
-    if (!world_to_screen(bottom, sx, sy) || !world_to_screen(top, tx, ty))
+    // Project several points along the vertical axis. Requiring both feet and
+    // head to project dropped the target when the feet were behind the near
+    // plane (common when standing over/next to something).
+    float min_sy = 1e9f, max_sy = -1e9f, low_x = 0.0f;
+    bool projected = false;
+    const int VSAMPLES = 6;
+    for (int k = 0; k <= VSAMPLES; k++) {
+      float z = origin.z + minz +
+                (maxz - minz) * (float)k / (float)VSAMPLES;
+      float px, py;
+      if (!world_to_screen(Vector{origin.x, origin.y, z}, px, py))
+        continue;
+      if (px < -2.0f * (float)g_scr_w || px > 3.0f * (float)g_scr_w)
+        continue;
+      projected = true;
+      if (py < min_sy)
+        min_sy = py;
+      if (py > max_sy) {
+        max_sy = py;
+        low_x = px;
+      }
+    }
+    if (!projected) {
+      static int fail_logs = 0;
+      float ddx = origin.x - g_cam_eye.x;
+      float ddy = origin.y - g_cam_eye.y;
+      float ddz = origin.z - g_cam_eye.z;
+      if (fail_logs < 8 && ddx * ddx + ddy * ddy + ddz * ddz < 400.0f * 400.0f) {
+        fail_logs++;
+        logf("ESP: close target %d model=%s failed projection at "
+             "(%.1f %.1f %.1f)",
+             idx, model ? model : "?", origin.x, origin.y, origin.z);
+      }
+      continue;
+    }
+    float h = max_sy - min_sy;
+    if (h < 3.0f || max_sy < 0 || min_sy > (float)g_scr_h)
+      continue; // behind / offscreen
+    if (low_x < -(float)g_scr_w || low_x > 2.0f * (float)g_scr_w)
       continue;
-    float h = sy - ty;
-    if (h < 3.0f || sy < 0 || ty > (float)g_scr_h) continue; // behind / offscreen
-    if (sx < -(float)g_scr_w || sx > 2.0f * (float)g_scr_w) continue;
+    float sx = low_x, sy = max_sy;
 
     EspTarget &t = g_targets[g_ntargets++];
     t.idx = idx;
@@ -2088,6 +2142,7 @@ enum ItemKind {
 struct ItemTarget {
   int idx;
   int kind;
+  int ammo_type; // m_iAmmo index for IK_AMMO, -1 otherwise
   Vector origin;
   char label[128];
 };
@@ -2235,6 +2290,117 @@ static int weapon_type_id(const char *model, const char *cls) {
   return WT_NONE;
 }
 
+static int weapon_ammo_type(int wt) {
+  switch (wt) {
+  case WT_PISTOL: return 2;
+  case WT_357: return 4;
+  case WT_SMG: return 3;
+  case WT_AR2: return 0;
+  case WT_SHOTGUN: return 6;
+  case WT_CROSSBOW: return 5;
+  case WT_RPG: return 7;
+  case WT_GRENADE: return 11;
+  case WT_SNIPER: return 9;
+  default: return -1;
+  }
+}
+
+// Ammo type index used by CBasePlayer::m_iAmmo (order of AddAmmoType in
+// hl2_gamerules.cpp).
+static int item_ammo_type(const char *model) {
+  if (!model)
+    return -1;
+  if (item_icontains(model, "boxsrounds") ||
+      item_icontains(model, "ammocrate_pistol") ||
+      item_icontains(model, "w_pistol"))
+    return 2;
+  if (item_icontains(model, "boxmrounds") ||
+      item_icontains(model, "ammocrate_smg1"))
+    return 3;
+  if (item_icontains(model, "boxlrounds") ||
+      item_icontains(model, "combine_rifle") ||
+      item_icontains(model, "ammocrate_ar2") ||
+      item_icontains(model, "w_ar2") || item_icontains(model, "w_irifle"))
+    return 0;
+  if (item_icontains(model, "357ammo") ||
+      item_icontains(model, "357ammobox") ||
+      item_icontains(model, "w_357"))
+    return 4;
+  if (item_icontains(model, "crossbowrounds") ||
+      item_icontains(model, "w_crossbow"))
+    return 5;
+  if (item_icontains(model, "boxbuckshot") ||
+      item_icontains(model, "ammocrate_buckshot") ||
+      item_icontains(model, "w_shotgun"))
+    return 6;
+  if (item_icontains(model, "w_missile_closed") ||
+      item_icontains(model, "ammocrate_rockets") ||
+      item_icontains(model, "w_rocket_launcher"))
+    return 7;
+  if (item_icontains(model, "ar2_grenade") ||
+      item_icontains(model, "ammocrate_smg2"))
+    return 8;
+  if (item_icontains(model, "ammocrate_grenade") ||
+      item_icontains(model, "w_grenade") || item_icontains(model, "w_frag"))
+    return 11;
+  if (item_icontains(model, "w_smg1") || item_icontains(model, "w_smg2"))
+    return 3;
+  return -1;
+}
+
+static int convar_int(const char *name) {
+  if (!g_iface.cvar || !name)
+    return -1;
+  using FindFn = void *(*)(void *, const char *);
+  void *v = vfunc<FindFn>(g_iface.cvar, 12)(g_iface.cvar, name);
+  if (!v)
+    return -1;
+  return (int)*(float *)((uintptr_t)v + 0x2c); // ConVar m_Value.f
+}
+
+// Maximum reserve ammo for an m_iAmmo index. Prefers the sk_max_* cvar and
+// falls back to the stock HL2 cap so the RPG's 3-rocket limit is honoured
+// even when server cvars are not visible from the client.
+static int ammo_max(int type) {
+  static int cache[16];
+  static bool init = false;
+  if (type < 0 || type >= 16)
+    return -1;
+  if (!init) {
+    for (int i = 0; i < 16; i++)
+      cache[i] = -2;
+    init = true;
+  }
+  if (cache[type] != -2)
+    return cache[type];
+  const char *name = nullptr;
+  int stock = -1;
+  switch (type) {
+  case 0: name = "sk_max_ar2"; stock = 60; break;
+  case 2: name = "sk_max_pistol"; stock = 150; break;
+  case 3: name = "sk_max_smg1"; stock = 225; break;
+  case 4: name = "sk_max_357"; stock = 12; break;
+  case 5: name = "sk_max_crossbow"; stock = 10; break;
+  case 6: name = "sk_max_buckshot"; stock = 30; break;
+  case 7: name = "sk_max_rpg_round"; stock = 3; break;
+  case 8: name = "sk_max_smg1_grenade"; stock = 3; break;
+  case 9: name = "sk_max_sniper_round"; stock = 30; break;
+  case 11: name = "sk_max_grenade"; stock = 5; break;
+  default: break;
+  }
+  int v = convar_int(name);
+  if (v <= 0)
+    v = stock;
+  cache[type] = v;
+  return v;
+}
+
+static int local_ammo(void *local_ent, int type) {
+  if (!local_ent || g_net.ammo < 0 || type < 0 || type >= 32)
+    return -1;
+  return *(int *)((uintptr_t)local_ent + g_net.ammo + type * 4);
+}
+
 static int classify_item(const char *model, const char *cls, char *label,
                          size_t outn) {
   if (!model && !cls)
@@ -2535,6 +2701,12 @@ static void items_collect(int local_idx) {
     ItemTarget &t = g_item_targets[g_nitems++];
     t.idx = idx;
     t.kind = kind;
+    t.ammo_type = -1;
+    if (kind == IK_AMMO) {
+      t.ammo_type = item_ammo_type(model);
+      if (t.ammo_type < 0)
+        t.ammo_type = weapon_ammo_type(weapon_type_id(model, cls));
+    }
     t.origin = origin;
     snprintf(t.label, sizeof(t.label), "%s", label);
     if (dbg_lines < 8) {
@@ -2605,6 +2777,12 @@ void esp_draw_items() {
         continue;
       if (t.kind == IK_ARMOR && vit_armor >= 0 && vit_armor >= 100)
         continue;
+      if (t.kind == IK_AMMO && t.ammo_type >= 0) {
+        int maxa = ammo_max(t.ammo_type);
+        int cura = local_ammo(entitylist_get(local), t.ammo_type);
+        if (maxa > 0 && cura >= 0 && cura >= maxa)
+          continue;
+      }
     }
     float sx, sy;
     if (!world_to_screen(t.origin, sx, sy))
diff --git a/src/hl2h.h b/src/hl2h.h
index 0c8ffb5..4f3552e 100644
--- a/src/hl2h.h
+++ b/src/hl2h.h
@@ -100,6 +100,8 @@ struct NetVars {
   int punch = -1;        // client m_vecPunchAngle (aim punch)
   int default_fov = -1;  // client m_iDefaultFOV (camera fov)
   int dmg_radius = -1;   // client C_BaseGrenade::m_DmgRadius
+  int my_weapons = -1;   // client m_hMyWeapons[48] array base
+  int ammo = -1;         // client m_iAmmo[] array base
   // ponytail: mins/maxs may be absent from some HL2 netvar tables; esp.cpp falls back to h=72
   bool ok() const { return flags >= 0 && velocity >= 0 && movetype >= 0; }
   // ponytail: m_iMaxHealth isn't a netvar in HL2 SP; esp.cpp falls back to 100.
diff --git a/src/netvars.cpp b/src/netvars.cpp
index ef564cd..2747c29 100644
--- a/src/netvars.cpp
+++ b/src/netvars.cpp
@@ -112,6 +112,15 @@ static void collect_netvars(uintptr_t table, uintptr_t base_off, int depth) {
       int off = (int)(base_off + (uint32_t)poff);
       if (off >= 0x20 && off <= 0x2000)
         g_net.dmg_radius = off;
+    } else if (strcmp(pname2, "m_hMyWeapons") == 0 &&
+               g_net.my_weapons < 0) {
+      int off = (int)(base_off + (uint32_t)poff);
+      if (off >= 0x20 && off <= 0x2000)
+        g_net.my_weapons = off;
+    } else if (strcmp(pname2, "m_iAmmo") == 0 && g_net.ammo < 0) {
+      int off = (int)(base_off + (uint32_t)poff);
+      if (off >= 0x20 && off <= 0x2000)
+        g_net.ammo = off;
     } else if (strcmp(pname2, "m_iTeamNum") == 0 && g_net.teamnum < 0) {
       g_net.teamnum = (int)(base_off + (uint32_t)poff);
     } else if (strcmp(pname2, "m_vecOrigin") == 0 && g_net.origin < 0) {
@@ -294,11 +303,11 @@ void resolve_netvars() {
        "teamnum=%d origin=%d viewoffset=%d mins=%d maxs=%d lifeste=%d "
        "modelindex=%d absvelocity=%d activeweapon=%d owner=%d "
        "weapon_owner=%d clr_render=%d punch=%d default_fov=%d "
-       "dmg_radius=%d",
+       "dmg_radius=%d my_weapons=%d ammo=%d",
        g_net.flags, g_net.velocity, g_net.movetype, g_net.health,
        g_net.maxhealth, g_net.teamnum, g_net.origin, g_net.viewoffset,
        g_net.mins, g_net.maxs, g_net.lifestate, g_net.modelindex,
        g_net.absvelocity, g_net.activeweapon, g_net.owner,
        g_net.weapon_owner, g_net.clr_render, g_net.punch,
-       g_net.default_fov, g_net.dmg_radius);
+       g_net.default_fov, g_net.dmg_radius, g_net.my_weapons, g_net.ammo);
 }