Add pseudo-ID for items at player's feet

It's a bit silly and tedious play-wise to force player to actually
pick things up for pseudo-ID to kick in.

3 files changed, 94 insertions, 76 deletions

diff --git a/src/dungeon.cc b/src/dungeon.cc
index abcc6cae..34dd781d 100644
--- a/src/dungeon.cc
+++ b/src/dungeon.cc
@@ -70,11 +70,15 @@
 #define AUTO_CURSE_CHANCE 15
 #define CHAINSWORD_NOISE 100
 
+/**
+ * Type of a "sense" function
+ */
+typedef byte (*sense_function_t)(object_type const *o_ptr);
 
 /*
  * Return a "feeling" (or NULL) about an item.  Method 1 (Heavy).
  */
-static byte value_check_aux1(object_type *o_ptr)
+static byte value_check_aux1(object_type const *o_ptr)
 {
 	/* Artifacts */
 	if (artifact_p(o_ptr))
@@ -109,7 +113,7 @@ static byte value_check_aux1(object_type *o_ptr)
 	return (SENSE_AVERAGE);
 }
 
-static byte value_check_aux1_magic(object_type *o_ptr)
+static byte value_check_aux1_magic(object_type const *o_ptr)
 {
 	object_kind *k_ptr = &k_info[o_ptr->k_idx];
 
@@ -176,7 +180,7 @@ static byte value_check_aux1_magic(object_type *o_ptr)
 /*
  * Return a "feeling" (or NULL) about an item.  Method 2 (Light).
  */
-static byte value_check_aux2(object_type *o_ptr)
+static byte value_check_aux2(object_type const *o_ptr)
 {
 	/* Cursed items (all of them) */
 	if (cursed_p(o_ptr)) return (SENSE_CURSED);
@@ -198,7 +202,7 @@ static byte value_check_aux2(object_type *o_ptr)
 }
 
 
-static byte value_check_aux2_magic(object_type *o_ptr)
+static byte value_check_aux2_magic(object_type const *o_ptr)
 {
 	object_kind *k_ptr = &k_info[o_ptr->k_idx];
 
@@ -278,9 +282,8 @@ static bool_ granted_resurrection(void)
 	return (FALSE);
 }
 
-static byte select_sense(object_type *o_ptr)
+static sense_function_t select_sense(object_type *o_ptr, sense_function_t combat, sense_function_t magic)
 {
-	/* Valid "tval" codes */
 	switch (o_ptr->tval)
 	{
 	case TV_SHOT:
@@ -305,8 +308,7 @@ static byte select_sense(object_type *o_ptr)
 	case TV_BOOMERANG:
 	case TV_TRAPKIT:
 		{
-			return 1;
-			break;
+			return combat;
 		}
 
 	case TV_POTION:
@@ -317,22 +319,21 @@ static byte select_sense(object_type *o_ptr)
 	case TV_ROD:
 	case TV_ROD_MAIN:
 		{
-			return 2;
-			break;
+			return magic;
 		}
 
 		/* Dual use? */
 	case TV_DAEMON_BOOK:
 		{
-			return 1;
-			break;
+			return combat;
 		}
 	}
-	return 0;
+
+	return nullptr;
 }
 
 /*
- * Sense the inventory
+ * Sense quality of specific list of objects.
  *
  * Combat items (weapons and armour) - Fast, weak if combat skill < 10, strong
  * otherwise.
@@ -344,21 +345,8 @@ static byte select_sense(object_type *o_ptr)
  * they learn one form of ID or another, and because most magic items are
  * easy_know.
  */
-void sense_inventory(void)
+void sense_objects(std::vector<int> const &object_idxs)
 {
-	int i, combat_lev, magic_lev;
-
-	bool_ heavy_combat, heavy_magic;
-
-	byte feel;
-
-	object_type *o_ptr;
-
-	char o_name[80];
-
-
-	/*** Check for "sensing" ***/
-
 	/* No sensing when confused */
 	if (p_ptr->confused) return;
 
@@ -388,24 +376,21 @@ void sense_inventory(void)
 	 */
 
 	/* The combat skill affects weapon/armour pseudo-ID */
-	combat_lev = get_skill(SKILL_COMBAT);
+	int combat_lev = get_skill(SKILL_COMBAT);
 
 	/* The magic skill affects magic item pseudo-ID */
-	magic_lev = get_skill(SKILL_MAGIC);
+	int magic_lev = get_skill(SKILL_MAGIC);
 
 	/* Higher skill levels give the player better sense of items */
-	heavy_combat = (combat_lev > 10) ? TRUE : FALSE;
-	heavy_magic = (magic_lev > 10) ? TRUE : FALSE;
-
+	auto feel_combat = (combat_lev > 10) ? value_check_aux1 : value_check_aux2;
+	auto feel_magic = (magic_lev > 10) ? value_check_aux1_magic : value_check_aux2_magic;
 
 	/*** Sense everything ***/
 
 	/* Check everything */
-	for (i = 0; i < INVEN_TOTAL; i++)
+	for (auto i : object_idxs)
 	{
-		byte okay = 0;
-
-		o_ptr = &p_ptr->inventory[i];
+		object_type *o_ptr = get_object(i);
 
 		/* Skip empty slots */
 		if (!o_ptr->k_idx) continue;
@@ -416,37 +401,39 @@ void sense_inventory(void)
 		/* It is fully known, no information needed */
 		if (object_known_p(o_ptr)) continue;
 
-		/* Valid "tval" codes */
-		okay = select_sense(o_ptr);
+		/* Select appropriate sensing function, if any */
+		sense_function_t sense = select_sense(o_ptr, feel_combat, feel_magic);
 
-		/* Skip non-sense machines */
-		if (!okay) continue;
-
-		/* Check for a feeling */
-		if (okay == 1)
-		{
-			feel = (heavy_combat ? value_check_aux1(o_ptr) : value_check_aux2(o_ptr));
-		}
-		else
+		/* Skip non-sensed items */
+		if (!sense)
 		{
-			feel = (heavy_magic ? value_check_aux1_magic(o_ptr) : value_check_aux2_magic(o_ptr));
+			continue;
 		}
 
+		/* Check for a feeling */
+		byte feel = sense(o_ptr);
+
 		/* Skip non-feelings */
-		if (feel == SENSE_NONE) continue;
+		if (feel == SENSE_NONE)
+		{
+			continue;
+		}
 
 		/* Get an object description */
+		char o_name[80];
 		object_desc(o_name, o_ptr, FALSE, 0);
 
-		/* Message (equipment) */
-		if (i >= INVEN_WIELD)
+		/* Messages */
+		if (i < 0) {
+			// We get a message from the floor handling code, so
+			// it would be overkill to have a message here too.
+		}
+		else if (i >= INVEN_WIELD)
 		{
 			msg_format("You feel the %s (%c) you are %s %s %s...",
 			           o_name, index_to_label(i), describe_use(i),
 			           ((o_ptr->number == 1) ? "is" : "are"), sense_desc[feel]);
 		}
-
-		/* Message (inventory) */
 		else
 		{
 			msg_format("You feel the %s (%c) in your pack %s %s...",
@@ -471,6 +458,20 @@ void sense_inventory(void)
 	squeltch_inventory();
 }
 
+void sense_inventory(void)
+{
+	static std::vector<int> idxs;
+	// Initialize static vector if necessary
+	if (idxs.empty())
+	{
+		idxs.reserve(INVEN_TOTAL);
+		for (int i = 0; i < INVEN_TOTAL; i++)
+		{
+			idxs.push_back(i);
+		}
+	}
+	sense_objects(idxs);
+}
 
 /*
  * Go to any level (ripped off from wiz_jump)
diff --git a/src/dungeon.hpp b/src/dungeon.hpp
index 37d54d39..bbe6da87 100644
--- a/src/dungeon.hpp
+++ b/src/dungeon.hpp
@@ -1,3 +1,6 @@
 #pragma once
 
+#include <vector>
+
 extern void sense_inventory();
+extern void sense_objects(std::vector<int> const &object_idxs);
diff --git a/src/object1.cc b/src/object1.cc
index cb1a6604..25b848a0 100644
--- a/src/object1.cc
+++ b/src/object1.cc
@@ -4229,7 +4229,7 @@ static cptr mention_use(int i)
  */
 cptr describe_use(int i)
 {
-	cptr p;
+	cptr p = nullptr;
 
 	switch (i)
 	{
@@ -6113,48 +6113,57 @@ void object_pickup(int this_o_idx)
 
 void py_pickup_floor(int pickup)
 {
-	s16b this_o_idx, next_o_idx = 0;
-
-	char o_name[80] = "";
-	object_type *o_ptr = 0;
-
-	int floor_num = 0, floor_o_idx = 0;
-
-	bool_ do_pickup = TRUE;
-
-	bool_ do_ask = TRUE;
-
 	/* Hack -- ignore monster traps */
 	if (cave[p_ptr->py][p_ptr->px].feat == FEAT_MON_TRAP) return;
 
 	/* Try to grab ammo */
 	pickup_ammo();
 
+	/* Build a list of the floor objects. */
+	std::vector<int> floor_object_idxs;
+	{
+		s16b this_o_idx = cave[p_ptr->py][p_ptr->px].o_idx;
+		/* Reserve a number of slots if at least one is needed */
+		if (this_o_idx)
+		{
+			floor_object_idxs.reserve(16); // Avoid resizing in the common case
+		}
+		/* Fill in the indexes */
+		for (; this_o_idx; this_o_idx = o_list[this_o_idx].next_o_idx)
+		{
+			// Note the "-"! We need it for get_object()
+			// lookups to function correctly.
+			floor_object_idxs.push_back(0 - this_o_idx);
+		}
+	}
+
 	/* Mega Hack -- If we have auto-Id, do an ID sweep *before* squleching,
 	 * so that we don't have to walk over things twice to get them
 	 * squelched.  --dsb */
 	if (p_ptr->auto_id)
 	{
-		this_o_idx = cave[p_ptr->py][p_ptr->px].o_idx;
-
-		for (; this_o_idx; this_o_idx = next_o_idx)
+		for (auto const o_idx : floor_object_idxs)
 		{
-			/* Aquire the object */
-			o_ptr = &o_list[this_o_idx];
-
-			/* Acquire the next object index */
-			next_o_idx = o_ptr->next_o_idx;
-
-			/* Identify Object */
+			object_type *o_ptr = get_object(o_idx);
 			object_aware(o_ptr);
 			object_known(o_ptr);
 		}
 	}
 
+	/* Sense floor tile */
+	sense_objects(floor_object_idxs);
+
 	/* Squeltch the floor */
 	squeltch_grid();
 
 	/* Scan the pile of objects */
+	s16b next_o_idx = 0;
+	char o_name[80] = "";
+	object_type *o_ptr = 0;
+	int floor_num = 0;
+	int floor_o_idx = 0;
+
+	s16b this_o_idx;
 	for (this_o_idx = cave[p_ptr->py][p_ptr->px].o_idx; this_o_idx; this_o_idx = next_o_idx)
 	{
 		/* Acquire object */
@@ -6190,6 +6199,7 @@ void py_pickup_floor(int pickup)
 			continue;
 		}
 
+		/* Describe */
 		{
 			char testdesc[80];
 
@@ -6234,6 +6244,10 @@ void py_pickup_floor(int pickup)
 		return;
 	}
 
+	/* Are we actually going to pick up and/or ask about which item to pick up? */
+	bool_ do_pickup = TRUE;
+	bool_ do_ask = TRUE;
+
 	/* One item */
 	if (floor_num == 1)
 	{