Add NewGRF object property/flag to use land as object ground sprite

This handles variable ground densities, snow/desert, etc.

docs/landscape.html

@@ -1853,6 +1853,52 @@
      <li>m3: random bits</li>
      <li>m5: index into the array of objects, bits 16 to 23 (lower bits in m2)</li>
      <li>m7: animation counter</li>
+     <li style="color: blue">m4 bits 7..5: update counter (for objects using land ground sprites), incremented on every periodic processing.<BR>
+         For snow and desert, these bits are not used, tile is updated on every periodic processing.</li>
+     <li style="color: blue">m4 bits 3..2: ground type (for objects using land ground sprites):
+      <table style="color: blue">
+       <tr>
+        <td nowrap valign=top><tt>0</tt>&nbsp; </td>
+        <td align=left>bare land / grass</td>
+       </tr>
+
+       <tr>
+        <td nowrap valign=top><tt>1</tt>&nbsp; </td>
+        <td align=left>snow or desert</td>
+       </tr>
+      </table>
+     </li>
+     <li style="color: blue">m4 bits 1..0: density (for objects using land ground sprites):
+      <table style="color: blue">
+       <tr>
+        <td nowrap valign=top><tt>0</tt>&nbsp; </td>
+        <td>bare land</td>
+        <td>1/4 snow</td>
+        <td></td>
+       </tr>
+
+       <tr>
+        <td nowrap valign=top><tt>1</tt>&nbsp; </td>
+        <td>1/3 grass</td>
+        <td>2/4 snow;&nbsp;</td>
+        <td>1/2 desert</td>
+       </tr>
+
+       <tr>
+        <td nowrap valign=top><tt>2</tt>&nbsp; </td>
+        <td>2/3 grass</td>
+        <td>3/4 snow</td>
+        <td></td>
+       </tr>
+
+       <tr>
+        <td nowrap valign=top><tt>3</tt>&nbsp; </td>
+        <td>full grass;&nbsp;</td>
+        <td>full snow;&nbsp;</td>
+        <td>full desert</td>
+       </tr>
+      </table>
+     </li>
     </ul>
    </td>
   </tr>

docs/landscape_grid.html

@@ -324,7 +324,7 @@ the array so you can quickly see what is used and what is not.
       <td class="bits"><span class="free">O</span><span class="used" title="Water class">XX</span> <span class="used" title="Owner">XXXXX</span></td>
       <td class="bits"><span class="pool" title="Object index on pool (m2 + m5)">XXXX XXXX XXXX XXXX</span></td>
       <td class="bits"><span class="used" title="Random bits">XXXX XXXX</span></td>
-      <td class="bits"><span class="free">OOOO OOOO</span></td>
+      <td class="bits"><span class="patch" title="Ground update counter">PPP</span><span class="free">O</span> <span class="patch" title="Ground type: grass/bare, snow/desert">PP</span> <span class="patch" title="Ground density">PP</span></td>
       <td class="bits"><span class="pool" title="Object index on pool (m2 + m5)">XXXX XXXX</span></td>
       <td class="bits"><span class="free">OOOO OOOO</span></td>
       <td class="bits"><span class="used" title="Animation counter">XXXX XXXX</span></td>

src/newgrf.cpp

@@ -4296,6 +4296,11 @@ static ChangeInfoResult ObjectChangeInfo(uint id, int numinfo, int prop, const G
 				spec->generate_amount = buf->ReadByte();
 				break;
 
+			case A0RPI_OBJECT_USE_LAND_GROUND:
+				if (MappedPropertyLengthMismatch(buf, 1, mapping_entry)) break;
+				SB(spec->ctrl_flags, OBJECT_CTRL_FLAG_USE_LAND_GROUND, 1, (buf->ReadByte() != 0 ? 1 : 0));
+				break;
+
 			default:
 				ret = HandleAction0PropertyDefault(buf, prop);
 				break;

src/newgrf_extension.cpp

@@ -42,6 +42,7 @@ extern const GRFFeatureInfo _grf_feature_list[] = {
 	GRFFeatureInfo("action0_signals_recolour", 1),
 	GRFFeatureInfo("action0_signals_extra_aspects", 1),
 	GRFFeatureInfo("action3_signals_custom_signal_sprites", 1),
+	GRFFeatureInfo("action0_object_use_land_ground", 1),
 	GRFFeatureInfo(),
 };
 
@@ -66,6 +67,7 @@ extern const GRFPropertyMapDefinition _grf_action0_remappable_properties[] = {
 	GRFPropertyMapDefinition(GSF_SIGNALS, A0RPI_SIGNALS_ENABLE_RESTRICTED_SIGNALS, "signals_enable_restricted_signals"),
 	GRFPropertyMapDefinition(GSF_SIGNALS, A0RPI_SIGNALS_ENABLE_SIGNAL_RECOLOUR, "signals_enable_signal_recolour"),
 	GRFPropertyMapDefinition(GSF_SIGNALS, A0RPI_SIGNALS_EXTRA_ASPECTS, "signals_extra_aspects"),
+	GRFPropertyMapDefinition(GSF_OBJECTS, A0RPI_OBJECT_USE_LAND_GROUND, "object_use_land_ground"),
 	GRFPropertyMapDefinition(),
 };
 

src/newgrf_extension.h

@@ -32,6 +32,7 @@ enum Action0RemapPropertyIds {
 	A0RPI_SIGNALS_ENABLE_RESTRICTED_SIGNALS,
 	A0RPI_SIGNALS_ENABLE_SIGNAL_RECOLOUR,
 	A0RPI_SIGNALS_EXTRA_ASPECTS,
+	A0RPI_OBJECT_USE_LAND_GROUND,
 };
 
 

src/newgrf_object.cpp

@@ -20,6 +20,7 @@
 #include "tile_cmd.h"
 #include "town.h"
 #include "water.h"
+#include "clear_func.h"
 #include "newgrf_animation_base.h"
 
 #include "safeguards.h"
@@ -425,7 +426,26 @@ static void DrawTileLayout(const TileInfo *ti, const TileLayoutSpriteGroup *grou
 	SpriteID image = dts->ground.sprite;
 	PaletteID pal  = dts->ground.pal;
 
-	if (GB(image, 0, SPRITE_WIDTH) != 0) {
+	if (spec->ctrl_flags & OBJECT_CTRL_FLAG_USE_LAND_GROUND) {
+		if (IsTileOnWater(ti->tile)) {
+			DrawWaterClassGround(ti);
+		} else {
+			switch (GetObjectGroundType(ti->tile)) {
+				case OBJECT_GROUND_GRASS:
+					DrawClearLandTile(ti, GetObjectGroundDensity(ti->tile));
+					break;
+
+				case OBJECT_GROUND_SNOW_DESERT:
+					DrawGroundSprite(GetSpriteIDForSnowDesert(ti->tileh, GetObjectGroundDensity(ti->tile)), PAL_NONE);
+					break;
+
+				default:
+					/* This should never be reached, just draw a black sprite to make the problem clear without being unnecessarily punitive */
+					DrawGroundSprite(SPR_FLAT_BARE_LAND + SlopeToSpriteOffset(ti->tileh), PALETTE_ALL_BLACK);
+					break;
+			}
+		}
+	} else if (GB(image, 0, SPRITE_WIDTH) != 0) {
 		/* If the ground sprite is the default flat water sprite, draw also canal/river borders
 		 * Do not do this if the tile's WaterClass is 'land'. */
 		if ((image == SPR_FLAT_WATER_TILE || spec->flags & OBJECT_FLAG_DRAW_WATER) && IsTileOnWater(ti->tile)) {

src/newgrf_object.h

@@ -40,6 +40,12 @@ enum ObjectFlags {
 };
 DECLARE_ENUM_AS_BIT_SET(ObjectFlags)
 
+enum ObjectCtrlFlags {
+	OBJECT_CTRL_FLAG_NONE               =       0, ///< Just nothing.
+	OBJECT_CTRL_FLAG_USE_LAND_GROUND    = 1 <<  0, ///< Use land for ground sprite.
+};
+DECLARE_ENUM_AS_BIT_SET(ObjectCtrlFlags)
+
 void ResetObjects();
 
 /** Class IDs for objects. */
@@ -68,6 +74,7 @@ struct ObjectSpec {
 	Date introduction_date;       ///< From when can this object be built.
 	Date end_of_life_date;        ///< When can't this object be built anymore.
 	ObjectFlags flags;            ///< Flags/settings related to the object.
+	ObjectCtrlFlags ctrl_flags;   ///< Extra control flags.
 	AnimationInfo animation;      ///< Information about the animation.
 	uint16 callback_mask;         ///< Bitmask of requested/allowed callbacks.
 	uint8 height;                 ///< The height of this structure, in heightlevels; max MAX_TILE_HEIGHT.

src/object_cmd.cpp

@@ -126,6 +126,9 @@ void BuildObject(ObjectType type, TileIndex tile, CompanyID owner, Town *town, u
 		bool remove = IsDockingTile(t);
 		MakeObject(t, owner, o->index, wc, Random());
 		if (remove) RemoveDockingTile(t);
+		if ((spec->ctrl_flags & OBJECT_CTRL_FLAG_USE_LAND_GROUND) && wc == WATER_CLASS_INVALID) {
+			SetObjectGroundTypeDensity(t, OBJECT_GROUND_GRASS, 0);
+		}
 		MarkTileDirtyByTile(t, VMDF_NOT_MAP_MODE);
 	}
 
@@ -740,6 +743,84 @@ static void GetTileDesc_Object(TileIndex tile, TileDesc *td)
 	}
 }
 
+/** Convert to or from snowy tiles. */
+static void TileLoopObjectGroundAlps(TileIndex tile)
+{
+	int k;
+	if ((int)TileHeight(tile) < GetSnowLine() - 1) {
+		/* Fast path to avoid needing to check all 4 corners */
+		k = -1;
+	} else {
+		k = GetTileZ(tile) - GetSnowLine() + 1;
+	}
+
+	if (k < 0) {
+		/* Below the snow line, do nothing if no snow. */
+		if (GetObjectGroundType(tile) != OBJECT_GROUND_SNOW_DESERT) return;
+	} else {
+		/* At or above the snow line, make snow tile if needed. */
+		if (GetObjectGroundType(tile) != OBJECT_GROUND_SNOW_DESERT) {
+			SetObjectGroundTypeDensity(tile, OBJECT_GROUND_SNOW_DESERT, 0);
+			MarkTileDirtyByTile(tile);
+			return;
+		}
+	}
+	/* Update snow density. */
+	uint current_density = GetObjectGroundDensity(tile);
+	uint req_density = (k < 0) ? 0u : std::min<uint>(k, 3u);
+
+	if (current_density < req_density) {
+		SetObjectGroundDensity(tile, current_density + 1);
+	} else if (current_density > req_density) {
+		SetObjectGroundDensity(tile, current_density - 1);
+	} else {
+		/* Density at the required level. */
+		if (k >= 0) return;
+		SetObjectGroundTypeDensity(tile, OBJECT_GROUND_GRASS, 3);
+	}
+	MarkTileDirtyByTile(tile);
+}
+
+/**
+ * Tests if at least one surrounding tile is non-desert
+ * @param tile tile to check
+ * @return does this tile have at least one non-desert tile around?
+ */
+static inline bool NeighbourIsNormal(TileIndex tile)
+{
+	for (DiagDirection dir = DIAGDIR_BEGIN; dir < DIAGDIR_END; dir++) {
+		TileIndex t = tile + TileOffsByDiagDir(dir);
+		if (!IsValidTile(t)) continue;
+		if (GetTropicZone(t) != TROPICZONE_DESERT) return true;
+		if (HasTileWaterClass(t) && GetWaterClass(t) == WATER_CLASS_SEA) return true;
+	}
+	return false;
+}
+
+static void TileLoopObjectGroundDesert(TileIndex tile)
+{
+	/* Current desert level - 0 if it is not desert */
+	uint current = 0;
+	if (GetObjectGroundType(tile) == OBJECT_GROUND_SNOW_DESERT) current = GetObjectGroundDensity(tile);
+
+	/* Expected desert level - 0 if it shouldn't be desert */
+	uint expected = 0;
+	if (GetTropicZone(tile) == TROPICZONE_DESERT) {
+		expected = NeighbourIsNormal(tile) ? 1 : 3;
+	}
+
+	if (current == expected) return;
+
+	if (expected == 0) {
+		SetObjectGroundTypeDensity(tile, OBJECT_GROUND_GRASS, 3);
+	} else {
+		/* Transition from clear to desert is not smooth (after clearing desert tile) */
+		SetObjectGroundTypeDensity(tile, OBJECT_GROUND_SNOW_DESERT, expected);
+	}
+
+	MarkTileDirtyByTile(tile);
+}
+
 static void TileLoop_Object(TileIndex tile)
 {
 	const ObjectSpec *spec = ObjectSpec::GetByTile(tile);
@@ -749,7 +830,29 @@ static void TileLoop_Object(TileIndex tile)
 		if (o->location.tile == tile) TriggerObjectAnimation(o, OAT_256_TICKS, spec);
 	}
 
-	if (IsTileOnWater(tile)) TileLoop_Water(tile);
+	if (IsTileOnWater(tile)) {
+		TileLoop_Water(tile);
+	} else if (spec->ctrl_flags & OBJECT_CTRL_FLAG_USE_LAND_GROUND) {
+		switch (_settings_game.game_creation.landscape) {
+			case LT_TROPIC: TileLoopObjectGroundDesert(tile); break;
+			case LT_ARCTIC: TileLoopObjectGroundAlps(tile);   break;
+		}
+
+		if (GetObjectGroundType(tile) == OBJECT_GROUND_GRASS && GetObjectGroundDensity(tile) != 3) {
+			if (_game_mode != GM_EDITOR) {
+				if (GetObjectGroundCounter(tile) < 7) {
+					AddObjectGroundCounter(tile, 1);
+				} else {
+					SetObjectGroundCounter(tile, 0);
+					SetObjectGroundDensity(tile, GetObjectGroundDensity(tile) + 1);
+					MarkTileDirtyByTile(tile, VMDF_NOT_MAP_MODE);
+				}
+			} else {
+				SetObjectGroundTypeDensity(tile, OBJECT_GROUND_GRASS, 3);
+				MarkTileDirtyByTile(tile, VMDF_NOT_MAP_MODE);
+			}
+		}
+	}
 
 	if (!IsObjectType(tile, OBJECT_HQ)) return;
 

src/object_map.h

@@ -13,6 +13,11 @@
 #include "water_map.h"
 #include "object_type.h"
 
+enum ObjectGround {
+	OBJECT_GROUND_GRASS       = 0, ///< Grass or bare
+	OBJECT_GROUND_SNOW_DESERT = 1, ///< Snow or desert
+};
+
 ObjectType GetObjectType(TileIndex t);
 
 /**
@@ -62,6 +67,93 @@ static inline byte GetObjectRandomBits(TileIndex t)
 	return _m[t].m3;
 }
 
+/**
+ * Get the ground type of ths tile.
+ * @param t The tile to get the ground type of.
+ * @pre IsTileType(t, MP_OBJECT)
+ * @return The ground type.
+ */
+static inline ObjectGround GetObjectGroundType(TileIndex t)
+{
+	assert_tile(IsTileType(t, MP_OBJECT), t);
+	return (ObjectGround)GB(_m[t].m4, 2, 2);
+}
+
+/**
+ * Get the ground density of this tile.
+ * Only meaningful for some ground types.
+ * @param t The tile to get the density of.
+ * @pre IsTileType(t, MP_OBJECT)
+ * @return the density
+ */
+static inline uint GetObjectGroundDensity(TileIndex t)
+{
+	assert_tile(IsTileType(t, MP_OBJECT), t);
+	return GB(_m[t].m4, 0, 2);
+}
+
+/**
+ * Set the ground density of this tile.
+ * Only meaningful for some ground types.
+ * @param t The tile to set the density of.
+ * @param d the new density
+ * @pre IsTileType(t, MP_OBJECT)
+ */
+static inline void SetObjectGroundDensity(TileIndex t, uint d)
+{
+	assert_tile(IsTileType(t, MP_OBJECT), t);
+	SB(_m[t].m4, 0, 2, d);
+}
+
+/**
+ * Get the counter used to advance to the next ground density type.
+ * @param t The tile to get the counter of.
+ * @pre IsTileType(t, MP_OBJECT)
+ * @return The value of the counter
+ */
+static inline uint GetObjectGroundCounter(TileIndex t)
+{
+	assert_tile(IsTileType(t, MP_OBJECT), t);
+	return GB(_m[t].m4, 5, 3);
+}
+
+/**
+ * Increments the counter used to advance to the next ground density type.
+ * @param t the tile to increment the counter of
+ * @param c the amount to increment the counter with
+ * @pre IsTileType(t, MP_OBJECT)
+ */
+static inline void AddObjectGroundCounter(TileIndex t, int c)
+{
+	assert_tile(IsTileType(t, MP_OBJECT), t);
+	_m[t].m4 += c << 5;
+}
+
+/**
+ * Sets the counter used to advance to the next ground density type.
+ * @param t The tile to set the counter of.
+ * @param c The amount to set the counter to.
+ * @pre IsTileType(t, MP_OBJECT)
+ */
+static inline void SetObjectGroundCounter(TileIndex t, uint c)
+{
+	assert_tile(IsTileType(t, MP_OBJECT), t);
+	SB(_m[t].m4, 5, 3, c);
+}
+
+
+/**
+ * Sets ground type and density in one go, also sets the counter to 0
+ * @param t       the tile to set the ground type and density for
+ * @param type    the new ground type of the tile
+ * @param density the density of the ground tile
+ * @pre IsTileType(t, MP_OBJECT)
+ */
+static inline void SetObjectGroundTypeDensity(TileIndex t, ObjectGround type, uint density)
+{
+	assert_tile(IsTileType(t, MP_OBJECT), t);
+	_m[t].m4 = 0 << 5 | type << 2 | density;
+}
 
 /**
  * Make an Object tile.

src/table/newgrf_debug_data.h

@@ -868,11 +868,15 @@ class NIHObject : public NIHelper {
 			seprintf(buffer, lastof(buffer), "  [%c] flags: 0x%X", output.flags & 1 ? '-' : '+', spec->flags);
 			output.print(buffer);
 			if (output.flags & 1) {
+				auto print = [&](const char *name) {
+					seprintf(buffer, lastof(buffer), "    %s", name);
+					output.print(buffer);
+				};
 				auto check_flag = [&](ObjectFlags flag, const char *name) {
-					if (spec->flags & flag) {
-						seprintf(buffer, lastof(buffer), "    %s", name);
-						output.print(buffer);
-					}
+					if (spec->flags & flag) print(name);
+				};
+				auto check_ctrl_flag = [&](ObjectCtrlFlags flag, const char *name) {
+					if (spec->ctrl_flags & flag) print(name);
 				};
 				check_flag(OBJECT_FLAG_ONLY_IN_SCENEDIT,   "OBJECT_FLAG_ONLY_IN_SCENEDIT");
 				check_flag(OBJECT_FLAG_CANNOT_REMOVE,      "OBJECT_FLAG_CANNOT_REMOVE");
@@ -888,6 +892,7 @@ class NIHObject : public NIHelper {
 				check_flag(OBJECT_FLAG_ALLOW_UNDER_BRIDGE, "OBJECT_FLAG_ALLOW_UNDER_BRIDGE");
 				check_flag(OBJECT_FLAG_ANIM_RANDOM_BITS,   "OBJECT_FLAG_ANIM_RANDOM_BITS");
 				check_flag(OBJECT_FLAG_SCALE_BY_WATER,     "OBJECT_FLAG_SCALE_BY_WATER");
+				check_ctrl_flag(OBJECT_CTRL_FLAG_USE_LAND_GROUND, "OBJECT_CTRL_FLAG_USE_LAND_GROUND");
 			}
 		}
 	}

src/table/object_land.h

@@ -121,7 +121,7 @@ static const DrawTileSprites _object_hq[] = {
 
 #undef TILE_SPRITE_LINE
 
-#define M(name, size, build_cost_multiplier, clear_cost_multiplier, height, climate, gen_amount, flags) { GRFFilePropsBase<2>(), INVALID_OBJECT_CLASS, name, climate, size, build_cost_multiplier, clear_cost_multiplier, 0, MAX_DAY + 1, flags, {0, 0, 0, 0}, 0, height, 1, gen_amount, true }
+#define M(name, size, build_cost_multiplier, clear_cost_multiplier, height, climate, gen_amount, flags) { GRFFilePropsBase<2>(), INVALID_OBJECT_CLASS, name, climate, size, build_cost_multiplier, clear_cost_multiplier, 0, MAX_DAY + 1, flags, OBJECT_CTRL_FLAG_NONE, {0, 0, 0, 0}, 0, height, 1, gen_amount, true }
 
 /* Climates
  * T = Temperate