Allow pollution spawns to alternatively reduce population instead of …

C3X.h

@@ -227,6 +227,12 @@ enum ai_auto_build_great_wall_strategy {
 	AAGWS_OTHER_CIV_BORDERED_ONLY
 };
 
+enum pollution_spawn_effect {
+	PSE_DEFAULT = 0,
+	PSE_REDUCE_POPULATION,
+	PSE_REDUCE_POPULATION_AND_POLLUTE_TILE
+};
+
 enum perfume_kind {
 	PK_PRODUCTION = 0,
 	PK_TECHNOLOGY,
@@ -327,6 +333,7 @@ struct c3x_config {
 	bool dont_end_units_turn_after_airdrop;
 	bool allow_airdrop_without_airport;
 	bool enable_negative_pop_pollution;
+	enum pollution_spawn_effect pollution_spawn_effect;
 	bool enable_pollution_from_free_improvements;
 	enum retreat_rules land_retreat_rules;
 	enum retreat_rules sea_retreat_rules;
@@ -669,6 +676,7 @@ enum c3x_label {
 	CL_OBSOLETED_BY,
 	CL_NO_STEALTH_ATTACK,
 	CL_DODGED_SAM,
+	CL_POLLUTION_REDUCES_POP,
 	CL_PREVIEW,
 	CL_CITY_TOO_CLOSE_BUTTON_TOOLTIP,
 	CL_TOTAL_CITIES,

Text/c3x-labels.txt

@@ -52,6 +52,9 @@ Obsoleted By
 ; Pops up on the map when a bomber gets intercepted by enemy AA buildings but dodges the damage
 We were chased off by enemy air defenses.
 
+; Pops up on the map when pollution reduces a city's population instead of spawning on a tile.
+Pollution reduces population of
+
 ; As in a "preview" version of the mod. Used on the mod info popup.
 Preview
 

civ_prog_objects.csv

@@ -214,6 +214,7 @@ inlead,	   0x4BED80,	0x4C6350,	0x4BEE10,	"City_cycle_specialist_type",			"bool (
 inlead,	   0x4B1C10,	0x4B8BC0,	0x4B1CA0,	"City_get_total_pollution",			"int (__fastcall *) (City * this)"
 inlead,	   0x4B1B40,	0x4B8B00,	0x4B1BD0,	"City_get_pollution_from_buildings",		"int (__fastcall *) (City * this)"
 inlead,	   0x4B1A50,	0x4B8A10,	0x4B1AE0,	"City_get_pollution_from_pop",			"int (__fastcall *) (City * this)"
+inlead,    0x4B2F80,    0x0,        0x0,        "City_update_spawn_pollution",          "void (__fastcall *) (City * this)"
 inlead,	   0x4ACF40,	0x4B3F20,	0x4ACFD0,	"City_add_or_remove_improvement",		"void (__fastcall *) (City * this, int edx, int improv_id, int add, bool param_3)"
 define,	   0x57E943,	0x58B68E,	0x57E6A3,	"ADDR_RESOURCE_TILE_COUNT_MASK",		"void *"
 define,	   0x57E5EB,	0x58B328,	0x57E34B,	"ADDR_RESOURCE_TILE_COUNT_ZERO_COMPARE",	"void *"

default.c3x_config.ini

@@ -486,6 +486,11 @@ dont_end_units_turn_after_airdrop = false
 allow_airdrop_without_airport = false
 enable_negative_pop_pollution = true
 
+; Controls what happens when pollution may spawn from a city.
+; Options are "default", "reduce-population", and "reduce-population-and-pollute-tile".
+; In "reduce-population-and-pollute-tile" mode, the population reduction and tile pollution checks run independently.
+pollution_spawn_effect = default
+
 ; Causes improvements granted for free by great or small wonders to contribute pollution as though they had been built in the city.
 enable_pollution_from_free_improvements = false
 

injected_code.c

@@ -2182,6 +2182,17 @@ read_ai_auto_build_great_wall_strategy (struct string_slice const * s, int * out
 		return false;
 }
 
+bool
+read_pollution_spawn_effect (struct string_slice const * s, int * out_val)
+{
+	struct string_slice trimmed = trim_string_slice (s, 1);
+	if      (slice_matches_str (&trimmed, "default"                            )) { *out_val = PSE_DEFAULT;                                  return true; }
+	else if (slice_matches_str (&trimmed, "reduce-population"                  )) { *out_val = PSE_REDUCE_POPULATION;                        return true; }
+	else if (slice_matches_str (&trimmed, "reduce-population-and-pollute-tile" )) { *out_val = PSE_REDUCE_POPULATION_AND_POLLUTE_TILE;       return true; }
+	else
+		return false;
+}
+
 bool
 read_tile_terrain_type_value (struct string_slice const * s, enum SquareTypes * out_type)
 {
@@ -2754,6 +2765,9 @@ load_config (char const * file_path, int path_is_relative_to_mod_dir)
 				} else if (slice_matches_str (&p.key, "sea_retreat_rules")) {
 					if (! read_retreat_rules (&value, (int *)&cfg->sea_retreat_rules))
 						handle_config_error (&p, CPE_BAD_VALUE);
+				} else if (slice_matches_str (&p.key, "pollution_spawn_effect")) {
+					if (! read_pollution_spawn_effect (&value, (int *)&cfg->pollution_spawn_effect))
+						handle_config_error (&p, CPE_BAD_VALUE);
 				} else if (slice_matches_str (&p.key, "draw_lines_using_gdi_plus")) {
 					if (! read_line_drawing_override (&value, (int *)&cfg->draw_lines_using_gdi_plus))
 						handle_config_error (&p, CPE_BAD_VALUE);
@@ -19532,6 +19546,7 @@ patch_init_floating_point ()
 	base_config.distribution_hub_yield_division_mode = DHYDM_FLAT;
 	base_config.ai_distribution_hub_build_strategy = ADHBS_BY_CITY_COUNT;
 	base_config.ai_auto_build_great_wall_strategy = AAGWS_ALL_BORDERS;
+	base_config.pollution_spawn_effect = PSE_DEFAULT;
 	base_config.great_wall_auto_build_wonder_improv_id = -1;
 	for (int n = 0; n < ARRAY_LEN (boolean_config_options); n++)
 		*((char *)&base_config + boolean_config_options[n].offset) = boolean_config_options[n].base_val;
@@ -26287,6 +26302,29 @@ patch_City_get_total_pollution (City * this)
 	return patch_City_get_pollution_from_buildings (this) + patch_City_get_pollution_from_pop (this);
 }
 
+void __fastcall
+patch_City_update_spawn_pollution (City * this)
+{
+	enum pollution_spawn_effect effect = is->current_config.pollution_spawn_effect;
+	if (effect == PSE_DEFAULT) {
+		City_update_spawn_pollution (this);
+		return;
+	} else if (effect == PSE_REDUCE_POPULATION_AND_POLLUTE_TILE)
+		City_update_spawn_pollution (this);
+
+	int pollution = patch_City_get_total_pollution (this);
+	if ((pollution > 0) && (rand_int (p_rand_object, __, 100) < pollution) && (this->Body.Population.Size > 1)) {
+		City_remove_population (this, __, 1, -1, '\0');
+
+		if (this->Body.CivID == p_main_screen_form->Player_CivID) {
+			char msg[160];
+			snprintf (msg, sizeof msg, "%s %s", is->c3x_labels[CL_POLLUTION_REDUCES_POP], this->Body.CityName);
+			msg[(sizeof msg) - 1] = '\0';
+			show_map_specific_text (this->Body.X, this->Body.Y, msg, true);
+		}
+	}
+}
+
 void remove_extra_palaces (City * city, City * excluded_destination);
 
 void