fix explosions breaking old replays

src/game/boe.combat.cpp

@@ -1599,7 +1599,8 @@ void do_combat_cast(location target) {
 	if(ashes_loc.x > 0){
 		// If ashes are going to appear, there'd better be a visible blast on the spot.
 		if(!hit_ashes_loc){
-			add_explosion(ashes_loc,0,0,get_boom_type(eDamageType::FIRE),1,0);
+			// the last argument is true so this doesn't break RNG of older replays:
+			add_explosion(ashes_loc,0,0,get_boom_type(eDamageType::FIRE),1,0,true);
 		}
 
 		univ.town.set_ash(ashes_loc.x,ashes_loc.y,true);

src/game/boe.main.cpp

@@ -264,6 +264,9 @@ static void process_args(int argc, char* argv[]) {
 		cli.writeToStream(std::cout);
 		exit(0);
 	}
+	// This obsolete preference should always be true unless running an old replay
+	// (which will set it false after this line if it needs to)
+	set_pref("DrawTerrainFrills", true);
 	if(replay){
 		if(record_to){
 			std::cout << "Warning: flag --record conflicts with --replay and will be ignored." << std::endl;

src/game/boe.newgraph.cpp

@@ -302,7 +302,9 @@ void mondo_boom(location l,short type,short snd) {
 	end_missile_anim();
 }
 
-void add_explosion(location dest,short val_to_place,short place_type,short boom_type,short x_adj,short y_adj) {
+void add_explosion(location dest,short val_to_place,short place_type,short boom_type,short x_adj,short y_adj, bool use_unique_ran) {
+	if(!get_bool_pref("DrawTerrainFrills", true))
+		return;
 	if(!boom_anim_active)
 		return;
 	// lose redundant explosions
@@ -316,7 +318,7 @@ void add_explosion(location dest,short val_to_place,short place_type,short boom_
 	for(short i = 0; i < 30; i++)
 		if(store_booms[i].boom_type < 0) {
 			have_boom = true;
-			store_booms[i].offset = (i == 0) ? 0 : -1 * get_ran(1,0,2);
+			store_booms[i].offset = (i == 0) ? 0 : -1 * get_ran(1,0,2,use_unique_ran);
 			store_booms[i].dest = dest;
 			store_booms[i].val_to_place = val_to_place;
 			store_booms[i].place_type = place_type;

src/game/boe.newgraph.hpp

@@ -56,7 +56,7 @@ void run_a_missile(location from,location fire_to,miss_num_t miss_type,short pat
 void run_a_boom(location boom_where,short type,short x_adj,short y_adj,short snd = -1);
 void mondo_boom(location l,short type,short snd = -1);
 void add_missile(location dest,miss_num_t missile_type,short path_type,short x_adj,short y_adj);
-void add_explosion(location dest,short val_to_place,short place_type,short boom_type,short x_adj,short y_adj);
+void add_explosion(location dest,short val_to_place,short place_type,short boom_type,short x_adj,short y_adj, bool use_unique_ran = false);
 void do_missile_anim(short num_steps,location missile_origin,short sound_num) ;
 void do_explosion_anim(short sound_num,short expand,short snd = -1);
 void click_shop_rect(rectangle area_rect);

src/mathutil.cpp

@@ -10,8 +10,9 @@
 #include "mathutil.hpp"
 
 std::mt19937 game_rand;
+std::mt19937 unique_rand;
 
-short get_ran (short times,short  min,short  max){
+short get_ran (short times,short min,short max, bool use_unique_ran){
 	long unsigned int store;
 	short to_ret = 0;
 	
@@ -19,6 +20,9 @@ short get_ran (short times,short  min,short  max){
 	if(max == min) return times * min;
 	
 	for(short i = 1; i < times + 1; i++) {
+		if(use_unique_ran)
+			store = unique_rand();
+		else
 			store = game_rand();
 		to_ret += min + (store % (max - min + 1));
 	}

src/mathutil.hpp

@@ -25,7 +25,8 @@ using std::abs;
 
 extern std::mt19937 game_rand;
 
-short get_ran(short times, short min, short max);
+// unique_ran: pass true for get_ran() calls that would break replay compatibility
+short get_ran(short times, short min, short max, bool use_unique_ran = false);
 short max(short a,short b);
 short min(short a,short b);
 short minmax(short min,short max,short k);

src/tools/prefs.mac.mm

@@ -38,6 +38,11 @@ NSDictionary* prefsToRecord = @{
 	@"UIScale": @(kFloat),
 	@"UIScaleMap": @(kFloat)
 };
+// Some legacy preferences influenced RNG and must be
+// known by replays
+NSDictionary* prefsToReplay = @{
+	@"DrawTerrainFrills": @(kBool)
+};
 
 bool prefsLoaded = false;
 
@@ -133,11 +138,17 @@ static bool load_prefs(std::istream& istream) {
 
 		std::string key = line.substr(0, key_end + 1), val = line.substr(val_beg);
 		NSString* pref_key = [NSString stringWithUTF8String: key.c_str()];
+		NSInteger type;
 		// Skip obsolete preferences from legacy replays
 		if([prefsToRecord valueForKey: pref_key] == nil){
+			if([prefsToReplay valueForKey: pref_key] == nil){
 				continue;
+			}else{
+				type = [prefsToReplay[pref_key] integerValue];
+			}
+		}else{
+			type = [prefsToRecord[pref_key] integerValue];
 		}
-		NSInteger type = [prefsToRecord[pref_key] integerValue];
 		switch((int)type) {
 			case kBool:
 				if(val == "true") set_pref(key, true);