(svn r3044) -NewGRF, Codechange: Improve handling of non-existent sprite sets.

newgrf.c

@@ -1404,14 +1404,10 @@ static void NewSpriteGroup(byte *buf, int len)
 			if (HASBIT(groupid, 15)) {
 				dg->ranges[i].group = NewCallBackResultSpriteGroup(groupid);
 				dg->ranges[i].group->ref_count++;
-			} else if (groupid >= _cur_grffile->spritegroups_count) {
-				/* This doesn't exist for us. */
-				grf_load_word(&buf); // skip range
-				i--; dg->num_ranges--;
-				continue;
+			} else if (groupid >= _cur_grffile->spritegroups_count || _cur_grffile->spritegroups[groupid] == NULL) {
+				grfmsg(GMS_WARN, "NewSpriteGroup(%02x:0x%x): Groupid %04x does not exist, leaving empty.", setid, numloaded, groupid);
+				dg->ranges[i].group = NULL;
 			} else {
-			/* XXX: If multiple surreal sets attach a surreal
-			 * set this way, we are in trouble. */
 				dg->ranges[i].group = _cur_grffile->spritegroups[groupid];
 				dg->ranges[i].group->ref_count++;
 			}
@@ -1423,15 +1419,14 @@ static void NewSpriteGroup(byte *buf, int len)
 		groupid = grf_load_word(&buf);
 		if (HASBIT(groupid, 15)) {
 			dg->default_group = NewCallBackResultSpriteGroup(groupid);
-		} else if (groupid >= _cur_grffile->spritegroups_count) {
-			/* This spritegroup stinks. */
-			free(dg->ranges), dg->ranges = NULL;
-			grfmsg(GMS_WARN, "NewSpriteGroup(%02x:0x%x): Default groupid %04x is cargo callback or unknown, ignoring spritegroup.", setid, numloaded, groupid);
-			return;
+			dg->default_group->ref_count++;
+		} else if (groupid >= _cur_grffile->spritegroups_count || _cur_grffile->spritegroups[groupid] == NULL) {
+			grfmsg(GMS_WARN, "NewSpriteGroup(%02x:0x%x): Groupid %04x does not exist, leaving empty.", setid, numloaded, groupid);
+			dg->default_group = NULL;
 		} else {
 			dg->default_group = _cur_grffile->spritegroups[groupid];
-		}
 		dg->default_group->ref_count++;
+		}
 
 		if (_cur_grffile->spritegroups[setid] != NULL)
 			UnloadSpriteGroup(&_cur_grffile->spritegroups[setid]);
@@ -1474,11 +1469,9 @@ static void NewSpriteGroup(byte *buf, int len)
 			if (HASBIT(groupid, 15)) {
 				rg->groups[i] = NewCallBackResultSpriteGroup(groupid);
 				rg->groups[i]->ref_count++;
-			} else if (groupid >= _cur_grffile->spritegroups_count) {
-				/* This doesn't exist for us. */
-				i--;
-				rg->num_groups--;
-				continue;
+			} else if (groupid >= _cur_grffile->spritegroups_count || _cur_grffile->spritegroups[groupid] == NULL) {
+				grfmsg(GMS_WARN, "NewSpriteGroup(%02x:0x%x): Groupid %04x does not exist, leaving empty.", setid, numloaded, groupid);
+				rg->groups[i] = NULL;
 			} else {
 				rg->groups[i] = _cur_grffile->spritegroups[groupid];
 				rg->groups[i]->ref_count++;

sprite.c

@@ -127,10 +127,10 @@ void UnloadSpriteGroup(SpriteGroup **group_ptr)
 		{
 			RealSpriteGroup *rsg = &group->g.real;
 			for (i = 0; i < rsg->loading_count; i++) {
-				UnloadSpriteGroup(&rsg->loading[i]);
+				if (rsg->loading[i] != NULL) UnloadSpriteGroup(&rsg->loading[i]);
 			}
 			for (i = 0; i < rsg->loaded_count; i++) {
-				UnloadSpriteGroup(&rsg->loaded[i]);
+				if (rsg->loaded[i] != NULL) UnloadSpriteGroup(&rsg->loaded[i]);
 			}
 			free(group);
 			return;
@@ -140,9 +140,9 @@ void UnloadSpriteGroup(SpriteGroup **group_ptr)
 		{
 			DeterministicSpriteGroup *dsg = &group->g.determ;
 			for (i = 0; i < group->g.determ.num_ranges; i++) {
-				UnloadSpriteGroup(&dsg->ranges[i].group);
+				if (dsg->ranges[i].group != NULL) UnloadSpriteGroup(&dsg->ranges[i].group);
 			}
-			UnloadSpriteGroup(&dsg->default_group);
+			if (dsg->default_group != NULL) UnloadSpriteGroup(&dsg->default_group);
 			free(group->g.determ.ranges);
 			free(group);
 			return;
@@ -151,7 +151,7 @@ void UnloadSpriteGroup(SpriteGroup **group_ptr)
 		case SGT_RANDOMIZED:
 		{
 			for (i = 0; i < group->g.random.num_groups; i++) {
-				UnloadSpriteGroup(&group->g.random.groups[i]);
+				if (group->g.random.groups[i] != NULL) UnloadSpriteGroup(&group->g.random.groups[i]);
 			}
 			free(group->g.random.groups);
 			free(group);