Voxelmanip: Do not emerge or blit to blocks over map gen limit

paramat · paramat · commit 111e7e1cc831 · 2017-02-18T22:47:24.000Z
Placing a structure that extends into mapblocks that extend past
map_gen_limit causes a crash. For example a sapling growing at the
world edge which adds leaves beyond the edge, or placing a structure
using the lua voxelmanip, or placing a schematic or l-system tree.

Do not run the 'load_if_inexistent' block of code if the mapblock
is over limit, this also marks the mapblock with the flag
VMANIP_BLOCK_DATA_INEXIST which later prevents blitting back those
mapblocks.

This fix therefore uses existing functionality by having the same
effect as the 'load_if_inexistent' bool being false.
diff --git a/src/map.cpp b/src/map.cpp
@@ -3161,7 +3161,7 @@ void MMVManip::initialEmerge(v3s16 blockpos_min, v3s16 blockpos_max,
 		if(block_data_inexistent)
 		{
 
-			if (load_if_inexistent) {
+			if (load_if_inexistent && !blockpos_over_limit(p)) {
 				ServerMap *svrmap = (ServerMap *)m_map;
 				block = svrmap->emergeBlock(p, false);
 				if (block == NULL)

Original file line number	Diff line number	Diff line change
`@@ -3161,7 +3161,7 @@ void MMVManip::initialEmerge(v3s16 blockpos_min, v3s16 blockpos_max,`
`3161`	`3161`	`if(block_data_inexistent)`
`3162`	`3162`	`{`
`3163`	`3163`
`3164`		`- if (load_if_inexistent) {`
	`3164`	`+ if (load_if_inexistent && !blockpos_over_limit(p)) {`
`3165`	`3165`	`ServerMap svrmap = (ServerMap )m_map;`
`3166`	`3166`	`block = svrmap->emergeBlock(p, false);`
`3167`	`3167`	`if (block == NULL)`