diff --git a/src/api/types/mesh.c b/src/api/types/mesh.c
index 814aec07..93042048 100644
--- a/src/api/types/mesh.c
+++ b/src/api/types/mesh.c
@@ -185,11 +185,22 @@ int l_lovrMeshGetVertexMap(lua_State* L) {
     return 1;
   }
 
-  lua_newtable(L);
+  if (lua_istable(L, 2)) {
+    lua_settop(L, 2);
+  } else if (lua_isuserdata(L, 2)) {
+    Blob* blob = luax_checktypeof(L, 2, Blob);
+    lovrAssert(size * count <= blob->size, "Mesh vertex map is %zu bytes, but Blob can only hold %zu", size * count, blob->size);
+    memcpy(blob->data, indices.raw, size * count);
+    return 0;
+  } else {
+    lua_settop(L, 1);
+    lua_createtable(L, count, 0);
+  }
+
   for (size_t i = 0; i < count; i++) {
     uint32_t index = size == sizeof(uint32_t) ? indices.ints[i] : indices.shorts[i];
     lua_pushinteger(L, index + 1);
-    lua_rawseti(L, -2, i + 1);
+    lua_rawseti(L, 2, i + 1);
   }
 
   return 1;
diff --git a/src/graphics/mesh.c b/src/graphics/mesh.c
index 10eb4f5b..bcb62c5b 100644
--- a/src/graphics/mesh.c
+++ b/src/graphics/mesh.c
@@ -237,6 +237,8 @@ void lovrMeshUnmapVertices(Mesh* mesh) {
 IndexPointer lovrMeshReadIndices(Mesh* mesh, uint32_t* count, size_t* size) {
   if (mesh->indexCount == 0) {
     return (IndexPointer) { .raw = NULL };
+  } else if (mesh->mappedIndices) {
+    lovrMeshUnmapIndices(mesh);
   }
 
   *size = mesh->indexSize;
@@ -252,6 +254,10 @@ IndexPointer lovrMeshReadIndices(Mesh* mesh, uint32_t* count, size_t* size) {
 }
 
 IndexPointer lovrMeshWriteIndices(Mesh* mesh, uint32_t count, size_t size) {
+  if (mesh->mappedIndices) {
+    lovrMeshUnmapIndices(mesh);
+  }
+
   mesh->indexSize = size;
   mesh->indexCount = count;