From 8591713405419c434801c61ca59a9b6c019eb957 Mon Sep 17 00:00:00 2001 From: paramat Date: Sun, 21 Feb 2016 13:28:34 +0000 Subject: [PATCH] Sheet Ore: Eliminate crash caused by PcgRandom range max < min In the calculation of y_start, when 'column height max' was large it caused nmin.Y + max_height > nmax.Y - max_height Now, in this situation y_start is set to the midpoint between nmin.Y and nmax.Y Limit y0 and y1 to between nmin.Y and nmax.Y, otherwise index calculation, which has no checks for limits, places them at unwanted locations in the voxelmanip --- src/mg_ore.cpp | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/src/mg_ore.cpp b/src/mg_ore.cpp index 6b6e0d7a7..257901614 100644 --- a/src/mg_ore.cpp +++ b/src/mg_ore.cpp @@ -179,7 +179,12 @@ void OreSheet::generate(MMVManip *vm, int mapseed, u32 blockseed, MapNode n_ore(c_ore, 0, ore_param2); u16 max_height = column_height_max; - int y_start = pr.range(nmin.Y + max_height, nmax.Y - max_height); + int y_start_min = nmin.Y + max_height; + int y_start_max = nmax.Y - max_height; + + int y_start = y_start_min < y_start_max ? + pr.range(y_start_min, y_start_max) : + (y_start_min + y_start_max) / 2; if (!noise) { int sx = nmax.X - nmin.X + 1; @@ -204,10 +209,10 @@ void OreSheet::generate(MMVManip *vm, int mapseed, u32 blockseed, u16 height = pr.range(column_height_min, column_height_max); int ymidpoint = y_start + noiseval; - int y0 = ymidpoint - height * (1 - column_midpoint_factor); - int y1 = y0 + height; + int y0 = MYMAX(nmin.Y, ymidpoint - height * (1 - column_midpoint_factor)); + int y1 = MYMIN(nmax.Y, y0 + height - 1); - for (int y = y0; y < y1; y++) { + for (int y = y0; y <= y1; y++) { u32 i = vm->m_area.index(x, y, z); if (!vm->m_area.contains(i)) continue;