From 766e3d882cdbacd2b296ed28ddcb00e98578efd9 Mon Sep 17 00:00:00 2001
From: Marc Gilleron <marc.gilleron@gmail.com>
Date: Sun, 28 Apr 2019 03:51:24 +0100
Subject: [PATCH] Subtract should actually use inverted signed distance

---
 voxel_isosurface_tool.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/voxel_isosurface_tool.cpp b/voxel_isosurface_tool.cpp
index 09ccc10..59af720 100644
--- a/voxel_isosurface_tool.cpp
+++ b/voxel_isosurface_tool.cpp
@@ -42,7 +42,7 @@ inline void do_op(VoxelBuffer &buffer, int x, int y, int z, float d1, VoxelIsoSu
 			break;
 
 		case VoxelIsoSurfaceTool::OP_SUBTRACT:
-			res = MAX(d1, buffer.get_voxel_iso(x, y, z, VoxelBuffer::CHANNEL_ISOLEVEL));
+			res = MAX(1.0 - d1, buffer.get_voxel_iso(x, y, z, VoxelBuffer::CHANNEL_ISOLEVEL));
 			break;
 
 		case VoxelIsoSurfaceTool::OP_SET: