Fix T47189: Large smoke simulation sometimes make Blender crash.

Issue was with very thin domains along one or two axes, these could lead to simulation
with only one cell width - and smoke code assumes we have at least 4 cells in each direction.

So now, we clamp resolution to a minimum of 4 in smoke_set_domain_from_derivedmesh().

Note: in extreme cases like this report, this will generate very un-cubic cells,
check it still works OK in 3DView is needed here.

Thanks to @genscher and @kevindietrich for help on this issue. :)

1 files changed, 6 insertions, 6 deletions

diff --git a/source/blender/blenkernel/intern/smoke.c b/source/blender/blenkernel/intern/smoke.c
index f5a6644e1bb..2d3fa2a3818 100644
--- a/source/blender/blenkernel/intern/smoke.c
+++ b/source/blender/blenkernel/intern/smoke.c
@@ -246,21 +246,21 @@ static void smoke_set_domain_from_derivedmesh(SmokeDomainSettings *sds, Object *
 		scale = res / size[0];
 		sds->scale = size[0] / fabsf(ob->size[0]);
 		sds->base_res[0] = res;
-		sds->base_res[1] = (int)(size[1] * scale + 0.5f);
-		sds->base_res[2] = (int)(size[2] * scale + 0.5f);
+		sds->base_res[1] = max_ii((int)(size[1] * scale + 0.5f), 4);
+		sds->base_res[2] = max_ii((int)(size[2] * scale + 0.5f), 4);
 	}
 	else if (size[1] >= MAX2(size[0], size[2])) {
 		scale = res / size[1];
 		sds->scale = size[1] / fabsf(ob->size[1]);
-		sds->base_res[0] = (int)(size[0] * scale + 0.5f);
+		sds->base_res[0] = max_ii((int)(size[0] * scale + 0.5f), 4);
 		sds->base_res[1] = res;
-		sds->base_res[2] = (int)(size[2] * scale + 0.5f);
+		sds->base_res[2] = max_ii((int)(size[2] * scale + 0.5f), 4);
 	}
 	else {
 		scale = res / size[2];
 		sds->scale = size[2] / fabsf(ob->size[2]);
-		sds->base_res[0] = (int)(size[0] * scale + 0.5f);
-		sds->base_res[1] = (int)(size[1] * scale + 0.5f);
+		sds->base_res[0] = max_ii((int)(size[0] * scale + 0.5f), 4);
+		sds->base_res[1] = max_ii((int)(size[1] * scale + 0.5f), 4);
 		sds->base_res[2] = res;
 	}