Fix T63283: Second subdivision modifier does not ignore crease

This is something where there is no single correct behavior,
sometimes it's needed to ignore the crease to make mesh more
smooth. But sometimes crease is to be considered after first
subdivision surface: for example, when adding extra subdivisions
for render-time displacement.

Made it an option whether modifier needs to take crease into
account or not.

Existing files should be openable in the 2.7 compatible way,
to re-create an old behavior the options is to be manually
disabled in the modifier settings.

Reviewers: brecht

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D4652

2 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/modifiers/intern/MOD_multires.c b/source/blender/modifiers/intern/MOD_multires.c
index af17bd7d53c..a8760d05834 100644
--- a/source/blender/modifiers/intern/MOD_multires.c
+++ b/source/blender/modifiers/intern/MOD_multires.c
@@ -61,6 +61,7 @@ static void initData(ModifierData *md)
 	mmd->totlvl = 0;
 	mmd->uv_smooth = SUBSURF_UV_SMOOTH_PRESERVE_CORNERS;
 	mmd->quality = 3;
+	mmd->flags |= eMultiresModifierFlag_UseCrease;
 }
 
 static void copyData(const ModifierData *md_src, ModifierData *md_dst, const int flag)
diff --git a/source/blender/modifiers/intern/MOD_subsurf.c b/source/blender/modifiers/intern/MOD_subsurf.c
index 40c9e5c3b1b..74bf6b7e976 100644
--- a/source/blender/modifiers/intern/MOD_subsurf.c
+++ b/source/blender/modifiers/intern/MOD_subsurf.c
@@ -59,6 +59,7 @@ static void initData(ModifierData *md)
 	smd->renderLevels = 2;
 	smd->uv_smooth = SUBSURF_UV_SMOOTH_PRESERVE_CORNERS;
 	smd->quality = 3;
+	smd->flags |= eSubsurfModifierFlag_UseCrease;
 }
 
 static void copyData(const ModifierData *md, ModifierData *target, const int flag)
@@ -126,6 +127,7 @@ static void subdiv_settings_init(SubdivSettings *settings,
 	settings->is_simple = (smd->subdivType == SUBSURF_TYPE_SIMPLE);
 	settings->is_adaptive = true;
 	settings->level = settings->is_simple ? 1 : smd->quality;
+	settings->use_creases = (smd->flags & eSubsurfModifierFlag_UseCrease);
 	settings->vtx_boundary_interpolation = SUBDIV_VTX_BOUNDARY_EDGE_ONLY;
 	settings->fvar_linear_interpolation =
 	        BKE_subdiv_fvar_interpolation_from_uv_smooth(smd->uv_smooth);