Undo the front-facing only commit for clay strips brushes, it adds an

attenuation that should really be optional. There's also a minor
performance penalty and all this only for one problematic case. In case
the tool flattens two surfaces, users can manually set the front face
only option. A better non-attenuating way to cull such vertices can be
added later.

Also flatten brush should calculate the flatten plane from the original
vertices or the flattening will not converge for planes offsets
different than zero.

Reported by Michalis Zissiou, thanks!

1 files changed, 8 insertions, 13 deletions

diff --git a/source/blender/editors/sculpt_paint/sculpt.c b/source/blender/editors/sculpt_paint/sculpt.c
index a7d851d7a67..d07f447b2fa 100644
--- a/source/blender/editors/sculpt_paint/sculpt.c
+++ b/source/blender/editors/sculpt_paint/sculpt.c
@@ -318,8 +318,6 @@ typedef struct StrokeCache {
 	float plane_trim_squared;
 
 	rcti previous_r; /* previous redraw rectangle */
-
-	bool frontface; /* use front face */
 } StrokeCache;
 
 /************** Access to original unmodified vertex data *************/
@@ -671,10 +669,10 @@ static int sculpt_brush_test_cube(SculptBrushTest *test, float co[3], float loca
 	}
 }
 
-static float frontface(bool ff, const float sculpt_normal[3],
+static float frontface(Brush *br, const float sculpt_normal[3],
                        const short no[3], const float fno[3])
 {
-	if (ff) {
+	if (br->flag & BRUSH_FRONTFACE) {
 		float dot;
 
 		if (no) {
@@ -1011,7 +1009,7 @@ static float tex_strength(SculptSession *ss, Brush *br,
 	/* Falloff curve */
 	avg *= BKE_brush_curve_strength(br, len, cache->radius);
 
-	avg *= frontface(cache->frontface, sculpt_normal, vno, fno);
+	avg *= frontface(br, sculpt_normal, vno, fno);
 
 	/* Paint mask */
 	avg *= 1.0f - mask;
@@ -1289,13 +1287,13 @@ static void update_brush_local_mat(Sculpt *sd, Object *ob)
 
 /* Test whether the StrokeCache.sculpt_normal needs update in
  * do_brush_action() */
-static int brush_needs_sculpt_normal(const Brush *brush, SculptSession *ss)
+static int brush_needs_sculpt_normal(const Brush *brush)
 {
 	return ((ELEM(brush->sculpt_tool,
 	              SCULPT_TOOL_GRAB,
 	              SCULPT_TOOL_SNAKE_HOOK) &&
 	         ((brush->normal_weight > 0) ||
-	          ss->cache->frontface)) ||
+	          (brush->flag & BRUSH_FRONTFACE))) ||
 
 	        ELEM7(brush->sculpt_tool,
 	              SCULPT_TOOL_BLOB,
@@ -3139,7 +3137,7 @@ static void do_brush_action(Sculpt *sd, Object *ob, Brush *brush)
 			BKE_pbvh_node_mark_update(nodes[n]);
 		}
 
-		if (brush_needs_sculpt_normal(brush, ss))
+		if (brush_needs_sculpt_normal(brush))
 			update_sculpt_normal(sd, ob, nodes, totnode);
 
 		if (brush->mtex.brush_map_mode == MTEX_MAP_MODE_AREA)
@@ -3905,10 +3903,10 @@ static void sculpt_update_cache_invariants(bContext *C, Sculpt *sd, SculptSessio
 		cache->original = 1;
 	}
 
-	if (ELEM8(brush->sculpt_tool,
+	if (ELEM9(brush->sculpt_tool,
 	          SCULPT_TOOL_DRAW, SCULPT_TOOL_CREASE, SCULPT_TOOL_BLOB,
 	          SCULPT_TOOL_LAYER, SCULPT_TOOL_INFLATE, SCULPT_TOOL_CLAY,
-	          SCULPT_TOOL_CLAY_STRIPS, SCULPT_TOOL_ROTATE))
+	          SCULPT_TOOL_CLAY_STRIPS, SCULPT_TOOL_ROTATE, SCULPT_TOOL_FLATTEN))
 	{
 		if (!(brush->flag & BRUSH_ACCUMULATE)) {
 			cache->original = 1;
@@ -3922,9 +3920,6 @@ static void sculpt_update_cache_invariants(bContext *C, Sculpt *sd, SculptSessio
 	cache->previous_vertex_rotation = 0;
 	cache->init_dir_set = false;
 
-	cache->frontface = ((brush->flag & BRUSH_FRONTFACE) != 0) ||
-	                     BKE_sculpt_brush_frontface_only(brush);
-
 	sculpt_omp_start(sd, ss);
 }