Vertex Paint: projection options

This makes vertex paint match image painting more closely.

- Add falloff shape option sphere/circle
  where sphere uses a 3D radius around the cursor and
  circle uses a 2D radius (projected), like previous releases.
- Add normal angle option so you can control the falloff.
- Add Cull option, to paint onto faces pointing away.

Disabling normals, culling and using circle falloff
allows you to paint through the mesh.

9 files changed, 382 insertions, 163 deletions

diff --git a/source/blender/blenkernel/BKE_brush.h b/source/blender/blenkernel/BKE_brush.h
index dedb75a080a..c1e107e101a 100644
--- a/source/blender/blenkernel/BKE_brush.h
+++ b/source/blender/blenkernel/BKE_brush.h
@@ -70,7 +70,7 @@ void BKE_brush_randomize_texture_coords(struct UnifiedPaintSettings *ups, bool m
 /* brush curve */
 void BKE_brush_curve_preset(struct Brush *b, int preset);
 float BKE_brush_curve_strength_clamped(struct Brush *br, float p, const float len);
-float BKE_brush_curve_strength(struct Brush *br, float p, const float len);
+float BKE_brush_curve_strength(const struct Brush *br, float p, const float len);
 
 /* sampling */
 float BKE_brush_sample_tex_3D(
diff --git a/source/blender/blenkernel/BKE_paint.h b/source/blender/blenkernel/BKE_paint.h
index fe7461c810d..19f332f5f54 100644
--- a/source/blender/blenkernel/BKE_paint.h
+++ b/source/blender/blenkernel/BKE_paint.h
@@ -231,7 +231,7 @@ typedef struct SculptSession {
 			/* Keep track of how much each vertex has been painted (non-airbrush only). */
 			float *alpha_weight;
 
-			/* Needed to continuously re-apply over the same weights (VP_SPRAY disabled).
+			/* Needed to continuously re-apply over the same weights (VP_FLAG_SPRAY disabled).
 			 * Lazy initialize as needed (flag is set to 1 to tag it as uninitialized). */
 			struct MDeformVert *dvert_prev;
 		} wpaint;
diff --git a/source/blender/blenkernel/intern/brush.c b/source/blender/blenkernel/intern/brush.c
index 03b0710c8fc..0300dfe5891 100644
--- a/source/blender/blenkernel/intern/brush.c
+++ b/source/blender/blenkernel/intern/brush.c
@@ -966,7 +966,7 @@ void BKE_brush_randomize_texture_coords(UnifiedPaintSettings *ups, bool mask)
 }
 
 /* Uses the brush curve control to find a strength value */
-float BKE_brush_curve_strength(Brush *br, float p, const float len)
+float BKE_brush_curve_strength(const Brush *br, float p, const float len)
 {
 	float strength;
 
diff --git a/source/blender/blenloader/intern/versioning_270.c b/source/blender/blenloader/intern/versioning_270.c
index 8459e080f99..b374e49fc83 100644
--- a/source/blender/blenloader/intern/versioning_270.c
+++ b/source/blender/blenloader/intern/versioning_270.c
@@ -1699,6 +1699,20 @@ void blo_do_versions_270(FileData *fd, Library *UNUSED(lib), Main *main)
 				}
 			}
 		}
+
+		if (!DNA_struct_elem_find(fd->filesdna, "VPaint", "char", "falloff_shape")) {
+			for (Scene *scene = main->scene.first; scene; scene = scene->id.next) {
+				ToolSettings *ts = scene->toolsettings;
+				for (int i = 0; i < 2; i++) {
+					VPaint *vp = i ? ts->vpaint : ts->wpaint;
+					if (vp != NULL) {
+						/* remove all other flags */
+						vp->flag &= (VP_FLAG_SPRAY | VP_FLAG_VGROUP_RESTRICT);
+						vp->normal_angle = 80;
+					}
+				}
+			}
+		}
 	}
 }
 
diff --git a/source/blender/editors/sculpt_paint/paint_vertex.c b/source/blender/editors/sculpt_paint/paint_vertex.c
index 7b534e12f31..ea85ae70794 100644
--- a/source/blender/editors/sculpt_paint/paint_vertex.c
+++ b/source/blender/editors/sculpt_paint/paint_vertex.c
@@ -88,6 +88,66 @@ struct WPaintAverageAccum {
 	double value;
 };
 
+struct NormalAnglePrecalc {
+	bool do_mask_normal;
+	/* what angle to mask at */
+	float angle;
+	/* cos(angle), faster to compare */
+	float angle__cos;
+	float angle_inner;
+	float angle_inner__cos;
+	/* difference between angle and angle_inner, for easy access */
+	float angle_range;
+};
+
+
+static void view_angle_limits_init(
+        struct NormalAnglePrecalc *a, float angle, bool do_mask_normal)
+{
+	a->do_mask_normal = do_mask_normal;
+	if (do_mask_normal) {
+		a->angle_inner = angle;
+		a->angle = (a->angle_inner + 90.0f) * 0.5f;
+	}
+	else {
+		a->angle_inner = a->angle = angle;
+	}
+
+	a->angle_inner *=   (float)(M_PI_2 / 90);
+	a->angle *=         (float)(M_PI_2 / 90);
+	a->angle_range = a->angle - a->angle_inner;
+
+	if (a->angle_range <= 0.0f) {
+		a->do_mask_normal = false;  /* no need to do blending */
+	}
+
+	a->angle__cos       = cosf(a->angle);
+	a->angle_inner__cos = cosf(a->angle_inner);
+}
+
+static float view_angle_limits_apply_falloff(
+        const struct NormalAnglePrecalc *a, float angle_cos, float *mask_p)
+{
+	if (angle_cos <= a->angle__cos) {
+		/* outsize the normal limit */
+		return false;
+	}
+	else if (angle_cos < a->angle_inner__cos) {
+		*mask_p *= (a->angle - acosf(angle_cos)) / a->angle_range;
+		return true;
+	}
+	else {
+		return true;
+	}
+}
+
+static bool vwpaint_use_normal(const VPaint *vp)
+{
+	return ((vp->flag & VP_FLAG_PROJECT_BACKFACE) == 0) ||
+	       ((vp->flag & VP_FLAG_PROJECT_FLAT) == 0);
+}
+
+
 static void defweight_prev_restore_or_init(MDeformVert *dvert_prev, MDeformVert *dvert_curr, int index)
 {
 	MDeformVert *dv_curr = &dvert_curr[index];
@@ -185,7 +245,7 @@ static VPaint *new_vpaint(int wpaint)
 {
 	VPaint *vp = MEM_callocN(sizeof(VPaint), "VPaint");
 
-	vp->flag = (wpaint) ? 0 : VP_SPRAY;
+	vp->flag = (wpaint) ? 0 : VP_FLAG_SPRAY;
 	vp->paint.flags |= PAINT_SHOW_BRUSH;
 
 	return vp;
@@ -213,7 +273,7 @@ static uint vpaint_blend(
 	uint color_blend = ED_vpaint_blend_tool(tool, color_curr, color_paint, alpha_i);
 
 	/* if no spray, clip color adding with colorig & orig alpha */
-	if ((vp->flag & VP_SPRAY) == 0) {
+	if ((vp->flag & VP_FLAG_SPRAY) == 0) {
 		uint color_test, a;
 		char *cp, *ct, *co;
 
@@ -299,7 +359,7 @@ static float calc_vp_alpha_col_dl(
 	if (strength > 0.0f) {
 		float alpha = brush_alpha_pressure * strength;
 
-		if (vp->flag & VP_NORMALS) {
+		if ((vp->flag & VP_FLAG_PROJECT_FLAT) == 0) {
 			float dvec[3];
 
 			/* transpose ! */
@@ -670,7 +730,7 @@ static void do_weight_paint_vertex_single(
 		index_mirr = vgroup_mirr = -1;
 	}
 
-	if ((wp->flag & VP_SPRAY) == 0) {
+	if ((wp->flag & VP_FLAG_SPRAY) == 0) {
 		struct MDeformVert *dvert_prev = ob->sculpt->mode.wpaint.dvert_prev;
 		defweight_prev_restore_or_init(dvert_prev, me->dvert, index);
 		if (index_mirr != -1) {
@@ -678,7 +738,7 @@ static void do_weight_paint_vertex_single(
 		}
 	}
 
-	if (wp->flag & VP_ONLYVGROUP) {
+	if (wp->flag & VP_FLAG_VGROUP_RESTRICT) {
 		dw = defvert_find_index(dv, wpi->active.index);
 	}
 	else {
@@ -692,7 +752,7 @@ static void do_weight_paint_vertex_single(
 	/* get the mirror def vars */
 	if (index_mirr != -1) {
 		dv_mirr = &me->dvert[index_mirr];
-		if (wp->flag & VP_ONLYVGROUP) {
+		if (wp->flag & VP_FLAG_VGROUP_RESTRICT) {
 			dw_mirr = defvert_find_index(dv_mirr, vgroup_mirr);
 
 			if (dw_mirr == NULL) {
@@ -814,7 +874,7 @@ static void do_weight_paint_vertex_multi(
 		}
 	}
 
-	if ((wp->flag & VP_SPRAY) == 0) {
+	if ((wp->flag & VP_FLAG_SPRAY) == 0) {
 		struct MDeformVert *dvert_prev = ob->sculpt->mode.wpaint.dvert_prev;
 		defweight_prev_restore_or_init(dvert_prev, me->dvert, index);
 		if (index_mirr != -1) {
@@ -947,7 +1007,7 @@ static void vertex_paint_init_session_data(const ToolSettings *ts, Object *ob)
 
 	/* Create average brush arrays */
 	if (ob->mode == OB_MODE_VERTEX_PAINT) {
-		if ((ts->vpaint->flag & VP_SPRAY) == 0) {
+		if ((ts->vpaint->flag & VP_FLAG_SPRAY) == 0) {
 			if (ob->sculpt->mode.vpaint.previous_color == NULL) {
 				ob->sculpt->mode.vpaint.previous_color =
 				        MEM_callocN(me->totloop * sizeof(uint), __func__);
@@ -968,7 +1028,7 @@ static void vertex_paint_init_session_data(const ToolSettings *ts, Object *ob)
 		}
 	}
 	else if (ob->mode == OB_MODE_WEIGHT_PAINT) {
-		if ((ts->wpaint->flag & VP_SPRAY) == 0) {
+		if ((ts->wpaint->flag & VP_FLAG_SPRAY) == 0) {
 			if (ob->sculpt->mode.wpaint.alpha_weight == NULL) {
 				ob->sculpt->mode.wpaint.alpha_weight =
 				        MEM_callocN(me->totvert * sizeof(float), __func__);
@@ -1116,6 +1176,7 @@ void PAINT_OT_weight_paint_toggle(wmOperatorType *ot)
 
 struct WPaintData {
 	ViewContext vc;
+	struct NormalAnglePrecalc normal_angle_precalc;
 
 	struct WeightPaintGroupData active, mirror;
 
@@ -1138,12 +1199,12 @@ struct WPaintData {
 
 /* Initialize the stroke cache invariants from operator properties */
 static void vwpaint_update_cache_invariants(
-        bContext *C, VPaint *vd, SculptSession *ss, wmOperator *op, const float mouse[2])
+        bContext *C, VPaint *vp, SculptSession *ss, wmOperator *op, const float mouse[2])
 {
 	StrokeCache *cache;
 	Scene *scene = CTX_data_scene(C);
 	UnifiedPaintSettings *ups = &CTX_data_tool_settings(C)->unified_paint_settings;
-	Brush *brush = BKE_paint_brush(&vd->paint);
+	Brush *brush = BKE_paint_brush(&vp->paint);
 	ViewContext *vc = paint_stroke_view_context(op->customdata);
 	Object *ob = CTX_data_active_object(C);
 	float mat[3][3];
@@ -1195,12 +1256,12 @@ static void vwpaint_update_cache_invariants(
 }
 
 /* Initialize the stroke cache variants from operator properties */
-static void vwpaint_update_cache_variants(bContext *C, VPaint *vd, Object *ob, PointerRNA *ptr)
+static void vwpaint_update_cache_variants(bContext *C, VPaint *vp, Object *ob, PointerRNA *ptr)
 {
 	Scene *scene = CTX_data_scene(C);
 	SculptSession *ss = ob->sculpt;
 	StrokeCache *cache = ss->cache;
-	Brush *brush = BKE_paint_brush(&vd->paint);
+	Brush *brush = BKE_paint_brush(&vp->paint);
 
 	/* This effects the actual brush radius, so things farther away
 	 * are compared with a larger radius and vise versa. */
@@ -1258,7 +1319,7 @@ static bool wpaint_stroke_test_start(bContext *C, wmOperator *op, const float mo
 	int defbase_tot, defbase_tot_sel;
 	bool *defbase_sel;
 	SculptSession *ss = ob->sculpt;
-	VPaint *vd = CTX_data_tool_settings(C)->wpaint;
+	VPaint *vp = CTX_data_tool_settings(C)->wpaint;
 
 	float mat[4][4], imat[4][4];
 
@@ -1313,6 +1374,7 @@ static bool wpaint_stroke_test_start(bContext *C, wmOperator *op, const float mo
 	wpd = MEM_callocN(sizeof(struct WPaintData), "WPaintData");
 	paint_stroke_set_mode_data(stroke, wpd);
 	view3d_set_viewcontext(C, &wpd->vc);
+	view_angle_limits_init(&wpd->normal_angle_precalc, vp->normal_angle, (vp->flag & VP_FLAG_PROJECT_FLAT) == 0);
 
 	wpd->active.index = vgroup_index.active;
 	wpd->mirror.index = vgroup_index.mirror;
@@ -1369,7 +1431,7 @@ static bool wpaint_stroke_test_start(bContext *C, wmOperator *op, const float mo
 
 	/* If not previously created, create vertex/weight paint mode session data */
 	vertex_paint_init_session(scene, ob);
-	vwpaint_update_cache_invariants(C, vd, ss, op, mouse);
+	vwpaint_update_cache_invariants(C, vp, ss, op, mouse);
 	vertex_paint_init_session_data(ts, ob);
 
 	if (ob->sculpt->mode.wpaint.dvert_prev != NULL) {
@@ -1391,7 +1453,7 @@ static float dot_vf3vs3(const float brushNormal[3], const short vertexNormal[3])
 }
 
 static void get_brush_alpha_data(
-        Scene *scene, SculptSession *ss, Brush *brush,
+        const Scene *scene, const SculptSession *ss, const Brush *brush,
         float *r_brush_size_pressure, float *r_brush_alpha_value, float *r_brush_alpha_pressure)
 {
 	*r_brush_size_pressure =
@@ -1417,6 +1479,22 @@ static float wpaint_get_active_weight(const MDeformVert *dv, const WeightPaintIn
 	}
 }
 
+static SculptBrushTestFn sculpt_brush_test_init_with_falloff_shape(
+        SculptSession *ss, SculptBrushTest *test, char falloff_shape)
+{
+	sculpt_brush_test_init(ss, test);
+	SculptBrushTestFn sculpt_brush_test_sq_fn;
+	if (falloff_shape == VP_FALLOFF_SHAPE_SPHERE) {
+		sculpt_brush_test_sq_fn = sculpt_brush_test_sphere_sq;
+	}
+	else {
+		/* VP_FALLOFF_SHAPE_TUBE */
+		plane_from_point_normal_v3(test->plane, test->location, ss->cache->view_normal);
+		sculpt_brush_test_sq_fn = sculpt_brush_test_circle_sq;
+	}
+	return sculpt_brush_test_sq_fn;
+}
+
 static void do_wpaint_brush_blur_task_cb_ex(
         void *userdata, void *UNUSED(userdata_chunk), const int n, const int UNUSED(thread_id))
 {
@@ -1425,25 +1503,26 @@ static void do_wpaint_brush_blur_task_cb_ex(
 	CCGDerivedMesh *ccgdm = BKE_pbvh_get_ccgdm(ss->pbvh);
 	const struct SculptVertexPaintGeomMap *gmap = &ss->mode.wpaint.gmap;
 
-	Brush *brush = data->brush;
-	StrokeCache *cache = ss->cache;
+	const Brush *brush = data->brush;
+	const StrokeCache *cache = ss->cache;
 	Scene *scene = CTX_data_scene(data->C);
 
-	const float brush_strength = cache->bstrength;
 	float brush_size_pressure, brush_alpha_value, brush_alpha_pressure;
 	get_brush_alpha_data(scene, ss, brush, &brush_size_pressure, &brush_alpha_value, &brush_alpha_pressure);
+	const bool use_normal = vwpaint_use_normal(data->vp);
 	const bool use_face_sel = (data->me->editflag & ME_EDIT_PAINT_FACE_SEL) != 0;
 	const bool use_vert_sel = (data->me->editflag & ME_EDIT_PAINT_VERT_SEL) != 0;
 
 	SculptBrushTest test;
-	sculpt_brush_test_init(ss, &test);
+	SculptBrushTestFn sculpt_brush_test_sq_fn =
+	        sculpt_brush_test_init_with_falloff_shape(ss, &test, data->vp->falloff_shape);
 
 	/* For each vertex */
 	PBVHVertexIter vd;
 	BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
 	{
 		/* Test to see if the vertex coordinates are within the spherical brush region. */
-		if (sculpt_brush_test_sphere_sq(&test, vd.co)) {
+		if (sculpt_brush_test_sq_fn(&test, vd.co)) {
 			/* For grid based pbvh, take the vert whose loop coopresponds to the current grid.
 			 * Otherwise, take the current vert. */
 			const int v_index = ccgdm ? data->me->mloop[vd.grid_indices[vd.g]].v : vd.vert_indices[vd.i];
@@ -1469,16 +1548,19 @@ static void do_wpaint_brush_blur_task_cb_ex(
 
 				/* Apply the weight to the vertex. */
 				if (total_hit_loops != 0) {
-					const float view_dot = (vd.no) ? dot_vf3vs3(cache->sculpt_normal_symm, vd.no) : 1.0;
-					if (view_dot > 0.0f) {
+					float brush_strength = cache->bstrength;
+					const float angle_cos = (use_normal && vd.no) ?
+					        dot_vf3vs3(ss->cache->sculpt_normal_symm, vd.no) : 1.0f;
+					if (((data->vp->flag & VP_FLAG_PROJECT_BACKFACE) ||
+					     (angle_cos > 0.0f)) &&
+					    ((data->vp->flag & VP_FLAG_PROJECT_FLAT) ||
+					     view_angle_limits_apply_falloff(&data->wpd->normal_angle_precalc, angle_cos, &brush_strength)))
+					{
 						const float brush_fade = BKE_brush_curve_strength(brush, sqrtf(test.dist), cache->radius);
 						float final_alpha =
 						        brush_fade * brush_strength *
 						        grid_alpha * brush_alpha_pressure;
 
-						if (data->vp->flag & VP_NORMALS) {
-							final_alpha *= view_dot;
-						}
 						if (brush->flag & BRUSH_ACCUMULATE) {
 							float mask_accum = ss->mode.wpaint.previous_accum[v_index];
 							final_alpha = min_ff(final_alpha + mask_accum, brush_strength);
@@ -1506,12 +1588,12 @@ static void do_wpaint_brush_smear_task_cb_ex(
 	CCGDerivedMesh *ccgdm = BKE_pbvh_get_ccgdm(ss->pbvh);
 	const struct SculptVertexPaintGeomMap *gmap = &ss->mode.wpaint.gmap;
 
-	Brush *brush = data->brush;
-	Scene *scene = CTX_data_scene(data->C);
-	StrokeCache *cache = ss->cache;
-	const float brush_strength = cache->bstrength;
+	const Brush *brush = data->brush;
+	const Scene *scene = CTX_data_scene(data->C);
+	const StrokeCache *cache = ss->cache;
 	float brush_size_pressure, brush_alpha_value, brush_alpha_pressure;
 	get_brush_alpha_data(scene, ss, brush, &brush_size_pressure, &brush_alpha_value, &brush_alpha_pressure);
+	const bool use_normal = vwpaint_use_normal(data->vp);
 	const bool use_face_sel = (data->me->editflag & ME_EDIT_PAINT_FACE_SEL) != 0;
 	const bool use_vert_sel = (data->me->editflag & ME_EDIT_PAINT_VERT_SEL) != 0;
 	float brush_dir[3];
@@ -1522,26 +1604,32 @@ static void do_wpaint_brush_smear_task_cb_ex(
 	if (normalize_v3(brush_dir) != 0.0f) {
 
 		SculptBrushTest test;
-		sculpt_brush_test_init(ss, &test);
+		SculptBrushTestFn sculpt_brush_test_sq_fn =
+		        sculpt_brush_test_init_with_falloff_shape(ss, &test, data->vp->falloff_shape);
 
 		/* For each vertex */
 		PBVHVertexIter vd;
 		BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
 		{
 			/* Test to see if the vertex coordinates are within the spherical brush region. */
-			if (sculpt_brush_test_sphere_fast(&test, vd.co)) {
-				const float view_dot = (vd.no) ? dot_vf3vs3(cache->sculpt_normal_symm, vd.no) : 1.0;
-				if (view_dot > 0.0f) {
-					bool do_color = false;
-
-					/* For grid based pbvh, take the vert whose loop cooresponds to the current grid.
-					 * Otherwise, take the current vert. */
-					const int v_index = ccgdm ? data->me->mloop[vd.grid_indices[vd.g]].v : vd.vert_indices[vd.i];
-					const float grid_alpha = ccgdm ? 1.0f / vd.gridsize : 1.0f;
-					const MVert *mv_curr = &data->me->mvert[v_index];
-
-					/* If the vertex is selected */
-					if (!(use_face_sel || use_vert_sel) || mv_curr->flag & SELECT) {
+			if (sculpt_brush_test_sq_fn(&test, vd.co)) {
+				/* For grid based pbvh, take the vert whose loop cooresponds to the current grid.
+				 * Otherwise, take the current vert. */
+				const int v_index = ccgdm ? data->me->mloop[vd.grid_indices[vd.g]].v : vd.vert_indices[vd.i];
+				const float grid_alpha = ccgdm ? 1.0f / vd.gridsize : 1.0f;
+				const MVert *mv_curr = &data->me->mvert[v_index];
+
+				/* If the vertex is selected */
+				if (!(use_face_sel || use_vert_sel) || mv_curr->flag & SELECT) {
+					float brush_strength = cache->bstrength;
+					const float angle_cos = (use_normal && vd.no) ?
+					        dot_vf3vs3(ss->cache->sculpt_normal_symm, vd.no) : 1.0f;
+					if (((data->vp->flag & VP_FLAG_PROJECT_BACKFACE) ||
+					     (angle_cos > 0.0f)) &&
+					    ((data->vp->flag & VP_FLAG_PROJECT_FLAT) ||
+					     view_angle_limits_apply_falloff(&data->wpd->normal_angle_precalc, angle_cos, &brush_strength)))
+					{
+						bool do_color = false;
 						/* Minimum dot product between brush direction and current
 						 * to neighbor direction is 0.0, meaning orthogonal. */
 						float stroke_dot_max = 0.0f;
@@ -1578,14 +1666,10 @@ static void do_wpaint_brush_smear_task_cb_ex(
 						}
 						/* Apply weight to vertex */
 						if (do_color) {
-							const float brush_fade = BKE_brush_curve_strength(brush, test.dist, cache->radius);
+							const float brush_fade = BKE_brush_curve_strength(brush, 0.0f, cache->radius);
 							float final_alpha =
 							        brush_fade * brush_strength *
 							        grid_alpha * brush_alpha_pressure;
-
-							if (data->vp->flag & VP_NORMALS) {
-								final_alpha *= view_dot;
-							}
 							do_weight_paint_vertex(
 							        data->vp, data->ob, data->wpi,
 							        v_index, final_alpha, (float)weight_final);
@@ -1604,26 +1688,27 @@ static void do_wpaint_brush_draw_task_cb_ex(
 	SculptThreadedTaskData *data = userdata;
 	SculptSession *ss = data->ob->sculpt;
 	CCGDerivedMesh *ccgdm = BKE_pbvh_get_ccgdm(ss->pbvh);
-	Scene *scene = CTX_data_scene(data->C);
+	const Scene *scene = CTX_data_scene(data->C);
 
-	Brush *brush = data->brush;
-	StrokeCache *cache = ss->cache;
-	const float brush_strength = cache->bstrength;
+	const Brush *brush = data->brush;
+	const StrokeCache *cache = ss->cache;
 	const float paintweight = BKE_brush_weight_get(scene, brush);
 	float brush_size_pressure, brush_alpha_value, brush_alpha_pressure;
 	get_brush_alpha_data(scene, ss, brush, &brush_size_pressure, &brush_alpha_value, &brush_alpha_pressure);
+	const bool use_normal = vwpaint_use_normal(data->vp);
 	const bool use_face_sel = (data->me->editflag & ME_EDIT_PAINT_FACE_SEL) != 0;
 	const bool use_vert_sel = (data->me->editflag & ME_EDIT_PAINT_VERT_SEL) != 0;
 
 	SculptBrushTest test;
-	sculpt_brush_test_init(ss, &test);
+	SculptBrushTestFn sculpt_brush_test_sq_fn =
+	        sculpt_brush_test_init_with_falloff_shape(ss, &test, data->vp->falloff_shape);
 
 	/* For each vertex */
 	PBVHVertexIter vd;
 	BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
 	{
 		/* Test to see if the vertex coordinates are within the spherical brush region. */
-		if (sculpt_brush_test_sphere_sq(&test, vd.co)) {
+		if (sculpt_brush_test_sq_fn(&test, vd.co)) {
 			/* Note: grids are 1:1 with corners (aka loops).
 			 * For multires, take the vert whose loop cooresponds to the current grid.
 			 * Otherwise, take the current vert. */
@@ -1633,14 +1718,16 @@ static void do_wpaint_brush_draw_task_cb_ex(
 			const char v_flag = data->me->mvert[v_index].flag;
 			/* If the vertex is selected */
 			if (!(use_face_sel || use_vert_sel) || v_flag & SELECT) {
-				const float view_dot = (vd.no) ? dot_vf3vs3(cache->sculpt_normal_symm, vd.no) : 1.0;
-				if (view_dot > 0.0f) {
+				float brush_strength = cache->bstrength;
+				const float angle_cos = (use_normal && vd.no) ?
+				        dot_vf3vs3(ss->cache->sculpt_normal_symm, vd.no) : 1.0f;
+				if (((data->vp->flag & VP_FLAG_PROJECT_BACKFACE) ||
+				     (angle_cos > 0.0f)) &&
+				    ((data->vp->flag & VP_FLAG_PROJECT_FLAT) ||
+				     view_angle_limits_apply_falloff(&data->wpd->normal_angle_precalc, angle_cos, &brush_strength)))
+				{
 					const float brush_fade = BKE_brush_curve_strength(brush, sqrtf(test.dist), cache->radius);
 					float final_alpha = brush_fade * brush_strength * grid_alpha * brush_alpha_pressure;
-
-					if (data->vp->flag & VP_NORMALS) {
-						final_alpha *= view_dot;
-					}
 					if (brush->flag & BRUSH_ACCUMULATE) {
 						float mask_accum = ss->mode.wpaint.previous_accum[v_index];
 						final_alpha = min_ff(final_alpha + mask_accum, brush_strength);
@@ -1648,7 +1735,7 @@ static void do_wpaint_brush_draw_task_cb_ex(
 					}
 
 					/* Non-spray logic. */
-					if ((data->vp->flag & VP_SPRAY) == 0) {
+					if ((data->vp->flag & VP_FLAG_SPRAY) == 0) {
 						/* Only paint if we have greater alpha. */
 						if (ss->mode.wpaint.alpha_weight[v_index] < final_alpha) {
 							ss->mode.wpaint.alpha_weight[v_index] = final_alpha;
@@ -1676,6 +1763,7 @@ static void do_wpaint_brush_calc_average_weight_cb_ex(
 	StrokeCache *cache = ss->cache;
 	CCGDerivedMesh *ccgdm = BKE_pbvh_get_ccgdm(ss->pbvh);
 
+	const bool use_normal = vwpaint_use_normal(data->vp);
 	const bool use_face_sel = (data->me->editflag & ME_EDIT_PAINT_FACE_SEL) != 0;
 	const bool use_vert_sel = (data->me->editflag & ME_EDIT_PAINT_VERT_SEL) != 0;
 
@@ -1684,16 +1772,18 @@ static void do_wpaint_brush_calc_average_weight_cb_ex(
 	accum->value = 0.0;
 
 	SculptBrushTest test;
-	sculpt_brush_test_init(ss, &test);
+	SculptBrushTestFn sculpt_brush_test_sq_fn =
+	        sculpt_brush_test_init_with_falloff_shape(ss, &test, data->vp->falloff_shape);
 
 	/* For each vertex */
 	PBVHVertexIter vd;
 	BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
 	{
 		/* Test to see if the vertex coordinates are within the spherical brush region. */
-		if (sculpt_brush_test_sphere_sq(&test, vd.co)) {
-			const float view_dot = (vd.no) ? dot_vf3vs3(cache->sculpt_normal_symm, vd.no) : 1.0;
-			if (view_dot > 0.0 && BKE_brush_curve_strength(data->brush, sqrtf(test.dist), cache->radius) > 0.0) {
+		if (sculpt_brush_test_sq_fn(&test, vd.co)) {
+			const float angle_cos = (use_normal && vd.no) ?
+			        dot_vf3vs3(ss->cache->sculpt_normal_symm, vd.no) : 1.0f;
+			if (angle_cos > 0.0 && BKE_brush_curve_strength(data->brush, sqrtf(test.dist), cache->radius) > 0.0) {
 				const int v_index = ccgdm ? data->me->mloop[vd.grid_indices[vd.g]].v : vd.vert_indices[vd.i];
 				// const float grid_alpha = ccgdm ? 1.0f / vd.gridsize : 1.0f;
 				const char v_flag = data->me->mvert[v_index].flag;
@@ -1776,6 +1866,50 @@ static void wpaint_paint_leaves(
 	}
 }
 
+static PBVHNode **vwpaint_pbvh_gather_generic(
+        Object *ob, VPaint *wp, Sculpt *sd, Brush *brush, int *r_totnode)
+{
+	SculptSession *ss = ob->sculpt;
+	const bool use_normal = vwpaint_use_normal(wp);
+	PBVHNode **nodes = NULL;
+
+	/* Build a list of all nodes that are potentially within the brush's area of influence */
+	if (wp->falloff_shape == VP_FALLOFF_SHAPE_SPHERE) {
+		SculptSearchSphereData data = {
+			.ss = ss,
+			.sd = sd,
+			.radius_squared = ss->cache->radius_squared,
+			.original = true,
+		};
+		BKE_pbvh_search_gather(ss->pbvh, sculpt_search_sphere_cb, &data, &nodes, r_totnode);
+		if (use_normal) {
+			sculpt_pbvh_calc_area_normal(brush, ob, nodes, *r_totnode, true, ss->cache->sculpt_normal_symm);
+		}
+		else {
+			zero_v3(ss->cache->sculpt_normal_symm);
+		}
+	}
+	else {
+		struct DistRayAABB_Precalc dist_ray_to_aabb_precalc;
+		dist_squared_ray_to_aabb_precalc(&dist_ray_to_aabb_precalc, ss->cache->location, ss->cache->view_normal);
+		SculptSearchCircleData data = {
+			.ss = ss,
+			.sd = sd,
+			.radius_squared = ss->cache->radius_squared,
+			.original = true,
+			.dist_ray_to_aabb_precalc = &dist_ray_to_aabb_precalc,
+		};
+		BKE_pbvh_search_gather(ss->pbvh, sculpt_search_circle_cb, &data, &nodes, r_totnode);
+		if (use_normal) {
+			copy_v3_v3(ss->cache->sculpt_normal_symm, ss->cache->view_normal);
+		}
+		else {
+			zero_v3(ss->cache->sculpt_normal_symm);
+		}
+	}
+	return nodes;
+}
+
 static void wpaint_do_paint(
         bContext *C, Object *ob, VPaint *wp, Sculpt *sd, struct WPaintData *wpd, WeightPaintInfo *wpi,
         Mesh *me, Brush *brush, const char symm, const int axis, const int i, const float angle)
@@ -1784,19 +1918,9 @@ static void wpaint_do_paint(
 	ss->cache->radial_symmetry_pass = i;
 	sculpt_cache_calc_brushdata_symm(ss->cache, symm, axis, angle);
 
-	SculptSearchSphereData data;
-	PBVHNode **nodes = NULL;
 	int totnode;
+	PBVHNode **nodes = vwpaint_pbvh_gather_generic(ob, wp, sd, brush, &totnode);
 
-
-	/* Build a list of all nodes that are potentially within the brush's area of influence */
-	data.ss = ss;
-	data.sd = sd;
-	data.radius_squared = ss->cache->radius_squared;
-	data.original = true;
-	BKE_pbvh_search_gather(ss->pbvh, sculpt_search_sphere_cb, &data, &nodes, &totnode);
-
-	sculpt_pbvh_calc_area_normal(brush, ob, nodes, totnode, true, ss->cache->sculpt_normal_symm);
 	wpaint_paint_leaves(C, ob, sd, wp, wpd, wpi, me, nodes, totnode);
 
 	if (nodes)
@@ -2179,6 +2303,8 @@ typedef struct PolyFaceMap {
 
 struct VPaintData {
 	ViewContext vc;
+	struct NormalAnglePrecalc normal_angle_precalc;
+
 	uint paintcol;
 
 	struct VertProjHandle *vp_handle;
@@ -2223,6 +2349,7 @@ static bool vpaint_stroke_test_start(bContext *C, struct wmOperator *op, const f
 	vpd = MEM_callocN(sizeof(*vpd), "VPaintData");
 	paint_stroke_set_mode_data(stroke, vpd);
 	view3d_set_viewcontext(C, &vpd->vc);
+	view_angle_limits_init(&vpd->normal_angle_precalc, vp->normal_angle, (vp->flag & VP_FLAG_PROJECT_FLAT) == 0);
 
 	vpd->paintcol = vpaint_get_current_col(scene, vp);
 
@@ -2287,16 +2414,17 @@ static void do_vpaint_brush_calc_average_color_cb_ex(
 	memset(accum->value, 0, sizeof(accum->value));
 
 	SculptBrushTest test;
-	sculpt_brush_test_init(ss, &test);
+	SculptBrushTestFn sculpt_brush_test_sq_fn =
+	        sculpt_brush_test_init_with_falloff_shape(ss, &test, data->vp->falloff_shape);
 
 	/* For each vertex */
 	PBVHVertexIter vd;
 	BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
 	{
 		/* Test to see if the vertex coordinates are within the spherical brush region. */
-		if (sculpt_brush_test_sphere_fast(&test, vd.co)) {
+		if (sculpt_brush_test_sq_fn(&test, vd.co)) {
 			const int v_index = ccgdm ? data->me->mloop[vd.grid_indices[vd.g]].v : vd.vert_indices[vd.i];
-			if (BKE_brush_curve_strength(data->brush, test.dist, cache->radius) > 0.0) {
+			if (BKE_brush_curve_strength(data->brush, 0.0, cache->radius) > 0.0) {
 				/* If the vertex is selected for painting. */
 				const MVert *mv = &data->me->mvert[v_index];
 				if (!use_vert_sel || mv->flag & SELECT) {
@@ -2344,25 +2472,26 @@ static void do_vpaint_brush_draw_task_cb_ex(
 	CCGDerivedMesh *ccgdm = BKE_pbvh_get_ccgdm(ss->pbvh);
 	const struct SculptVertexPaintGeomMap *gmap = &ss->mode.vpaint.gmap;
 
-	Brush *brush = data->brush;
-	StrokeCache *cache = ss->cache;
-	const float brush_strength = cache->bstrength;
+	const Brush *brush = data->brush;
+	const StrokeCache *cache = ss->cache;
 	uint *lcol = data->lcol;
-	Scene *scene = CTX_data_scene(data->C);
+	const Scene *scene = CTX_data_scene(data->C);
 	float brush_size_pressure, brush_alpha_value, brush_alpha_pressure;
 	get_brush_alpha_data(scene, ss, brush, &brush_size_pressure, &brush_alpha_value, &brush_alpha_pressure);
+	const bool use_normal = vwpaint_use_normal(data->vp);
 	const bool use_vert_sel = (data->me->editflag & (ME_EDIT_PAINT_FACE_SEL | ME_EDIT_PAINT_VERT_SEL)) != 0;
 	const bool use_face_sel = (data->me->editflag & ME_EDIT_PAINT_FACE_SEL) != 0;
 
 	SculptBrushTest test;
-	sculpt_brush_test_init(ss, &test);
+	SculptBrushTestFn sculpt_brush_test_sq_fn =
+	        sculpt_brush_test_init_with_falloff_shape(ss, &test, data->vp->falloff_shape);
 
 	/* For each vertex */
 	PBVHVertexIter vd;
 	BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
 	{
 		/* Test to see if the vertex coordinates are within the spherical brush region. */
-		if (sculpt_brush_test_sphere_sq(&test, vd.co)) {
+		if (sculpt_brush_test_sq_fn(&test, vd.co)) {
 			/* Note: Grids are 1:1 with corners (aka loops).
 			 * For grid based pbvh, take the vert whose loop cooresponds to the current grid.
 			 * Otherwise, take the current vert. */
@@ -2374,8 +2503,14 @@ static void do_vpaint_brush_draw_task_cb_ex(
 			if (!use_vert_sel || mv->flag & SELECT) {
 				/* Calc the dot prod. between ray norm on surf and current vert
 				 * (ie splash prevention factor), and only paint front facing verts. */
-				const float view_dot = (vd.no) ? dot_vf3vs3(cache->sculpt_normal_symm, vd.no) : 1.0;
-				if (view_dot > 0.0f) {
+				float brush_strength = cache->bstrength;
+				const float angle_cos = (use_normal && vd.no) ?
+				        dot_vf3vs3(ss->cache->sculpt_normal_symm, vd.no) : 1.0f;
+				if (((data->vp->flag & VP_FLAG_PROJECT_BACKFACE) ||
+				     (angle_cos > 0.0f)) &&
+				    ((data->vp->flag & VP_FLAG_PROJECT_FLAT) ||
+				     view_angle_limits_apply_falloff(&data->vpd->normal_angle_precalc, angle_cos, &brush_strength)))
+				{
 					const float brush_fade = BKE_brush_curve_strength(brush, sqrtf(test.dist), cache->radius);
 					uint color_final = data->vpd->paintcol;
 
@@ -2404,10 +2539,6 @@ static void do_vpaint_brush_draw_task_cb_ex(
 							float final_alpha =
 							        255 * brush_fade * brush_strength *
 							        tex_alpha * brush_alpha_pressure * grid_alpha;
-
-							if (data->vp->flag & VP_NORMALS) {
-								final_alpha *= view_dot;
-							}
 							if (brush->flag & BRUSH_ACCUMULATE) {
 								float mask_accum = ss->mode.vpaint.previous_accum[l_index];
 								final_alpha = min_ff(final_alpha + mask_accum, 255.0f * brush_strength);
@@ -2436,36 +2567,43 @@ static void do_vpaint_brush_blur_task_cb_ex(
 
 	Scene *scene = CTX_data_scene(data->C);
 	const struct SculptVertexPaintGeomMap *gmap = &ss->mode.vpaint.gmap;
-	Brush *brush = data->brush;
-	StrokeCache *cache = ss->cache;
-	const float brush_strength = cache->bstrength;
+	const Brush *brush = data->brush;
+	const StrokeCache *cache = ss->cache;
 	uint *lcol = data->lcol;
 	float brush_size_pressure, brush_alpha_value, brush_alpha_pressure;
 	get_brush_alpha_data(scene, ss, brush, &brush_size_pressure, &brush_alpha_value, &brush_alpha_pressure);
+	const bool use_normal = vwpaint_use_normal(data->vp);
 	const bool use_vert_sel = (data->me->editflag & (ME_EDIT_PAINT_FACE_SEL | ME_EDIT_PAINT_VERT_SEL)) != 0;
 	const bool use_face_sel = (data->me->editflag & ME_EDIT_PAINT_FACE_SEL) != 0;
 
 	SculptBrushTest test;
-	sculpt_brush_test_init(ss, &test);
+	SculptBrushTestFn sculpt_brush_test_sq_fn =
+	        sculpt_brush_test_init_with_falloff_shape(ss, &test, data->vp->falloff_shape);
 
 	/* For each vertex */
 	PBVHVertexIter vd;
 	BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
 	{
 		/* Test to see if the vertex coordinates are within the spherical brush region. */
-		if (sculpt_brush_test_sphere_sq(&test, vd.co)) {
+		if (sculpt_brush_test_sq_fn(&test, vd.co)) {
 			/* For grid based pbvh, take the vert whose loop cooresponds to the current grid.
 			 * Otherwise, take the current vert. */
 			const int v_index = ccgdm ? data->me->mloop[vd.grid_indices[vd.g]].v : vd.vert_indices[vd.i];
 			const float grid_alpha = ccgdm ? 1.0f / vd.gridsize : 1.0f;
 			const MVert *mv = &data->me->mvert[v_index];
 
-			const float view_dot = (vd.no) ? dot_vf3vs3(cache->sculpt_normal_symm, vd.no) : 1.0;
-			if (view_dot > 0.0f) {
-				const float brush_fade = BKE_brush_curve_strength(brush, sqrtf(test.dist), cache->radius);
+			/* If the vertex is selected for painting. */
+			if (!use_vert_sel || mv->flag & SELECT) {
+				float brush_strength = cache->bstrength;
+				const float angle_cos = (use_normal && vd.no) ?
+				        dot_vf3vs3(ss->cache->sculpt_normal_symm, vd.no) : 1.0f;
+				if (((data->vp->flag & VP_FLAG_PROJECT_BACKFACE) ||
+				     (angle_cos > 0.0f)) &&
+				    ((data->vp->flag & VP_FLAG_PROJECT_FLAT) ||
+				     view_angle_limits_apply_falloff(&data->vpd->normal_angle_precalc, angle_cos, &brush_strength)))
+				{
+					const float brush_fade = BKE_brush_curve_strength(brush, sqrtf(test.dist), cache->radius);
 
-				/* If the vertex is selected for painting. */
-				if (!use_vert_sel || mv->flag & SELECT) {
 					/* Get the average poly color */
 					uint color_final = 0;
 					int total_hit_loops = 0;
@@ -2512,10 +2650,6 @@ static void do_vpaint_brush_blur_task_cb_ex(
 								float final_alpha =
 								        255 * brush_fade * brush_strength *
 								        brush_alpha_pressure * grid_alpha;
-
-								if (data->vp->flag & VP_NORMALS) {
-									final_alpha *= view_dot;
-								}
 								/* Mix the new color with the original
 								 * based on the brush strength and the curve. */
 								lcol[l_index] = vpaint_blend(
@@ -2540,13 +2674,13 @@ static void do_vpaint_brush_smear_task_cb_ex(
 
 	Scene *scene = CTX_data_scene(data->C);
 	const struct SculptVertexPaintGeomMap *gmap = &ss->mode.vpaint.gmap;
-	Brush *brush = data->brush;
-	StrokeCache *cache = ss->cache;
-	const float brush_strength = cache->bstrength;
+	const Brush *brush = data->brush;
+	const StrokeCache *cache = ss->cache;
 	uint *lcol = data->lcol;
 	float brush_size_pressure, brush_alpha_value, brush_alpha_pressure;
 	get_brush_alpha_data(scene, ss, brush, &brush_size_pressure, &brush_alpha_value, &brush_alpha_pressure);
 	float brush_dir[3];
+	const bool use_normal = vwpaint_use_normal(data->vp);
 	const bool use_vert_sel = (data->me->editflag & (ME_EDIT_PAINT_FACE_SEL | ME_EDIT_PAINT_VERT_SEL)) != 0;
 	const bool use_face_sel = (data->me->editflag & ME_EDIT_PAINT_FACE_SEL) != 0;
 
@@ -2556,14 +2690,15 @@ static void do_vpaint_brush_smear_task_cb_ex(
 	if (normalize_v3(brush_dir) != 0.0f) {
 
 		SculptBrushTest test;
-		sculpt_brush_test_init(ss, &test);
+		SculptBrushTestFn sculpt_brush_test_sq_fn =
+		        sculpt_brush_test_init_with_falloff_shape(ss, &test, data->vp->falloff_shape);
 
 		/* For each vertex */
 		PBVHVertexIter vd;
 		BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
 		{
 			/* Test to see if the vertex coordinates are within the spherical brush region. */
-			if (sculpt_brush_test_sphere_sq(&test, vd.co)) {
+			if (sculpt_brush_test_sq_fn(&test, vd.co)) {
 				/* For grid based pbvh, take the vert whose loop cooresponds to the current grid.
 				 * Otherwise, take the current vert. */
 				const int v_index = ccgdm ? data->me->mloop[vd.grid_indices[vd.g]].v : vd.vert_indices[vd.i];
@@ -2574,8 +2709,14 @@ static void do_vpaint_brush_smear_task_cb_ex(
 				if (!use_vert_sel || mv_curr->flag & SELECT) {
 					/* Calc the dot prod. between ray norm on surf and current vert
 					 * (ie splash prevention factor), and only paint front facing verts. */
-					const float view_dot = (vd.no) ? dot_vf3vs3(cache->sculpt_normal_symm, vd.no) : 1.0;
-					if (view_dot > 0.0f) {
+					float brush_strength = cache->bstrength;
+					const float angle_cos = (use_normal && vd.no) ?
+					        dot_vf3vs3(ss->cache->sculpt_normal_symm, vd.no) : 1.0f;
+					if (((data->vp->flag & VP_FLAG_PROJECT_BACKFACE) ||
+					     (angle_cos > 0.0f)) &&
+					    ((data->vp->flag & VP_FLAG_PROJECT_FLAT) ||
+					     view_angle_limits_apply_falloff(&data->vpd->normal_angle_precalc, angle_cos, &brush_strength)))
+					{
 						const float brush_fade = BKE_brush_curve_strength(brush, sqrtf(test.dist), cache->radius);
 
 						bool do_color = false;
@@ -2636,10 +2777,6 @@ static void do_vpaint_brush_smear_task_cb_ex(
 									float final_alpha =
 									        255 * brush_fade * brush_strength *
 									        brush_alpha_pressure * grid_alpha;
-
-									if (data->vp->flag & VP_NORMALS) {
-										final_alpha *= view_dot;
-									}
 									/* Mix the new color with the original
 									 * based on the brush strength and the curve. */
 									lcol[l_index] = vpaint_blend(
@@ -2721,27 +2858,18 @@ static void vpaint_paint_leaves(
 }
 
 static void vpaint_do_paint(
-        bContext *C, Sculpt *sd, VPaint *vd, struct VPaintData *vpd,
+        bContext *C, Sculpt *sd, VPaint *vp, struct VPaintData *vpd,
         Object *ob, Mesh *me, Brush *brush, const char symm, const int axis, const int i, const float angle)
 {
 	SculptSession *ss = ob->sculpt;
 	ss->cache->radial_symmetry_pass = i;
 	sculpt_cache_calc_brushdata_symm(ss->cache, symm, axis, angle);
-	SculptSearchSphereData data;
-	PBVHNode **nodes = NULL;
-	int totnode;
-
-	/* Build a list of all nodes that are potentially within the brush's area of influence */
-	data.ss = ss;
-	data.sd = sd;
-	data.radius_squared = ss->cache->radius_squared;
-	data.original = true;
-	BKE_pbvh_search_gather(ss->pbvh, sculpt_search_sphere_cb, &data, &nodes, &totnode);
 
-	sculpt_pbvh_calc_area_normal(brush, ob, nodes, totnode, true, ss->cache->sculpt_normal_symm);
+	int totnode;
+	PBVHNode **nodes = vwpaint_pbvh_gather_generic(ob, vp, sd, brush, &totnode);
 
 	/* Paint those leaves. */
-	vpaint_paint_leaves(C, sd, vd, vpd, ob, me, nodes, totnode);
+	vpaint_paint_leaves(C, sd, vp, vpd, ob, me, nodes, totnode);
 
 	if (nodes) {
 		MEM_freeN(nodes);
@@ -2749,31 +2877,31 @@ static void vpaint_do_paint(
 }
 
 static void vpaint_do_radial_symmetry(
-        bContext *C, Sculpt *sd, VPaint *vd, struct VPaintData *vpd, Object *ob, Mesh *me,
+        bContext *C, Sculpt *sd, VPaint *vp, struct VPaintData *vpd, Object *ob, Mesh *me,
         Brush *brush, const char symm, const int axis)
 {
-	for (int i = 1; i < vd->radial_symm[axis - 'X']; i++) {
-		const float angle = (2.0 * M_PI) * i / vd->radial_symm[axis - 'X'];
-		vpaint_do_paint(C, sd, vd, vpd, ob, me, brush, symm, axis, i, angle);
+	for (int i = 1; i < vp->radial_symm[axis - 'X']; i++) {
+		const float angle = (2.0 * M_PI) * i / vp->radial_symm[axis - 'X'];
+		vpaint_do_paint(C, sd, vp, vpd, ob, me, brush, symm, axis, i, angle);
 	}
 }
 
 /* near duplicate of: sculpt.c's, 'do_symmetrical_brush_actions' and 'wpaint_do_symmetrical_brush_actions'. */
 static void vpaint_do_symmetrical_brush_actions(
-        bContext *C, Sculpt *sd, VPaint *vd, struct VPaintData *vpd, Object *ob)
+        bContext *C, Sculpt *sd, VPaint *vp, struct VPaintData *vpd, Object *ob)
 {
-	Brush *brush = BKE_paint_brush(&vd->paint);
+	Brush *brush = BKE_paint_brush(&vp->paint);
 	Mesh *me = ob->data;
 	SculptSession *ss = ob->sculpt;
 	StrokeCache *cache = ss->cache;
-	const char symm = vd->paint.symmetry_flags & PAINT_SYMM_AXIS_ALL;
+	const char symm = vp->paint.symmetry_flags & PAINT_SYMM_AXIS_ALL;
 	int i = 0;
 
 	/* initial stroke */
-	vpaint_do_paint(C, sd, vd, vpd, ob, me, brush, i, 'X', 0, 0);
-	vpaint_do_radial_symmetry(C, sd, vd, vpd, ob, me, brush, i, 'X');
-	vpaint_do_radial_symmetry(C, sd, vd, vpd, ob, me, brush, i, 'Y');
-	vpaint_do_radial_symmetry(C, sd, vd, vpd, ob, me, brush, i, 'Z');
+	vpaint_do_paint(C, sd, vp, vpd, ob, me, brush, i, 'X', 0, 0);
+	vpaint_do_radial_symmetry(C, sd, vp, vpd, ob, me, brush, i, 'X');
+	vpaint_do_radial_symmetry(C, sd, vp, vpd, ob, me, brush, i, 'Y');
+	vpaint_do_radial_symmetry(C, sd, vp, vpd, ob, me, brush, i, 'Z');
 
 	cache->symmetry = symm;
 
@@ -2785,16 +2913,16 @@ static void vpaint_do_symmetrical_brush_actions(
 			sculpt_cache_calc_brushdata_symm(cache, i, 0, 0);
 
 			if (i & (1 << 0)) {
-				vpaint_do_paint(C, sd, vd, vpd, ob, me, brush, i, 'X', 0, 0);
-				vpaint_do_radial_symmetry(C, sd, vd, vpd, ob, me, brush, i, 'X');
+				vpaint_do_paint(C, sd, vp, vpd, ob, me, brush, i, 'X', 0, 0);
+				vpaint_do_radial_symmetry(C, sd, vp, vpd, ob, me, brush, i, 'X');
 			}
 			if (i & (1 << 1)) {
-				vpaint_do_paint(C, sd, vd, vpd, ob, me, brush, i, 'Y', 0, 0);
-				vpaint_do_radial_symmetry(C, sd, vd, vpd, ob, me, brush, i, 'Y');
+				vpaint_do_paint(C, sd, vp, vpd, ob, me, brush, i, 'Y', 0, 0);
+				vpaint_do_radial_symmetry(C, sd, vp, vpd, ob, me, brush, i, 'Y');
 			}
 			if (i & (1 << 2)) {
-				vpaint_do_paint(C, sd, vd, vpd, ob, me, brush, i, 'Z', 0, 0);
-				vpaint_do_radial_symmetry(C, sd, vd, vpd, ob, me, brush, i, 'Z');
+				vpaint_do_paint(C, sd, vp, vpd, ob, me, brush, i, 'Z', 0, 0);
+				vpaint_do_radial_symmetry(C, sd, vp, vpd, ob, me, brush, i, 'Z');
 			}
 		}
 	}
diff --git a/source/blender/editors/sculpt_paint/sculpt.c b/source/blender/editors/sculpt_paint/sculpt.c
index 69ae47790a0..1698ab9e5c7 100644
--- a/source/blender/editors/sculpt_paint/sculpt.c
+++ b/source/blender/editors/sculpt_paint/sculpt.c
@@ -587,6 +587,24 @@ bool sculpt_brush_test_sphere_fast(const SculptBrushTest *test, const float co[3
 	return len_squared_v3v3(co, test->location) <= test->radius_squared;
 }
 
+bool sculpt_brush_test_circle_sq(SculptBrushTest *test, const float co[3])
+{
+	float co_proj[3];
+	closest_to_plane_normalized_v3(co_proj, test->plane, co);
+	float distsq = len_squared_v3v3(co_proj, test->location);
+
+	if (distsq <= test->radius_squared) {
+		if (sculpt_brush_test_clipping(test, co)) {
+			return 0;
+		}
+		test->dist = distsq;
+		return 1;
+	}
+	else {
+		return 0;
+	}
+}
+
 bool sculpt_brush_test_cube(SculptBrushTest *test, const float co[3], float local[4][4])
 {
 	float side = M_SQRT1_2;
@@ -1216,6 +1234,24 @@ bool sculpt_search_sphere_cb(PBVHNode *node, void *data_v)
 	return len_squared_v3(t) < data->radius_squared;
 }
 
+/* 2D projection (distance to line). */
+bool sculpt_search_circle_cb(PBVHNode *node, void *data_v)
+{
+	SculptSearchCircleData *data = data_v;
+	float bb_min[3], bb_max[3];
+
+	if (data->original)
+		BKE_pbvh_node_get_original_BB(node, bb_min, bb_max);
+	else
+		BKE_pbvh_node_get_BB(node, bb_min, bb_min);
+
+	float dummy_co[3], dummy_depth;
+	const float dist_sq = dist_squared_ray_to_aabb(
+	        data->dist_ray_to_aabb_precalc, bb_min, bb_max, dummy_co, &dummy_depth);
+
+	return dist_sq < data->radius_squared;
+}
+
 /* Handles clipping against a mirror modifier and SCULPT_LOCK axis flags */
 static void sculpt_clip(Sculpt *sd, SculptSession *ss, float co[3], const float val[3])
 {
diff --git a/source/blender/editors/sculpt_paint/sculpt_intern.h b/source/blender/editors/sculpt_paint/sculpt_intern.h
index 7d9d3ad783d..425cecb0010 100644
--- a/source/blender/editors/sculpt_paint/sculpt_intern.h
+++ b/source/blender/editors/sculpt_paint/sculpt_intern.h
@@ -188,6 +188,8 @@ typedef struct SculptBrushTest {
 	struct RegionView3D *clip_rv3d;
 } SculptBrushTest;
 
+typedef bool (*SculptBrushTestFn)(SculptBrushTest *test, const float co[3]);
+
 typedef struct {
 	struct Sculpt *sd;
 	struct SculptSession *ss;
@@ -195,12 +197,22 @@ typedef struct {
 	bool original;
 } SculptSearchSphereData;
 
+typedef struct {
+	struct Sculpt *sd;
+	struct SculptSession *ss;
+	float radius_squared;
+	bool original;
+	struct DistRayAABB_Precalc *dist_ray_to_aabb_precalc;
+} SculptSearchCircleData;
+
 void sculpt_brush_test_init(struct SculptSession *ss, SculptBrushTest *test);
 bool sculpt_brush_test_sphere(SculptBrushTest *test, const float co[3]);
 bool sculpt_brush_test_sphere_sq(SculptBrushTest *test, const float co[3]);
 bool sculpt_brush_test_sphere_fast(const SculptBrushTest *test, const float co[3]);
 bool sculpt_brush_test_cube(SculptBrushTest *test, const float co[3], float local[4][4]);
+bool sculpt_brush_test_circle_sq(SculptBrushTest *test, const float co[3]);
 bool sculpt_search_sphere_cb(PBVHNode *node, void *data_v);
+bool sculpt_search_circle_cb(PBVHNode *node, void *data_v);
 float tex_strength(
         struct SculptSession *ss, struct Brush *br,
         const float point[3],
diff --git a/source/blender/makesdna/DNA_scene_types.h b/source/blender/makesdna/DNA_scene_types.h
index 3201b75ee1e..e9caf7ada1c 100644
--- a/source/blender/makesdna/DNA_scene_types.h
+++ b/source/blender/makesdna/DNA_scene_types.h
@@ -1117,18 +1117,26 @@ typedef struct UvSculpt {
 /* Vertex Paint */
 typedef struct VPaint {
 	Paint paint;
-	short flag, pad;
+	short flag;
+	char falloff_shape, normal_angle;
 	int radial_symm[3]; /* For mirrored painting */
 } VPaint;
 
 /* VPaint.flag */
 enum {
-	// VP_COLINDEX  = (1 << 0),  /* only paint onto active material*/  /* deprecated since before 2.49 */
-	// VP_AREA      = (1 << 1),  /* deprecated since 2.70 */
-	VP_NORMALS      = (1 << 3),
-	VP_SPRAY        = (1 << 4),
-	// VP_MIRROR_X  = (1 << 5),  /* deprecated in 2.5x use (me->editflag & ME_EDIT_MIRROR_X) */
-	VP_ONLYVGROUP   = (1 << 7)   /* weight paint only */
+	VP_FLAG_PROJECT_BACKFACE    = (1 << 0),
+	/* TODO */
+	// VP_FLAG_PROJECT_XRAY        = (1 << 1),
+	VP_FLAG_PROJECT_FLAT        = (1 << 3),
+	VP_FLAG_SPRAY               = (1 << 4),
+	/* weight paint only */
+	VP_FLAG_VGROUP_RESTRICT     = (1 << 7)
+};
+
+/* VPaint.falloff_shape */
+enum {
+	VP_FALLOFF_SHAPE_SPHERE = 0,
+	VP_FALLOFF_SHAPE_TUBE = 1,
 };
 
 /* ------------------------------------------- */
diff --git a/source/blender/makesrna/intern/rna_sculpt_paint.c b/source/blender/makesrna/intern/rna_sculpt_paint.c
index 09da34d59d8..6c89767ad29 100644
--- a/source/blender/makesrna/intern/rna_sculpt_paint.c
+++ b/source/blender/makesrna/intern/rna_sculpt_paint.c
@@ -671,23 +671,44 @@ static void rna_def_vertex_paint(BlenderRNA *brna)
 	RNA_def_struct_path_func(srna, "rna_VertexPaint_path");
 	RNA_def_struct_ui_text(srna, "Vertex Paint", "Properties of vertex and weight paint mode");
 
-	/* vertex paint only */
-	prop = RNA_def_property(srna, "use_normal", PROP_BOOLEAN, PROP_NONE);
-	RNA_def_property_boolean_sdna(prop, NULL, "flag", VP_NORMALS);
-	RNA_def_property_ui_text(prop, "Normals", "Apply the vertex normal before painting");
+	static EnumPropertyItem prop_falloff_items[] = {
+		{VP_FALLOFF_SHAPE_SPHERE, "SPHERE", 0, "Sphere", "Spherical falloff from the brush"},
+		{VP_FALLOFF_SHAPE_TUBE, "TUBE", 0, "Circle", "Circular falloff from the brush along the view"},
+		{0, NULL, 0, NULL, NULL}
+	};
+
+	prop = RNA_def_property(srna, "falloff_shape", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "falloff_shape");
+	RNA_def_property_enum_items(prop, prop_falloff_items);
+	RNA_def_property_ui_text(prop, "Falloff", "");
+	RNA_def_property_update(prop, NC_SCENE | ND_TOOLSETTINGS, NULL);
+
+	prop = RNA_def_property(srna, "use_backface_culling", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_negative_sdna(prop, NULL, "flag", VP_FLAG_PROJECT_BACKFACE);
+	RNA_def_property_ui_text(prop, "Cull", "Ignore vertices pointing away from the view (faster)");
+	RNA_def_property_update(prop, NC_SCENE | ND_TOOLSETTINGS, NULL);
+
+	prop = RNA_def_property(srna, "use_normal_falloff", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_negative_sdna(prop, NULL, "flag", VP_FLAG_PROJECT_FLAT);
+	RNA_def_property_ui_text(prop, "Normals", "Paint most on faces pointing towards the view");
 	RNA_def_property_update(prop, NC_SCENE | ND_TOOLSETTINGS, NULL);
 	
+
 	prop = RNA_def_property(srna, "use_spray", PROP_BOOLEAN, PROP_NONE);
-	RNA_def_property_boolean_sdna(prop, NULL, "flag", VP_SPRAY);
+	RNA_def_property_boolean_sdna(prop, NULL, "flag", VP_FLAG_SPRAY);
 	RNA_def_property_ui_text(prop, "Spray", "Keep applying paint effect while holding mouse");
 	RNA_def_property_update(prop, NC_SCENE | ND_TOOLSETTINGS, NULL);
 
 	/* weight paint only */
 	prop = RNA_def_property(srna, "use_group_restrict", PROP_BOOLEAN, PROP_NONE);
-	RNA_def_property_boolean_sdna(prop, NULL, "flag", VP_ONLYVGROUP);
+	RNA_def_property_boolean_sdna(prop, NULL, "flag", VP_FLAG_VGROUP_RESTRICT);
 	RNA_def_property_ui_text(prop, "Restrict", "Restrict painting to vertices in the group");
 	RNA_def_property_update(prop, NC_SCENE | ND_TOOLSETTINGS, NULL);
 
+	prop = RNA_def_property(srna, "normal_angle", PROP_INT, PROP_UNSIGNED);
+	RNA_def_property_range(prop, 0, 90);
+	RNA_def_property_ui_text(prop, "Angle", "Paint most on faces pointing towards the view according to this angle");
+
 	/* Mirroring */
 	prop = RNA_def_property(srna, "radial_symmetry", PROP_INT, PROP_XYZ);
 	RNA_def_property_int_sdna(prop, NULL, "radial_symm");