GPencil: Improve smooth operation

This patch makes the grease pencil smooth operation symmetric.
It also increases the performance a lot if strong smoothing is
required. Additionally there is an option for the position smooth
operation to keep the shape closer to the original for more iterations.

Since the result differs from the previous algorithm, versioning is used
to change the iterations and factor to match the old result.

Differential Revision: http://developer.blender.org/D14325

2 files changed, 45 insertions, 42 deletions

diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilshrinkwrap.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilshrinkwrap.c
index 8eaed56dc58..d80224e6639 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilshrinkwrap.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilshrinkwrap.c
@@ -105,15 +105,15 @@ static void deformStroke(GpencilModifierData *md,
 
   /* Apply deformed coordinates. */
   pt = gps->points;
+  bGPDstroke gps_old = *gps;
+  gps_old.points = (bGPDspoint *)MEM_dupallocN(gps->points);
   for (i = 0; i < gps->totpoints; i++, pt++) {
     copy_v3_v3(&pt->x, vert_coords[i]);
     /* Smooth stroke. */
-    if (mmd->smooth_factor > 0.0f) {
-      for (int r = 0; r < mmd->smooth_step; r++) {
-        BKE_gpencil_stroke_smooth_point(gps, i, mmd->smooth_factor, true);
-      }
-    }
+    BKE_gpencil_stroke_smooth_point(
+        &gps_old, i, mmd->smooth_factor, mmd->smooth_step, true, false, gps);
   }
+  MEM_freeN(gps_old.points);
 
   MEM_freeN(vert_coords);
 
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilsmooth.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilsmooth.c
index f8201eb6b4f..eb51a247d87 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilsmooth.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilsmooth.c
@@ -34,10 +34,14 @@
 #include "UI_interface.h"
 #include "UI_resources.h"
 
+#include "RNA_access.h"
+
 #include "MOD_gpencil_modifiertypes.h"
 #include "MOD_gpencil_ui_common.h"
 #include "MOD_gpencil_util.h"
 
+#include "MEM_guardedalloc.h"
+
 static void initData(GpencilModifierData *md)
 {
   SmoothGpencilModifierData *gpmd = (SmoothGpencilModifierData *)md;
@@ -94,45 +98,40 @@ static void deformStroke(GpencilModifierData *md,
     return;
   }
 
-  /* smooth stroke */
-  if (mmd->factor > 0.0f) {
-    for (int r = 0; r < mmd->step; r++) {
-      for (int i = 0; i < gps->totpoints; i++) {
-        MDeformVert *dvert = gps->dvert != NULL ? &gps->dvert[i] : NULL;
-
-        /* verify vertex group */
-        float weight = get_modifier_point_weight(
-            dvert, (mmd->flag & GP_SMOOTH_INVERT_VGROUP) != 0, def_nr);
-        if (weight < 0.0f) {
-          continue;
-        }
-
-        /* Custom curve to modulate value. */
-        if (use_curve) {
-          float value = (float)i / (gps->totpoints - 1);
-          weight *= BKE_curvemapping_evaluateF(mmd->curve_intensity, 0, value);
-        }
-
-        const float val = mmd->factor * weight;
-        /* perform smoothing */
-        if (mmd->flag & GP_SMOOTH_MOD_LOCATION) {
-          BKE_gpencil_stroke_smooth_point(gps, i, val, false);
-        }
-        if (mmd->flag & GP_SMOOTH_MOD_STRENGTH) {
-          BKE_gpencil_stroke_smooth_strength(gps, i, val);
-        }
-        if ((mmd->flag & GP_SMOOTH_MOD_THICKNESS) && (val > 0.0f)) {
-          /* thickness need to repeat process several times */
-          for (int r2 = 0; r2 < r * 10; r2++) {
-            BKE_gpencil_stroke_smooth_thickness(gps, i, val);
-          }
-        }
-        if (mmd->flag & GP_SMOOTH_MOD_UV) {
-          BKE_gpencil_stroke_smooth_uv(gps, i, val);
-        }
+  if (mmd->factor <= 0.0f || mmd->step <= 0) {
+    return;
+  }
+
+  float *weights = NULL;
+  if (def_nr != -1 || use_curve) {
+    weights = MEM_malloc_arrayN(gps->totpoints, sizeof(*weights), __func__);
+    /* Calculate weights. */
+    for (int i = 0; i < gps->totpoints; i++) {
+      MDeformVert *dvert = gps->dvert != NULL ? &gps->dvert[i] : NULL;
+
+      /* Verify vertex group. */
+      float weight = get_modifier_point_weight(
+          dvert, (mmd->flag & GP_SMOOTH_INVERT_VGROUP) != 0, def_nr);
+
+      /* Custom curve to modulate value. */
+      if (use_curve && weight > 0.0f) {
+        float value = (float)i / (gps->totpoints - 1);
+        weight *= BKE_curvemapping_evaluateF(mmd->curve_intensity, 0, value);
       }
+
+      weights[i] = weight;
     }
   }
+  BKE_gpencil_stroke_smooth(gps,
+                            mmd->factor,
+                            mmd->step,
+                            mmd->flag & GP_SMOOTH_MOD_LOCATION,
+                            mmd->flag & GP_SMOOTH_MOD_STRENGTH,
+                            mmd->flag & GP_SMOOTH_MOD_THICKNESS,
+                            mmd->flag & GP_SMOOTH_MOD_UV,
+                            mmd->flag & GP_SMOOTH_KEEP_SHAPE,
+                            weights);
+  MEM_SAFE_FREE(weights);
 }
 
 static void bakeModifier(struct Main *UNUSED(bmain),
@@ -161,7 +160,7 @@ static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk,
 
 static void panel_draw(const bContext *UNUSED(C), Panel *panel)
 {
-  uiLayout *row;
+  uiLayout *row, *col;
   uiLayout *layout = panel->layout;
 
   PointerRNA *ptr = gpencil_modifier_panel_get_property_pointers(panel, NULL);
@@ -177,6 +176,10 @@ static void panel_draw(const bContext *UNUSED(C), Panel *panel)
   uiItemR(layout, ptr, "factor", 0, NULL, ICON_NONE);
   uiItemR(layout, ptr, "step", 0, IFACE_("Repeat"), ICON_NONE);
 
+  col = uiLayoutColumn(layout, false);
+  uiLayoutSetActive(col, RNA_boolean_get(ptr, "use_edit_position"));
+  uiItemR(col, ptr, "keep_shape", 0, NULL, ICON_NONE);
+
   gpencil_modifier_panel_end(layout, ptr);
 }