GPencil: Fix unreported jagged lines when using Stroke mode

When use the Stroke reproject mode, the precission of the conversion makes the line produce a very small noise effect.

Now, if the stroke mode is enabled, a small smooth is done using a factor depending of the input samples.

The values of the smooth effect were provided by @pepeland after several testing.

1 files changed, 10 insertions, 0 deletions

diff --git a/source/blender/editors/gpencil/gpencil_paint.c b/source/blender/editors/gpencil/gpencil_paint.c
index 9de15c411cc..e1854ae8c03 100644
--- a/source/blender/editors/gpencil/gpencil_paint.c
+++ b/source/blender/editors/gpencil/gpencil_paint.c
@@ -1145,6 +1145,16 @@ static void gp_stroke_newfrombuffer(tGPsdata *p)
         reduce += 0.25f; /* reduce the factor */
       }
     }
+    /* If reproject the stroke using Stroke mode, need to apply a smooth because
+     * the reprojection creates small jitter. */
+    if (ts->gpencil_v3d_align & GP_PROJECT_DEPTH_STROKE) {
+      float ifac = (float)brush->gpencil_settings->input_samples / 10.0f;
+      float sfac = interpf(1.0f, 0.2f, ifac);
+      for (i = 0; i < gps->totpoints - 1; i++) {
+        BKE_gpencil_stroke_smooth(gps, i, sfac);
+        BKE_gpencil_stroke_smooth_strength(gps, i, sfac);
+      }
+    }
 
     /* Simplify adaptive */
     if ((brush->gpencil_settings->flag & GP_BRUSH_GROUP_SETTINGS) &&