GP: Fix strange pressure values when drawing

This strange values produced an "explosion" of the stoke and it was very annoying.

2 files changed, 4 insertions, 3 deletions

diff --git a/source/blender/blenkernel/intern/gpencil.c b/source/blender/blenkernel/intern/gpencil.c
index b5230afa0bb..45163de559e 100644
--- a/source/blender/blenkernel/intern/gpencil.c
+++ b/source/blender/blenkernel/intern/gpencil.c
@@ -1350,7 +1350,7 @@ bool BKE_gpencil_smooth_stroke_thickness(bGPDstroke *gps, int point_index, float
 	bGPDspoint *ptb = &gps->points[point_index];
 
 	/* Do nothing if not enough points */
-	if (gps->totpoints <= 2) {
+	if ((gps->totpoints <= 2) || (point_index < 1)) {
 		return false;
 	}
 
@@ -1369,6 +1369,7 @@ bool BKE_gpencil_smooth_stroke_thickness(bGPDstroke *gps, int point_index, float
 	 * at the distance of point b
 	 */
 	float fac = line_point_factor_v3(&ptb->x, &pta->x, &ptc->x);
+	CLAMP(fac, 0.0f, 1.0f);
 	float optimal = interpf(ptc->pressure, pta->pressure, fac);
 
 	/* Based on influence factor, blend between original and optimal */
diff --git a/source/blender/editors/gpencil/gpencil_paint.c b/source/blender/editors/gpencil/gpencil_paint.c
index 27eba6581db..4ce3899e288 100644
--- a/source/blender/editors/gpencil/gpencil_paint.c
+++ b/source/blender/editors/gpencil/gpencil_paint.c
@@ -1199,7 +1199,7 @@ static void gp_stroke_newfrombuffer(tGPsdata *p)
 		{
 			float reduce = 0.0f;
 			for (int r = 0; r < brush->gpencil_settings->draw_smoothlvl; r++) {
-				for (i = 0; i < gps->totpoints; i++) {
+				for (i = 0; i < gps->totpoints - 1; i++) {
 					BKE_gpencil_smooth_stroke(gps, i, brush->gpencil_settings->draw_smoothfac - reduce);
 					BKE_gpencil_smooth_stroke_strength(gps, i, brush->gpencil_settings->draw_smoothfac);
 				}
@@ -1211,7 +1211,7 @@ static void gp_stroke_newfrombuffer(tGPsdata *p)
 		    (brush->gpencil_settings->thick_smoothfac > 0.0f))
 		{
 			for (int r = 0; r < brush->gpencil_settings->thick_smoothlvl * 2; r++) {
-				for (i = 0; i < gps->totpoints; i++) {
+				for (i = 0; i < gps->totpoints - 1; i++) {
 					BKE_gpencil_smooth_stroke_thickness(gps, i, brush->gpencil_settings->thick_smoothfac);
 				}
 			}