GP: Remove duplicate code moving to single function

1 files changed, 45 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/gpencil.c b/source/blender/blenkernel/intern/gpencil.c
index 5f444541890..f8dfa82e2a2 100644
--- a/source/blender/blenkernel/intern/gpencil.c
+++ b/source/blender/blenkernel/intern/gpencil.c
@@ -1559,3 +1559,48 @@ int BKE_gpencil_get_material_index(Object *ob, Material *ma)
 
 	return 0;
 }
+
+/* Get points of stroke always flat to view not affected by camera view or view position */
+void BKE_gpencil_stroke_2d_flat(const bGPDspoint *points, int totpoints, float(*points2d)[2], int *r_direction)
+{
+	const bGPDspoint *pt0 = &points[0];
+	const bGPDspoint *pt1 = &points[1];
+	const bGPDspoint *pt3 = &points[(int)(totpoints * 0.75)];
+
+	float locx[3];
+	float locy[3];
+	float loc3[3];
+	float normal[3];
+
+	/* local X axis (p0 -> p1) */
+	sub_v3_v3v3(locx, &pt1->x, &pt0->x);
+
+	/* point vector at 3/4 */
+	sub_v3_v3v3(loc3, &pt3->x, &pt0->x);
+
+	/* vector orthogonal to polygon plane */
+	cross_v3_v3v3(normal, locx, loc3);
+
+	/* local Y axis (cross to normal/x axis) */
+	cross_v3_v3v3(locy, normal, locx);
+
+	/* Normalize vectors */
+	normalize_v3(locx);
+	normalize_v3(locy);
+
+	/* Get all points in local space */
+	for (int i = 0; i < totpoints; i++) {
+		const bGPDspoint *pt = &points[i];
+		float loc[3];
+
+		/* Get local space using first point as origin */
+		sub_v3_v3v3(loc, &pt->x, &pt0->x);
+
+		points2d[i][0] = dot_v3v3(loc, locx);
+		points2d[i][1] = dot_v3v3(loc, locy);
+	}
+
+	/* Concave (-1), Convex (1), or Autodetect (0)? */
+	*r_direction = (int)locy[2];
+}
+