fix for [#19655] Curve is a disaster

when changing curve twist I assumed 2D curves would not need dir or quat values set, however these are used when getting a path from a curve.
also added interp_v3_v3v3v3v3

4 files changed, 57 insertions, 29 deletions

diff --git a/source/blender/blenkernel/intern/anim.c b/source/blender/blenkernel/intern/anim.c
index a1b138b9a74..6b8b604cb94 100644
--- a/source/blender/blenkernel/intern/anim.c
+++ b/source/blender/blenkernel/intern/anim.c
@@ -250,17 +250,13 @@ int where_on_path(Object *ob, float ctime, float *vec, float *dir, float *quat,
 
 	/* note, commented out for follow constraint */
 	//if(cu->flag & CU_FOLLOW) {
-		
+
 		key_curve_tangent_weights(1.0f-fac, data, KEY_BSPLINE);
-		
-		dir[0]= data[0]*p0->vec[0] + data[1]*p1->vec[0] + data[2]*p2->vec[0] + data[3]*p3->vec[0] ;
-		dir[1]= data[0]*p0->vec[1] + data[1]*p1->vec[1] + data[2]*p2->vec[1] + data[3]*p3->vec[1] ;
-		dir[2]= data[0]*p0->vec[2] + data[1]*p1->vec[2] + data[2]*p2->vec[2] + data[3]*p3->vec[2] ;
-		
+
+		interp_v3_v3v3v3v3(dir, p0->vec, p1->vec, p2->vec, p3->vec, data);
+
 		/* make compatible with vectoquat */
-		dir[0]= -dir[0];
-		dir[1]= -dir[1];
-		dir[2]= -dir[2];
+		negate_v3(dir);
 	//}
 	
 	nu= cu->nurb.first;
diff --git a/source/blender/blenkernel/intern/curve.c b/source/blender/blenkernel/intern/curve.c
index 83e2e0c29d9..75759733cad 100644
--- a/source/blender/blenkernel/intern/curve.c
+++ b/source/blender/blenkernel/intern/curve.c
@@ -1569,7 +1569,7 @@ static void alfa_bezpart(BezTriple *prevbezt, BezTriple *bezt, Nurb *nu, float *
 
 /* correct non-cyclic cases by copying direction and rotation
  * values onto the first & last end-points */
-static void bevel_list_cyclic_fix(BevList *bl)
+static void bevel_list_cyclic_fix_3D(BevList *bl)
 {
 	BevPoint *bevp, *bevp1;
 
@@ -1837,7 +1837,7 @@ static void make_bevel_list_3D_tangent(BevList *bl)
 
 	bevel_list_calc_bisect(bl);
 	if(bl->poly== -1) /* check its not cyclic */
-		bevel_list_cyclic_fix(bl); // XXX - run this now so tangents will be right before doing the flipping
+		bevel_list_cyclic_fix_3D(bl); // XXX - run this now so tangents will be right before doing the flipping
 	bevel_list_flip_tangents(bl);
 
 	/* correct the tangents */
@@ -1896,7 +1896,7 @@ static void make_bevel_list_3D(BevList *bl, int smooth_iter, int twist_mode)
 	}
 
 	if(bl->poly== -1) /* check its not cyclic */
-		bevel_list_cyclic_fix(bl);
+		bevel_list_cyclic_fix_3D(bl);
 
 	if(smooth_iter)
 		bevel_list_smooth(bl, smooth_iter);
@@ -1906,6 +1906,29 @@ static void make_bevel_list_3D(BevList *bl, int smooth_iter, int twist_mode)
 
 
 
+/* only for 2 points */
+static void make_bevel_list_segment_3D(BevList *bl)
+{
+	float q[4];
+
+	BevPoint *bevp2= (BevPoint *)(bl+1);
+	BevPoint *bevp1= bevp2+1;
+
+	/* simple quat/dir */
+	sub_v3_v3v3(bevp1->dir, bevp1->vec, bevp2->vec);
+	normalize_v3(bevp1->dir);
+
+	vec_to_quat( bevp1->quat,bevp1->dir, 5, 1);
+
+	axis_angle_to_quat(q, bevp1->dir, bevp1->alfa);
+	mul_qt_qtqt(bevp1->quat, q, bevp1->quat);
+	normalize_qt(bevp1->quat);
+	VECCOPY(bevp2->dir, bevp1->dir);
+	QUATCOPY(bevp2->quat, bevp1->quat);
+}
+
+
+
 void makeBevelList(Object *ob)
 {
 	/*
@@ -2213,7 +2236,9 @@ void makeBevelList(Object *ob)
 	}
 
 	/* STEP 4: 2D-COSINES or 3D ORIENTATION */
-	if((cu->flag & CU_3D)==0) { /* 3D */
+	if((cu->flag & CU_3D)==0) {
+		/* note: bevp->dir and bevp->quat are not needed for beveling but are
+		 * used when making a path from a 2D curve, therefor they need to be set - Campbell */
 		bl= cu->bev.first;
 		while(bl) {
 
@@ -2230,6 +2255,9 @@ void makeBevelList(Object *ob)
 				calc_bevel_sin_cos(x1, y1, -x1, -y1, &(bevp1->sina), &(bevp1->cosa));
 				bevp2->sina= bevp1->sina;
 				bevp2->cosa= bevp1->cosa;
+
+				/* fill in dir & quat */
+				make_bevel_list_segment_3D(bl);
 			}
 			else {
 				bevp2= (BevPoint *)(bl+1);
@@ -2245,6 +2273,12 @@ void makeBevelList(Object *ob)
 
 					calc_bevel_sin_cos(x1, y1, x2, y2, &(bevp1->sina), &(bevp1->cosa));
 
+					/* from: make_bevel_list_3D_zup, could call but avoid a second loop.
+					 * no need for tricky tilt calculation as with 3D curves */
+					bisect_v3_v3v3v3(bevp1->dir, bevp0->vec, bevp1->vec, bevp2->vec);
+					vec_to_quat( bevp1->quat,bevp1->dir, 5, 1);
+					/* done with inline make_bevel_list_3D_zup */
+
 					bevp0= bevp1;
 					bevp1= bevp2;
 					bevp2++;
@@ -2261,6 +2295,9 @@ void makeBevelList(Object *ob)
 					bevp1= bevp-1;
 					bevp->sina= bevp1->sina;
 					bevp->cosa= bevp1->cosa;
+
+					/* correct for the dir/quat, see above why its needed */
+					bevel_list_cyclic_fix_3D(bl);
 				}
 			}
 			bl= bl->next;
@@ -2274,22 +2311,7 @@ void makeBevelList(Object *ob)
 				/* do nothing */
 			}
 			else if(bl->nr==2) {	/* 2 pnt, treat separate */
-				float q[4];
-
-				bevp2= (BevPoint *)(bl+1);
-				bevp1= bevp2+1;
-
-				/* simple quat/dir */
-				sub_v3_v3v3(bevp1->dir, bevp1->vec, bevp2->vec);
-				normalize_v3(bevp1->dir);
-				
-				vec_to_quat( bevp1->quat,bevp1->dir, 5, 1);
-				
-				axis_angle_to_quat(q, bevp1->dir, bevp1->alfa);
-				mul_qt_qtqt(bevp1->quat, q, bevp1->quat);
-				normalize_qt(bevp1->quat);
-				VECCOPY(bevp2->dir, bevp1->dir);
-				QUATCOPY(bevp2->quat, bevp1->quat);
+				make_bevel_list_segment_3D(bl);
 			}
 			else {
 				make_bevel_list_3D(bl, (int)(resolu*cu->twist_smooth), cu->twist_mode);
diff --git a/source/blender/blenlib/BLI_math_vector.h b/source/blender/blenlib/BLI_math_vector.h
index 26602353425..e21c3800acc 100644
--- a/source/blender/blenlib/BLI_math_vector.h
+++ b/source/blender/blenlib/BLI_math_vector.h
@@ -99,6 +99,7 @@ void interp_v2_v2v2(float r[2], float a[2], float b[2], float t);
 void interp_v2_v2v2v2(float r[2], float a[2], float b[2], float c[3], float t[3]);
 void interp_v3_v3v3(float r[3], float a[3], float b[3], float t);
 void interp_v3_v3v3v3(float p[3], float v1[3], float v2[3], float v3[3], float w[3]);
+void interp_v3_v3v3v3v3(float p[3], float v1[3], float v2[3], float v3[3], float v4[3], float w[4]);
 
 void mid_v3_v3v3(float r[3], float a[3], float b[3]);
 
diff --git a/source/blender/blenlib/intern/math_vector.c b/source/blender/blenlib/intern/math_vector.c
index 8d36c3ac524..502f241c195 100644
--- a/source/blender/blenlib/intern/math_vector.c
+++ b/source/blender/blenlib/intern/math_vector.c
@@ -68,6 +68,15 @@ void interp_v3_v3v3v3(float p[3], float v1[3], float v2[3], float v3[3], float w
 	p[2] = v1[2]*w[0] + v2[2]*w[1] + v3[2]*w[2];
 }
 
+/* weight 3 vectors,
+ * 'w' must be unit length but is not a vector, just 3 weights */
+void interp_v3_v3v3v3v3(float p[3], float v1[3], float v2[3], float v3[3], float v4[3], float w[4])
+{
+	p[0] = v1[0]*w[0] + v2[0]*w[1] + v3[0]*w[2] + v4[0]*w[3];
+	p[1] = v1[1]*w[0] + v2[1]*w[1] + v3[1]*w[2] + v4[1]*w[3];
+	p[2] = v1[2]*w[0] + v2[2]*w[1] + v3[2]*w[2] + v4[2]*w[3];
+}
+
 void mid_v3_v3v3(float *v, float *v1, float *v2)
 {
 	v[0]= 0.5f*(v1[0] + v2[0]);