Fix T81707: Spline IK Joints "Floating" above curve

The issue was that where_on_path uses a resampled curve to get the data
from the curve. This leads to disconnects between the curve the user
sees and the evaluated location data.

To fix this we simply use the actual curve data the user can see.

The older code needed a cleanup either way as there were hacks in other
parts of the code trying to work around some brokenness. This is now
fixed and we no longer need to clamp the evaluation range to 0-1 or make
helper functions to make it do what we actually want.

Reviewed By: Campbell, Sybren

Differential Revision: http://developer.blender.org/D10898

1 files changed, 11 insertions, 75 deletions

diff --git a/source/blender/blenkernel/intern/curve_deform.c b/source/blender/blenkernel/intern/curve_deform.c
index 63da7c1dd11..10c6d2213ff 100644
--- a/source/blender/blenkernel/intern/curve_deform.c
+++ b/source/blender/blenkernel/intern/curve_deform.c
@@ -68,75 +68,7 @@ static void init_curve_deform(const Object *ob_curve, const Object *ob_target, C
 }
 
 /**
- * This makes sure we can extend for non-cyclic.
- *
- * \return Success.
- */
-static bool where_on_path_deform(const Object *ob_curve,
-                                 float ctime,
-                                 float r_vec[4],
-                                 float r_dir[3],
-                                 float r_quat[4],
-                                 float *r_radius)
-{
-  BevList *bl;
-  float ctime1;
-  int cycl = 0;
-
-  /* test for cyclic */
-  bl = ob_curve->runtime.curve_cache->bev.first;
-  if (!bl->nr) {
-    return false;
-  }
-  if (bl->poly > -1) {
-    cycl = 1;
-  }
-
-  if (cycl == 0) {
-    ctime1 = CLAMPIS(ctime, 0.0f, 1.0f);
-  }
-  else {
-    ctime1 = ctime;
-  }
-
-  /* vec needs 4 items */
-  if (where_on_path(ob_curve, ctime1, r_vec, r_dir, r_quat, r_radius, NULL)) {
-
-    if (cycl == 0) {
-      Path *path = ob_curve->runtime.curve_cache->path;
-      float dvec[3];
-
-      if (ctime < 0.0f) {
-        sub_v3_v3v3(dvec, path->data[1].vec, path->data[0].vec);
-        mul_v3_fl(dvec, ctime * (float)path->len);
-        add_v3_v3(r_vec, dvec);
-        if (r_quat) {
-          copy_qt_qt(r_quat, path->data[0].quat);
-        }
-        if (r_radius) {
-          *r_radius = path->data[0].radius;
-        }
-      }
-      else if (ctime > 1.0f) {
-        sub_v3_v3v3(dvec, path->data[path->len - 1].vec, path->data[path->len - 2].vec);
-        mul_v3_fl(dvec, (ctime - 1.0f) * (float)path->len);
-        add_v3_v3(r_vec, dvec);
-        if (r_quat) {
-          copy_qt_qt(r_quat, path->data[path->len - 1].quat);
-        }
-        if (r_radius) {
-          *r_radius = path->data[path->len - 1].radius;
-        }
-        /* weight - not used but could be added */
-      }
-    }
-    return true;
-  }
-  return false;
-}
-
-/**
- * For each point, rotate & translate to curve use path, since it has constant distances.
+ * For each point, rotate & translate to curve.
  *
  * \param co: local coord, result local too.
  * \param r_quat: returns quaternion for rotation,
@@ -155,7 +87,7 @@ static bool calc_curve_deform(
     return false;
   }
 
-  if (ob_curve->runtime.curve_cache->path == NULL) {
+  if (ob_curve->runtime.curve_cache->anim_path_accum_length == NULL) {
     return false; /* happens on append, cyclic dependencies and empty curves */
   }
 
@@ -172,8 +104,10 @@ static bool calc_curve_deform(
       }
     }
     else {
-      if (LIKELY(ob_curve->runtime.curve_cache->path->totdist > FLT_EPSILON)) {
-        fac = -(co[index] - cd->dmax[index]) / (ob_curve->runtime.curve_cache->path->totdist);
+      CurveCache *cc = ob_curve->runtime.curve_cache;
+      float totdist = BKE_anim_path_get_length(cc);
+      if (LIKELY(totdist > FLT_EPSILON)) {
+        fac = -(co[index] - cd->dmax[index]) / totdist;
       }
       else {
         fac = 0.0f;
@@ -192,8 +126,10 @@ static bool calc_curve_deform(
       }
     }
     else {
-      if (LIKELY(ob_curve->runtime.curve_cache->path->totdist > FLT_EPSILON)) {
-        fac = +(co[index] - cd->dmin[index]) / (ob_curve->runtime.curve_cache->path->totdist);
+      CurveCache *cc = ob_curve->runtime.curve_cache;
+      float totdist = BKE_anim_path_get_length(cc);
+      if (LIKELY(totdist > FLT_EPSILON)) {
+        fac = +(co[index] - cd->dmin[index]) / totdist;
       }
       else {
         fac = 0.0f;
@@ -201,7 +137,7 @@ static bool calc_curve_deform(
     }
   }
 
-  if (where_on_path_deform(ob_curve, fac, loc, dir, new_quat, &radius)) { /* returns OK */
+  if (BKE_where_on_path(ob_curve, fac, loc, dir, new_quat, &radius, NULL)) { /* returns OK */
     float quat[4], cent[3];
 
     if (cd->no_rot_axis) { /* set by caller */