Fix T92043: Relax/Push Pose does nothing for quaternion rotation.

As can be confirmed by checking generic code for this operation,
it is supposed to blend between the result of Breakdown based on
actual frame range, and the current pose. However for some reason
the quaternion specific code was blending between the current pose
and the current keyframed pose. This means that the operation does
nothing if invoked without modifying the pose first.

This rewrites the code to match the non-quaternion behavior.

Differential Revision: https://developer.blender.org/D13030

1 files changed, 21 insertions, 24 deletions

diff --git a/source/blender/editors/armature/pose_slide.c b/source/blender/editors/armature/pose_slide.c
index ca024f1d4d6..42211d847ff 100644
--- a/source/blender/editors/armature/pose_slide.c
+++ b/source/blender/editors/armature/pose_slide.c
@@ -613,11 +613,8 @@ static void pose_slide_apply_quat(tPoseSlideOp *pso, tPChanFCurveLink *pfl)
     float quat_final[4];
 
     /* Perform blending. */
-    if (pso->mode == POSESLIDE_BREAKDOWN) {
-      /* Just perform the interpolation between quat_prev and
-       * quat_next using pso->factor as a guide. */
-      float quat_prev[4];
-      float quat_next[4];
+    if (ELEM(pso->mode, POSESLIDE_BREAKDOWN, POSESLIDE_PUSH, POSESLIDE_RELAX)) {
+      float quat_prev[4], quat_next[4];
 
       quat_prev[0] = evaluate_fcurve(fcu_w, prevFrameF);
       quat_prev[1] = evaluate_fcurve(fcu_x, prevFrameF);
@@ -632,29 +629,29 @@ static void pose_slide_apply_quat(tPoseSlideOp *pso, tPChanFCurveLink *pfl)
       normalize_qt(quat_prev);
       normalize_qt(quat_next);
 
-      interp_qt_qtqt(quat_final, quat_prev, quat_next, ED_slider_factor_get(pso->slider));
-    }
-    else if (ELEM(pso->mode, POSESLIDE_PUSH, POSESLIDE_RELAX)) {
-      float quat_breakdown[4];
-      float quat_curr[4];
+      if (pso->mode == POSESLIDE_BREAKDOWN) {
+        /* Just perform the interpolation between quat_prev and
+         * quat_next using pso->factor as a guide. */
+        interp_qt_qtqt(quat_final, quat_prev, quat_next, ED_slider_factor_get(pso->slider));
+      }
+      else {
+        float quat_curr[4], quat_breakdown[4];
 
-      copy_qt_qt(quat_curr, pchan->quat);
+        normalize_qt_qt(quat_curr, pchan->quat);
 
-      quat_breakdown[0] = evaluate_fcurve(fcu_w, cframe);
-      quat_breakdown[1] = evaluate_fcurve(fcu_x, cframe);
-      quat_breakdown[2] = evaluate_fcurve(fcu_y, cframe);
-      quat_breakdown[3] = evaluate_fcurve(fcu_z, cframe);
+        /* Compute breakdown based on actual frame range. */
+        const float factor = (cframe - pso->prevFrame) / (float)(pso->nextFrame - pso->prevFrame);
 
-      normalize_qt(quat_breakdown);
-      normalize_qt(quat_curr);
+        interp_qt_qtqt(quat_breakdown, quat_prev, quat_next, factor);
 
-      if (pso->mode == POSESLIDE_PUSH) {
-        interp_qt_qtqt(
-            quat_final, quat_breakdown, quat_curr, 1.0f + ED_slider_factor_get(pso->slider));
-      }
-      else {
-        BLI_assert(pso->mode == POSESLIDE_RELAX);
-        interp_qt_qtqt(quat_final, quat_curr, quat_breakdown, ED_slider_factor_get(pso->slider));
+        if (pso->mode == POSESLIDE_PUSH) {
+          interp_qt_qtqt(
+              quat_final, quat_breakdown, quat_curr, 1.0f + ED_slider_factor_get(pso->slider));
+        }
+        else {
+          BLI_assert(pso->mode == POSESLIDE_RELAX);
+          interp_qt_qtqt(quat_final, quat_curr, quat_breakdown, ED_slider_factor_get(pso->slider));
+        }
       }
     }
     else if (pso->mode == POSESLIDE_BLEND) {