Cleanup: NLA transforms, simplify `recalcData_nla()`

Refactor the `recalcData_nla()` function, which takes data from the
transform system and updates NLA strips, such that the actual logic to
change the strip is moved into its own function.

This also moves some generic code (find prev/next strip) from that
function to BKE.

This is to make the code easier to adjust when different transform
operations need to perform different modifications of the strip (i.e. to
fix T101130).

Manifest Task: T101130

Reviewed By: sybren

Differential Revision: https://developer.blender.org/D16181

1 files changed, 26 insertions, 17 deletions

diff --git a/source/blender/editors/transform/transform_convert_nla.c b/source/blender/editors/transform/transform_convert_nla.c
index cfa933d1600..af5a51cbff6 100644
--- a/source/blender/editors/transform/transform_convert_nla.c
+++ b/source/blender/editors/transform/transform_convert_nla.c
@@ -56,6 +56,29 @@ typedef struct TransDataNla {
 } TransDataNla;
 
 /* -------------------------------------------------------------------- */
+/** \name Transform application to NLA strips
+ * \{ */
+
+/**
+ * \brief Applies a translation to the given NlaStrip.
+ * \param strip_rna_ptr The RNA pointer of the NLA strip to modify.
+ * \param transdata The transformation info structure.
+ */
+static void applyTransformNLA_translation(PointerRNA *strip_rna_ptr, const TransDataNla *transdata)
+{
+  /* NOTE: we write these twice to avoid truncation errors which can arise when
+   * moving the strips a large distance using numeric input T33852.
+   */
+  RNA_float_set(strip_rna_ptr, "frame_start", transdata->h1[0]);
+  RNA_float_set(strip_rna_ptr, "frame_end", transdata->h2[0]);
+
+  RNA_float_set(strip_rna_ptr, "frame_start", transdata->h1[0]);
+  RNA_float_set(strip_rna_ptr, "frame_end", transdata->h2[0]);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
 /** \name NLA Transform Creation
  * \{ */
 
@@ -329,15 +352,8 @@ static void recalcData_nla(TransInfo *t)
      *
      * this is done as a iterative procedure (done 5 times max for now)
      */
-    NlaStrip *prev = strip->prev;
-    while (prev != NULL && (prev->type & NLASTRIP_TYPE_TRANSITION)) {
-      prev = prev->prev;
-    }
-
-    NlaStrip *next = strip->next;
-    while (next != NULL && (next->type & NLASTRIP_TYPE_TRANSITION)) {
-      next = next->next;
-    }
+    NlaStrip *prev = BKE_nlastrip_prev_in_track(strip, true);
+    NlaStrip *next = BKE_nlastrip_next_in_track(strip, true);
 
     for (short iter = 0; iter < 5; iter++) {
       const bool pExceeded = (prev != NULL) && (tdn->h1[0] < prev->end);
@@ -380,17 +396,10 @@ static void recalcData_nla(TransInfo *t)
 
     /* Use RNA to write the values to ensure that constraints on these are obeyed
      * (e.g. for transition strips, the values are taken from the neighbors)
-     *
-     * NOTE: we write these twice to avoid truncation errors which can arise when
-     * moving the strips a large distance using numeric input T33852.
      */
     RNA_pointer_create(NULL, &RNA_NlaStrip, strip, &strip_ptr);
 
-    RNA_float_set(&strip_ptr, "frame_start", tdn->h1[0]);
-    RNA_float_set(&strip_ptr, "frame_end", tdn->h2[0]);
-
-    RNA_float_set(&strip_ptr, "frame_start", tdn->h1[0]);
-    RNA_float_set(&strip_ptr, "frame_end", tdn->h2[0]);
+    applyTransformNLA_translation(&strip_ptr, tdn);
 
     /* flush transforms to child strips (since this should be a meta) */
     BKE_nlameta_flush_transforms(strip);