VSE: Fix assigning effect strip inputs

Partialy fixes T73828

Currently all 3 effect inputs were assigned even if not all 3 were used.
This causes problems with reassigning effects in python, because 3rd input is
not accessible.

This patch will only assign inputs that are necessary for effect to work
properly.

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D6868

1 files changed, 16 insertions, 24 deletions

diff --git a/source/blender/blenkernel/intern/sequencer.c b/source/blender/blenkernel/intern/sequencer.c
index 019d4fff0e5..7ec4797a998 100644
--- a/source/blender/blenkernel/intern/sequencer.c
+++ b/source/blender/blenkernel/intern/sequencer.c
@@ -842,30 +842,22 @@ void BKE_sequence_calc(Scene *scene, Sequence *seq)
   }
 
   /* effects and meta: automatic start and end */
-
   if (seq->type & SEQ_TYPE_EFFECT) {
-    /* pointers */
-    if (seq->seq2 == NULL) {
-      seq->seq2 = seq->seq1;
-    }
-    if (seq->seq3 == NULL) {
-      seq->seq3 = seq->seq1;
-    }
-
-    /* effecten go from seq1 -> seq2: test */
-
-    /* we take the largest start and smallest end */
-
-    // seq->start = seq->startdisp = MAX2(seq->seq1->startdisp, seq->seq2->startdisp);
-    // seq->enddisp = MIN2(seq->seq1->enddisp, seq->seq2->enddisp);
-
     if (seq->seq1) {
-      /* XXX These resets should not be necessary, but users used to be able to
-       *     edit effect's length, leading to strange results. See [#29190] */
       seq->startofs = seq->endofs = seq->startstill = seq->endstill = 0;
-      seq->start = seq->startdisp = max_iii(
-          seq->seq1->startdisp, seq->seq2->startdisp, seq->seq3->startdisp);
-      seq->enddisp = min_iii(seq->seq1->enddisp, seq->seq2->enddisp, seq->seq3->enddisp);
+      if (seq->seq3) {
+        seq->start = seq->startdisp = max_iii(
+            seq->seq1->startdisp, seq->seq2->startdisp, seq->seq3->startdisp);
+        seq->enddisp = min_iii(seq->seq1->enddisp, seq->seq2->enddisp, seq->seq3->enddisp);
+      }
+      else if (seq->seq2) {
+        seq->start = seq->startdisp = max_ii(seq->seq1->startdisp, seq->seq2->startdisp);
+        seq->enddisp = min_ii(seq->seq1->enddisp, seq->seq2->enddisp);
+      }
+      else {
+        seq->start = seq->startdisp = seq->seq1->startdisp;
+        seq->enddisp = seq->seq1->enddisp;
+      }
       /* we cant help if strips don't overlap, it wont give useful results.
        * but at least ensure 'len' is never negative which causes bad bugs elsewhere. */
       if (seq->enddisp < seq->startdisp) {
@@ -2949,9 +2941,9 @@ static ImBuf *seq_render_effect_strip_impl(const SeqRenderData *context,
     case EARLY_DO_EFFECT:
       for (i = 0; i < 3; i++) {
         /* Speed effect requires time remapping of cfra for input(s). */
-        if (input[1] && seq->type == SEQ_TYPE_SPEED) {
+        if (input[0] && seq->type == SEQ_TYPE_SPEED) {
           float target_frame = BKE_sequencer_speed_effect_target_frame_get(context, seq, cfra, i);
-          ibuf[i] = seq_render_strip(context, state, input[i], target_frame);
+          ibuf[i] = seq_render_strip(context, state, input[0], target_frame);
         }
         else { /* Other effects. */
           if (input[i]) {
@@ -2960,7 +2952,7 @@ static ImBuf *seq_render_effect_strip_impl(const SeqRenderData *context,
         }
       }
 
-      if (ibuf[0] && ibuf[1]) {
+      if (ibuf[0] && (ibuf[1] || BKE_sequence_effect_get_num_inputs(seq->type) == 1)) {
         if (sh.multithreaded) {
           out = BKE_sequencer_effect_execute_threaded(
               &sh, context, seq, cfra, fac, facf, ibuf[0], ibuf[1], ibuf[2]);