VSE: Use alpha over as default blend mode

With transform tools, it is expected to see backgroud image when overlay
is transformed.

Alpha over caused performance to be not optimal when used with opaque
media. This should be addressed with D12914 at least partially. There
may be some corner cases not addressed.

Differential Revision: https://developer.blender.org/D12952

1 files changed, 8 insertions, 14 deletions

diff --git a/source/blender/sequencer/intern/strip_add.c b/source/blender/sequencer/intern/strip_add.c
index 70ac2620e20..382fdd4953f 100644
--- a/source/blender/sequencer/intern/strip_add.c
+++ b/source/blender/sequencer/intern/strip_add.c
@@ -159,7 +159,7 @@ Sequence *SEQ_add_scene_strip(Scene *scene, ListBase *seqbase, struct SeqLoadDat
 {
   Sequence *seq = SEQ_sequence_alloc(
       seqbase, load_data->start_frame, load_data->channel, SEQ_TYPE_SCENE);
-  seq->blend_mode = SEQ_TYPE_CROSS;
+  seq->blend_mode = SEQ_TYPE_ALPHAOVER;
   seq->scene = load_data->scene;
   seq->len = load_data->scene->r.efra - load_data->scene->r.sfra + 1;
   id_us_ensure_real((ID *)load_data->scene);
@@ -180,7 +180,7 @@ Sequence *SEQ_add_movieclip_strip(Scene *scene, ListBase *seqbase, struct SeqLoa
 {
   Sequence *seq = SEQ_sequence_alloc(
       seqbase, load_data->start_frame, load_data->channel, SEQ_TYPE_MOVIECLIP);
-  seq->blend_mode = SEQ_TYPE_CROSS;
+  seq->blend_mode = SEQ_TYPE_ALPHAOVER;
   seq->clip = load_data->clip;
   seq->len = BKE_movieclip_get_duration(load_data->clip);
   id_us_ensure_real((ID *)load_data->clip);
@@ -201,7 +201,7 @@ Sequence *SEQ_add_mask_strip(Scene *scene, ListBase *seqbase, struct SeqLoadData
 {
   Sequence *seq = SEQ_sequence_alloc(
       seqbase, load_data->start_frame, load_data->channel, SEQ_TYPE_MASK);
-  seq->blend_mode = SEQ_TYPE_CROSS;
+  seq->blend_mode = SEQ_TYPE_ALPHAOVER;
   seq->mask = load_data->mask;
   seq->len = BKE_mask_get_duration(load_data->mask);
   id_us_ensure_real((ID *)load_data->mask);
@@ -230,18 +230,12 @@ Sequence *SEQ_add_effect_strip(Scene *scene, ListBase *seqbase, struct SeqLoadDa
   seq->seq2 = load_data->effect.seq2;
   seq->seq3 = load_data->effect.seq3;
 
-  if (seq->type == SEQ_TYPE_COLOR) {
-    seq->blend_mode = SEQ_TYPE_CROSS;
-  }
-  else if (seq->type == SEQ_TYPE_ADJUSTMENT) {
-    seq->blend_mode = SEQ_TYPE_CROSS;
+  if (SEQ_effect_get_num_inputs(seq->type) == 1) {
+    seq->blend_mode = seq->seq1->blend_mode;
   }
-  else if (seq->type == SEQ_TYPE_TEXT) {
+  else {
     seq->blend_mode = SEQ_TYPE_ALPHAOVER;
   }
-  else if (SEQ_effect_get_num_inputs(seq->type) == 1) {
-    seq->blend_mode = seq->seq1->blend_mode;
-  }
 
   if (!load_data->effect.seq1) {
     seq->len = 1; /* Effect is generator, set non zero length. */
@@ -326,7 +320,7 @@ Sequence *SEQ_add_image_strip(Main *bmain, Scene *scene, ListBase *seqbase, SeqL
 {
   Sequence *seq = SEQ_sequence_alloc(
       seqbase, load_data->start_frame, load_data->channel, SEQ_TYPE_IMAGE);
-  seq->blend_mode = SEQ_TYPE_CROSS; /* so alpha adjustment fade to the strip below */
+  seq->blend_mode = SEQ_TYPE_ALPHAOVER; /* so alpha adjustment fade to the strip below */
   seq->len = load_data->image.len;
   Strip *strip = seq->strip;
   strip->stripdata = MEM_callocN(load_data->image.len * sizeof(StripElem), "stripelem");
@@ -587,7 +581,7 @@ Sequence *SEQ_add_movie_strip(
     }
   }
 
-  seq->blend_mode = SEQ_TYPE_CROSS; /* so alpha adjustment fade to the strip below */
+  seq->blend_mode = SEQ_TYPE_ALPHAOVER; /* so alpha adjustment fade to the strip below */
 
   if (anim_arr[0] != NULL) {
     seq->len = IMB_anim_get_duration(anim_arr[0], IMB_TC_RECORD_RUN);