== Sequencer ==

This fixes [#21087] Opacity of 0 turns off effect rather than affecting transparency
and makes the whole early_out-business in strip stack a lot more readable.

The actual fix is just using the composited result in layer fall through
case (se1->ibuf_comp instead of se1->ibuf).

1 files changed, 53 insertions, 25 deletions

diff --git a/source/blender/blenkernel/intern/sequencer.c b/source/blender/blenkernel/intern/sequencer.c
index 341d0a542e6..d43747cf3f3 100644
--- a/source/blender/blenkernel/intern/sequencer.c
+++ b/source/blender/blenkernel/intern/sequencer.c
@@ -2452,6 +2452,42 @@ static TStripElem* do_build_seq_recursively(Scene *scene, Sequence * seq, int cf
 	return se;
 }
 
+static int seq_must_swap_input_in_blend_mode(Sequence * seq)
+{
+	int swap_input = FALSE;
+
+	/* bad hack, to fix crazy input ordering of 
+	   those two effects */
+
+	if (seq->blend_mode == SEQ_ALPHAOVER ||
+	    seq->blend_mode == SEQ_ALPHAUNDER ||
+	    seq->blend_mode == SEQ_OVERDROP) {
+		swap_input = TRUE;
+	}
+	
+	return swap_input;
+}
+
+static int seq_get_early_out_for_blend_mode(Sequence * seq)
+{
+	struct SeqEffectHandle sh = get_sequence_blend(seq);
+	float facf = seq->blend_opacity / 100.0;
+	int early_out = sh.early_out(seq, facf, facf);
+	
+	if (early_out < 1) {
+		return early_out;
+	}
+
+	if (seq_must_swap_input_in_blend_mode(seq)) {
+		if (early_out == 2) {
+			return 1;
+		} else if (early_out == 1) {
+			return 2;
+		}
+	}
+	return early_out;
+}
+
 static TStripElem* do_build_seq_array_recursively(Scene *scene,
 	ListBase *seqbasep, int cfra, int chanshown, int render_size)
 {
@@ -2460,7 +2496,8 @@ static TStripElem* do_build_seq_array_recursively(Scene *scene,
 	int i;
 	TStripElem* se = 0;
 
-	count = get_shown_sequences(seqbasep, cfra, chanshown, (Sequence **)&seq_arr);
+	count = get_shown_sequences(seqbasep, cfra, chanshown, 
+				    (Sequence **)&seq_arr);
 
 	if (!count) {
 		return 0;
@@ -2483,7 +2520,8 @@ static TStripElem* do_build_seq_array_recursively(Scene *scene,
 
 	
 	if(count == 1) {
-		se = do_build_seq_recursively(scene, seq_arr[0], cfra, render_size);
+		se = do_build_seq_recursively(scene, seq_arr[0],
+					      cfra, render_size);
 		if (se->ibuf) {
 			se->ibuf_comp = se->ibuf;
 			IMB_refImBuf(se->ibuf_comp);
@@ -2495,8 +2533,6 @@ static TStripElem* do_build_seq_array_recursively(Scene *scene,
 	for (i = count - 1; i >= 0; i--) {
 		int early_out;
 		Sequence * seq = seq_arr[i];
-		struct SeqEffectHandle sh;
-		float facf;
 
 		se = give_tstripelem(seq, cfra);
 
@@ -2506,7 +2542,9 @@ static TStripElem* do_build_seq_array_recursively(Scene *scene,
 			break;
 		}
 		if (seq->blend_mode == SEQ_BLEND_REPLACE) {
-			do_build_seq_recursively(scene, seq, cfra, render_size);
+			do_build_seq_recursively(
+				scene, seq, cfra, render_size);
+
 			if (se->ibuf) {
 				se->ibuf_comp = se->ibuf;
 				IMB_refImBuf(se->ibuf);
@@ -2521,16 +2559,14 @@ static TStripElem* do_build_seq_array_recursively(Scene *scene,
 			break;
 		}
 
-		sh = get_sequence_blend(seq);
-
-		facf = seq->blend_opacity / 100.0;
-
-		early_out = sh.early_out(seq, facf, facf);
+		early_out = seq_get_early_out_for_blend_mode(seq);
 
 		switch (early_out) {
 		case -1:
 		case 2:
-			do_build_seq_recursively(scene, seq, cfra, render_size);
+			do_build_seq_recursively(
+				scene, seq, cfra, render_size);
+
 			if (se->ibuf) {
 				se->ibuf_comp = se->ibuf;
 				IMB_refImBuf(se->ibuf_comp);
@@ -2554,7 +2590,9 @@ static TStripElem* do_build_seq_array_recursively(Scene *scene,
 			}
 			break;
 		case 0:
-			do_build_seq_recursively(scene, seq, cfra, render_size);
+			do_build_seq_recursively(
+				scene, seq, cfra, render_size);
+
 			if (!se->ibuf) {
 				se->ibuf = IMB_allocImBuf(
 					(short)seqrectx, (short)seqrecty, 
@@ -2584,14 +2622,13 @@ static TStripElem* do_build_seq_array_recursively(Scene *scene,
 		TStripElem* se2 = give_tstripelem(seq_arr[i], cfra);
 
 		float facf = seq->blend_opacity / 100.0;
-
-		int early_out = sh.early_out(seq, facf, facf);
+		int swap_input = seq_must_swap_input_in_blend_mode(seq);
+		int early_out = seq_get_early_out_for_blend_mode(seq);
 
 		switch (early_out) {
 		case 0: {
 			int x= se2->ibuf->x;
 			int y= se2->ibuf->y;
-			int swap_input = FALSE;
 
 			if(se1->ibuf_comp == NULL)
 				continue;
@@ -2626,15 +2663,6 @@ static TStripElem* do_build_seq_array_recursively(Scene *scene,
 				IMB_rect_from_float(se2->ibuf);
 			}
 			
-			/* bad hack, to fix crazy input ordering of 
-			   those two effects */
-
-			if (seq->blend_mode == SEQ_ALPHAOVER ||
-			    seq->blend_mode == SEQ_ALPHAUNDER ||
-			    seq->blend_mode == SEQ_OVERDROP) {
-				swap_input = TRUE;
-			}
-
 			if (swap_input) {
 				sh.execute(scene, seq, cfra, 
 					   facf, facf, x, y, 
@@ -2657,7 +2685,7 @@ static TStripElem* do_build_seq_array_recursively(Scene *scene,
 			break;
 		}
 		case 1: {
-			se2->ibuf_comp = se1->ibuf;
+			se2->ibuf_comp = se1->ibuf_comp;
 			if(se2->ibuf_comp)
 				IMB_refImBuf(se2->ibuf_comp);