Cycles F-Curve Modifier: 'Mirrored' Option

Using this cycling mode option, the keyframe range will be repeated in reverse order every second repeat. Thanks for the idea mfoxdogg :)

4 files changed, 19 insertions, 6 deletions

diff --git a/source/blender/blenkernel/intern/fcurve.c b/source/blender/blenkernel/intern/fcurve.c
index 3bc80d64329..0585717e13e 100644
--- a/source/blender/blenkernel/intern/fcurve.c
+++ b/source/blender/blenkernel/intern/fcurve.c
@@ -1736,6 +1736,7 @@ static float fcm_cycles_time (FCurve *fcu, FModifier *fcm, float cvalue, float e
 	/* find relative place within a cycle */
 	{
 		float cycdx=0, cycdy=0, ofs=0;
+		float cycle= 0;
 		
 		/* ofs is start frame of cycle */
 		ofs= prevkey[0];
@@ -1748,13 +1749,16 @@ static float fcm_cycles_time (FCurve *fcu, FModifier *fcm, float cvalue, float e
 		if (cycdx == 0)
 			return evaltime;
 			
+		/* calculate the 'number' of the cycle */
+		cycle= ((float)side * (evaltime - ofs) / cycdx);
+		
 		/* check that cyclic is still enabled for the specified time */
 		if (cycles == 0) {
 			/* catch this case so that we don't exit when we have cycles=0
 			 * as this indicates infinite cycles...
 			 */
 		}
-		else if ( ((float)side * (evaltime - ofs) / cycdx) > (cycles+1) ) {
+		else if (cycle > (cycles+1)) {
 			/* we are too far away from range to evaluate
 			 * TODO: but we should still hold last value... 
 			 */
@@ -1768,7 +1772,14 @@ static float fcm_cycles_time (FCurve *fcu, FModifier *fcm, float cvalue, float e
 		}
 		
 		/* calculate where in the cycle we are (overwrite evaltime to reflect this) */
-		evaltime= (float)(fmod(evaltime-ofs, cycdx) + ofs);
+		if ((mode == FCM_EXTRAPOLATE_MIRROR) && ((int)(cycle) % 2)) {
+			/* when 'mirror' option is used and cycle number is odd, this cycle is played in reverse */
+			evaltime= (float)(lastkey[0] - fmod(evaltime-ofs, cycdx));
+		}
+		else {
+			/* the cycle is played normally... */
+			evaltime= (float)(fmod(evaltime-ofs, cycdx) + ofs);
+		}
 		if (evaltime < ofs) evaltime += cycdx;
 	}
 	
diff --git a/source/blender/editors/space_graph/graph_buttons.c b/source/blender/editors/space_graph/graph_buttons.c
index ee10e4ef3b3..16628f31b63 100644
--- a/source/blender/editors/space_graph/graph_buttons.c
+++ b/source/blender/editors/space_graph/graph_buttons.c
@@ -545,7 +545,7 @@ static void draw_modifier__generator(uiBlock *block, FCurve *fcu, FModifier *fcm
 static void draw_modifier__cycles(uiBlock *block, FCurve *fcu, FModifier *fcm, int *yco, short *height, short width, short active, int rb_col)
 {
 	FMod_Cycles *data= (FMod_Cycles *)fcm->data;
-	char cyc_mode[]="Cycling Mode%t|No Cycles%x0|Repeat Motion%x1|Repeat with Offset%x2";
+	char cyc_mode[]="Cycling Mode%t|No Cycles%x0|Repeat Motion%x1|Repeat with Offset%x2|Repeat Mirrored%x3";
 	int cy= (*yco - 30), cy1= (*yco - 50), cy2= (*yco - 70);
 	
 	/* set the height */
diff --git a/source/blender/makesdna/DNA_anim_types.h b/source/blender/makesdna/DNA_anim_types.h
index 755569fe0cb..f30cd63242a 100644
--- a/source/blender/makesdna/DNA_anim_types.h
+++ b/source/blender/makesdna/DNA_anim_types.h
@@ -144,6 +144,7 @@ enum {
 	FCM_EXTRAPOLATE_NONE = 0,			/* don't do anything */
 	FCM_EXTRAPOLATE_CYCLIC,				/* repeat keyframe range as-is */
 	FCM_EXTRAPOLATE_CYCLIC_OFFSET,		/* repeat keyframe range, but with offset based on gradient between values */
+	FCM_EXTRAPOLATE_MIRROR,				/* alternate between forward and reverse playback of keyframe range */
 } eFMod_Cycling_Modes;
 
 
diff --git a/source/blender/makesrna/intern/rna_fcurve.c b/source/blender/makesrna/intern/rna_fcurve.c
index 5b8e05f840b..6c58c521535 100644
--- a/source/blender/makesrna/intern/rna_fcurve.c
+++ b/source/blender/makesrna/intern/rna_fcurve.c
@@ -325,9 +325,10 @@ static void rna_def_fmodifier_cycles(BlenderRNA *brna)
 	PropertyRNA *prop;
 	
 	static EnumPropertyItem prop_type_items[] = {
-		{0, "NONE", "No Cycles", ""},
-		{1, "REPEAT", "Repeat Motion", ""},
-		{1, "REPEAT_OFFSET", "Repeat with Offset", ""},
+		{FCM_EXTRAPOLATE_NONE, "NONE", "No Cycles", "Don't do anything."},
+		{FCM_EXTRAPOLATE_CYCLIC, "REPEAT", "Repeat Motion", "Repeat keyframe range as-is."},
+		{FCM_EXTRAPOLATE_CYCLIC_OFFSET, "REPEAT_OFFSET", "Repeat with Offset", "Repeat keyframe range, but with offset based on gradient between values"},
+		{FCM_EXTRAPOLATE_MIRROR, "MIRROR", "Repeat Mirrored", "Alternate between forward and reverse playback of keyframe range"},
 		{0, NULL, NULL, NULL}};
 	
 	srna= RNA_def_struct(brna, "FModifierCycles", "FModifier");