Patch #7767: Constraint Subtargets can now target anywhere on a bone, not just the head or tail

Patch by: Roland Hess (harkyman)

For example, a constraint can be sub-targeted at the 50% (or 31.2% or 85% etc.) point of its target bone, giving you enormous rigging flexibility and removing the need for complex contraptions to do such things as:

- A bone whose base slides only between to points on a rig (CopyLoc with a variable, animated subtarget point)
- Bones that attach to multiple points along another bone (CopyLocs, each with a different head/tail percentage)
- Bones that need to stretch to a point midway between specific spots on two other bones (old way: too crazy to mention; new way: stretch bone between points on end bones, then another stretch to the midpoint of the first stretch)

It is only used for the constraint types for which it is relevant: CopyLoc, TrackTo, StretchTo and MinMax, TrackTo, and Floor.

Notes:
- This is accessed by the Head/Tail number-slider. 
- This value can be animated per constraint
- The old "Copy Bone Tail" option for the CopyLoc constraint has been automatically converted to 1.0 Head/Bone values for the affected constraints
- In the code, this value is in the bConstraint struct, so it is available for all constraints, even though only a few implement it.

2 files changed, 41 insertions, 11 deletions

diff --git a/source/blender/src/buttons_object.c b/source/blender/src/buttons_object.c
index 98c2914cee4..3a2c7bda497 100644
--- a/source/blender/src/buttons_object.c
+++ b/source/blender/src/buttons_object.c
@@ -494,7 +494,7 @@ static void draw_constraint (uiBlock *block, ListBase *list, bConstraint *con, s
 	Object *ob= OBACT;
 	bConstraintTypeInfo *cti;
 	uiBut *but;
-	char typestr[64];
+	char typestr[32];
 	short height, width = 265;
 	int rb_col;
 
@@ -807,7 +807,7 @@ static void draw_constraint (uiBlock *block, ListBase *list, bConstraint *con, s
 				/* Draw options */
 				uiDefButBitI(block, TOG, LOCLIKE_OFFSET, B_CONSTRAINT_TEST, "Offset", *xco, *yco-89, (width/2), 18, &data->flag, 0, 24, 0, 0, "Add original location onto copied location");
 				if (is_armature_target(data->tar)) {
-					uiDefButBitI(block, TOG, LOCLIKE_TIP, B_CONSTRAINT_TEST, "Target Bone Tail", *xco+(width/2), *yco-89, (width/2), 18, &data->flag, 0, 24, 0, 0, "Copy Location of Target Bone's Tail");
+					uiDefButF(block, NUM, B_CONSTRAINT_TEST, "Head/Tail:", *xco+(width/2), *yco-89, (width/2), 18, &con->headtail, 0.0, 1, 0.1, 0.1, "Target along length of bone: Head=0, Tail=1");
 				}
 				
 				/* constraint space settings */
@@ -978,7 +978,11 @@ static void draw_constraint (uiBlock *block, ListBase *list, bConstraint *con, s
 			{
 				bTrackToConstraint *data = con->data;
 				
-				height = 96;
+				if (is_armature_target(data->tar)) 
+					height = 118;
+				else
+					height = 96;
+					
 				uiDefBut(block, ROUNDBOX, B_DIFF, "", *xco-10, *yco-height, width+40,height-1, NULL, 5.0, 0.0, 12, rb_col, ""); 
 				
 				uiDefBut(block, LABEL, B_CONSTRAINT_TEST, "Target:", *xco+65, *yco-24, 50, 18, NULL, 0.0, 0.0, 0.0, 0.0, ""); 
@@ -1025,15 +1029,27 @@ static void draw_constraint (uiBlock *block, ListBase *list, bConstraint *con, s
 					uiDefButI(block, ROW,B_CONSTRAINT_TEST,"Z",	*xco+238, *yco-64,17,18, &data->reserved2, 13.0, 2.0, 0, 0, "Z axis points upward");
 				uiBlockEndAlign(block);
 				
-				/* constraint space settings */
-				draw_constraint_spaceselect(block, con, *xco, *yco-94, is_armature_owner(ob), is_armature_target(data->tar));
+				if (is_armature_target(data->tar)) {
+					uiDefButF(block, NUM, B_CONSTRAINT_TEST, "Head/Tail:", *xco, *yco-94, 241, 18, &con->headtail, 0.0, 1, 0.1, 0.1, "Target along length of bone: Head=0, Tail=1");
+					
+					/* constraint space settings */
+					draw_constraint_spaceselect(block, con, *xco, *yco-116, is_armature_owner(ob), is_armature_target(data->tar));
+				}
+				else {
+					/* constraint space settings */
+					draw_constraint_spaceselect(block, con, *xco, *yco-94, is_armature_owner(ob), is_armature_target(data->tar));
+				}
 			}
 			break;
 		case CONSTRAINT_TYPE_MINMAX:
 			{
 				bMinMaxConstraint *data = con->data;
 				
-				height = 66;
+				if (is_armature_target(data->tar)) 
+					height = 88;
+				else
+					height = 66;
+					
 				uiDefBut(block, ROUNDBOX, B_DIFF, "", *xco-10, *yco-height, width+40,height-1, NULL, 5.0, 0.0, 12, rb_col, ""); 
 				
 				uiDefBut(block, LABEL, B_CONSTRAINT_TEST, "Target:", *xco+65, *yco-24, 50, 18, NULL, 0.0, 0.0, 0.0, 0.0, ""); 
@@ -1070,6 +1086,11 @@ static void draw_constraint (uiBlock *block, ListBase *list, bConstraint *con, s
 					uiDefButI(block, ROW, B_CONSTRAINT_TEST,"-Y",	*xco+126, *yco-64,24,18, &data->minmaxflag, 12.0, 4.0, 0, 0, "Will not pass above Y of target");
 					uiDefButI(block, ROW, B_CONSTRAINT_TEST,"-Z",	*xco+150, *yco-64,24,18, &data->minmaxflag, 12.0, 5.0, 0, 0, "Will not pass above Z of target");
 				uiBlockEndAlign(block);
+				
+				if (is_armature_target(data->tar)) {
+					uiDefButF(block, NUM, B_CONSTRAINT_TEST, "Head/Tail:", *xco, *yco-86, 241, 18, &con->headtail, 0.0, 1, 0.1, 0.1, "Target along length of bone: Head=0, Tail=1");
+				}
+				
 			}
 			break;
 		case CONSTRAINT_TYPE_LOCKTRACK:
@@ -1181,13 +1202,19 @@ static void draw_constraint (uiBlock *block, ListBase *list, bConstraint *con, s
 					}
 				uiBlockEndAlign(block);
 				
-				
 				uiBlockBeginAlign(block);
-					uiDefButF(block,BUTM,B_CONSTRAINT_TEST,"R",*xco, *yco-60,20,18,&(data->orglength),0.0,0,0,0,"Recalculate RLength");
-					uiDefButF(block,NUM,B_CONSTRAINT_TEST,"Rest Length:",*xco+18, *yco-60,237,18,&(data->orglength),0.0,100,0.5,0.5,"Length at Rest Position");
+					if (is_armature_target(data->tar)) {
+						uiDefButF(block, BUTM, B_CONSTRAINT_TEST, "R", *xco, *yco-60, 20, 18, &data->orglength, 0.0, 0, 0, 0, "Recalculate RLength");
+						uiDefButF(block, NUM, B_CONSTRAINT_TEST, "Rest Length:", *xco+18, *yco-60,139,18, &data->orglength, 0.0, 100, 0.5, 0.5, "Length at Rest Position");
+						uiDefButF(block, NUM, B_CONSTRAINT_TEST, "Head/Tail:", *xco+155, *yco-60,97,18, &con->headtail, 0.0, 1, 0.1, 0.1, "Target along length of bone: Head=0, Tail=1");
+					}
+					else {
+						uiDefButF(block, BUTM, B_CONSTRAINT_TEST, "R", *xco, *yco-60, 20, 18, &data->orglength, 0.0, 0, 0, 0, "Recalculate RLength");
+						uiDefButF(block, NUM, B_CONSTRAINT_TEST, "Rest Length:", *xco+18, *yco-60, 237, 18, &data->orglength, 0.0, 100, 0.5, 0.5, "Length at Rest Position");
+					}
 				uiBlockEndAlign(block);
 				
-				uiDefButF(block,NUM,B_CONSTRAINT_TEST,"Volume Variation:",*xco+18, *yco-82,237,18,&(data->bulge),0.0,100,0.5,0.5,"Factor between volume variation and stretching");
+				uiDefButF(block, NUM, B_CONSTRAINT_TEST, "Volume Variation:", *xco+18, *yco-82, 237, 18, &data->bulge, 0.0, 100, 0.5, 0.5, "Factor between volume variation and stretching");
 				
 				uiBlockBeginAlign(block);
 					uiDefBut(block, LABEL, B_CONSTRAINT_TEST, "Vol:",*xco+14, *yco-104,30,18, NULL, 0.0, 0.0, 0.0, 0.0, ""); 
diff --git a/source/blender/src/editipo_lib.c b/source/blender/src/editipo_lib.c
index f10e100df7d..6ef45f32620 100644
--- a/source/blender/src/editipo_lib.c
+++ b/source/blender/src/editipo_lib.c
@@ -61,7 +61,7 @@ char *ob_ic_names[OB_TOTNAM] = { "LocX", "LocY", "LocZ", "dLocX", "dLocY", "dLoc
 	"Layer", "Time", "ColR", "ColG", "ColB", "ColA",
 	"FStreng", "FFall", "RDamp", "Damping", "Perm" };
 
-char *co_ic_names[CO_TOTNAM] = { "Inf" };
+char *co_ic_names[CO_TOTNAM] = { "Inf", "HeadTail" };
 char *mtex_ic_names[TEX_TOTNAM] = { "OfsX", "OfsY", "OfsZ", "SizeX", "SizeY", "SizeZ",
 	"texR", "texG", "texB", "DefVar", "Col", "Nor", "Var",
 	"Disp" };
@@ -191,6 +191,7 @@ char *getname_co_ei(int nr)
 {
 	switch(nr){
 		case CO_ENFORCE:
+		case CO_HEADTAIL:
 			return co_ic_names[nr-1];
 	}
 	return ic_name_empty[0];
@@ -388,3 +389,5 @@ int texchannel_to_adrcode(int channel)
 }
 
 
+
+