Pydrivers: Ipo Drivers controlled by Python expressions

wiki with info: http://mediawiki.blender.org/index.php/BlenderDev/PyDrivers

(there are two sample .blends in the patch tracker entry, last link in
the wiki page)

Notes:

In usiblender.c I just made Python exit before the main library gets
freed. I found a situation with pydrivers where py's gc tried to del
objects on exit and their ID's were not valid anymore (so sigsegv).

Ton needs to check the depsgraph part.

For now pydrivers can reference their own object, something normal
ipodrivers can't. This seems to work fine and is quite useful, but if
tests prove the restriction is necessary, we just need to uncomment a
piece of code in EXPP_interface.c, marked with "XXX".

Thanks Ton for the ipodrivers code and adding the hooks for the py part
and Martin for the "Button Python Evaluation" patch from which I started
this one.

Anyone interested, please check the wiki, the .blends (they have
README's) and tell me about any issue.

1 files changed, 44 insertions, 7 deletions

diff --git a/source/blender/src/drawipo.c b/source/blender/src/drawipo.c
index 642a7a0602e..ffbc8a67f9d 100644
--- a/source/blender/src/drawipo.c
+++ b/source/blender/src/drawipo.c
@@ -84,6 +84,8 @@
 #include "BSE_editipo_types.h"
 #include "BSE_editnla_types.h"
 
+#include "BPY_extern.h"
+
 #include "mydevice.h"
 #include "blendef.h"
 #include "butspace.h"	// shouldnt be...
@@ -1561,6 +1563,7 @@ static void draw_key(SpaceIpo *sipo, int visible)
 #define B_IPO_DRIVER	3405
 #define B_IPO_REDR		3406
 #define B_IPO_DEPCHANGE	3407
+#define B_IPO_DRIVERTYPE 3408
 
 static float hspeed= 0;
 
@@ -1755,7 +1758,12 @@ void do_ipobuts(unsigned short event)
 		ei= get_active_editipo();
 		if(ei) {
 			if(ei->icu->driver) {
-				if(G.sipo->blocktype==ID_KE || G.sipo->blocktype==ID_AC) 
+				if (ei->icu->driver->type == IPO_DRIVER_TYPE_PYTHON) {
+					/* eval user's expression once for validity */
+					BPY_pydriver_eval(ei->icu->driver);
+					DAG_scene_sort(G.scene);
+				}
+				else if(G.sipo->blocktype==ID_KE || G.sipo->blocktype==ID_AC) 
 					DAG_object_flush_update(G.scene, ob, OB_RECALC_DATA);
 				else
 					DAG_object_flush_update(G.scene, ob, OB_RECALC_OB);
@@ -1814,14 +1822,39 @@ void do_ipobuts(unsigned short event)
 			BIF_undo_push("Add/Remove Ipo driver");
 		}
 		break;
+	case B_IPO_DRIVERTYPE:
+		ei= get_active_editipo();
+		if(ei) {
+			if(ei->icu->driver) {
+				IpoDriver *driver= ei->icu->driver;
+
+				if(driver->type == IPO_DRIVER_TYPE_PYTHON) {
+					/* pydriver expression shouldn't reference own ob,
+					 * so we need to store ob ptr to check against it */
+					driver->ob= ob;
+				}
+				else {
+					driver->ob= NULL;
+					driver->blocktype= ID_OB;
+					driver->adrcode= OB_LOC_X;
+					driver->flag &= ~IPO_DRIVER_FLAG_INVALID;
+				}
+			}
+			allqueue(REDRAWVIEW3D, 0);
+			allqueue(REDRAWIPO, 0);
+			allqueue(REDRAWBUTSEDIT, 0);
+			DAG_scene_sort(G.scene);
+	
+			BIF_undo_push("Change Ipo driver type");
+		}
+		break;
 	case B_IPO_DEPCHANGE:
 		ei= get_active_editipo();
 		if(ei) {
 			if(ei->icu->driver) {
 				IpoDriver *driver= ei->icu->driver;
 				
-				if(driver->flag & IPO_DRIVER_PYTHON) {
-					driver->ob= NULL;
+				if(driver->type == IPO_DRIVER_TYPE_PYTHON) {
 				}
 				else {
 					if(driver->ob) {
@@ -1918,14 +1951,18 @@ static void ipo_panel_properties(short cntrl)	// IPO_HANDLER_PROPERTIES
 		
 		if(ei->icu && ei->icu->driver) {
 			IpoDriver *driver= ei->icu->driver;
-			
+
 			uiDefBut(block, BUT, B_IPO_DRIVER, "Remove",				210,265,100,20, NULL, 0.0f, 0.0f, 0, 0, "Remove Driver for this Ipo Channel");
 			
 			uiBlockBeginAlign(block);
-			uiDefIconButBitS(block, TOG, IPO_DRIVER_PYTHON, B_IPO_DEPCHANGE, ICON_PYTHON, 10,240,25,20, &driver->flag, 0, 0, 0, 0, "Use a one-line Python Expression as Driver");
-			
-			if(driver->flag & IPO_DRIVER_PYTHON) {
+			uiDefIconButS(block, TOG, B_IPO_DRIVERTYPE, ICON_PYTHON, 10,240,25,20, &driver->type, (float)IPO_DRIVER_TYPE_NORMAL, (float)IPO_DRIVER_TYPE_PYTHON, 0, 0, "Use a one-line Python Expression as Driver");
+
+			if(driver->type == IPO_DRIVER_TYPE_PYTHON) {
 				uiDefBut(block, TEX, B_IPO_REDR, "",				35,240,275,20, driver->name, 0, 127, 0, 0, "Python Expression");
+	 			if(driver->flag & IPO_DRIVER_FLAG_INVALID) {
+					uiDefBut(block, LABEL, 0, "Error: invalid Python expression",
+							5,215,230,19, NULL, 0, 0, 0, 0, "");
+				}
 				uiBlockEndAlign(block);
 			}
 			else {