bge camera actuator: -X and -Y axis

The camera actuator only allows to look the object from its front face.

Given that Blender takes -Y as the default forward orientation, the current
functionality doesn't let a camera to track an actor from behind.

This patch allows for -X and -Y axis tracking. This way a camera over the
shoulders of a character is possible (without resorting to rotate the
mesh/armature original orientation.

- patch reviewed by Campbell Barton, thanks

7 files changed, 74 insertions, 33 deletions

diff --git a/source/blender/blenkernel/intern/sca.c b/source/blender/blenkernel/intern/sca.c
index f7eda6bd9b3..92dfe90eec1 100644
--- a/source/blender/blenkernel/intern/sca.c
+++ b/source/blender/blenkernel/intern/sca.c
@@ -428,7 +428,7 @@ void init_actuator(bActuator *act)
 	case ACT_CAMERA:
 		act->data= MEM_callocN(sizeof(bCameraActuator), "camact");
 		ca = act->data;
-		ca->axis = ACT_CAMERA_X;
+		ca->axis = OB_POSX;
 		ca->damping = 1.0/32.0;
 		break;
 	case ACT_EDIT_OBJECT:
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index bb5682f4ebd..1f45be6848d 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -12941,7 +12941,23 @@ static void do_versions(FileData *fd, Library *lib, Main *main)
 
 	/* put compatibility code here until next subversion bump */
 	{
-		
+		{
+			/* convert Camera Actuator values to defines */
+			Object *ob;
+			bActuator *act;
+			for(ob = main->object.first; ob; ob= ob->id.next) {
+				for(act= ob->actuators.first; act; act= act->next) {
+					if (act->type == ACT_CAMERA) {
+						bCameraActuator *ba= act->data;
+
+						if(ba->axis==(float) 'x') ba->axis=OB_POSX;
+						else if (ba->axis==(float)'y') ba->axis=OB_POSY;
+						/* don't do an if/else to avoid imediate subversion bump*/
+//					ba->axis=((ba->axis == (float) 'x')?OB_POSX_X:OB_POSY);
+					}
+				}
+			}
+		}
 	}
 
 	/* WATCH IT!!!: pointers from libdata have not been converted yet here! */
diff --git a/source/blender/makesdna/DNA_actuator_types.h b/source/blender/makesdna/DNA_actuator_types.h
index a4280a6e463..076910ade1f 100644
--- a/source/blender/makesdna/DNA_actuator_types.h
+++ b/source/blender/makesdna/DNA_actuator_types.h
@@ -520,10 +520,6 @@ typedef struct bActuator {
 #define ACT_STATE_REMOVE	2
 #define ACT_STATE_CHANGE	3
 
-/* cameraactuator->axis */
-#define ACT_CAMERA_X		(float)'x'
-#define ACT_CAMERA_Y		(float)'y'
-
 /* steeringactuator->type */
 #define ACT_STEERING_SEEK   0
 #define ACT_STEERING_FLEE   1
diff --git a/source/blender/makesrna/intern/rna_actuator.c b/source/blender/makesrna/intern/rna_actuator.c
index 612c34d1c92..6098e885df5 100644
--- a/source/blender/makesrna/intern/rna_actuator.c
+++ b/source/blender/makesrna/intern/rna_actuator.c
@@ -867,8 +867,10 @@ static void rna_def_camera_actuator(BlenderRNA *brna)
 	PropertyRNA *prop;
 
 	static EnumPropertyItem prop_axis_items[] ={
-		{ACT_CAMERA_X, "X", 0, "X", "Camera tries to get behind the X axis"},
-		{ACT_CAMERA_Y, "Y", 0, "Y", "Camera tries to get behind the Y axis"},
+		{OB_POSX, "POS_X", 0, "+X", "Camera tries to get behind the X axis"},
+		{OB_POSY, "POS_Y", 0, "+Y", "Camera tries to get behind the Y axis"},
+		{OB_NEGX, "NEG_X", 0, "-X", "Camera tries to get behind the -X axis"},
+		{OB_NEGY, "NEG_Y", 0, "-Y", "Camera tries to get behind the -Y axis"},
 		{0, NULL, 0, NULL, NULL}};
 	
 	srna= RNA_def_struct(brna, "CameraActuator", "Actuator");
@@ -905,7 +907,7 @@ static void rna_def_camera_actuator(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Damping", "Strength of the constraint that drives the camera behind the target");
 	RNA_def_property_update(prop, NC_LOGIC, NULL);
 
-	/* x/y */
+	/* +x/+y/-x/-y */
 	prop= RNA_def_property(srna, "axis", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_sdna(prop, NULL, "axis");
 	RNA_def_property_enum_items(prop, prop_axis_items);
diff --git a/source/gameengine/Converter/KX_ConvertActuators.cpp b/source/gameengine/Converter/KX_ConvertActuators.cpp
index f4b173763d3..be14400f33a 100644
--- a/source/gameengine/Converter/KX_ConvertActuators.cpp
+++ b/source/gameengine/Converter/KX_ConvertActuators.cpp
@@ -300,7 +300,7 @@ void BL_ConvertActuators(const char* maggiename,
 						camact->height,
 						camact->min,
 						camact->max,
-						camact->axis=='x',
+						camact->axis,
 						camact->damping);
 					baseact = tmpcamact;
 				}
diff --git a/source/gameengine/Ketsji/KX_CameraActuator.cpp b/source/gameengine/Ketsji/KX_CameraActuator.cpp
index d4aae68dafb..cd0aff0a87b 100644
--- a/source/gameengine/Ketsji/KX_CameraActuator.cpp
+++ b/source/gameengine/Ketsji/KX_CameraActuator.cpp
@@ -53,7 +53,7 @@ KX_CameraActuator::KX_CameraActuator(
 	float hght,
 	float minhght,
 	float maxhght,
-	bool  xytog,
+	short axis,
 	float damping
 ): 
 	SCA_IActuator(gameobj, KX_ACT_CAMERA),
@@ -61,7 +61,7 @@ KX_CameraActuator::KX_CameraActuator(
 	m_height (hght),
 	m_minHeight (minhght),
 	m_maxHeight (maxhght),
-	m_x (xytog),
+	m_axis(axis),
 	m_damping (damping)
 {
 	if (m_ob)
@@ -264,23 +264,50 @@ bool KX_CameraActuator::Update(double curtime, bool frame)
 
 
 	/* C4: camera behind actor   */
-	if (m_x) {
-		fp1[0] = actormat[0][0];
-		fp1[1] = actormat[1][0];
-		fp1[2] = actormat[2][0];
-
-		fp2[0] = frommat[0][0];
-		fp2[1] = frommat[1][0];
-		fp2[2] = frommat[2][0];
-	} 
-	else {
-		fp1[0] = actormat[0][1];
-		fp1[1] = actormat[1][1];
-		fp1[2] = actormat[2][1];
-
-		fp2[0] = frommat[0][1];
-		fp2[1] = frommat[1][1];
-		fp2[2] = frommat[2][1];
+	switch (m_axis) {
+		case OB_POSX:
+			/* X */
+			fp1[0] = actormat[0][0];
+			fp1[1] = actormat[1][0];
+			fp1[2] = actormat[2][0];
+
+			fp2[0] = frommat[0][0];
+			fp2[1] = frommat[1][0];
+			fp2[2] = frommat[2][0];
+			break;
+		case OB_POSY:
+			/* Y */
+			fp1[0] = actormat[0][1];
+			fp1[1] = actormat[1][1];
+			fp1[2] = actormat[2][1];
+
+			fp2[0] = frommat[0][1];
+			fp2[1] = frommat[1][1];
+			fp2[2] = frommat[2][1];
+			break;
+		case OB_NEGX:
+			/* -X */
+			fp1[0] = -actormat[0][0];
+			fp1[1] = -actormat[1][0];
+			fp1[2] = -actormat[2][0];
+
+			fp2[0] = frommat[0][0];
+			fp2[1] = frommat[1][0];
+			fp2[2] = frommat[2][0];
+			break;
+		case OB_NEGY:
+			/* -Y */
+			fp1[0] = -actormat[0][1];
+			fp1[1] = -actormat[1][1];
+			fp1[2] = -actormat[2][1];
+
+			fp2[0] = frommat[0][1];
+			fp2[1] = frommat[1][1];
+			fp2[2] = frommat[2][1];
+			break;
+		default:
+			assert(0);
+			break;
 	}
 	
 	inp= fp1[0]*fp2[0] + fp1[1]*fp2[1] + fp1[2]*fp2[2];
@@ -389,7 +416,7 @@ PyAttributeDef KX_CameraActuator::Attributes[] = {
 	KX_PYATTRIBUTE_FLOAT_RW("min",-FLT_MAX,FLT_MAX,KX_CameraActuator,m_minHeight),
 	KX_PYATTRIBUTE_FLOAT_RW("max",-FLT_MAX,FLT_MAX,KX_CameraActuator,m_maxHeight),
 	KX_PYATTRIBUTE_FLOAT_RW("height",-FLT_MAX,FLT_MAX,KX_CameraActuator,m_height),
-	KX_PYATTRIBUTE_BOOL_RW("useXY",KX_CameraActuator,m_x),
+	KX_PYATTRIBUTE_SHORT_RW("axis", 0, 3, true, KX_CameraActuator,m_axis),
 	KX_PYATTRIBUTE_RW_FUNCTION("object", KX_CameraActuator, pyattr_get_object,	pyattr_set_object),
 	KX_PYATTRIBUTE_FLOAT_RW("damping",0.f,10.f,KX_CameraActuator,m_damping),
 	{NULL}
diff --git a/source/gameengine/Ketsji/KX_CameraActuator.h b/source/gameengine/Ketsji/KX_CameraActuator.h
index a6344ae380a..1cae676fe3f 100644
--- a/source/gameengine/Ketsji/KX_CameraActuator.h
+++ b/source/gameengine/Ketsji/KX_CameraActuator.h
@@ -70,8 +70,8 @@ private :
 	/** max (float), */
 	float m_maxHeight;
 	
-	/** xy toggle (pick one): true == x, false == y */
-	bool m_x;
+	/** axis the camera tries to get behind: +x/+y/-x/-y */
+	short m_axis;
 	
 	/** damping (float), */
 	float m_damping;
@@ -97,7 +97,7 @@ private :
 		float hght,
 		float minhght,
 		float maxhght,
-		bool xytog,
+		short axis,
 		float damping
 	);