BGE Patch: [#27425] Allow to change the damping of the camera actuator

##########
original name: "Allow to change the strenght of the "go behind" constraint of the camera actuator"

The camera actuator is an actuator that drive the camera to follow an object, with a set of constraint.
Currently, when the object followed rotate on himself (like a person, or an helicopter), the camera is really slow to go behind (at least 10 seconds).

This patch gives the UI to tweak the strenght of the 'go behind'[named damping] constraint.
###########

epydocs (rst) updated too

5 files changed, 26 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/sca.c b/source/blender/blenkernel/intern/sca.c
index 16cef67ea6d..0d523599598 100644
--- a/source/blender/blenkernel/intern/sca.c
+++ b/source/blender/blenkernel/intern/sca.c
@@ -430,6 +430,7 @@ void init_actuator(bActuator *act)
 		act->data= MEM_callocN(sizeof(bCameraActuator), "camact");
 		ca = act->data;
 		ca->axis = ACT_CAMERA_X;
+		ca->damping = 1.0/32.0;
 		break;
 	case ACT_EDIT_OBJECT:
 		act->data= MEM_callocN(sizeof(bEditObjectActuator), "editobact");
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 9d3035057ba..1e604c45772 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -11647,6 +11647,21 @@ static void do_versions(FileData *fd, Library *lib, Main *main)
 				}
 			}
 		}
+
+		{
+			/* add default value for behind strength of camera actuator */
+			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;
+
+						ba->damping = 1.0/32.0;
+					}
+				}
+			}
+		}
 	}
 	
 	/* WATCH IT!!!: pointers from libdata have not been converted yet here! */
diff --git a/source/blender/editors/space_logic/logic_window.c b/source/blender/editors/space_logic/logic_window.c
index bce492f5a04..019ce2a714a 100644
--- a/source/blender/editors/space_logic/logic_window.c
+++ b/source/blender/editors/space_logic/logic_window.c
@@ -3786,6 +3786,8 @@ static void draw_actuator_camera(uiLayout *layout, PointerRNA *ptr)
 	row = uiLayoutRow(layout, 1);
 	uiItemR(row, ptr, "min", 0, NULL, ICON_NONE);
 	uiItemR(row, ptr, "max", 0, NULL, ICON_NONE);
+
+	uiItemR(layout, ptr, "damping", 0, NULL, ICON_NONE);
 }
 
 static void draw_actuator_constraint(uiLayout *layout, PointerRNA *ptr, bContext *C)
diff --git a/source/blender/makesdna/DNA_actuator_types.h b/source/blender/makesdna/DNA_actuator_types.h
index 683d8142cc9..887a0300ee2 100644
--- a/source/blender/makesdna/DNA_actuator_types.h
+++ b/source/blender/makesdna/DNA_actuator_types.h
@@ -133,7 +133,7 @@ typedef struct bIpoActuator {
 typedef struct bCameraActuator {
 	struct Object *ob;
 	float height, min, max;
-	float pad;
+	float damping;
 	short pad1, axis;
 	float pad2;
 } bCameraActuator ;
diff --git a/source/blender/makesrna/intern/rna_actuator.c b/source/blender/makesrna/intern/rna_actuator.c
index c7cf511d5c7..cddba59f979 100644
--- a/source/blender/makesrna/intern/rna_actuator.c
+++ b/source/blender/makesrna/intern/rna_actuator.c
@@ -922,6 +922,13 @@ static void rna_def_camera_actuator(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Max", "");
 	RNA_def_property_update(prop, NC_LOGIC, NULL);
 
+	prop= RNA_def_property(srna, "damping", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_sdna(prop, NULL, "damping");
+	RNA_def_property_range(prop, 0, 10.0);
+	RNA_def_property_ui_range(prop, 0, 5.0, 1, 2);
+	RNA_def_property_ui_text(prop, "Damping", "Specify the strength of the constraint that drive the camera behind the target");
+	RNA_def_property_update(prop, NC_LOGIC, NULL);
+
 	/* x/y */
 	prop= RNA_def_property(srna, "axis", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_sdna(prop, NULL, "axis");