New exporter option: Export only key frames (#127)

The exporter will now only export key frames of an animation.

SkeletalAnimation.md

@@ -60,8 +60,11 @@ So what the exporter does is go frame by frame and have Blender calculate the bo
 This means that your animation in Ogre has a keyframe for every single frame from the start of the animation to the end.
 As a result of this setting IM_SPLINE for frame interpolation in Ogre would make no difference and might even slow down the skeletal animation.
 
+If you only require key frames exported, then make sure the "Only Keyframes" option is ticked in the exporter properties.
+
 ## Exporter Options:
  - *EX_ARMATURE_ANIMATION* (Armature Animation) : Export armature animations (updates the .skeleton file), enable this option to export the armature animations.
+ - *EX_ONLY_KEYFRAMES* (Only Keyframes) : Exports only the key frames. Influences that Inverse Kinematics, Drivers and modified F-Curves have on the animation will be lost.
  - *EX_ONLY_DEFORMABLE_BONES* (Only Deformable Bones) : Only exports bones that are deformable. Useful for hiding IK-Bones used in Blender. NOTE: Any bone with deformable children/descendants will be output as well
  - *EX_ONLY_KEYFRAMED_BONES* (Only Keyframed Bones) : Only exports bones that have been keyframed for a given animation. Useful to limit the set of bones on a per-animation basis
  - *EX_OGRE_INHERIT_SCALE* (OGRE Inherit Scale) : Whether the OGRE bones have the 'inherit scale' flag on. If the animation has scale in it, the exported animation needs to be adjusted to account for the state of the inherit-scale flag in OGRE.

io_ogre/config.py

@@ -58,6 +58,7 @@
     'OGRE_INHERIT_SCALE' : False,
     'ARMATURE_ANIMATION' : True,
     'TRIM_BONE_WEIGHTS' : 0.01,
+    'ONLY_KEYFRAMES' : False,
 
     # Mesh
     'MESH' : True,

io_ogre/ogre/skeleton.py

@@ -23,6 +23,8 @@
 
 logger = logging.getLogger('skeleton')
 
+# Function exports the Ogre .skeleton file
+# Called from ogre/scene.py > dot_scene_node_export() function
 def dot_skeleton(obj, path, **kwargs):
     """
     Create the .skeleton file for this object. 
@@ -374,13 +376,31 @@ def write_animation( self, arm, actionName, frameBegin, frameEnd, doc, parentEle
             if bone.shouldOutput:
                 bone_tracks.append( Bone_Track(bone) )
             bone.clear_pose_transform()  # clear out any leftover pose transforms in case this bone isn't keyframed
-        for frame in range( int(frameBegin), int(frameEnd)+1, bpy.context.scene.frame_step):#thanks to Vesa
+
+        # Decide keyframes to export:
+        # ONLY keyframes (Exported animation won't be affected by Inverse Kinematics, Drivers and modified F-Curves)
+        # OR export keyframe each frame over animation range (Exported animation will be affected by Inverse Kinematics, Drivers and modified F-Curves)
+        if config.get('ONLY_KEYFRAMES'): # Only keyframes 
+            frame_range = [] # Holds a list of keyframes for export
+            action = bpy.data.actions[actionName] # actionName is the animation name (NLAtrack child)
+            # loops through all channels on the f-curve --> Code taken from: https://blender.stackexchange.com/questions/8387/how-to-get-keyframe-data-from-python
+            for fcu in action.fcurves:
+                for keyframe in fcu.keyframe_points: # Loops through all the keyframes in the channel
+                    kf = keyframe.co[0] # key frame number
+                    if kf not in frame_range: # only add the key frames in once. Keyframes repeat in different channels
+                        frame_range.append(kf)
+        else: # Keyframes each frame
+            frame_range = range( int(frameBegin), int(frameEnd)+1, bpy.context.scene.frame_step) #thanks to Vesa, NOTE: frame_step is [( # of frames / FPS ) / # of frames ] -- I think??
+
+        # Add keyframes to export
+        for frame in frame_range:
             bpy.context.scene.frame_set(frame)
             for bone in self.roots:
                 bone.update()
             for track in bone_tracks:
                 track.add_keyframe((frame - frameBegin) / _fps)
-        # check to see if any animation tracks would be output
+
+        # Check to see if any animation tracks would be output
         animationFound = False
         for track in bone_tracks:
             if track.is_pos_animated() or track.is_rot_animated() or track.is_scale_animated():
@@ -392,8 +412,15 @@ def write_animation( self, arm, actionName, frameBegin, frameEnd, doc, parentEle
         parentElement.appendChild( anim )
         tracks = doc.createElement('tracks')
         anim.appendChild( tracks )
-        Report.armature_animations.append( '%s : %s [start frame=%s  end frame=%s]' %(arm.name, actionName, frameBegin, frameEnd) )
-
+
+        # Report and log
+        suffix_text = ''
+        if config.get('ONLY_KEYFRAMES'):
+            suffix_text = ' - Key frames: ' + str(key_frame_numbers)
+            logger.info('+ %s Key frames: %s' %(actionName,str(key_frame_numbers)))            
+        Report.armature_animations.append( '%s : %s [start frame=%s  end frame=%s]%s' %(arm.name, actionName, frameBegin, frameEnd,suffix_text) )        
+
+        # Write stuff to skeleton.xml file
         anim.setAttribute('name', actionName)                       # USE the action name
         anim.setAttribute('length', '%6f' %( (frameEnd - frameBegin)/_fps ) )
 
@@ -460,6 +487,10 @@ def to_xml( self ):
             if not len( arm.animation_data.nla_tracks ):
                 Report.warnings.append('You must assign an NLA strip to armature (%s) that defines the start and end frames' % arm.name)
 
+            # Log to console
+            if config.get('ONLY_KEYFRAMES'):
+                logger.info('+ Only exporting keyframes')
+
             actions = {}  # actions by name
             # the only thing NLA is used for is to gather the names of the actions
             # it doesn't matter if the actions are all in the same NLA track or in different tracks

io_ogre/ui/export.py

@@ -96,7 +96,7 @@ def draw(self, context):
             "Scene" : ["EX_SCENE", "EX_SELECTED_ONLY", "EX_EXPORT_HIDDEN", "EX_FORCE_CAMERA", "EX_FORCE_LAMPS", "EX_NODE_ANIMATION"], 
             "Materials" : ["EX_MATERIALS", "EX_SEPARATE_MATERIALS", "EX_COPY_SHADER_PROGRAMS"], 
             "Textures" : ["EX_DDS_MIPS", "EX_FORCE_IMAGE_FORMAT"], 
-            "Armature" : ["EX_ARMATURE_ANIMATION", "EX_ONLY_DEFORMABLE_BONES", "EX_ONLY_KEYFRAMED_BONES", "EX_OGRE_INHERIT_SCALE", "EX_TRIM_BONE_WEIGHTS"], 
+            "Armature" : ["EX_ARMATURE_ANIMATION", "EX_ONLY_KEYFRAMES", "EX_ONLY_DEFORMABLE_BONES", "EX_ONLY_KEYFRAMED_BONES", "EX_OGRE_INHERIT_SCALE", "EX_TRIM_BONE_WEIGHTS"], 
             "Mesh" : ["EX_MESH", "EX_MESH_OVERWRITE", "EX_V1_EXTREMITY_POINTS", "EX_Vx_GENERATE_EDGE_LISTS", "EX_GENERATE_TANGENTS", "EX_Vx_OPTIMISE_ANIMATIONS", "EX_V2_OPTIMISE_VERTEX_BUFFERS", "EX_V2_OPTIMISE_VERTEX_BUFFERS_OPTIONS"], 
             "LOD" : ["EX_LOD_LEVELS", "EX_LOD_DISTANCE", "EX_LOD_PERCENT", "EX_LOD_MESH_TOOLS"], 
             "Shape Animation" : ["EX_SHAPE_ANIMATIONS", "EX_SHAPE_NORMALS"], 
@@ -165,7 +165,7 @@ def execute(self, context):
                 kw[ name[3:] ] = getattr(self,name)
         config.update(**kw)
 
-        print ("_" * 80)
+        print ("_" * 80,"\n")
 
         target_path, target_file_name = os.path.split(os.path.abspath(self.filepath))
         target_file_name = clean_object_name(target_file_name)
@@ -311,6 +311,10 @@ def execute(self, context):
         name="Armature Animation",
         description="Export armature animations (updates the .skeleton file)",
         default=config.get('ARMATURE_ANIMATION')) = {}
+    EX_ONLY_KEYFRAMES : BoolProperty(
+        name="Only Keyframes",
+        description="Only export keyframes.\nNOTE: Exported animation won't be affected by Inverse Kinematics, Drivers and modified F-Curves",
+        default=config.get('ONLY_KEYFRAMES')) = {}
     EX_ONLY_DEFORMABLE_BONES : BoolProperty(
         name="Only Deformable Bones",
         description="Only exports bones that are deformable. Useful for hiding IK-Bones used in Blender.\nNOTE: Any bone with deformable children/descendants will be output as well",