auto_walk/OP_animate_path.py

import bpy
from . import fn

## step 2 : Auto animate the path (with feet selection) and modal to adjust speed

def anim_path_from_y_translate():
    print(fn.helper())

    obj = bpy.context.object
    if obj.type != 'ARMATURE':
        return ('ERROR', 'active is not an armature type')

    # found curve through constraint
    b = bpy.context.active_pose_bone

    if not 'shoe' in b.bone.name:
        return ('ERROR', 'No "shoe" in active bone name\n-> Select foot that has the most reliable contact')

    curve = None
    if bpy.context.scene.anim_cycle_settings.path_to_follow:
        curve = bpy.context.scene.anim_cycle_settings.path_to_follow

    # if curve is not defined try to track it from constraints on armature
    if not curve:
        curve, _const = fn.get_follow_curve_from_armature(obj)
        if isinstance(curve, str):
            return curve, _const

    act = fn.get_obj_action(obj)
    if not act:
        return ('ERROR', f'No action active on {obj.name}')
    
    # use original action as ref
    if '_expanded' in act.name:
        base_act_name = act.name.split('_expanded')[0]
        base_act = bpy.data.action.get(base_act_name)
        if base_act:
            act = base_act
            print(f'Using for {base_act_name} as reference')
        else:
            print(f'No base action found (searching for {base_act_name})')
            
    # CHANGE - retiré le int de la frame
    # keyframes = [int(k.co[0]) for fcu in act.fcurves for k in fcu.keyframe_points]
    

    
    ## calculate offset from bones
    locy_fcu = None
    for fcu in act.fcurves:
        if fcu.data_path.split('"')[1] != b.bone.name:
            continue
        if fcu.data_path.split('.')[-1] == 'location' and fcu.array_index == 1:
            locy_fcu = fcu
    
    if not locy_fcu:
        return ('ERROR', 'Current bone, location.y animation not found')

    start = None
    end = None

    ## based on extreme
    for k in locy_fcu.keyframe_points:
        # if k.select_control_point: # based on selection
        if k.type == 'EXTREME': # using extreme keys.
            if start is None:
                start = k
            end = k
        else:
            if start is not None:
                ## means back to other frame type after passed breakdown we stop
                break
    
    if start and end:
        print(f'Offset from key range. start: {start.co.x} - end: {end.co.x}')

    if not start:
        return ('ERROR', f"No extreme marked frame was found on bone {b.bone.name}.{['x','y','z'][locy_fcu.array_index]}")
    if start == end:
       return ('ERROR', f'Only one key detected as extreme (at frame {start.co.x}) !\nNeed at least two chained marked keys')
    
    start_frame = start.co.x
    start_val = start.co.y

    end_frame = end.co.x
    end_val = end.co.y

    move_frame = end_frame - start_frame

    # Y positive value (forward) -> 
    move_val = abs(start_val - end_val)
    print('move_val: ', move_val)

    length = fn.get_curve_length(curve)    
    
    steps = length / move_val

    frame_duration = steps * move_frame


    ### Clear keyframe before creating new ones 
    # curve.data.animation_data_clear() # too much.. delete only eval_time
    if curve.data.animation_data and curve.data.animation_data.action:
        for fcu in curve.data.animation_data.action.fcurves:
            if fcu.data_path == 'eval_time':
                curve.data.animation_data.action.fcurves.remove(fcu)
                break

    anim_frame = bpy.context.scene.anim_cycle_settings.start_frame
    curve.data.path_duration = frame_duration
    curve.data.eval_time = 0
    curve.data.keyframe_insert('eval_time', frame=anim_frame)# , options={'INSERTKEY_AVAILABLE'}
    
    curve.data.eval_time = frame_duration
    curve.data.keyframe_insert('eval_time', frame=anim_frame + frame_duration)

    ## all to linear (will be set to CONSTANT at the moment of sampling)
    for fcu in curve.data.animation_data.action.fcurves:
        if fcu.data_path == 'eval_time':
            for k in fcu.keyframe_points:
                k.interpolation = 'LINEAR'
    
    ## set all to constant
    # for k in t_fcu.keyframe_points:
    #     k.interpolation = 'CONSTANT'
    
    print('end of set_follow_path_anim')

class UAC_OT_animate_path(bpy.types.Operator):
    bl_idname = "anim.animate_path"
    bl_label = "Animate Path"
    bl_description = "Select the most representative 'in contact' feet of the cycle"
    bl_options = {"REGISTER", "UNDO"}

    @classmethod
    def poll(cls, context):
        return context.object and context.object.type == 'ARMATURE'

    # def invoke(self, context, event):
    #     self.shift = event.shift
    #     return self.execute(context)

    def execute(self, context):
        # TODO clear previous animation (keys) if there is any
        err = anim_path_from_y_translate()
        if err:
            self.report({err[0]}, err[1])
            if err[0] == 'ERROR':
                return {"CANCELLED"}
        return {"FINISHED"}


class UAC_OT_adjust_animation_length(bpy.types.Operator):
    bl_idname = "anim.adjust_animation_length"
    bl_label = "Adjust Anim speed"
    bl_description = "Adjust speed\nOnce pressed, move up/down to move animation path last key value"
    bl_options = {"REGISTER"} # , "UNDO"

    @classmethod
    def poll(cls, context):
        return context.object and context.object.type in ('ARMATURE', 'CURVE')

    val : bpy.props.FloatProperty(name='End key value')

    def invoke(self, context, event):
        # check animation data of curve
        # self.pref = fn.get_addon_prefs()
        curve = bpy.context.scene.anim_cycle_settings.path_to_follow
        if not curve:
            if context.object.type != 'ARMATURE':
                self.report({'ERROR'}, 'no curve targeted in "Path" field')
                return {"CANCELLED"}

            curve, _const = fn.get_follow_curve_from_armature(context.object)
            if isinstance(curve, str):
                self.report({curve}, _const)
                return {"CANCELLED"}
        
        self.act = fn.get_obj_action(curve.data)
        if not self.act:
            self.report({'ERROR'}, f'No action on {curve.name} data')
            return {"CANCELLED"}

        # if '_expanded' in self.act.name:
        #     self.report({'WARNING'}, f'Action is expanded')

        self.fcu = None
        for fcu in self.act.fcurves:
            if fcu.data_path == 'eval_time':
                self.fcu = fcu
                break

        if not self.fcu or not len(self.fcu.keyframe_points):
            self.report({'ERROR'}, f'No eval_time animated on {curve.name} data action (or no keys)')
            return {"CANCELLED"}

        if len(self.fcu.keyframe_points) > 2:
            self.report({'WARNING'}, f'{curve.name} eval_time has {len(self.fcu.keyframe_points)} keyframe (should just have 2 to redefine speed)')
        
        self.k = self.fcu.keyframe_points[-1]
        self.val = self.init_ky = self.k.co.y
        self.init_my = event.mouse_y
        
        context.window_manager.modal_handler_add(self)
        return {'RUNNING_MODAL'}


    def modal(self, context, event):
        # added reduction factor
        self.val = self.init_ky + ((event.mouse_y - self.init_my) * 0.1)
        offset = self.val - self.init_ky
        display_text = f"Path animation end key value {self.val:.3f}, offset {offset:.3f}"
        context.area.header_text_set(display_text)
        self.k.co.y = self.val
        if event.type == 'LEFTMOUSE' and event.value == "PRESS":
            context.area.header_text_set(None)
            self.execute(context)
            return {"FINISHED"}
        
        if event.type in ('RIGHTMOUSE', 'ESC') and event.value == "PRESS":
            self.k.co.y = self.init_ky
            context.area.header_text_set(None)
            return {"CANCELLED"}
        if event.type in ('MIDDLEMOUSE', 'SPACE'): # Mmaybe not mid mouse ?
            return {'PASS_THROUGH'}
        return {"RUNNING_MODAL"}

    def execute(self, context):
        self.k.co.y = self.val
        return {"FINISHED"}

    # def draw(self, context):
    #     layout = self.layout
    #     layout.prop(self, "val")

classes=(
UAC_OT_animate_path,
UAC_OT_adjust_animation_length,
)

def register():
    for cls in classes:
        bpy.utils.register_class(cls)

def unregister():
    for cls in reversed(classes):
        bpy.utils.unregister_class(cls)