class GroundFollowing(avango.script.Script):
## input fields
sf_mat = avango.gua.SFMatrix4()
## ouput fields
sf_modified_mat = avango.gua.SFMatrix4()
## internal fields
mf_pick_result = avango.gua.MFPickResult()
## constructor
def __init__(self):
self.super(GroundFollowing).__init__()
def my_constructor(
self,
SCENEGRAPH=None,
START_MATRIX=avango.gua.make_identity_mat(),
):
### parameters ###
self.fall_velocity = 0.003 # in meter/sec
self.pick_length = 1.0 # in meter
self.pick_direction = avango.gua.Vec3(0.0, -1.0, 0.0)
### variables ###
self.fall_vec = avango.gua.Vec3()
self.lf_time = time.time()
## init internal sub-classes
self.gravity_intersection = Intersection()
self.gravity_intersection.my_constructor(SCENEGRAPH, self.sf_mat,
self.pick_length,
self.pick_direction)
## init field connections
self.mf_pick_result.connect_from(
self.gravity_intersection.mf_pick_result)
## set initial state
self.sf_modified_mat.value = START_MATRIX
### callback functions ###
def evaluate(
self): # evaluated once every frame if any input field has changed
self.lf_time = time.time(
) # save absolute time of last frame (required for frame-rate independent mapping)
#print(len(self.mf_pick_result.value))
if len(self.mf_pick_result.value) > 0: # intersection found
## compute gravity response
_pick_result = self.mf_pick_result.value[
0] # get first intersection target from list
_distance = _pick_result.Distance.value # distance from ray matrix to intersection point
_distance -= 0.025 # subtract half avatar height from distance
_distance -= self.fall_velocity
if _distance > 0.01: # avatar above ground
self.fall_vec.y = self.fall_velocity * -1.0
else: # avatar (almost) on ground
self.fall_vec.y = 0.0
#print(self.fall_vec)
self.sf_modified_mat.value = \
avango.gua.make_trans_mat(self.fall_vec) * \
self.sf_mat.value
else: # no intersection found
self.sf_modified_mat.value = self.sf_mat.value # no changes needed
