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fgdata/Aircraft/Generic/WalkView/walkview.nas
2010-11-05 10:02:11 +01:00

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###############################################################################
##
## Walk view module for FlightGear.
##
## Inspired by the work of Stewart Andreason.
##
## Copyright (C) 2010 Anders Gidenstam (anders(at)gidenstam.org)
## This file is licensed under the GPL license v2 or later.
##
###############################################################################
# Global API. Automatically selects the right walker for the current view.
# NOTE: Coordinates are always 3 component lists: [x, y, z] in meters.
# The coordinate system is the same as the main 3d model one.
# X - back, Y - right and Z - up.
# Set the forward speed of the active walker.
# speed - walker speed in m/sec
# Returns 1 of there is an active walker and 0 otherwise.
var forward = func (speed) {
var cv = view.current.getPath();
if (contains(walkers, cv)) {
walkers[cv].forward(speed);
return 1;
} else {
return 0;
}
}
# Set the side step speed of the active walker.
# speed - walker speed in m/sec
# Returns 1 of there is an active walker and 0 otherwise.
var side_step = func (speed) {
var cv = view.current.getPath();
if (contains(walkers, cv)) {
walkers[cv].side_step(speed);
return 1;
} else {
return 0;
}
}
# Get the currently active walker.
# Returns the active walker object or nil otherwise.
var active_walker = func {
var cv = view.current.getPath();
if (contains(walkers, cv)) {
return walkers[cv];
} else {
return nil;
}
}
###############################################################################
# The walker class.
# ==============================================================================
# Class for a moving view.
#
# CONSTRUCTOR:
# walker.new(<view name>, <constraints>, <managers>);
#
# view name ... The name of the view : string
# constraints ... The movement constraints : constraint hash
# Determines where the view can go.
# managers ... Optional list of custom managers. A manager is a
# a hash that contains an update function of the type
# func(walker instance). The update function
# of each manager will be called as the last part of
# each walker update. Intended for controlling a
# a 3d model or similar.
#
# METHODS:
# active() : bool
# returns true if this walk view is active.
#
# forward(speed)
# Sets the forward speed of this walk view.
# speed ... speed in m/sec : double
#
# side_step(speed)
# Sets the side step speed of this walk view.
# speed ... speed in m/sec : double
#
# set_pos(pos)
# pos ... position in meter : [double, double, double]
# get_pos() : position ([meter, meter, meter])
#
# set_eye_height(h)
# get_eye_height() : int (meter)
#
# set_constraints(constraints)
# get_constraints() : constraint hash
#
# EXAMPLE:
# var constraint =
# walkview.slopingYAlignedPlane.new([19.1, -0.3, -8.85],
# [19.5, 0.3, -8.85]);
# var walker = walkview.walker.new("Passenger View", constraint);
#
# See Aircraft/Nordstern, Aircraft/Short_Empire and Aircraft/ZLT-NT
# for working examples of walk views.
#
# NOTES:
# Currently there can only be one view manager per view so the
# walk view should not have any other view manager.
var Walker = {
new : func (view_name, constraints = nil, managers = nil) {
var obj = { parents : [Walker] };
obj.view_name = view_name;
obj.view = view.views[view.indexof(view_name)];
obj.constraints = constraints;
obj.managers = managers;
obj.position = [
obj.view.getNode("config/z-offset-m").getValue(),
obj.view.getNode("config/x-offset-m").getValue(),
obj.view.getNode("config/y-offset-m").getValue()
];
obj.heading =
obj.view.getNode("config/heading-offset-deg").getValue();
obj.speed_fwd = 0.0;
obj.speed_side = 0.0;
obj.isactive = 0;
obj.eye_height = 1.60;
obj.goal_height = obj.position[2] + obj.eye_height;
# Register this walker.
view.manager.register(view_name, obj);
walkers[obj.view.getPath()] = obj;
#debug.dump(obj);
return obj;
},
active : func {
return me.isactive;
},
forward : func (speed) {
me.speed_fwd = speed;
},
side_step : func (speed) {
me.speed_side = speed;
},
set_pos : func (pos) {
me.position[0] = pos[0];
me.position[1] = pos[1];
me.position[2] = pos[2];
},
get_pos : func {
return [me.position[0], me.position[1], me.position[2]];
},
set_eye_height : func (h) {
me.eye_height = h;
},
get_eye_height : func {
return me.eye_height;
},
set_constraints : func (constraints) {
me.constraints = constraints;
},
get_constraints : func {
return me.constraints;
},
# View handler implementation.
init : func {
},
start : func {
me.isactive = 1;
me.last_time = getprop("/sim/time/elapsed-sec") - 0.0001;
me.update();
me.position[2] = me.goal_height;
},
stop : func {
me.isactive = 0;
},
# The update function is called by the view manager when the view is active.
update : func {
var t = getprop("/sim/time/elapsed-sec");
var dt = t - me.last_time;
if (dt == 0.0) return;
var cur = props.globals.getNode("/sim/current-view");
me.heading = cur.getNode("heading-offset-deg").getValue();
var new_pos =
[me.position[0] -
(me.speed_fwd * dt * math.cos(me.heading * TO_RAD) +
me.speed_side * dt * math.sin(me.heading * TO_RAD)),
me.position[1] -
(me.speed_fwd * dt * math.sin(me.heading * TO_RAD) -
me.speed_side * dt * math.cos(me.heading * TO_RAD)),
me.position[2]];
var cur_height = me.position[2];
if (me.constraints != nil) {
new_pos = me.constraints.constrain(new_pos);
if (new_pos == NO_POS) {
printlog("warn",
"WalkView: Constraint for " ~ me.view_name ~
" returned NO_POS.");
} else {
me.position = new_pos;
me.goal_height = me.position[2] + me.eye_height;
}
}
# Change the view height smoothly
if (math.abs(me.goal_height - cur_height) > 2.0 * dt) {
me.position[2] =
cur_height +
2.0 * dt *
((me.goal_height > cur_height) ? 1 : -1);
} else {
me.position[2] = me.goal_height;
}
cur.getNode("z-offset-m").setValue(me.position[0]);
cur.getNode("x-offset-m").setValue(me.position[1]);
cur.getNode("y-offset-m").setValue(me.position[2]);
if (me.managers != nil) {
foreach(var m; me.managers) {
m.update(me);
}
}
me.last_time = t;
return 0.0;
},
};
###############################################################################
# Constraint classes. Determines where the view can walk.
#
# Convenience functions.
# Build a UnionConstraint hierarchy from a list of constraints.
# cs - list of constraints : [constraint]
var makeUnionConstraint = func (cs) {
if (size(cs) < 2) return cs[0];
var ret = cs[0];
for (var i = 1; i < size(cs); i += 1) {
ret = UnionConstraint.new(ret, cs[i]);
}
return ret;
}
# Build a UnionConstraint hierachy that represents a polyline path
# with a certain width. Each internal point gets a circular surface.
# points - list of points : [position] ([[meter, meter, meter]])
# width - width of the path : length (meter)
# round_ends - put a circle also on the first and last points : bool
var makePolylinePath = func (points, width, round_ends = 0) {
if (size(points) < 2) return nil;
var ret = LinePlane.new(points[0], points[1], width);
if (round_ends) {
ret = UnionConstraint.new(line,
CircularXYSurface.new(points[0], width/2));
}
for (var i = 2; i < size(points); i += 1) {
var line = LinePlane.new(points[i-1], points[i], width);
if (i + 1 < size(points) or round_ends) {
line = UnionConstraint.new
(line,
CircularXYSurface.new(points[i], width/2));
}
ret = UnionConstraint.new(line, ret);
}
return ret;
}
# The union of two constraints.
# c1, c2 - the constraints : constraint
# NOTE: Assumes that the constraints are convex.
var UnionConstraint = {
new : func (c1, c2) {
var obj = { parents : [UnionConstraint] };
obj.c1 = c1;
obj.c2 = c2;
return obj;
},
constrain : func (pos) {
var p1 = me.c1.constrain(pos);
var p2 = me.c2.constrain(pos);
if (p1[0] == pos[0] and p1[1] == pos[1]) {
return p1;
} elsif (p2[0] == pos[0] and p2[1] == pos[1]) {
return p2;
} else {
if (closerXY(pos, p1, p2) <= 0) {
return p1;
} else {
return p2;
}
}
}
};
# Rectangular plane defined by a straight line and a width.
# The line is extruded horizontally on each side by width/2 into a
# planar surface.
# p1, p2 - the line endpoints. : position ([meter, meter, meter])
# width - total width of the plane. : length (meter)
var LinePlane = {
new : func (p1, p2, width) {
var obj = { parents : [LinePlane] };
obj.p1 = p1;
obj.p2 = p2;
obj.halfwidth = width/2;
obj.length = vec2.length(vec2.sub(p2, p1));
obj.e1 = vec2.normalize(vec2.sub(p2, p1));
obj.e2 = [obj.e1[1], -obj.e1[0]];
obj.k = (p2[2] - p1[2]) / obj.length;
return obj;
},
constrain : func (pos) {
var p = [pos[0], pos[1], pos[2]];
var pXY = vec2.sub(pos, me.p1);
var along = vec2.dot(pXY, me.e1);
var across = vec2.dot(pXY, me.e2);
var along2 = max(0, min(along, me.length));
var across2 = max(-me.halfwidth, min(across, me.halfwidth));
if (along2 != along or across2 != across) {
# Compute new XY position.
var t = vec2.add(vec2.mul(along2, me.e1), vec2.mul(across2, me.e2));
p[0] = me.p1[0] + t[0];
p[1] = me.p1[1] + t[1];
}
# Compute Z positition.
p[2] = me.p1[2] + me.k * along2;
return p;
}
};
# Circular surface aligned with the XY plane
# center - the center point : position ([meter, meter, meter])
# radius - radius in the XY plane : length (meter)
var CircularXYSurface = {
new : func (center, radius) {
var obj = { parents : [CircularXYSurface] };
obj.center = center;
obj.radius = radius;
return obj;
},
constrain : func (pos) {
var p = [pos[0], pos[1], me.center[2]];
var pXY = vec2.sub(pos, me.center);
var lXY = vec2.length(pXY);
if (lXY > me.radius) {
var t = vec2.add(me.center, vec2.mul(me.radius/lXY, pXY));
p[0] = t[0];
p[1] = t[1];
}
return p;
},
};
# Mostly aligned plane sloping along the X axis.
# NOTE: Obsolete. Use linePlane instead.
# minp - the X,Y minimum point : position ([meter, meter, meter])
# maxp - the X,Y maximum point : position ([meter, meter, meter])
var SlopingYAlignedPlane = {
new : func (minp, maxp) {
return LinePlane.new([minp[0], (minp[1] + maxp[1])/2, minp[2]],
[maxp[0], (minp[1] + maxp[1])/2, maxp[2]],
(maxp[1] - minp[1]));
}
};
# Action constraint
# Triggers an action when entering or exiting the constraint.
# constraint - the area in question : constraint
# on_enter() - function that is called when the walker enters the area.
# on_exit(x, y) - function that is called when the walker leaves the area.
# x and y are <0, 0 or >0 depending on in which direction(s)
# the walker left the constraint.
var ActionConstraint = {
new : func (constraint, on_enter = nil, on_exit = nil) {
var obj = { parents : [ActionConstraint] };
obj.constraint = constraint;
obj.on_enter = on_enter;
obj.on_exit = on_exit;
obj.inside = 0;
return obj;
},
constrain : func (pos) {
var p = me.constraint.constrain(pos);
if (p[0] == pos[0] and p[1] == pos[1]) {
if (!me.inside) {
me.inside = 1;
if (me.on_enter != nil) {
me.on_enter();
}
}
} else {
if (me.inside) {
me.inside -= 1;
if (!me.inside and me.on_exit != nil) {
me.on_exit(pos[0] - p[0], pos[1] - p[1]);
}
}
}
return p;
}
};
# Conditional constraint
# The area is only available when the predicate function returns true.
# constraint - the area in question : constraint
# predicate() - boolean function that determines if the area is available.
var ConditionalConstraint = {
new : func (constraint, predicate = nil) {
var obj = { parents : [ConditionalConstraint] };
obj.constraint = constraint;
obj.predicate = predicate;
return obj;
},
constrain : func (pos) {
if (me.predicate == nil or me.predicate()) {
return me.constraint.constrain(pos);
} else {
return NO_POS;
}
}
};
###############################################################################
# Manager classes.
# JSBSim pointmass manager.
# Moves a pointmass representing the crew member together with the view.
# CONSTRUCTOR:
# JSBSimPointmass.new(<pointmass index>);
#
# pointmass index ... The index of the pointmass : int
# offsets ... [x, y ,z] position in meter of the origin of the
# JSBSim structural frame in the 3d model frame.
#
# NOTE: Only supports aligned frames (yet).
#
var JSBSimPointmass = {
new : func (index, offsets = nil) {
var base = props.globals.getNode("fdm/jsbsim/inertia");
var prefix = "pointmass-location-";
var postfix = "-inches[" ~ index ~"]";
var obj = { parents : [JSBSimPointmass] };
obj.pos_ft =
[
base.getNode(prefix ~ "X" ~ postfix),
base.getNode(prefix ~ "Y" ~ postfix),
base.getNode(prefix ~ "Z" ~ postfix)
];
obj.offset = (offsets == nil) ? [0.0, 0.0, 0.0] : offsets;
return obj;
},
update : func (walker) {
var pos = walker.get_pos();
pos[2] += walker.get_eye_height()/2;
forindex (var i; pos) {
me.pos_ft[i].setValue((pos[i] - me.offset[i])*M2FT*12);
}
}
};
###############################################################################
# Module implementation below
var TO_RAD = math.pi/180;
var TO_DEG = 180/math.pi;
var NO_POS = [-9999.0, -9999.0, -9999.0];
var walkers = {};
var closerXY = func (pos, p1, p2) {
var l1 = [p1[0] - pos[0], p1[1] - pos[1]];
var l2 = [p2[0] - pos[0], p2[1] - pos[1]];
return (l1[0]*l1[0] + l1[1]*l1[1]) - (l2[0]*l2[0] + l2[1]*l2[1]);
}
var max = func (a, b) {
return b > a ? b : a;
}
var min = func (a, b) {
return a > b ? b : a;
}
# 2D vector math.
var vec2 = {
add : func (a, b) {
return [a[0] + b[0], a[1] + b[1]];
},
sub : func (a, b) {
return [a[0] - b[0], a[1] - b[1]];
},
mul : func (k, a) {
return [k * a[0], k * a[1]];
},
length : func (a) {
return math.sqrt(a[0]*a[0] + a[1]*a[1]);
},
dot : func (a, b) {
return a[0]*b[0] + a[1]*b[1];
},
normalize : func (a) {
var s = 1/vec2.length(a);
return [s * a[0], s * a[1]];
}
}