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RoadLane offset approx algorithm #155

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merged 3 commits into from
Feb 21, 2024
Merged

RoadLane offset approx algorithm #155

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770aa58
WIP improve road curve offsets
bdog2112 Feb 17, 2024
bbf86f4
Added rigid angle checking to curve offset algorithm
bdog2112 Feb 18, 2024
f7e5960
Applying static typing assignments to curve offset algorithm
TheDuckCow Feb 21, 2024
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89 changes: 74 additions & 15 deletions addons/road-generator/nodes/road_segment.gd
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@ extends Spatial
# const RoadSegment = preload("res://addons/road-generator/road_segment.gd")

const LOWPOLY_FACTOR = 3.0
const RAD_NINETY_DEG = PI/2 # aka 1.5707963267949, used for offset_curve algorithm

signal seg_ready(road_segment)

Expand Down Expand Up @@ -262,10 +263,6 @@ func generate_lane_segments(_debug: bool = false) -> bool:
new_ln.lane_next_tag = this_match[3]
new_ln.name = ln_name

# Now decide where the two poitns should go, and their magnitudes.
var in_pos: Vector3 = start_point.global_transform.origin
var out_pos: Vector3 = end_point.global_transform.origin

var tmp = get_transition_offset(
ln_type, ln_dir, lane_shift, end_is_wider, max_rev_shift)
var start_shift:float = tmp[0]
Expand All @@ -274,9 +271,6 @@ func generate_lane_segments(_debug: bool = false) -> bool:
var in_offset = lanes_added * start_point.lane_width - start_offset + start_shift
var out_offset = lanes_added * end_point.lane_width - end_offset + end_shift

in_pos += start_point.global_transform.basis.x * in_offset * _start_flip_mult
out_pos += end_point.global_transform.basis.x * out_offset * _end_flip_mult

# Set direction
# TODO: When directionality is made consistent, we should no longer
# need to invert the direction assignment here.
Expand All @@ -286,14 +280,7 @@ func generate_lane_segments(_debug: bool = false) -> bool:
# TODO(#46): Swtich to re-sampling and adding more points following the
# curve along from the parent path generator, including its use of ease
# in and out at the edges.
new_ln.curve.add_point(
new_ln.to_local(in_pos),
new_ln.to_local(to_global(curve.get_point_in(0))),
new_ln.to_local(to_global(curve.get_point_out(0))))
new_ln.curve.add_point(
new_ln.to_local(out_pos),
new_ln.to_local(to_global(curve.get_point_in(1))),
new_ln.to_local(to_global(curve.get_point_out(1))))
offset_curve(self, new_ln, in_offset, out_offset, start_point, end_point)

# Visually display.
new_ln.draw_in_editor = container.draw_lanes_editor
Expand Down Expand Up @@ -321,6 +308,78 @@ func generate_lane_segments(_debug: bool = false) -> bool:
return any_generated


## Offsets a destination curve from a source curve by a specified distance.
##
## Evaluates 4 points on source curve: Point 0 and 1 positions as well as
## point-0-out and point-1-in handles. Requires transforms for point 0
## and point 1, which determine the direction of the handles. Calculates best
## fit position for destination curve given the supplied curves, transforms,
## and distance.
func offset_curve(road_seg: Spatial, road_lane: Path, in_offset: float, out_offset: float, rp0: Spatial, rp1: Spatial):

var src:Curve3D = road_seg.curve
var dst:Curve3D = road_lane.curve
var a_gbasis := rp0.global_transform.basis
var d_gbasis := rp1.global_transform.basis
var in_pos := start_point.global_transform.origin + (a_gbasis.x * in_offset * _start_flip_mult)
var out_pos := end_point.global_transform.origin + (d_gbasis.x * out_offset * _end_flip_mult)

# Get initial point locations
var pt_a := to_global(src.get_point_position(0))
var pt_b := to_global(src.get_point_position(0) + src.get_point_out(0))
var pt_c := to_global(src.get_point_position(1) + src.get_point_in(1))
var pt_d := to_global(src.get_point_position(1))

# TTD: Project point(s) onto plane(s)

# Project primary curve points to secondary curve points
var pt_e := pt_a + (a_gbasis.x * in_offset)
var pt_i := pt_b + (a_gbasis.x * in_offset)
var pt_h := pt_d + (d_gbasis.x * out_offset)
var pt_j := pt_c + (d_gbasis.x * out_offset)

# Get vectors from points
var vec_ab := pt_b - pt_a
var vec_bc := pt_c - pt_b
var vec_cd := pt_d - pt_c

# Calculate secondary curve handles and setup curves
var angle_q := -vec_ab.signed_angle_to(vec_bc, a_gbasis.y) * 0.5
var angle_s := vec_cd.signed_angle_to(vec_bc, d_gbasis.y) * 0.5
var offset_q := tan(angle_q) * in_offset
var offset_s := tan(angle_s) * out_offset
var pt_f := a_gbasis.z * (vec_ab.length() + offset_q)
var pt_g := -d_gbasis.z * (vec_cd.length() + offset_s)

var margin := 0.1745329 # Margin to check above/below 90. 0.174 is roughly 10 degrees

if abs(angle_q) > RAD_NINETY_DEG - margin and abs(angle_q) < RAD_NINETY_DEG + margin:
# Angle is close to 90deg. Use default values.
dst.add_point(
road_lane.to_local(in_pos),
road_lane.to_local(to_global(curve.get_point_in(0))),
road_lane.to_local(to_global(curve.get_point_out(0))))
else:
# Use calculated values
dst.add_point(
road_lane.to_local(pt_e),
road_lane.to_local(to_global(src.get_point_in(0))),
road_lane.to_local(to_global(pt_f)))

if abs(angle_s) > RAD_NINETY_DEG - margin and abs(angle_s) < RAD_NINETY_DEG + margin:
# Angle is close to 90deg. Use default values.
dst.add_point(
road_lane.to_local(out_pos),
road_lane.to_local(to_global(curve.get_point_in(1))),
road_lane.to_local(to_global(curve.get_point_out(1))))
else:
# Use calculated values
dst.add_point(
road_lane.to_local(pt_h),
road_lane.to_local(to_global(pt_g)),
road_lane.to_local(to_global(src.get_point_out(1))))


## Offset the curve in/out points based on lane index.
##
## Track the init (for reverse) or the stacking (fwd) number of
Expand Down