Michael Fiano
a5fd73202d

5 months ago  

src  5 months ago  
LICENSE  5 months ago  
README.md  5 months ago  
cubicbezier.asd  5 months ago 
README.md
cubicbezier
A library for constructing and evaluating cubic Bézier curve paths.
Install
(ql:quickload :cubicbezier)
Usage
(makecurve points &key (divisions 100))
Create a cubic Bézier curve path from the given sequence of points
. points
is a sequence of
3dimensional vectors as constructed with #'origin.vec3:vec
. divisions
is the number of
subdivisions to use when estimating the arclength of the curve path: see the documentation for
#'evaluate
for more information.
(addpoints curve points)
Append the specified points
to curve
. points
should be a sequence of 3dimensional vectors
as constructed with #'origin.vec3:vec
. NOTE: It is an error to add less than a segment worth of
points. A cubic Bézier curve is defined by 4 points for the first segment, and three points for each
successive segment (since the first point of a segment is shared with the last point of the previous
segment.)
(editpoint curve index value)
Edit the point of curve
at index index
with value
. value
should be a 3dimensional vector
as constructed with #'origin.vec3:vec
.
(evaluate curve parameter &key evenspacingp)
Evaluate curve
at parameter parameter
. If evenspacingp
is nonNIL, arclength
reparameterization is applied, which evenly spaces points along the curve. The number of points is
defined by the divisions
argument supplied when constructing the curve with #'makecurve
.
Arclength reparameterization is a remapping of parameter
before evaluating the curve, in order to
allow for uses such as animation along a curve with a constant velocity.
(pointcountvalidp pointcount)
Check whether the integer pointcount
is a valid number of points for a cubic Bézier curve
path. To be valid, there must be at least 4 points, any increment of 3 thereafter: (4, 7, 10, 13,
...).
(pointindexpresentp curve index)
Check if curve
has a point at index index
.
(collectpoints curve count &key evenspacingp)
Evaluate count
points along curve, returning a list of 3dimensional vectors. If
evenspacingp
is supplied, arclength reparameterization is applied: see the documentation for
#'evaluate
for more information.
(collectsegments curve count &key evenspacingp)
Collect a list of count
segments of curve
. A segment is a list of two 3dimensional vectors.
If evenspacingp
is supplied, arclength reparameterization is applied: see the documentation
for #'evaluate
for more information.
License
Copyright © 20212022 Michael Fiano mail@mfiano.net.
Licensed under the MIT License.