grey/BOSL2
1
0
Fork 0
mirror of https://github.com/BelfrySCAD/BOSL2.git synced 2024-12-29 08:19:43 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Added tri_calc()

Browse source
This commit is contained in:
Revar Desmera 2019-07-17 01:49:51 -07:00
parent ad59d88ce2
commit d1abaf891d
1 changed files with 68 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

71
geometry.scad
View file

@ -252,6 +252,69 @@ function find_circle_3points(pt1, pt2, pt3) =
// Function: tri_calc()
// Usage:
// tri_calc(ang,ang2,adj,opp,hyp);
// Description:
// Given a side length and an angle, or two side lengths, calculates the rest of the side lengths
// and angles of a right triangle. Returns [ADJACENT, OPPOSITE, HYPOTENUSE, ANGLE, ANGLE2] where
// ADJACENT is the length of the side adjacent to ANGLE, and OPPOSITE is the length of the side
// opposite of ANGLE and adjacent to ANGLE2. ANGLE and ANGLE2 are measured in degrees.
// This is certainly more verbose and slower than writing your own calculations, but has the nice
// benefit that you can just specify the info you have, and don't have to figure out which trig
// formulas you need to use.
// Figure(2D):
// color("#ccc") {
// stroke(closed=false, width=0.5, [[45,0], [45,5], [50,5]]);
// stroke(closed=false, width=0.5, arc(N=6, r=15, cp=[0,0], start=0, angle=30));
// stroke(closed=false, width=0.5, arc(N=6, r=14, cp=[50,30], start=212, angle=58));
// }
// color("black") stroke(closed=true, [[0,0], [50,30], [50,0]]);
// color("#0c0") {
// translate([10.5,2.5]) text(size=3,text="ang",halign="center",valign="center");
// translate([44.5,22]) text(size=3,text="ang2",halign="center",valign="center");
// }
// color("blue") {
// translate([25,-3]) text(size=3,text="Adjacent",halign="center",valign="center");
// translate([53,15]) rotate(-90) text(size=3,text="Opposite",halign="center",valign="center");
// translate([25,18]) rotate(30) text(size=3,text="Hypotenuse",halign="center",valign="center");
// }
// Arguments:
// ang = The angle in degrees of the primary corner of the triangle.
// ang2 = The angle in degrees of the other non-right corner of the triangle.
// adj = The length of the side adjacent to the primary corner.
// opp = The length of the side opposite to the primary corner.
// hyp = The length of the hypotenuse.
// Example:
// tri = tri_calc(opp=15,hyp=30);
// echo(adjacent=tri[0], opposite=tri[1], hypotenuse=tri[2], angle=tri[3], angle2=tri[4]);
// Examples:
// adj = tri_calc(ang=30,opp=10)[0];
// opp = tri_calc(ang=20,hyp=30)[1];
// hyp = tri_calc(ang2=50,adj=20)[2];
// ang = tri_calc(adj=20,hyp=30)[3];
// ang2 = tri_calc(adj=20,hyp=40)[4];
function tri_calc(ang,ang2,adj,opp,hyp) =
assert(num_defined([ang,ang2])<2,"You cannot specify both ang and ang2.")
assert(num_defined([ang,ang2,adj,opp,hyp])==2, "You must specify exactly two arguments.")
let(
ang = ang!=undef? assert(ang>0&&ang<90) ang :
ang2!=undef? (90-ang2) :
adj==undef? asin(constrain(opp/hyp,-1,1)) :
opp==undef? acos(constrain(adj/hyp,-1,1)) :
atan2(opp,adj),
ang2 = ang2!=undef? assert(ang2>0&&ang2<90) ang2 : (90-ang),
adj = adj!=undef? assert(adj>0) adj :
(opp!=undef? (opp/tan(ang)) : (hyp*cos(ang))),
opp = opp!=undef? assert(opp>0) opp :
(adj!=undef? (adj*tan(ang)) : (hyp*sin(ang))),
hyp = hyp!=undef? assert(hyp>0) assert(adj<hyp) assert(opp<hyp) hyp :
(adj!=undef? (adj/cos(ang)) : (opp/sin(ang)))
)
[adj, opp, hyp, ang, ang2];
// Function: triangle_area()
// Usage:
// triangle_area(a,b,c);
@ -437,9 +500,11 @@ function polygon_area(vertices) =
// Given a simple polygon, returns the coordinates of the polygon's centroid.
// If the polygon is self-intersecting, the results are undefined.
function centroid(vertices) =
sum([for(i=[0:len(vertices)-1])
let(segment=select(vertices,i,i+1))
det2(segment)*sum(segment)]) / 6 / polygon_area(vertices);
sum([
for(i=[0:len(vertices)-1])
let(segment=select(vertices,i,i+1))
det2(segment)*sum(segment)
]) / 6 / polygon_area(vertices);
// Function: assemble_path_fragments()