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Rounded_polygons are now generated by a function returning a point list.

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The module version simply passes this to polygon.
The arcs now sections of a circle4n() rather than a circle().
This commit is contained in:
Chris Palmer 2021-09-26 10:54:01 +01:00
parent d6f344be3d
commit 30db66034c
4 changed files with 28 additions and 34 deletions
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5
readme.md
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@ -6312,8 +6312,9 @@ Because the tangents need to be calculated to find the length these can be calcu
| Function | Description |
|:--- |:--- |
| `circle_tangent(p1, p2)` | Compute the clockwise tangent between two circles represented as [x,y,r] |
| `rounded_polygon(points, _tangents = undef)` | Return the rounded polygon from the point list, can pass the tangent list to save it being calculated |
| `rounded_polygon_arcs(points, tangents)` | Compute the arcs at the points, for each point [angle, rotate_angle, length] |
| `rounded_polygon_length(points, tangents)` | Calculate the length given the point list and the list of tangents computed by ` rounded_polygon_tangents` |
| `rounded_polygon_length(points, tangents)` | Calculate the length given the point list and the list of tangents computed by `rounded_polygon_tangents` |
| `rounded_polygon_tangents(points)` | Compute the straight sections between a point and the next point, for each section [start_point, end_point, length] |
### Modules
@ -6506,7 +6507,7 @@ The `pose()` module allows assembly views in the readme to be posed differently
|:--- |:--- |
| `arg(value, default, name = "")` | Create string for arg if not default, helper for `vitamin()` |
| `bom_mode(n = 1)` | Current BOM mode, 0 = none, 1 = printed and routed parts and assemblies, 2 includes vitamins as well |
| `exploded()` | Returns the value of `$exploded` if it is defined, else `0` |
| `exploded()` | Returns the value of `$explode` if it is defined, else `0` |
| `show_supports()` | True if printed support material should be shown |
| `value_string(value)` | Convert `value` to a string or quote it if it is already a string |

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57
utils/rounded_polygon.scad
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@ -24,7 +24,7 @@
//! Because the tangents need to be calculated to find the length these can be calculated separately and re-used when drawing to save calculating them twice.
//
include <../utils/core/core.scad>
use <../utils/maths.scad>
use <maths.scad>
function circle_tangent(p1, p2) = //! Compute the clockwise tangent between two circles represented as [x,y,r]
let(
@ -49,14 +49,14 @@ function rounded_polygon_arcs(points, tangents) = //! Compute the arcs at the po
v2 = p2 - p,
sr = points[i][2],
r = abs(sr),
a = r < 0.001 ? 0 : let( aa = acos((v1 * v2) / sqr(r)) ) cross(v1, v2) * sign(sr) <= 0 ? aa : 360 - aa,
a = r < 0.001 ? 0 : let( aa = acos(limit((v1 * v2) / sqr(r), -1, 1)) ) cross(v1, v2) * sign(sr) <= 0 ? aa : 360 - aa,
l = PI * a * r / 180,
v0 = [r, 0],
v = let (
vv = norm(v0 - v2) < 0.001 ? 0 : abs(v2.y) < 0.001 ? 180 :
let( aa = acos((v0 * v2) / sqr(r)) ) cross(v0, v2) * sign(sr) <= 0 ? aa : 360 - aa
let( aa = acos( limit((v0 * v2) / sqr(r), -1, 1)) ) cross(v0, v2) * sign(sr) <= 0 ? aa : 360 - aa
) sr > 0 ? 360 - vv : vv - a
) [a, v, l]
) [a, v % 360, l]
];
function rounded_polygon_tangents(points) = //! Compute the straight sections between a point and the next point, for each section [start_point, end_point, length]
@ -67,36 +67,29 @@ function rounded_polygon_tangents(points) = //! Compute the straight sections be
];
// the cross product of 2D vectors is the area of the parallelogram between them. We use the sign of this to decide if the angle is bigger than 180.
function rounded_polygon_length(points, tangents) = //! Calculate the length given the point list and the list of tangents computed by ` rounded_polygon_tangents`
function rounded_polygon_length(points, tangents) = //! Calculate the length given the point list and the list of tangents computed by `rounded_polygon_tangents`
let(
arcs = rounded_polygon_arcs(points, tangents)
) sumv( map( concat(tangents, arcs), function(e) e[2] ) );
module rounded_polygon(points, _tangents = undef) { //! Draw the rounded polygon from the point list, can pass the tangent list to save it being calculated
len = len(points);
indices = [0 : len - 1];
tangents = _tangents ? _tangents : rounded_polygon_tangents(points);
function rounded_polygon(points, _tangents = undef) = //! Return the rounded polygon from the point list, can pass the tangent list to save it being calculated
let(
len = len(points),
tangents = _tangents ? _tangents : rounded_polygon_tangents(points),
arcs = rounded_polygon_arcs(points, tangents),
) [for(i = [0 : len - 1], last = (i - 1 + len) % len, R = points[i][2]) each [
vec2(tangents[last][1]), // End of last tangent
if(R) // If rounded
let(r = abs(R), // Get radius
n = r2sides4n(r), // Decide number of vertices
step = 360 / n, // Angular step
arc = arcs[i], // Get corner arc details
start = ceil(arc[1] / step + eps), // Starting index
end = floor((arc[0] + arc[1]) / step - eps), // Ending index
c = vec2(points[i]), // Centre of arc
) for(j = R > 0 ? [end : -1 : start] : [start : 1 : end], a = j * step) c + r * [cos(a), sin(a)], // Points on the arc
vec2(tangents[i][0])] // Start of next tangent
];
difference() {
union() {
for(i = indices, last = (i - 1 + len) % len)
if(points[i][2] > 0)
hull() {
translate(vec2(points[i]))
circle(points[i][2]);
polygon([vec2(tangents[last][1]), vec2(tangents[i][0]), vec2(points[i])]);
}
polygon([for(t = tangents) each(vec2(t))], convexity = points);
}
for(i = indices, last = (i - 1 + len) % len)
if(points[i][2] < 0)
hull() {
translate(vec2(points[i]))
circle(-points[i][2]);
polygon([vec2(tangents[last][1]), vec2(tangents[i][0]), vec2(points[i])]);
}
}
}
module rounded_polygon(points, _tangents = undef) //! Draw the rounded polygon from the point list, can pass the tangent list to save it being calculated
polygon(rounded_polygon(points, _tangents), convexity = len(points));