X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=reprap-play.git;a=blobdiff_plain;f=funcs.scad.cpp;h=5857c933a837f888bf22faedda5b455e6df0e973;hp=29d5a1e6dd2ab9bc0a103ad28203d98e20a7dd29;hb=9b3087a6117d4143978dad2af8901be6de9bcd15;hpb=f57afd91759a049296c6d454b2e3a2b46a5560f7 diff --git a/funcs.scad.cpp b/funcs.scad.cpp index 29d5a1e..5857c93 100644 --- a/funcs.scad.cpp +++ b/funcs.scad.cpp @@ -1,14 +1,63 @@ // -*- C -*- -function dist(a,b) = +function vecdiff2d(a,b) = [b[0]-a[0], b[1]-a[1]]; +function vecdiff(a,b) = [b[0]-a[0], b[1]-a[1], b[2]-a[2]]; + #define dsq(i) (a[i]-b[i])*(a[i]-b[i]) - sqrt(dsq(0) + dsq(1)); +function dist2d(a,b) = sqrt(dsq(0) + dsq(1)); +function dist(a,b) = sqrt(dsq(0) + dsq(1) + dsq(2)); #undef dsq +#define vsq(i) (v[i]*v[i]) +function vectorlen2d(v) = sqrt(vsq(0) + vsq(1)); +function vectorlen(v) = sqrt(vsq(0) + vsq(1) + vsq(2)); +#undef vsq + +function unitvector2d(v) = v / vectorlen2d(v); +function unitvector(v) = v / vectorlen(v); + +function atan2vector(v) = atan2(v[1], v[0]); + +// | m[0][0] m[0][1] | +// | m[1][0] m[1][1] | +function determinant2(m) = (m[0][0] * m[1][1] - m[0][1] * m[1][0]); + +function clockwise2d(v) = [v[1], -v[0]]; + +// intersection of lines p1..p2 and p3..p4 +function line_intersection_2d(p1,p2,p3,p4) = [ + // from https://en.wikipedia.org/wiki/Line%E2%80%93line_intersection#Given_two_points_on_each_line + #define XY12 determinant2([p1,p2]) + #define XY34 determinant2([p3,p4]) + #define XU12 QU(0,1,2) + #define XU34 QU(0,3,4) + #define YU12 QU(1,1,2) + #define YU34 QU(1,3,4) + #define QU(c,i,j) determinant2([[ p##i[c], 1 ], \ + [ p##j[c], 1 ]]) + #define DENOM \ + determinant2([[ XU12, YU12 ], \ + [ XU34, YU34 ]]) + //---- + determinant2([[ XY12, XU12 ], + [ XY34, XU34 ]]) / DENOM, + determinant2([[ XY12, YU12 ], + [ XY34, YU34 ]]) / DENOM, + ]; + #undef XY12 + #undef XY34 + #undef XU12 + #undef XU34 + #undef YU12 + #undef YU34 + #undef QU + #undef DENOM + + function circle_point(c, r, alpha) = [ c[0] + r * cos(alpha), c[1] + r * sin(alpha) ]; -#define d (dist(a,c)) +#define d (dist2d(a,c)) #define alpha (atan2(a[1]-c[1],a[0]-c[0])) #define gamma (asin(r / d)) #define beta (alpha + 90 - gamma) @@ -23,5 +72,12 @@ function tangent_intersect_b(c,r,a) = #undef gamma #undef beta +function tangents_intersect_beta(cbig,rbig,csmall,rsmall) = + tangent_intersect_beta(cbig,rbig-rsmall,csmall); + function reflect_in_y(p) = [-p[0], p[1]]; +function angle_map_range(in,base) = + in < base ? in + 360 : + in >= base + 360 ? in - 360 : + in;