move inset into stl_3d
This commit is contained in:
Trammell Hudson
parent
a6a08bf10a
commit
b5210c4d65
137
faces.c
137
faces.c
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@ -57,141 +57,6 @@ svg_circle(
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}
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// Determines the intersection point of the line defined by points A and B with the
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// line defined by points C and D.
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//
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// Returns YES if the intersection point was found, and stores that point in X,Y.
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// Returns NO if there is no determinable intersection point, in which case X,Y will
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// be unmodified.
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static int
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line_intersect(
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double Ax, double Ay,
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double Bx, double By,
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double Cx, double Cy,
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double Dx, double Dy,
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double *X, double *Y
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)
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{
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// Fail if either line is undefined.
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if ((Ax==Bx && Ay==By) || (Cx==Dx && Cy==Dy))
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return 0;
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// (1) Translate the system so that point A is on the origin.
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Bx-=Ax; By-=Ay;
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Cx-=Ax; Cy-=Ay;
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Dx-=Ax; Dy-=Ay;
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// Discover the length of segment A-B.
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const double distAB=sqrt(Bx*Bx+By*By);
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// (2) Rotate the system so that point B is on the positive X axis.
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const double theCos=Bx/distAB;
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const double theSin=By/distAB;
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double newX=Cx*theCos+Cy*theSin;
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Cy =Cy*theCos-Cx*theSin; Cx=newX;
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newX=Dx*theCos+Dy*theSin;
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Dy =Dy*theCos-Dx*theSin; Dx=newX;
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// Fail if the lines are parallel.
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if (Cy==Dy) return 0;
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// (3) Discover the position of the intersection point along line A-B.
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const double ABpos=Dx+(Cx-Dx)*Dy/(Dy-Cy);
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// (4) Apply the discovered position to line A-B in the original coordinate system.
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*X=Ax+ABpos*theCos;
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*Y=Ay+ABpos*theSin;
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return 1;
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}
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/** Compute the inset coordinate.
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* http://alienryderflex.com/polygon_inset/
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// Given the sequentially connected points (a,b), (c,d), and (e,f), this
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// function returns, in (C,D), a bevel-inset replacement for point (c,d).
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//
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// Note: If vectors (a,b)->(c,d) and (c,d)->(e,f) are exactly 180° opposed,
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// or if either segment is zero-length, this function will do
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// nothing; i.e. point (C,D) will not be set.
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*/
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void
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inset(
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const refframe_t * const ref,
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const double inset_dist,
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double * const x_out,
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double * const y_out,
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const v3_t p0, // previous point
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const v3_t p1, // current point to inset
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const v3_t p2 // next point
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)
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{
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double a, b, c, d, e, f;
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v3_project(ref, p0, &a, &b);
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v3_project(ref, p1, &c, &d);
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v3_project(ref, p2, &e, &f);
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double c1 = c;
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double d1 = d;
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double c2 = c;
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double d2 = d;
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// Calculate length of line segments.
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const double dx1 = c-a;
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const double dy1 = d-b;
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const double dist1 = sqrt(dx1*dx1+dy1*dy1);
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const double dx2 = e-c;
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const double dy2 = f-d;
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const double dist2 = sqrt(dx2*dx2+dy2*dy2);
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// Exit if either segment is zero-length.
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if (dist1==0. || dist2==0.)
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{
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*x_out = *y_out = 0;
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fprintf(stderr, "inset fail\n");
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return;
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}
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// Inset each of the two line segments.
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double insetX, insetY;
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insetX = dy1/dist1 * inset_dist;
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a+=insetX;
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c1+=insetX;
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insetY = -dx1/dist1 * inset_dist;
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b+=insetY;
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d1+=insetY;
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insetX = dy2/dist2 * inset_dist;
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e+=insetX;
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c2+=insetX;
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insetY = -dx2/dist2 * inset_dist;
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f+=insetY;
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d2+=insetY;
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// If inset segments connect perfectly, return the connection point.
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if (c1==c2 && d1==d2)
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{
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*x_out = c1;
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*y_out = d1;
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return;
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}
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// Return the intersection point of the two inset segments (if any).
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if (line_intersect(a,b,c1,d1,c2,d2,e,f, x_out, y_out))
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return;
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*x_out = *y_out = 0;
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fprintf(stderr, "inset failed 2\n");
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}
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int
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main(void)
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{
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@ -247,7 +112,7 @@ main(void)
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for (int j = 0 ; j < vertex_count ; j++)
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{
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double x, y;
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inset(&ref, inset_distance, &x, &y,
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refframe_inset(&ref, inset_distance, &x, &y,
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vertex_list[(j+0) % vertex_count]->p,
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vertex_list[(j+1) % vertex_count]->p,
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vertex_list[(j+2) % vertex_count]->p
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133
stl_3d.c
133
stl_3d.c
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@ -335,3 +335,136 @@ v3_project(
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}
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// Determines the intersection point of the line defined by points A and B with the
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// line defined by points C and D.
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//
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// Returns YES if the intersection point was found, and stores that point in X,Y.
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// Returns NO if there is no determinable intersection point, in which case X,Y will
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// be unmodified.
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static int
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line_intersect(
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double Ax, double Ay,
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double Bx, double By,
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double Cx, double Cy,
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double Dx, double Dy,
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double *X, double *Y
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)
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{
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// Fail if either line is undefined.
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if ((Ax==Bx && Ay==By) || (Cx==Dx && Cy==Dy))
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return 0;
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// (1) Translate the system so that point A is on the origin.
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Bx-=Ax; By-=Ay;
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Cx-=Ax; Cy-=Ay;
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Dx-=Ax; Dy-=Ay;
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// Discover the length of segment A-B.
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const double distAB=sqrt(Bx*Bx+By*By);
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// (2) Rotate the system so that point B is on the positive X axis.
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const double theCos=Bx/distAB;
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const double theSin=By/distAB;
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double newX=Cx*theCos+Cy*theSin;
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Cy =Cy*theCos-Cx*theSin; Cx=newX;
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newX=Dx*theCos+Dy*theSin;
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Dy =Dy*theCos-Dx*theSin; Dx=newX;
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// Fail if the lines are parallel.
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if (Cy==Dy) return 0;
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// (3) Discover the position of the intersection point along line A-B.
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const double ABpos=Dx+(Cx-Dx)*Dy/(Dy-Cy);
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// (4) Apply the discovered position to line A-B in the original coordinate system.
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*X=Ax+ABpos*theCos;
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*Y=Ay+ABpos*theSin;
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return 1;
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}
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/** Compute the inset coordinate.
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* http://alienryderflex.com/polygon_inset/
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// Given the sequentially connected points (a,b), (c,d), and (e,f), this
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// function returns, in (C,D), a bevel-inset replacement for point (c,d).
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//
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// Note: If vectors (a,b)->(c,d) and (c,d)->(e,f) are exactly 180° opposed,
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// or if either segment is zero-length, this function will do
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// nothing; i.e. point (C,D) will not be set.
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*/
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void
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refframe_inset(
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const refframe_t * const ref,
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const double inset_dist,
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double * const x_out,
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double * const y_out,
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const v3_t p0, // previous point
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const v3_t p1, // current point to inset
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const v3_t p2 // next point
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)
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{
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double a, b, c, d, e, f;
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v3_project(ref, p0, &a, &b);
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v3_project(ref, p1, &c, &d);
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v3_project(ref, p2, &e, &f);
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double c1 = c;
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double d1 = d;
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double c2 = c;
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double d2 = d;
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// Calculate length of line segments.
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const double dx1 = c-a;
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const double dy1 = d-b;
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const double dist1 = sqrt(dx1*dx1+dy1*dy1);
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const double dx2 = e-c;
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const double dy2 = f-d;
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const double dist2 = sqrt(dx2*dx2+dy2*dy2);
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// Exit if either segment is zero-length.
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if (dist1==0. || dist2==0.)
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{
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*x_out = *y_out = 0;
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fprintf(stderr, "inset fail\n");
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return;
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}
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// Inset each of the two line segments.
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double insetX, insetY;
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insetX = dy1/dist1 * inset_dist;
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a+=insetX;
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c1+=insetX;
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insetY = -dx1/dist1 * inset_dist;
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b+=insetY;
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d1+=insetY;
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insetX = dy2/dist2 * inset_dist;
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e+=insetX;
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c2+=insetX;
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insetY = -dx2/dist2 * inset_dist;
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f+=insetY;
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d2+=insetY;
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// If inset segments connect perfectly, return the connection point.
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if (c1==c2 && d1==d2)
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{
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*x_out = c1;
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*y_out = d1;
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return;
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}
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// Return the intersection point of the two inset segments (if any).
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if (line_intersect(a,b,c1,d1,c2,d2,e,f, x_out, y_out))
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return;
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*x_out = *y_out = 0;
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fprintf(stderr, "inset failed 2\n");
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}
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11
stl_3d.h
11
stl_3d.h
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@ -82,6 +82,17 @@ refframe_init(
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);
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void
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refframe_inset(
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const refframe_t * const ref,
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const double inset_dist,
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double * const x_out,
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double * const y_out,
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const v3_t p0, // previous point
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const v3_t p1, // current point to inset
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const v3_t p2 // next point
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);
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/** Project a 3D point onto a 2D space */
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void
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v3_project(
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