solvespace/constraint.cpp

284 lines
9.3 KiB
C++

#include "solvespace.h"
hConstraint Constraint::AddConstraint(Constraint *c) {
SS.constraint.AddAndAssignId(c);
return c->h;
}
void Constraint::ConstrainCoincident(hEntity ptA, hEntity ptB) {
Constraint c;
memset(&c, 0, sizeof(c));
c.group = SS.GW.activeGroup;
c.type = Constraint::POINTS_COINCIDENT;
c.ptA = ptA;
c.ptB = ptB;
SS.constraint.AddAndAssignId(&c);
}
void Constraint::MenuConstrain(int id) {
Constraint c;
memset(&c, 0, sizeof(c));
c.group = SS.GW.activeGroup;
SS.GW.GroupSelection();
#define gs (SS.GW.gs)
switch(id) {
case GraphicsWindow::MNU_DISTANCE_DIA:
if(gs.points == 2 && gs.n == 2) {
c.type = PT_PT_DISTANCE;
c.ptA = gs.point[0];
c.ptB = gs.point[1];
} else if(gs.lineSegments == 1 && gs.n == 1) {
c.type = PT_PT_DISTANCE;
Entity *e = SS.GetEntity(gs.entity[0]);
c.ptA = e->assoc[0];
c.ptB = e->assoc[1];
} else {
Error("Bad selection for distance / diameter constraint.");
return;
}
c.disp.offset = Vector::MakeFrom(50, 50, 50);
c.exprA = Expr::FromString("0")->DeepCopyKeep();
c.ModifyToSatisfy();
AddConstraint(&c);
break;
case GraphicsWindow::MNU_ON_ENTITY:
if(gs.points == 2 && gs.n == 2) {
c.type = POINTS_COINCIDENT;
c.ptA = gs.point[0];
c.ptB = gs.point[1];
} else if(gs.points == 1 && gs.planes == 1 && gs.n == 2) {
c.type = PT_IN_PLANE;
c.ptA = gs.point[0];
c.entityA = gs.entity[0];
} else {
Error("Bad selection for on point / curve / plane constraint.");
return;
}
AddConstraint(&c);
break;
case GraphicsWindow::MNU_EQUAL:
if(gs.lineSegments == 2 && gs.n == 2) {
c.type = EQUAL_LENGTH_LINES;
c.entityA = gs.entity[0];
c.entityB = gs.entity[1];
} else {
Error("Bad selection for equal length / radius constraint.");
return;
}
AddConstraint(&c);
break;
case GraphicsWindow::MNU_VERTICAL:
case GraphicsWindow::MNU_HORIZONTAL: {
hEntity ha, hb;
if(gs.lineSegments == 1 && gs.n == 1) {
c.entityA = gs.entity[0];
Entity *e = SS.GetEntity(c.entityA);
ha = e->assoc[0];
hb = e->assoc[1];
} else if(gs.points == 2 && gs.n == 2) {
ha = c.ptA = gs.point[0];
hb = c.ptB = gs.point[1];
} else {
Error("Bad selection for horizontal / vertical constraint.");
return;
}
Entity *ea = SS.GetEntity(ha);
Entity *eb = SS.GetEntity(hb);
if(ea->csys.v == Entity::NO_CSYS.v &&
eb->csys.v == Entity::NO_CSYS.v)
{
Error("Horizontal/vertical constraint applies only to "
"entities drawn in a 2d coordinate system.");
return;
}
if(eb->csys.v == SS.GW.activeCsys.v) {
// We are constraining two points in two different csyss; so
// we have two choices for the definitons of the coordinate
// directions. ptA's gets chosen, so make sure that's the
// active csys.
hEntity t = c.ptA;
c.ptA = c.ptB;
c.ptB = t;
}
if(id == GraphicsWindow::MNU_HORIZONTAL) {
c.type = HORIZONTAL;
} else {
c.type = VERTICAL;
}
AddConstraint(&c);
break;
}
case GraphicsWindow::MNU_SOLVE_NOW:
SS.Solve();
return;
default: oops();
}
SS.GW.ClearSelection();
InvalidateGraphics();
}
Expr *Constraint::Distance(hEntity hpa, hEntity hpb) {
Entity *pa = SS.GetEntity(hpa);
Entity *pb = SS.GetEntity(hpb);
if(!(pa->IsPoint() && pb->IsPoint())) oops();
if(pa->type == Entity::POINT_IN_2D &&
pb->type == Entity::POINT_IN_2D &&
pa->csys.v == pb->csys.v)
{
// A nice case; they are both in the same 2d csys, so I can write
// the equation in terms of the basis vectors in that csys.
Expr *du = Expr::FromParam(pa->param.h[0])->Minus(
Expr::FromParam(pb->param.h[0]));
Expr *dv = Expr::FromParam(pa->param.h[1])->Minus(
Expr::FromParam(pb->param.h[1]));
return ((du->Square())->Plus(dv->Square()))->Sqrt();
}
// The usual case, just write it in terms of the coordinates
ExprVector ea, eb, eab;
ea = pa->PointGetExprs();
eb = pb->PointGetExprs();
eab = ea.Minus(eb);
return eab.Magnitude();
}
void Constraint::ModifyToSatisfy(void) {
IdList<Equation,hEquation> l;
// An uninit IdList could lead us to free some random address, bad.
memset(&l, 0, sizeof(l));
Generate(&l);
if(l.n != 1) oops();
// These equations are written in the form f(...) - d = 0, where
// d is the value of the exprA.
double v = (l.elem[0].e)->Eval();
double nd = exprA->Eval() + v;
Expr::FreeKeep(&exprA);
exprA = Expr::FromConstant(nd)->DeepCopyKeep();
l.Clear();
}
void Constraint::AddEq(IdList<Equation,hEquation> *l, Expr *expr, int index) {
Equation eq;
eq.e = expr;
eq.h = h.equation(index);
l->Add(&eq);
}
void Constraint::Generate(IdList<Equation,hEquation> *l) {
switch(type) {
case PT_PT_DISTANCE:
AddEq(l, Distance(ptA, ptB)->Minus(exprA), 0);
break;
case EQUAL_LENGTH_LINES: {
Entity *a = SS.GetEntity(entityA);
Entity *b = SS.GetEntity(entityB);
AddEq(l, Distance(a->assoc[0], a->assoc[1])->Minus(
Distance(b->assoc[0], b->assoc[1])), 0);
break;
}
case POINTS_COINCIDENT: {
Entity *a = SS.GetEntity(ptA);
Entity *b = SS.GetEntity(ptB);
if(!a->IsPointIn3d() && b->IsPointIn3d()) {
Entity *t = a;
a = b; b = t;
}
if(a->IsPointIn3d() && b->IsPointIn3d()) {
// Easy case: both points have 3 DOF, so write three eqs.
ExprVector ea, eb, eab;
ea = a->PointGetExprs();
eb = b->PointGetExprs();
eab = ea.Minus(eb);
AddEq(l, eab.x, 0);
AddEq(l, eab.y, 1);
AddEq(l, eab.z, 2);
} else if(!(a->IsPointIn3d() || b->IsPointIn3d()) &&
(a->csys.v == b->csys.v))
{
// Both in same csys, nice.
AddEq(l, Expr::FromParam(a->param.h[0])->Minus(
Expr::FromParam(b->param.h[0])), 0);
AddEq(l, Expr::FromParam(a->param.h[1])->Minus(
Expr::FromParam(b->param.h[1])), 1);
} else {
// Either two 2 DOF points in different planes, or one
// 3 DOF point and one 2 DOF point. Either way, write two
// equations on the projection of a into b's plane.
ExprVector p3;
p3 = a->PointGetExprs();
Entity *csy = SS.GetEntity(b->csys);
ExprVector offset = csy->Csys2dGetOffsetExprs();
p3 = p3.Minus(offset);
ExprVector u, v;
csy->Csys2dGetBasisExprs(&u, &v);
AddEq(l, Expr::FromParam(b->param.h[0])->Minus(p3.Dot(u)), 0);
AddEq(l, Expr::FromParam(b->param.h[1])->Minus(p3.Dot(v)), 1);
}
break;
}
case PT_IN_PLANE: {
ExprVector p, n;
Expr *d;
p = SS.GetEntity(ptA)->PointGetExprs();
SS.GetEntity(entityA)->PlaneGetExprs(&n, &d);
AddEq(l, (p.Dot(n))->Minus(d), 0);
break;
}
case HORIZONTAL:
case VERTICAL: {
hEntity ha, hb;
if(entityA.v) {
Entity *e = SS.GetEntity(entityA);
ha = e->assoc[0];
hb = e->assoc[1];
} else {
ha = ptA;
hb = ptB;
}
Entity *a = SS.GetEntity(ha);
Entity *b = SS.GetEntity(hb);
if(a->csys.v == Entity::NO_CSYS.v) {
Entity *t = a;
a = b;
b = t;
}
if(a->csys.v == b->csys.v) {
int i = (type == HORIZONTAL) ? 1 : 0;
AddEq(l, Expr::FromParam(a->param.h[i])->Minus(
Expr::FromParam(b->param.h[i])), 0);
} else {
Entity *csy = SS.GetEntity(a->csys);
ExprVector u, v;
csy->Csys2dGetBasisExprs(&u, &v);
ExprVector norm = (type == HORIZONTAL) ? v : u;
ExprVector pa = a->PointGetExprs();
ExprVector pb = b->PointGetExprs();
AddEq(l, (pa.Minus(pb)).Dot(norm), 0);
}
break;
}
default: oops();
}
}