solvespace/drawentity.cpp

#include "solvespace.h"

char *Entity::DescriptionString(void) {
    if(h.isFromRequest()) {
        Request *r = SK.GetRequest(h.request());
        return r->DescriptionString();
    } else {
        Group *g = SK.GetGroup(h.group());
        return g->DescriptionString();
    }
}

void Entity::FatLineEndcap(Vector p, Vector u, Vector v) {
    // A table of cos and sin of (pi*i/10 + pi/2), as i goes from 0 to 10
    static const double Circle[11][2] = {
        {  0.0000,   1.0000 },
        { -0.3090,   0.9511 },
        { -0.5878,   0.8090 },
        { -0.8090,   0.5878 },
        { -0.9511,   0.3090 },
        { -1.0000,   0.0000 },
        { -0.9511,  -0.3090 },
        { -0.8090,  -0.5878 },
        { -0.5878,  -0.8090 },
        { -0.3090,  -0.9511 },
        {  0.0000,  -1.0000 },
    };
    glBegin(GL_TRIANGLE_FAN);
    for(int i = 0; i <= 10; i++) {
        double c = Circle[i][0], s = Circle[i][1];
        glxVertex3v(p.Plus(u.ScaledBy(c)).Plus(v.ScaledBy(s)));
    }
    glEnd();
}

void Entity::FatLine(Vector a, Vector b) {
    // The half-width of the line we're drawing.
    double hw = (dogd.lineWidth/SS.GW.scale) / 2;
    Vector ab  = b.Minus(a);
    Vector gn = (SS.GW.projRight).Cross(SS.GW.projUp);
    Vector abn = (ab.Cross(gn)).WithMagnitude(1);
    abn = abn.Minus(gn.ScaledBy(gn.Dot(abn)));
    // So now abn is normal to the projection of ab into the screen, so the
    // line will always have constant thickness as the view is rotated.

    abn = abn.WithMagnitude(hw);
    ab  = gn.Cross(abn);
    ab  = ab. WithMagnitude(hw);

    // The body of a line is a quad
    glBegin(GL_QUADS);
        glxVertex3v(a.Minus(abn));
        glxVertex3v(b.Minus(abn));
        glxVertex3v(b.Plus (abn));
        glxVertex3v(a.Plus (abn));
    glEnd();
    // And the line has two semi-circular end caps.
    FatLineEndcap(a, ab,              abn);
    FatLineEndcap(b, ab.ScaledBy(-1), abn);
}

void Entity::LineDrawOrGetDistance(Vector a, Vector b, bool maybeFat) {
    if(dogd.drawing) {
        // Draw lines from active group in front of those from previous
        glxDepthRangeOffset((group.v == SS.GW.activeGroup.v) ? 4 : 3);
        // Narrow lines are drawn as lines, but fat lines must be drawn as
        // filled polygons, to get the line join style right.
        if(!maybeFat || dogd.lineWidth < 3) {
            glBegin(GL_LINES);
                glxVertex3v(a);
                glxVertex3v(b);
            glEnd();
        } else {
            FatLine(a, b);
        }
            
        glxDepthRangeOffset(0);
    } else {
        Point2d ap = SS.GW.ProjectPoint(a);
        Point2d bp = SS.GW.ProjectPoint(b);

        double d = dogd.mp.DistanceToLine(ap, bp.Minus(ap), true);
        // A little bit easier to select in the active group
        if(group.v == SS.GW.activeGroup.v) d -= 1;
        dogd.dmin = min(dogd.dmin, d);
    }
    dogd.refp = (a.Plus(b)).ScaledBy(0.5);
}

void Entity::DrawAll(void) {
    // This handles points and line segments as a special case, because I
    // seem to be able to get a huge speedup that way, by consolidating
    // stuff to gl.
    int i;
    if(SS.GW.showPoints) {
        double s = 3.5/SS.GW.scale;
        Vector r = SS.GW.projRight.ScaledBy(s);
        Vector d = SS.GW.projUp.ScaledBy(s);
        glxColorRGB(Style::Color(Style::DATUM));
        glxDepthRangeOffset(6);
        glBegin(GL_QUADS);
        for(i = 0; i < SK.entity.n; i++) {
            Entity *e = &(SK.entity.elem[i]);
            if(!e->IsPoint()) continue;
            if(!(SK.GetGroup(e->group)->visible)) continue;
            if(SS.GroupsInOrder(SS.GW.activeGroup, e->group)) continue;
            if(e->forceHidden) continue;

            Vector v = e->PointGetNum();

            // If we're analyzing the sketch to show the degrees of freedom,
            // then we draw big colored squares over the points that are
            // free to move.
            bool free = false;
            if(e->type == POINT_IN_3D) {
                Param *px = SK.GetParam(e->param[0]),
                      *py = SK.GetParam(e->param[1]),
                      *pz = SK.GetParam(e->param[2]);

                free = (px->free) || (py->free) || (pz->free);
            } else if(e->type == POINT_IN_2D) {
                Param *pu = SK.GetParam(e->param[0]),
                      *pv = SK.GetParam(e->param[1]);

                free = (pu->free) || (pv->free);
            }
            if(free) {
                Vector re = r.ScaledBy(2.5), de = d.ScaledBy(2.5);

                glxColorRGB(Style::Color(Style::ANALYZE));
                glxVertex3v(v.Plus (re).Plus (de));
                glxVertex3v(v.Plus (re).Minus(de));
                glxVertex3v(v.Minus(re).Minus(de));
                glxVertex3v(v.Minus(re).Plus (de));
                glxColorRGB(Style::Color(Style::DATUM));
            }

            glxVertex3v(v.Plus (r).Plus (d));
            glxVertex3v(v.Plus (r).Minus(d));
            glxVertex3v(v.Minus(r).Minus(d));
            glxVertex3v(v.Minus(r).Plus (d));
        }
        glEnd();
        glxDepthRangeOffset(0);
    }

    for(i = 0; i < SK.entity.n; i++) {
        Entity *e = &(SK.entity.elem[i]);
        if(e->IsPoint())
        {
            continue; // already handled
        }
        e->Draw();
    }
}

void Entity::Draw(void) {
    hStyle hs = Style::ForEntity(h);
    dogd.lineWidth = Style::Width(hs);
    glLineWidth((float)dogd.lineWidth);
    glxColorRGB(Style::Color(hs));

    dogd.drawing = true;
    DrawOrGetDistance();
}

void Entity::GenerateEdges(SEdgeList *el, bool includingConstruction) {
    if(construction && !includingConstruction) return;

    SBezierList sbl;
    ZERO(&sbl);
    GenerateBezierCurves(&sbl);

    int i, j;
    for(i = 0; i < sbl.l.n; i++) {
        SBezier *sb = &(sbl.l.elem[i]);

        List<Vector> lv;
        ZERO(&lv);
        sb->MakePwlInto(&lv);
        for(j = 1; j < lv.n; j++) {
            el->AddEdge(lv.elem[j-1], lv.elem[j]);
        }
        lv.Clear();
    }

    sbl.Clear();
}

double Entity::GetDistance(Point2d mp) {
    dogd.drawing = false;
    dogd.mp = mp;
    dogd.dmin = 1e12;

    DrawOrGetDistance();
    
    return dogd.dmin;
}

Vector Entity::GetReferencePos(void) {
    dogd.drawing = false;

    dogd.refp = SS.GW.offset.ScaledBy(-1);
    DrawOrGetDistance();

    return dogd.refp;
}

bool Entity::IsVisible(void) {
    Group *g = SK.GetGroup(group);

    if(g->h.v == Group::HGROUP_REFERENCES.v && IsNormal()) {
        // The reference normals are always shown
        return true;
    }
    if(!g->visible) return false;
    if(SS.GroupsInOrder(SS.GW.activeGroup, group)) return false;

    // Don't check if points are hidden; this gets called only for
    // selected or hovered points, and those should always be shown.
    if(IsNormal() && !SS.GW.showNormals) return false;

    if(!SS.GW.showWorkplanes) {
        if(IsWorkplane() && !h.isFromRequest()) {
            if(g->h.v != SS.GW.activeGroup.v) {
                // The group-associated workplanes are hidden outside
                // their group.
                return false;
            }
        }
    }

    if(forceHidden) return false;

    return true;
}

void Entity::CalculateNumerical(bool forExport) {
    if(IsPoint()) actPoint = PointGetNum();
    if(IsNormal()) actNormal = NormalGetNum();
    if(type == DISTANCE || type == DISTANCE_N_COPY) {
        actDistance = DistanceGetNum();
    }
    if(IsFace()) {
        actPoint  = FaceGetPointNum();
        Vector n = FaceGetNormalNum();
        actNormal = Quaternion::From(0, n.x, n.y, n.z);
    }
    if(forExport) {
        // Visibility in copied import entities follows source file
        actVisible = IsVisible();
    } else {
        // Copied entities within a file are always visible
        actVisible = true;
    }
}

bool Entity::PointIsFromReferences(void) {
    return h.request().IsFromReferences();
}

void Entity::GenerateBezierCurves(SBezierList  *sbl) {
    SBezier sb;

    switch(type) {
        case LINE_SEGMENT: {
            Vector a = SK.GetEntity(point[0])->PointGetNum();
            Vector b = SK.GetEntity(point[1])->PointGetNum();
            sb = SBezier::From(a, b);
            sbl->l.Add(&sb);
            break;
        }
        case CUBIC: {
            Vector p0 = SK.GetEntity(point[0])->PointGetNum();
            Vector p1 = SK.GetEntity(point[1])->PointGetNum();
            Vector p2 = SK.GetEntity(point[2])->PointGetNum();
            Vector p3 = SK.GetEntity(point[3])->PointGetNum();
            sb = SBezier::From(p0, p1, p2, p3);
            sbl->l.Add(&sb);
            break;
        }

        case CIRCLE:
        case ARC_OF_CIRCLE: {
            Vector center = SK.GetEntity(point[0])->PointGetNum();
            Quaternion q = SK.GetEntity(normal)->NormalGetNum();
            Vector u = q.RotationU(), v = q.RotationV();
            double r = CircleGetRadiusNum();
            double thetaa, thetab, dtheta;

            if(r < LENGTH_EPS) {
                // If a circle or an arc gets dragged through zero radius,
                // then we just don't generate anything.
                break;
            }

            if(type == CIRCLE) {
                thetaa = 0;
                thetab = 2*PI;
                dtheta = 2*PI;
            } else {
                ArcGetAngles(&thetaa, &thetab, &dtheta);
            }
            int i, n;
            if(dtheta > (3*PI/2 + 0.01)) {
                n = 4;
            } else if(dtheta > (PI + 0.01)) {
                n = 3;
            } else if(dtheta > (PI/2 + 0.01)) {
                n = 2;
            } else {
                n = 1;
            }
            dtheta /= n;

            for(i = 0; i < n; i++) {
                double s, c;

                c = cos(thetaa);
                s = sin(thetaa);
                // The start point of the curve, and the tangent vector at
                // that start point.
                Vector p0 = center.Plus(u.ScaledBy( r*c)).Plus(v.ScaledBy(r*s)),
                       t0 =             u.ScaledBy(-r*s). Plus(v.ScaledBy(r*c));

                thetaa += dtheta;

                c = cos(thetaa);
                s = sin(thetaa);
                Vector p2 = center.Plus(u.ScaledBy( r*c)).Plus(v.ScaledBy(r*s)),
                       t2 =             u.ScaledBy(-r*s). Plus(v.ScaledBy(r*c));

                // The control point must lie on both tangents.
                Vector p1 = Vector::AtIntersectionOfLines(p0, p0.Plus(t0),
                                                          p2, p2.Plus(t2),
                                                          NULL);

                SBezier sb = SBezier::From(p0, p1, p2);
                sb.weight[1] = cos(dtheta/2);
                sbl->l.Add(&sb);
            }
            break;
        }
            
        case TTF_TEXT: {
            Vector topLeft = SK.GetEntity(point[0])->PointGetNum();
            Vector botLeft = SK.GetEntity(point[1])->PointGetNum();
            Vector n = Normal()->NormalN();
            Vector v = topLeft.Minus(botLeft);
            Vector u = (v.Cross(n)).WithMagnitude(v.Magnitude());

            SS.fonts.PlotString(font.str, str.str, 0, sbl, botLeft, u, v);
            break;
        }

        default:
            // Not a problem, points and normals and such don't generate curves
            break;
    }
}

void Entity::DrawOrGetDistance(void) {
    if(!IsVisible()) return;

    Group *g = SK.GetGroup(group);

    switch(type) {
        case POINT_N_COPY:
        case POINT_N_TRANS:
        case POINT_N_ROT_TRANS:
        case POINT_N_ROT_AA:
        case POINT_IN_3D:
        case POINT_IN_2D: {
            Vector v = PointGetNum();
            dogd.refp = v;

            if(dogd.drawing) {
                double s = 3.5;
                Vector r = SS.GW.projRight.ScaledBy(s/SS.GW.scale);
                Vector d = SS.GW.projUp.ScaledBy(s/SS.GW.scale);

                glxColorRGB(Style::Color(Style::DATUM));
                glxDepthRangeOffset(6);
                glBegin(GL_QUADS);
                    glxVertex3v(v.Plus (r).Plus (d));
                    glxVertex3v(v.Plus (r).Minus(d));
                    glxVertex3v(v.Minus(r).Minus(d));
                    glxVertex3v(v.Minus(r).Plus (d));
                glEnd();
                glxDepthRangeOffset(0);
            } else {
                Point2d pp = SS.GW.ProjectPoint(v);
                dogd.dmin = pp.DistanceTo(dogd.mp) - 6;
            }
            break;
        }

        case NORMAL_N_COPY:
        case NORMAL_N_ROT:
        case NORMAL_N_ROT_AA:
        case NORMAL_IN_3D:
        case NORMAL_IN_2D: {
            int i;
            for(i = 0; i < 2; i++) {
                if(i == 0 && !SS.GW.showNormals) {
                    // When the normals are hidden, we will continue to show
                    // the coordinate axes at the bottom left corner, but
                    // not at the origin.
                    continue;
                }

                hRequest hr = h.request();
                // Always draw the x, y, and z axes in red, green, and blue;
                // brighter for the ones at the bottom left of the screen,
                // dimmer for the ones at the model origin.
                int f = (i == 0 ? 100 : 255);
                if(hr.v == Request::HREQUEST_REFERENCE_XY.v) {
                    glxColorRGB(RGB(0, 0, f));
                } else if(hr.v == Request::HREQUEST_REFERENCE_YZ.v) {
                    glxColorRGB(RGB(f, 0, 0));
                } else if(hr.v == Request::HREQUEST_REFERENCE_ZX.v) {
                    glxColorRGB(RGB(0, f, 0));
                } else {
                    glxColorRGB(Style::Color(Style::NORMALS));
                    if(i > 0) break;
                }

                Quaternion q = NormalGetNum();
                Vector tail;
                if(i == 0) {
                    tail = SK.GetEntity(point[0])->PointGetNum();
                    glLineWidth(1);
                } else {
                    // Draw an extra copy of the x, y, and z axes, that's
                    // always in the corner of the view and at the front.
                    // So those are always available, perhaps useful.
                    double s = SS.GW.scale;
                    double h = 60 - SS.GW.height/2;
                    double w = 60 - SS.GW.width/2;
                    tail = SS.GW.projRight.ScaledBy(w/s).Plus(
                           SS.GW.projUp.   ScaledBy(h/s)).Minus(SS.GW.offset);
                    glxDepthRangeLockToFront(true);
                    glLineWidth(2);
                }

                Vector v = (q.RotationN()).WithMagnitude(50/SS.GW.scale);
                Vector tip = tail.Plus(v);
                LineDrawOrGetDistance(tail, tip);

                v = v.WithMagnitude(12/SS.GW.scale);
                Vector axis = q.RotationV();
                LineDrawOrGetDistance(tip,tip.Minus(v.RotatedAbout(axis, 0.6)));
                LineDrawOrGetDistance(tip,tip.Minus(v.RotatedAbout(axis,-0.6)));
            }
            glxDepthRangeLockToFront(false);
            break;
        }

        case DISTANCE:
        case DISTANCE_N_COPY:
            // These are used only as data structures, nothing to display.
            break;

        case WORKPLANE: {
            Vector p;
            p = SK.GetEntity(point[0])->PointGetNum();

            Vector u = Normal()->NormalU();
            Vector v = Normal()->NormalV();

            double s = (min(SS.GW.width, SS.GW.height))*0.45/SS.GW.scale;

            Vector us = u.ScaledBy(s);
            Vector vs = v.ScaledBy(s);

            Vector pp = p.Plus (us).Plus (vs);
            Vector pm = p.Plus (us).Minus(vs);
            Vector mm = p.Minus(us).Minus(vs), mm2 = mm;
            Vector mp = p.Minus(us).Plus (vs);

            glLineWidth(1);
            glxColorRGB(Style::Color(Style::NORMALS));
            glEnable(GL_LINE_STIPPLE);
            glLineStipple(3, 0x1111);
            if(!h.isFromRequest()) {
                mm = mm.Plus(v.ScaledBy(60/SS.GW.scale));
                mm2 = mm2.Plus(u.ScaledBy(60/SS.GW.scale));
                LineDrawOrGetDistance(mm2, mm);
            }
            LineDrawOrGetDistance(pp, pm);
            LineDrawOrGetDistance(pm, mm2);
            LineDrawOrGetDistance(mm, mp);
            LineDrawOrGetDistance(mp, pp);
            glDisable(GL_LINE_STIPPLE);

            char *str = DescriptionString()+5;
            if(dogd.drawing) {
                glxWriteText(str, mm2, u, v, NULL, NULL);
            } else {
                Vector pos = mm2.Plus(u.ScaledBy(glxStrWidth(str)/2)).Plus(
                                      v.ScaledBy(glxStrHeight()/2));
                Point2d pp = SS.GW.ProjectPoint(pos);
                dogd.dmin = min(dogd.dmin, pp.DistanceTo(dogd.mp) - 10);
                // If a line lies in a plane, then select the line, not
                // the plane.
                dogd.dmin += 3;
            }
            break;
        }

        case LINE_SEGMENT:
        case CIRCLE:
        case ARC_OF_CIRCLE:
        case CUBIC:
        case TTF_TEXT:
            // Nothing but the curve(s).
            break;

        case FACE_NORMAL_PT:
        case FACE_XPROD:
        case FACE_N_ROT_TRANS:
        case FACE_N_TRANS:
        case FACE_N_ROT_AA:
            // Do nothing; these are drawn with the triangle mesh
            break;

        default:
            oops();
    }

    // And draw the curves; generate the rational polynomial curves for
    // everything, then piecewise linearize them, and display those.
    SEdgeList sel;
    ZERO(&sel);
    GenerateEdges(&sel, true);
    int i;
    for(i = 0; i < sel.l.n; i++) {
        SEdge *se = &(sel.l.elem[i]);
        LineDrawOrGetDistance(se->a, se->b, true);
    }
    sel.Clear();
}