initial commit, 4.5 stable

thirdparty/msdfgen/core/edge-selectors.cpp

@@ -0,0 +1,261 @@
+
+#include "edge-selectors.h"
+
+#include "arithmetics.hpp"
+
+namespace msdfgen {
+
+#define DISTANCE_DELTA_FACTOR 1.001
+
+TrueDistanceSelector::EdgeCache::EdgeCache() : absDistance(0) { }
+
+void TrueDistanceSelector::reset(const Point2 &p) {
+    double delta = DISTANCE_DELTA_FACTOR*(p-this->p).length();
+    minDistance.distance += nonZeroSign(minDistance.distance)*delta;
+    this->p = p;
+}
+
+void TrueDistanceSelector::addEdge(EdgeCache &cache, const EdgeSegment *prevEdge, const EdgeSegment *edge, const EdgeSegment *nextEdge) {
+    double delta = DISTANCE_DELTA_FACTOR*(p-cache.point).length();
+    if (cache.absDistance-delta <= fabs(minDistance.distance)) {
+        double dummy;
+        SignedDistance distance = edge->signedDistance(p, dummy);
+        if (distance < minDistance)
+            minDistance = distance;
+        cache.point = p;
+        cache.absDistance = fabs(distance.distance);
+    }
+}
+
+void TrueDistanceSelector::merge(const TrueDistanceSelector &other) {
+    if (other.minDistance < minDistance)
+        minDistance = other.minDistance;
+}
+
+TrueDistanceSelector::DistanceType TrueDistanceSelector::distance() const {
+    return minDistance.distance;
+}
+
+PerpendicularDistanceSelectorBase::EdgeCache::EdgeCache() : absDistance(0), aDomainDistance(0), bDomainDistance(0), aPerpendicularDistance(0), bPerpendicularDistance(0) { }
+
+bool PerpendicularDistanceSelectorBase::getPerpendicularDistance(double &distance, const Vector2 &ep, const Vector2 &edgeDir) {
+    double ts = dotProduct(ep, edgeDir);
+    if (ts > 0) {
+        double perpendicularDistance = crossProduct(ep, edgeDir);
+        if (fabs(perpendicularDistance) < fabs(distance)) {
+            distance = perpendicularDistance;
+            return true;
+        }
+    }
+    return false;
+}
+
+PerpendicularDistanceSelectorBase::PerpendicularDistanceSelectorBase() : minNegativePerpendicularDistance(-fabs(minTrueDistance.distance)), minPositivePerpendicularDistance(fabs(minTrueDistance.distance)), nearEdge(NULL), nearEdgeParam(0) { }
+
+void PerpendicularDistanceSelectorBase::reset(double delta) {
+    minTrueDistance.distance += nonZeroSign(minTrueDistance.distance)*delta;
+    minNegativePerpendicularDistance = -fabs(minTrueDistance.distance);
+    minPositivePerpendicularDistance = fabs(minTrueDistance.distance);
+    nearEdge = NULL;
+    nearEdgeParam = 0;
+}
+
+bool PerpendicularDistanceSelectorBase::isEdgeRelevant(const EdgeCache &cache, const EdgeSegment *edge, const Point2 &p) const {
+    double delta = DISTANCE_DELTA_FACTOR*(p-cache.point).length();
+    return (
+        cache.absDistance-delta <= fabs(minTrueDistance.distance) ||
+        fabs(cache.aDomainDistance) < delta ||
+        fabs(cache.bDomainDistance) < delta ||
+        (cache.aDomainDistance > 0 && (cache.aPerpendicularDistance < 0 ?
+            cache.aPerpendicularDistance+delta >= minNegativePerpendicularDistance :
+            cache.aPerpendicularDistance-delta <= minPositivePerpendicularDistance
+        )) ||
+        (cache.bDomainDistance > 0 && (cache.bPerpendicularDistance < 0 ?
+            cache.bPerpendicularDistance+delta >= minNegativePerpendicularDistance :
+            cache.bPerpendicularDistance-delta <= minPositivePerpendicularDistance
+        ))
+    );
+}
+
+void PerpendicularDistanceSelectorBase::addEdgeTrueDistance(const EdgeSegment *edge, const SignedDistance &distance, double param) {
+    if (distance < minTrueDistance) {
+        minTrueDistance = distance;
+        nearEdge = edge;
+        nearEdgeParam = param;
+    }
+}
+
+void PerpendicularDistanceSelectorBase::addEdgePerpendicularDistance(double distance) {
+    if (distance <= 0 && distance > minNegativePerpendicularDistance)
+        minNegativePerpendicularDistance = distance;
+    if (distance >= 0 && distance < minPositivePerpendicularDistance)
+        minPositivePerpendicularDistance = distance;
+}
+
+void PerpendicularDistanceSelectorBase::merge(const PerpendicularDistanceSelectorBase &other) {
+    if (other.minTrueDistance < minTrueDistance) {
+        minTrueDistance = other.minTrueDistance;
+        nearEdge = other.nearEdge;
+        nearEdgeParam = other.nearEdgeParam;
+    }
+    if (other.minNegativePerpendicularDistance > minNegativePerpendicularDistance)
+        minNegativePerpendicularDistance = other.minNegativePerpendicularDistance;
+    if (other.minPositivePerpendicularDistance < minPositivePerpendicularDistance)
+        minPositivePerpendicularDistance = other.minPositivePerpendicularDistance;
+}
+
+double PerpendicularDistanceSelectorBase::computeDistance(const Point2 &p) const {
+    double minDistance = minTrueDistance.distance < 0 ? minNegativePerpendicularDistance : minPositivePerpendicularDistance;
+    if (nearEdge) {
+        SignedDistance distance = minTrueDistance;
+        nearEdge->distanceToPerpendicularDistance(distance, p, nearEdgeParam);
+        if (fabs(distance.distance) < fabs(minDistance))
+            minDistance = distance.distance;
+    }
+    return minDistance;
+}
+
+SignedDistance PerpendicularDistanceSelectorBase::trueDistance() const {
+    return minTrueDistance;
+}
+
+void PerpendicularDistanceSelector::reset(const Point2 &p) {
+    double delta = DISTANCE_DELTA_FACTOR*(p-this->p).length();
+    PerpendicularDistanceSelectorBase::reset(delta);
+    this->p = p;
+}
+
+void PerpendicularDistanceSelector::addEdge(EdgeCache &cache, const EdgeSegment *prevEdge, const EdgeSegment *edge, const EdgeSegment *nextEdge) {
+    if (isEdgeRelevant(cache, edge, p)) {
+        double param;
+        SignedDistance distance = edge->signedDistance(p, param);
+        addEdgeTrueDistance(edge, distance, param);
+        cache.point = p;
+        cache.absDistance = fabs(distance.distance);
+
+        Vector2 ap = p-edge->point(0);
+        Vector2 bp = p-edge->point(1);
+        Vector2 aDir = edge->direction(0).normalize(true);
+        Vector2 bDir = edge->direction(1).normalize(true);
+        Vector2 prevDir = prevEdge->direction(1).normalize(true);
+        Vector2 nextDir = nextEdge->direction(0).normalize(true);
+        double add = dotProduct(ap, (prevDir+aDir).normalize(true));
+        double bdd = -dotProduct(bp, (bDir+nextDir).normalize(true));
+        if (add > 0) {
+            double pd = distance.distance;
+            if (getPerpendicularDistance(pd, ap, -aDir))
+                addEdgePerpendicularDistance(pd = -pd);
+            cache.aPerpendicularDistance = pd;
+        }
+        if (bdd > 0) {
+            double pd = distance.distance;
+            if (getPerpendicularDistance(pd, bp, bDir))
+                addEdgePerpendicularDistance(pd);
+            cache.bPerpendicularDistance = pd;
+        }
+        cache.aDomainDistance = add;
+        cache.bDomainDistance = bdd;
+    }
+}
+
+PerpendicularDistanceSelector::DistanceType PerpendicularDistanceSelector::distance() const {
+    return computeDistance(p);
+}
+
+void MultiDistanceSelector::reset(const Point2 &p) {
+    double delta = DISTANCE_DELTA_FACTOR*(p-this->p).length();
+    r.reset(delta);
+    g.reset(delta);
+    b.reset(delta);
+    this->p = p;
+}
+
+void MultiDistanceSelector::addEdge(EdgeCache &cache, const EdgeSegment *prevEdge, const EdgeSegment *edge, const EdgeSegment *nextEdge) {
+    if (
+        (edge->color&RED && r.isEdgeRelevant(cache, edge, p)) ||
+        (edge->color&GREEN && g.isEdgeRelevant(cache, edge, p)) ||
+        (edge->color&BLUE && b.isEdgeRelevant(cache, edge, p))
+    ) {
+        double param;
+        SignedDistance distance = edge->signedDistance(p, param);
+        if (edge->color&RED)
+            r.addEdgeTrueDistance(edge, distance, param);
+        if (edge->color&GREEN)
+            g.addEdgeTrueDistance(edge, distance, param);
+        if (edge->color&BLUE)
+            b.addEdgeTrueDistance(edge, distance, param);
+        cache.point = p;
+        cache.absDistance = fabs(distance.distance);
+
+        Vector2 ap = p-edge->point(0);
+        Vector2 bp = p-edge->point(1);
+        Vector2 aDir = edge->direction(0).normalize(true);
+        Vector2 bDir = edge->direction(1).normalize(true);
+        Vector2 prevDir = prevEdge->direction(1).normalize(true);
+        Vector2 nextDir = nextEdge->direction(0).normalize(true);
+        double add = dotProduct(ap, (prevDir+aDir).normalize(true));
+        double bdd = -dotProduct(bp, (bDir+nextDir).normalize(true));
+        if (add > 0) {
+            double pd = distance.distance;
+            if (PerpendicularDistanceSelectorBase::getPerpendicularDistance(pd, ap, -aDir)) {
+                pd = -pd;
+                if (edge->color&RED)
+                    r.addEdgePerpendicularDistance(pd);
+                if (edge->color&GREEN)
+                    g.addEdgePerpendicularDistance(pd);
+                if (edge->color&BLUE)
+                    b.addEdgePerpendicularDistance(pd);
+            }
+            cache.aPerpendicularDistance = pd;
+        }
+        if (bdd > 0) {
+            double pd = distance.distance;
+            if (PerpendicularDistanceSelectorBase::getPerpendicularDistance(pd, bp, bDir)) {
+                if (edge->color&RED)
+                    r.addEdgePerpendicularDistance(pd);
+                if (edge->color&GREEN)
+                    g.addEdgePerpendicularDistance(pd);
+                if (edge->color&BLUE)
+                    b.addEdgePerpendicularDistance(pd);
+            }
+            cache.bPerpendicularDistance = pd;
+        }
+        cache.aDomainDistance = add;
+        cache.bDomainDistance = bdd;
+    }
+}
+
+void MultiDistanceSelector::merge(const MultiDistanceSelector &other) {
+    r.merge(other.r);
+    g.merge(other.g);
+    b.merge(other.b);
+}
+
+MultiDistanceSelector::DistanceType MultiDistanceSelector::distance() const {
+    MultiDistance multiDistance;
+    multiDistance.r = r.computeDistance(p);
+    multiDistance.g = g.computeDistance(p);
+    multiDistance.b = b.computeDistance(p);
+    return multiDistance;
+}
+
+SignedDistance MultiDistanceSelector::trueDistance() const {
+    SignedDistance distance = r.trueDistance();
+    if (g.trueDistance() < distance)
+        distance = g.trueDistance();
+    if (b.trueDistance() < distance)
+        distance = b.trueDistance();
+    return distance;
+}
+
+MultiAndTrueDistanceSelector::DistanceType MultiAndTrueDistanceSelector::distance() const {
+    MultiDistance multiDistance = MultiDistanceSelector::distance();
+    MultiAndTrueDistance mtd;
+    mtd.r = multiDistance.r;
+    mtd.g = multiDistance.g;
+    mtd.b = multiDistance.b;
+    mtd.a = trueDistance().distance;
+    return mtd;
+}
+
+}