initial commit, 4.5 stable

thirdparty/msdfgen/core/edge-selectors.h

@@ -0,0 +1,117 @@
+
+#pragma once
+
+#include "Vector2.hpp"
+#include "SignedDistance.hpp"
+#include "edge-segments.h"
+
+namespace msdfgen {
+
+struct MultiDistance {
+    double r, g, b;
+};
+struct MultiAndTrueDistance : MultiDistance {
+    double a;
+};
+
+/// Selects the nearest edge by its true distance.
+class TrueDistanceSelector {
+
+public:
+    typedef double DistanceType;
+
+    struct EdgeCache {
+        Point2 point;
+        double absDistance;
+
+        EdgeCache();
+    };
+
+    void reset(const Point2 &p);
+    void addEdge(EdgeCache &cache, const EdgeSegment *prevEdge, const EdgeSegment *edge, const EdgeSegment *nextEdge);
+    void merge(const TrueDistanceSelector &other);
+    DistanceType distance() const;
+
+private:
+    Point2 p;
+    SignedDistance minDistance;
+
+};
+
+class PerpendicularDistanceSelectorBase {
+
+public:
+    struct EdgeCache {
+        Point2 point;
+        double absDistance;
+        double aDomainDistance, bDomainDistance;
+        double aPerpendicularDistance, bPerpendicularDistance;
+
+        EdgeCache();
+    };
+
+    static bool getPerpendicularDistance(double &distance, const Vector2 &ep, const Vector2 &edgeDir);
+
+    PerpendicularDistanceSelectorBase();
+    void reset(double delta);
+    bool isEdgeRelevant(const EdgeCache &cache, const EdgeSegment *edge, const Point2 &p) const;
+    void addEdgeTrueDistance(const EdgeSegment *edge, const SignedDistance &distance, double param);
+    void addEdgePerpendicularDistance(double distance);
+    void merge(const PerpendicularDistanceSelectorBase &other);
+    double computeDistance(const Point2 &p) const;
+    SignedDistance trueDistance() const;
+
+private:
+    SignedDistance minTrueDistance;
+    double minNegativePerpendicularDistance;
+    double minPositivePerpendicularDistance;
+    const EdgeSegment *nearEdge;
+    double nearEdgeParam;
+
+};
+
+/// Selects the nearest edge by its perpendicular distance.
+class PerpendicularDistanceSelector : public PerpendicularDistanceSelectorBase {
+
+public:
+    typedef double DistanceType;
+
+    void reset(const Point2 &p);
+    void addEdge(EdgeCache &cache, const EdgeSegment *prevEdge, const EdgeSegment *edge, const EdgeSegment *nextEdge);
+    DistanceType distance() const;
+
+private:
+    Point2 p;
+
+};
+
+/// Selects the nearest edge for each of the three channels by its perpendicular distance.
+class MultiDistanceSelector {
+
+public:
+    typedef MultiDistance DistanceType;
+    typedef PerpendicularDistanceSelectorBase::EdgeCache EdgeCache;
+
+    void reset(const Point2 &p);
+    void addEdge(EdgeCache &cache, const EdgeSegment *prevEdge, const EdgeSegment *edge, const EdgeSegment *nextEdge);
+    void merge(const MultiDistanceSelector &other);
+    DistanceType distance() const;
+    SignedDistance trueDistance() const;
+
+private:
+    Point2 p;
+    PerpendicularDistanceSelectorBase r, g, b;
+
+};
+
+/// Selects the nearest edge for each of the three color channels by its perpendicular distance and by true distance for the alpha channel.
+class MultiAndTrueDistanceSelector : public MultiDistanceSelector {
+
+public:
+    typedef MultiAndTrueDistance DistanceType;
+
+    DistanceType distance() const;
+
+};
+
+}