Merge pull request #51908 from bruvzg/msdf_fonts2

Make FontData importable resource. Add multi-channel SDF font rendering.

1 files changed, 117 insertions, 0 deletions

diff --git a/thirdparty/msdfgen/core/edge-selectors.h b/thirdparty/msdfgen/core/edge-selectors.h
new file mode 100644
index 0000000000..3620999f82
--- /dev/null
+++ b/thirdparty/msdfgen/core/edge-selectors.h
@@ -0,0 +1,117 @@
+
+#pragma once
+
+#include "Vector2.h"
+#include "SignedDistance.h"
+#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 PseudoDistanceSelectorBase {
+
+public:
+    struct EdgeCache {
+        Point2 point;
+        double absDistance;
+        double aDomainDistance, bDomainDistance;
+        double aPseudoDistance, bPseudoDistance;
+
+        EdgeCache();
+    };
+
+    static bool getPseudoDistance(double &distance, const Vector2 &ep, const Vector2 &edgeDir);
+
+    PseudoDistanceSelectorBase();
+    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 addEdgePseudoDistance(double distance);
+    void merge(const PseudoDistanceSelectorBase &other);
+    double computeDistance(const Point2 &p) const;
+    SignedDistance trueDistance() const;
+
+private:
+    SignedDistance minTrueDistance;
+    double minNegativePseudoDistance;
+    double minPositivePseudoDistance;
+    const EdgeSegment *nearEdge;
+    double nearEdgeParam;
+
+};
+
+/// Selects the nearest edge by its pseudo-distance.
+class PseudoDistanceSelector : public PseudoDistanceSelectorBase {
+
+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 pseudo-distance.
+class MultiDistanceSelector {
+
+public:
+    typedef MultiDistance DistanceType;
+    typedef PseudoDistanceSelectorBase::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;
+    PseudoDistanceSelectorBase r, g, b;
+
+};
+
+/// Selects the nearest edge for each of the three color channels by its pseudo-distance and by true distance for the alpha channel.
+class MultiAndTrueDistanceSelector : public MultiDistanceSelector {
+
+public:
+    typedef MultiAndTrueDistance DistanceType;
+
+    DistanceType distance() const;
+
+};
+
+}