Add Text rendering

- Add FreeType as dependency
- Add MsdfGen as dependency
- Add MsdfAtlasGen as dependency

CopiumEngine/ext/include/msdfgen/core/Scanline.h

@@ -0,0 +1,55 @@
+
+#pragma once
+
+#include <vector>
+
+namespace msdfgen {
+
+/// Fill rule dictates how intersection total is interpreted during rasterization.
+enum FillRule {
+    FILL_NONZERO,
+    FILL_ODD, // "even-odd"
+    FILL_POSITIVE,
+    FILL_NEGATIVE
+};
+
+/// Resolves the number of intersection into a binary fill value based on fill rule.
+bool interpretFillRule(int intersections, FillRule fillRule);
+
+/// Represents a horizontal scanline intersecting a shape.
+class Scanline {
+
+public:
+    /// An intersection with the scanline.
+    struct Intersection {
+        /// X coordinate.
+        double x;
+        /// Normalized Y direction of the oriented edge at the point of intersection.
+        int direction;
+    };
+
+    static double overlap(const Scanline &a, const Scanline &b, double xFrom, double xTo, FillRule fillRule);
+
+    Scanline();
+    /// Populates the intersection list.
+    void setIntersections(const std::vector<Intersection> &intersections);
+#ifdef MSDFGEN_USE_CPP11
+    void setIntersections(std::vector<Intersection> &&intersections);
+#endif
+    /// Returns the number of intersections left of x.
+    int countIntersections(double x) const;
+    /// Returns the total sign of intersections left of x.
+    int sumIntersections(double x) const;
+    /// Decides whether the scanline is filled at x based on fill rule.
+    bool filled(double x, FillRule fillRule) const;
+
+private:
+    std::vector<Intersection> intersections;
+    mutable int lastIndex;
+
+    void preprocess();
+    int moveTo(double x) const;
+
+};
+
+}