mirror of https://github.com/Chlumsky/msdfgen.git
135 lines
5.2 KiB
C++
135 lines
5.2 KiB
C++
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#pragma once
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#include "Vector2.h"
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#include "SignedDistance.h"
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#include "EdgeColor.h"
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namespace msdfgen {
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// Parameters for iterative search of closest point on a cubic Bezier curve. Increase for higher precision.
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#define MSDFGEN_CUBIC_SEARCH_STARTS 4
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#define MSDFGEN_CUBIC_SEARCH_STEPS 4
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// Threshold of the dot product of adjacent edge directions to be considered convergent.
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#define MSDFGEN_CORNER_DOT_EPSILON 0.000001
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/// An abstract edge segment.
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class EdgeSegment {
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public:
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EdgeColor color;
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EdgeSegment(EdgeColor edgeColor = WHITE) : color(edgeColor) { }
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virtual ~EdgeSegment() { }
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/// Creates a copy of the edge segment.
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virtual EdgeSegment * clone() const = 0;
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/// Returns the point on the edge specified by the parameter (between 0 and 1).
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virtual Point2 point(double param) const = 0;
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/// Returns the direction the edge has at the point specified by the parameter.
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virtual Vector2 direction(double param) const = 0;
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/// Returns the change of direction (second derivative) at the point specified by the parameter.
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virtual Vector2 directionChange(double param) const = 0;
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/// Returns the direction tendency vector that can resolve cases where directions converge at a corner.
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virtual Vector2 directionTendency(double param, int polarity) const;
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/// Returns the minimum signed distance between origin and the edge.
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virtual SignedDistance signedDistance(Point2 origin, double ¶m) const = 0;
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/// Converts a previously retrieved signed distance from origin to pseudo-distance.
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virtual void distanceToPseudoDistance(SignedDistance &distance, Point2 origin, double param) const;
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/// Outputs a list of (at most three) intersections (their X coordinates) with an infinite horizontal scanline at y and returns how many there are.
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virtual int scanlineIntersections(double x[3], int dy[3], double y) const = 0;
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/// Adjusts the bounding box to fit the edge segment.
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virtual void bound(double &l, double &b, double &r, double &t) const = 0;
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/// Moves the start point of the edge segment.
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virtual void moveStartPoint(Point2 to) = 0;
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/// Moves the end point of the edge segment.
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virtual void moveEndPoint(Point2 to) = 0;
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/// Splits the edge segments into thirds which together represent the original edge.
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virtual void splitInThirds(EdgeSegment *&part1, EdgeSegment *&part2, EdgeSegment *&part3) const = 0;
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/// Converts convergent segment to a divergent segment. If NULL is returned, the object is already divergent and has been updated.
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virtual EdgeSegment * makeDivergent(int dStart, int dEnd) = 0;
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};
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/// A line segment.
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class LinearSegment : public EdgeSegment {
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public:
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Point2 p[2];
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LinearSegment(Point2 p0, Point2 p1, EdgeColor edgeColor = WHITE);
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LinearSegment * clone() const;
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Point2 point(double param) const;
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Vector2 direction(double param) const;
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Vector2 directionChange(double param) const;
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SignedDistance signedDistance(Point2 origin, double ¶m) const;
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int scanlineIntersections(double x[3], int dy[3], double y) const;
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void bound(double &l, double &b, double &r, double &t) const;
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void moveStartPoint(Point2 to);
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void moveEndPoint(Point2 to);
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void splitInThirds(EdgeSegment *&part1, EdgeSegment *&part2, EdgeSegment *&part3) const;
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EdgeSegment * makeDivergent(int dStart, int dEnd);
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};
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/// A quadratic Bezier curve.
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class QuadraticSegment : public EdgeSegment {
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public:
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Point2 p[3];
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QuadraticSegment(Point2 p0, Point2 p1, Point2 p2, EdgeColor edgeColor = WHITE);
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QuadraticSegment * clone() const;
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Point2 point(double param) const;
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Vector2 direction(double param) const;
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Vector2 directionChange(double param) const;
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SignedDistance signedDistance(Point2 origin, double ¶m) const;
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int scanlineIntersections(double x[3], int dy[3], double y) const;
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void bound(double &l, double &b, double &r, double &t) const;
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void moveStartPoint(Point2 to);
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void moveEndPoint(Point2 to);
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void splitInThirds(EdgeSegment *&part1, EdgeSegment *&part2, EdgeSegment *&part3) const;
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EdgeSegment * makeDivergent(int dStart, int dEnd);
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};
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/// A cubic Bezier curve.
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class CubicSegment : public EdgeSegment {
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public:
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Point2 p[4];
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CubicSegment(Point2 p0, Point2 p1, Point2 p2, Point2 p3, EdgeColor edgeColor = WHITE);
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CubicSegment * clone() const;
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Point2 point(double param) const;
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Vector2 direction(double param) const;
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Vector2 directionChange(double param) const;
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SignedDistance signedDistance(Point2 origin, double ¶m) const;
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int scanlineIntersections(double x[3], int dy[3], double y) const;
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void bound(double &l, double &b, double &r, double &t) const;
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void moveStartPoint(Point2 to);
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void moveEndPoint(Point2 to);
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void splitInThirds(EdgeSegment *&part1, EdgeSegment *&part2, EdgeSegment *&part3) const;
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EdgeSegment * makeDivergent(int dStart, int dEnd);
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};
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template <class BaseSegment>
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class DivergentEdgeSegment : public BaseSegment {
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public:
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int dStart, dEnd;
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explicit DivergentEdgeSegment(const BaseSegment &base, int dStart, int dEnd);
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SignedDistance signedDistance(Point2 origin, double ¶m) const;
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void distanceToPseudoDistance(SignedDistance &distance, Point2 origin, double param) const;
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EdgeSegment * makeDivergent(int dStart, int dEnd);
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};
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}
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