virtualx-engine/thirdparty/msdfgen/core/Shape.cpp
2024-03-13 09:12:50 +02:00

182 lines
7.4 KiB
C++

#include "Shape.h"
#include <cstdlib>
#include "arithmetics.hpp"
namespace msdfgen {
Shape::Shape() : inverseYAxis(false) { }
void Shape::addContour(const Contour &contour) {
contours.push_back(contour);
}
#ifdef MSDFGEN_USE_CPP11
void Shape::addContour(Contour &&contour) {
contours.push_back((Contour &&) contour);
}
#endif
Contour &Shape::addContour() {
contours.resize(contours.size()+1);
return contours.back();
}
bool Shape::validate() const {
for (std::vector<Contour>::const_iterator contour = contours.begin(); contour != contours.end(); ++contour) {
if (!contour->edges.empty()) {
Point2 corner = contour->edges.back()->point(1);
for (std::vector<EdgeHolder>::const_iterator edge = contour->edges.begin(); edge != contour->edges.end(); ++edge) {
if (!*edge)
return false;
if ((*edge)->point(0) != corner)
return false;
corner = (*edge)->point(1);
}
}
}
return true;
}
static void deconvergeEdge(EdgeHolder &edgeHolder, int param) {
switch (edgeHolder->type()) {
case (int) QuadraticSegment::EDGE_TYPE:
edgeHolder = static_cast<const QuadraticSegment *>(&*edgeHolder)->convertToCubic();
// fallthrough
case (int) CubicSegment::EDGE_TYPE:
static_cast<CubicSegment *>(&*edgeHolder)->deconverge(param, MSDFGEN_DECONVERGENCE_FACTOR);
}
}
void Shape::normalize() {
for (std::vector<Contour>::iterator contour = contours.begin(); contour != contours.end(); ++contour) {
if (contour->edges.size() == 1) {
EdgeSegment *parts[3] = { };
contour->edges[0]->splitInThirds(parts[0], parts[1], parts[2]);
contour->edges.clear();
contour->edges.push_back(EdgeHolder(parts[0]));
contour->edges.push_back(EdgeHolder(parts[1]));
contour->edges.push_back(EdgeHolder(parts[2]));
} else {
EdgeHolder *prevEdge = &contour->edges.back();
for (std::vector<EdgeHolder>::iterator edge = contour->edges.begin(); edge != contour->edges.end(); ++edge) {
Vector2 prevDir = (*prevEdge)->direction(1).normalize();
Vector2 curDir = (*edge)->direction(0).normalize();
if (dotProduct(prevDir, curDir) < MSDFGEN_CORNER_DOT_EPSILON-1) {
deconvergeEdge(*prevEdge, 1);
deconvergeEdge(*edge, 0);
}
prevEdge = &*edge;
}
}
}
}
void Shape::bound(double &l, double &b, double &r, double &t) const {
for (std::vector<Contour>::const_iterator contour = contours.begin(); contour != contours.end(); ++contour)
contour->bound(l, b, r, t);
}
void Shape::boundMiters(double &l, double &b, double &r, double &t, double border, double miterLimit, int polarity) const {
for (std::vector<Contour>::const_iterator contour = contours.begin(); contour != contours.end(); ++contour)
contour->boundMiters(l, b, r, t, border, miterLimit, polarity);
}
Shape::Bounds Shape::getBounds(double border, double miterLimit, int polarity) const {
static const double LARGE_VALUE = 1e240;
Shape::Bounds bounds = { +LARGE_VALUE, +LARGE_VALUE, -LARGE_VALUE, -LARGE_VALUE };
bound(bounds.l, bounds.b, bounds.r, bounds.t);
if (border > 0) {
bounds.l -= border, bounds.b -= border;
bounds.r += border, bounds.t += border;
if (miterLimit > 0)
boundMiters(bounds.l, bounds.b, bounds.r, bounds.t, border, miterLimit, polarity);
}
return bounds;
}
void Shape::scanline(Scanline &line, double y) const {
std::vector<Scanline::Intersection> intersections;
double x[3];
int dy[3];
for (std::vector<Contour>::const_iterator contour = contours.begin(); contour != contours.end(); ++contour) {
for (std::vector<EdgeHolder>::const_iterator edge = contour->edges.begin(); edge != contour->edges.end(); ++edge) {
int n = (*edge)->scanlineIntersections(x, dy, y);
for (int i = 0; i < n; ++i) {
Scanline::Intersection intersection = { x[i], dy[i] };
intersections.push_back(intersection);
}
}
}
#ifdef MSDFGEN_USE_CPP11
line.setIntersections((std::vector<Scanline::Intersection> &&) intersections);
#else
line.setIntersections(intersections);
#endif
}
int Shape::edgeCount() const {
int total = 0;
for (std::vector<Contour>::const_iterator contour = contours.begin(); contour != contours.end(); ++contour)
total += (int) contour->edges.size();
return total;
}
void Shape::orientContours() {
struct Intersection {
double x;
int direction;
int contourIndex;
static int compare(const void *a, const void *b) {
return sign(reinterpret_cast<const Intersection *>(a)->x-reinterpret_cast<const Intersection *>(b)->x);
}
};
const double ratio = .5*(sqrt(5)-1); // an irrational number to minimize chance of intersecting a corner or other point of interest
std::vector<int> orientations(contours.size());
std::vector<Intersection> intersections;
for (int i = 0; i < (int) contours.size(); ++i) {
if (!orientations[i] && !contours[i].edges.empty()) {
// Find an Y that crosses the contour
double y0 = contours[i].edges.front()->point(0).y;
double y1 = y0;
for (std::vector<EdgeHolder>::const_iterator edge = contours[i].edges.begin(); edge != contours[i].edges.end() && y0 == y1; ++edge)
y1 = (*edge)->point(1).y;
for (std::vector<EdgeHolder>::const_iterator edge = contours[i].edges.begin(); edge != contours[i].edges.end() && y0 == y1; ++edge)
y1 = (*edge)->point(ratio).y; // in case all endpoints are in a horizontal line
double y = mix(y0, y1, ratio);
// Scanline through whole shape at Y
double x[3];
int dy[3];
for (int j = 0; j < (int) contours.size(); ++j) {
for (std::vector<EdgeHolder>::const_iterator edge = contours[j].edges.begin(); edge != contours[j].edges.end(); ++edge) {
int n = (*edge)->scanlineIntersections(x, dy, y);
for (int k = 0; k < n; ++k) {
Intersection intersection = { x[k], dy[k], j };
intersections.push_back(intersection);
}
}
}
if (!intersections.empty()) {
qsort(&intersections[0], intersections.size(), sizeof(Intersection), &Intersection::compare);
// Disqualify multiple intersections
for (int j = 1; j < (int) intersections.size(); ++j)
if (intersections[j].x == intersections[j-1].x)
intersections[j].direction = intersections[j-1].direction = 0;
// Inspect scanline and deduce orientations of intersected contours
for (int j = 0; j < (int) intersections.size(); ++j)
if (intersections[j].direction)
orientations[intersections[j].contourIndex] += 2*((j&1)^(intersections[j].direction > 0))-1;
intersections.clear();
}
}
}
// Reverse contours that have the opposite orientation
for (int i = 0; i < (int) contours.size(); ++i)
if (orientations[i] < 0)
contours[i].reverse();
}
}