tessellator.cc

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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#include "tessellator.h"
 
#include <vector>
 
namespace impeller {
PathBuilder* CreatePathBuilder() {
  return new PathBuilder();
}
 
void DestroyPathBuilder(PathBuilder* builder) {
  delete builder;
}
 
void MoveTo(PathBuilder* builder, Scalar x, Scalar y) {
  builder->MoveTo(Point(x, y));
}
 
void LineTo(PathBuilder* builder, Scalar x, Scalar y) {
  builder->LineTo(Point(x, y));
}
 
void CubicTo(PathBuilder* builder,
             Scalar x1,
             Scalar y1,
             Scalar x2,
             Scalar y2,
             Scalar x3,
             Scalar y3) {
  builder->CubicCurveTo(Point(x1, y1), Point(x2, y2), Point(x3, y3));
}
 
void Close(PathBuilder* builder) {
  builder->Close();
}
 
struct Vertices* Tessellate(PathBuilder* builder,
                            int fill_type,
                            Scalar tolerance) {
  auto path = builder->CopyPath(static_cast<FillType>(fill_type));
  auto polyline = path.CreatePolyline(tolerance);
  std::vector<float> points;
  if (Tessellator{}.Tessellate(
          path.GetFillType(), polyline,
          [&points](const float* vertices, size_t vertices_count,
                    const uint16_t* indices, size_t indices_count) {
            // Results are expected to be re-duplicated.
            std::vector<Point> raw_points;
            for (auto i = 0u; i < vertices_count * 2; i += 2) {
              raw_points.emplace_back(Point{vertices[i], vertices[i + 1]});
            }
            for (auto i = 0u; i < indices_count; i++) {
              auto point = raw_points[indices[i]];
              points.push_back(point.x);
              points.push_back(point.y);
            }
            return true;
          }) != Tessellator::Result::kSuccess) {
    return nullptr;
  }
 
  Vertices* vertices = new Vertices();
  vertices->points = new float[points.size()];
  if (!vertices->points) {
    return nullptr;
  }
  vertices->length = points.size();
  std::copy(points.begin(), points.end(), vertices->points);
  return vertices;
}
 
void DestroyVertices(Vertices* vertices) {
  delete vertices->points;
  delete vertices;
}
 
}  // namespace impeller