renderer/gr_inner_fan_triangulator.hpp

/*
 * Copyright 2021 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef GrInnerFanTriangulator_DEFINED
#define GrInnerFanTriangulator_DEFINED

#if !defined(SK_ENABLE_OPTIMIZE_SIZE)

#include "gr_triangulator.hpp"

namespace rive
{
// Triangulates the inner polygon(s) of a path (i.e., the triangle fan for a Redbook rendering
// method). When combined with the outer curves and breadcrumb triangles, these produce a complete
// path. If a breadcrumbCollector is not provided, pathToPolys fails upon self intersection.
class GrInnerFanTriangulator : private GrTriangulator
{
public:
    using GrTriangulator::BreadcrumbTriangleList;

    GrInnerFanTriangulator(const RawPath& path,
                           FillRule fillRule,
                           const AABB& pathBounds,
                           TrivialBlockAllocator* alloc) :
        GrTriangulator(path, fillRule, pathBounds, alloc)
    {
        fPreserveCollinearVertices = true;
        fCollectBreadcrumbTriangles = true;
    }

    int pathToTriangles(GrEagerVertexAllocator* vertexAlloc,
                        BreadcrumbTriangleList* breadcrumbList,
                        bool* isLinear)
    {
        Poly* polys = this->pathToPolys(breadcrumbList, isLinear);
        return this->polysToTriangles(polys, vertexAlloc, breadcrumbList);
    }

    Poly* pathToPolys(BreadcrumbTriangleList* breadcrumbList, bool* isLinear)
    {
        auto [polys, success] = this->GrTriangulator::pathToPolys(0, AABB{}, isLinear);
        if (!success)
        {
            return nullptr;
        }
        breadcrumbList->concat(std::move(fBreadcrumbList));
        return polys;
    }

    int polysToTriangles(Poly* polys,
                         GrEagerVertexAllocator* vertexAlloc,
                         BreadcrumbTriangleList* breadcrumbList) const
    {
        int vertexCount = this->GrTriangulator::polysToTriangles(polys, vertexAlloc);
        breadcrumbList->concat(std::move(fBreadcrumbList));
        return vertexCount;
    }
};
} // namespace rive

#else

// Stub out GrInnerFanTriangulator::BreadcrumbTriangleList for function declarations.
namespace GrInnerFanTriangulator
{
struct BreadcrumbTriangleList
{
    BreadcrumbTriangleList() = delete;
};
}; // namespace GrInnerFanTriangulator

#endif // SK_ENABLE_OPTIMIZE_SIZE

#endif // GrInnerFanTriangulator_DEFINED