infinipaint/src/CanvasComponents/MeshCanvasComponent.cpp

/*  
 * InfiniPaint
 * Copyright (C) 2025-2026 Yousef Khadadeh
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "MeshCanvasComponent.hpp"
#include <Helpers/Serializers.hpp>
#include <cereal/types/vector.hpp>
#include <include/core/SkPathTypes.h>
#include <limits>
#include <Eigen/Geometry>
#include "BrushComponentCode.hpp"
#include "CanvasComponent.hpp"
#include "Eigen/Core"
#include "Helpers/MathExtras.hpp"
#include "../TimePoint.hpp"
#include <include/core/SkVertices.h>
#include <include/pathops/SkPathOps.h>
#include <memory>
#include "../DrawCollision.hpp"
#include "CanvasComponentContainer.hpp"
#include "Helpers/SCollision.hpp"
#include "../DrawingProgram/DrawingProgram.hpp"
#include "../World.hpp"
#include <CDT/include/CDT.h>
#include <clipper2/clipper.h>

template <typename Archive> void skpath_write(const SkPath& p, Archive& a) {
    std::vector<uint32_t> contourSizes;
    uint32_t contourSize = 0;
    auto verbs = p.verbs();
    auto points = p.points();
    for(size_t verbIndex = 0; verbIndex < verbs.size(); verbIndex++) {
        switch(verbs[verbIndex]) {
            case SkPathVerb::kClose:
                contourSizes.emplace_back(contourSize);
                contourSize = 0;
                break;
            case SkPathVerb::kMove:
            case SkPathVerb::kLine:
                contourSize++;
                break;
            default:
                throw std::runtime_error("[skpath_write] Illegal verb " + std::to_string(static_cast<unsigned>(verbs[verbIndex])));
                break;
        }
    }
    a(contourSizes);
    for(const SkPoint& p : points)
        a(p);
}

template <typename Archive> SkPath skpath_read(Archive& a) {
    SkPathBuilder builder;
    std::vector<uint32_t> contourSizes;
    a(contourSizes);
    for(uint32_t contourSize : contourSizes) {
        SkPoint p;
        if(contourSize == 0)
            continue;
        a(p);
        builder.moveTo(p);
        for(uint32_t i = 1; i < contourSize; i++) {
            a(p);
            builder.lineTo(p);
        }
        builder.close();
    }
    return builder.detach();
}

void MeshCanvasComponent::save(cereal::PortableBinaryOutputArchive& a) const {
    skpath_write(d.meshPath, a);
    a(d.color);
}

void MeshCanvasComponent::load(cereal::PortableBinaryInputArchive& a) {
    d.meshPath = skpath_read(a);
    a(d.color);
}

void MeshCanvasComponent::save_file(cereal::PortableBinaryOutputArchive& a) const {
    skpath_write(d.meshPath, a);
    a(d.color);
}

void MeshCanvasComponent::load_file(cereal::PortableBinaryInputArchive& a, VersionNumber version) {
    if(version >= VersionNumber(0, 6, 0)) {
        d.meshPath = skpath_read(a);
        a(d.color);
    }
    else {
        std::vector<BrushComponentCode::BrushPoint> brushPoints;
        bool hasRoundCaps;
        a(brushPoints, d.color, hasRoundCaps);
        d.meshPath = BrushComponentCode::brush_stroke_to_skpath(brushPoints, hasRoundCaps);
        std::optional<SkPath> simplified = Simplify(d.meshPath);
        if(simplified.has_value())
            d.meshPath = simplified.value();
    }
}

std::unique_ptr<CanvasComponent> MeshCanvasComponent::get_data_copy() const {
    auto toRet = std::make_unique<MeshCanvasComponent>();
    toRet->d = d;
    return toRet;
}

CanvasComponentType MeshCanvasComponent::get_type() const {
    return CanvasComponentType::MESH;
}

void MeshCanvasComponent::change_stroke_color(const Vector4f& newStrokeColor) {
    d.color = newStrokeColor;
}

std::optional<Vector4f> MeshCanvasComponent::get_stroke_color() const {
    return d.color;
}

void MeshCanvasComponent::draw(SkCanvas* canvas, const DrawData& drawData, const std::shared_ptr<void>& predrawData) const {
    SkPaint paint;
    paint.setColor4f(SkColor4f{d.color.x(), d.color.y(), d.color.z(), d.color.w()});
    paint.setAntiAlias(drawData.skiaAA);
    canvas->drawPath(d.meshPath, paint);

    //SkPaint paint2;
    //paint2.setColor4f(SkColor4f{1.0f, 0.0f, 0.0f, 1.0f});
    //paint2.setStroke(true);
    //draw_collider(canvas, drawData, collisionTree, paint2);
}

std::shared_ptr<void> MeshCanvasComponent::get_predraw_data_accurate(const DrawData& drawData, const CoordSpaceHelper& coords) const {
    SCollision::AABB<float> viewGenerousColliderInObjSpace = coords.world_collider_to_coords<SCollision::AABB<float>>(drawData.cam.viewingAreaGenerousCollider);
    viewGenerousColliderInObjSpace.min -= Vector2f{1.0f, 1.0f};
    viewGenerousColliderInObjSpace.max += Vector2f{1.0f, 1.0f};

    std::vector<std::array<SkPoint, 3>> finalTrianglePoints;

    collisionTree.is_collide_triangle_bounds_func(viewGenerousColliderInObjSpace, [&](const SCollision::Triangle<float>& triCollider) {
        auto clipListFunc = [](const std::vector<std::array<WorldVec, 3>>& clipList, const std::array<WorldVec, 2>& axisLineSegment, const std::function<bool(const WorldVec&)>& isInClippingAreaFunc) {
            std::vector<std::array<WorldVec, 3>> resultList;
            for(auto& t : clipList)
                clip_triangle_against_axis(resultList, t, axisLineSegment, isInClippingAreaFunc);
            return resultList;
        };

        std::vector<std::array<WorldVec, 3>> clipList;
        clipList.emplace_back(std::array<WorldVec, 3>{coords.from_space(triCollider.p[0]), coords.from_space(triCollider.p[1]), coords.from_space(triCollider.p[2])});
        clipList = clipListFunc(clipList, {drawData.cam.viewingAreaGenerousCollider.min, drawData.cam.viewingAreaGenerousCollider.top_right()}, [&](const WorldVec& p) {
            return p.y() > drawData.cam.viewingAreaGenerousCollider.min.y();
        });
        clipList = clipListFunc(clipList, {drawData.cam.viewingAreaGenerousCollider.max, drawData.cam.viewingAreaGenerousCollider.bottom_left()}, [&](const WorldVec& p) {
            return p.y() < drawData.cam.viewingAreaGenerousCollider.max.y();
        });
        clipList = clipListFunc(clipList, {drawData.cam.viewingAreaGenerousCollider.min, drawData.cam.viewingAreaGenerousCollider.bottom_left()}, [&](const WorldVec& p) {
            return p.x() > drawData.cam.viewingAreaGenerousCollider.min.x();
        });
        clipList = clipListFunc(clipList, {drawData.cam.viewingAreaGenerousCollider.max, drawData.cam.viewingAreaGenerousCollider.top_right()}, [&](const WorldVec& p) {
            return p.x() < drawData.cam.viewingAreaGenerousCollider.max.x();
        });
        for(auto& tri : clipList) {
            auto& c = drawData.cam.c;
            finalTrianglePoints.emplace_back(std::array<SkPoint, 3>{convert_vec2<SkPoint>(c.to_space(tri[0])), convert_vec2<SkPoint>(c.to_space(tri[1])), convert_vec2<SkPoint>(c.to_space(tri[2]))});
        }
    });

    // Match points that are close enough. I don't think this is required.
    //if(!finalTrianglePoints.empty()) {
    //    for(size_t i = 0; i < finalTrianglePoints.size() - 1; i++) {
    //        for(size_t j = 0; j < 3; j++) {
    //            for(size_t k = i + 1; k < finalTrianglePoints.size(); k++) {
    //                for(size_t l = 0; l < 3; l++) {
    //                    if(std::fabs(finalTrianglePoints[i][j].fX - finalTrianglePoints[k][l].fX) < 0.0001f && std::fabs(finalTrianglePoints[i][j].fY - finalTrianglePoints[k][l].fY) < 0.0001f && finalTrianglePoints[k][l] != finalTrianglePoints[i][j])
    //                        finalTrianglePoints[k][l] = finalTrianglePoints[i][j];
    //                }
    //            }
    //        }
    //    }
    //}

    if(finalTrianglePoints.empty())
        return nullptr;
    else if(drawData.isSVGRender) {
        auto pathsToDraw = std::make_shared<std::vector<SkPath>>();
        for(auto& finalTriangle : finalTrianglePoints) {
            SkPathBuilder pathBuilder;
            pathBuilder.addPolygon({finalTriangle.data(), finalTriangle.size()}, true);
            pathsToDraw->emplace_back(pathBuilder.detach());
        }
        return pathsToDraw;
    }
    else {
        std::vector<SkPoint> pointVec(finalTrianglePoints.size() * 3);
        for(size_t i = 0; i < finalTrianglePoints.size(); i++) {
            pointVec[i * 3 + 0] = finalTrianglePoints[i][0];
            pointVec[i * 3 + 1] = finalTrianglePoints[i][1];
            pointVec[i * 3 + 2] = finalTrianglePoints[i][2];
        }
        auto verticesToDraw = std::make_shared<sk_sp<SkVertices>>();
        *verticesToDraw = SkVertices::MakeCopy(SkVertices::kTriangles_VertexMode, pointVec.size(), pointVec.data(), nullptr, nullptr);
        return verticesToDraw;
    }
    return nullptr;
}

bool MeshCanvasComponent::accurate_draw(SkCanvas* canvas, const DrawData& drawData, const CoordSpaceHelper& coords, const std::shared_ptr<void>& predrawData) const {
    if(predrawData) {
        if(drawData.isSVGRender) { // SVG renders can't use saveLayer, so use this despite it being buggy in some scenarios
            auto pathsToDraw = std::static_pointer_cast<std::vector<SkPath>>(predrawData);
            SkPaint paint;
            paint.setColor4f(SkColor4f{d.color.x(), d.color.y(), d.color.z(), d.color.w()});
            for(const SkPath& p : *pathsToDraw)
                canvas->drawPath(p, paint);
        }
        else {
            auto verticesToDraw = std::static_pointer_cast<sk_sp<SkVertices>>(predrawData);
            SkPaint paint;
            paint.setColor4f(SkColor4f{d.color.x(), d.color.y(), d.color.z(), d.color.w()});
            canvas->drawVertices(*verticesToDraw, SkBlendMode::kSrcOver, paint);
        } // Test not using the saveLayerAlphaf code path, since I'm changing how the triangles are generated to prevent overlap
    }

    return true;
}

void MeshCanvasComponent::set_data_from(const CanvasComponent& other) {
    auto& otherStroke = static_cast<const MeshCanvasComponent&>(other);
    d = otherStroke.d;
}

void MeshCanvasComponent::initialize_draw_data(DrawingProgram& drawP) {
}

bool MeshCanvasComponent::collides_within_coords_point(const Vector2f& checkAgainst) const {
    bool intersectsAABB = d.meshPath.getBounds().contains(checkAgainst.x(), checkAgainst.y());
    if(!intersectsAABB)
        return false;
    return d.meshPath.contains(checkAgainst.x(), checkAgainst.y());
}

bool MeshCanvasComponent::collides_within_coords_skpath(const SkPath& checkAgainst) const {
    bool intersectsAABB = d.meshPath.getBounds().intersects(checkAgainst.getBounds());
    if(!intersectsAABB)
        return false;
    std::optional<SkPath> pathIntersectCheck = Op(checkAgainst, d.meshPath, SkPathOp::kIntersect_SkPathOp);
    return pathIntersectCheck.has_value() && !pathIntersectCheck.value().isEmpty();
}

bool MeshCanvasComponent::should_draw_extra(const DrawData& drawData, const CoordSpaceHelper& coords) const {
    SCollision::AABB<float> viewGenerousColliderInObjSpace = coords.world_collider_to_coords<SCollision::AABB<float>>(drawData.cam.viewingAreaGenerousCollider);
    viewGenerousColliderInObjSpace.min -= Vector2f{1.0f, 1.0f};
    viewGenerousColliderInObjSpace.max += Vector2f{1.0f, 1.0f};
    return true;
    //return collisionTree.is_collide(viewGenerousColliderInObjSpace);
}

bool MeshCanvasComponent::can_erase_detail() const {
    return true;
}

void sort_tree_into_sk_paths(std::vector<SkPath>& paths, const Clipper2Lib::PolyTreeD& tree) {
    using namespace Clipper2Lib;
    for(auto& treeChild : tree) {
        SkPathBuilder newPath;
        {
            const PathD& poly = treeChild->Polygon();
            if(poly.empty()) {
                continue;
            }
            newPath.moveTo(poly.front().x, poly.front().y);
            for(size_t i = 1; i < poly.size(); i++)
                newPath.lineTo(poly[i].x, poly[i].y);
            newPath.close();
        }
        for(auto& child : *treeChild) {
            if(child->IsHole()) {
                const PathD& poly = child->Polygon();
                newPath.moveTo(poly.front().x, poly.front().y);
                for(size_t i = 1; i < poly.size(); i++)
                    newPath.lineTo(poly[i].x, poly[i].y);
                newPath.close();
                for(auto& childChild : *child) {
                    if(childChild->IsHole())
                        continue;
                    else {
                        sort_tree_into_sk_paths(paths, *child);
                    }
                }
            }
            else {
                sort_tree_into_sk_paths(paths, *child);
            }
        }
        paths.emplace_back(newPath.detach());
    }
}

std::vector<CanvasComponentContainer*> MeshCanvasComponent::attempt_split(DrawingProgram& drawP) const {
    using namespace Clipper2Lib;

    std::vector<CanvasComponentContainer*> toRet;

    PathsD clippingSubjects;

    SkPath::Iter iter(d.meshPath, false);

    size_t moveCount = 0;
    for(;;) {
        std::optional<SkPath::IterRec> rec = iter.next();
        if(!rec.has_value())
            break;

        switch(rec->fVerb) {
            case SkPathVerb::kClose:
                break;
            case SkPathVerb::kLine:
                clippingSubjects.back().emplace_back(rec->fPoints[1].x(), rec->fPoints[1].y());
                break;
            case SkPathVerb::kMove:
                clippingSubjects.emplace_back();
                clippingSubjects.back().emplace_back(rec->fPoints[0].x(), rec->fPoints[0].y());
                moveCount++;
                break;
            default:
                throw std::runtime_error("[attempt_split] Illegal verb " + std::to_string(static_cast<unsigned>(rec->fVerb)));
                break;
        }
    }

    if(moveCount <= 1)
        return {};

    ClipperD clipper;
    PolyTreeD solutionTree;

    clipper.AddSubject(clippingSubjects);
    clipper.AddClip(clippingSubjects);
    clipper.Execute(ClipType::Union, FillRule::EvenOdd, solutionTree);

    std::vector<SkPath> splitPaths;

    sort_tree_into_sk_paths(splitPaths, solutionTree);

    if(splitPaths.size() <= 1)
        return toRet;

    for(const SkPath& p : splitPaths) {
        CanvasComponentContainer* newComp = new CanvasComponentContainer(drawP.world.netObjMan, CanvasComponentType::MESH);
        MeshCanvasComponent& mesh = static_cast<MeshCanvasComponent&>(newComp->get_comp());
        mesh.d.color = d.color;
        mesh.d.meshPath = p;
        newComp->coords = compContainer->coords;
        toRet.emplace_back(newComp);
    }

    return toRet;
}

CanvasComponentEraseDetailResult MeshCanvasComponent::erase_detail(const SkPath& eraseAgainst) {
    bool intersectsAABB = d.meshPath.getBounds().intersects(eraseAgainst.getBounds());
    if(!intersectsAABB)
        return CanvasComponentEraseDetailResult::NO_CHANGE;
    std::optional<SkPath> newPath = Op(d.meshPath, eraseAgainst, SkPathOp::kDifference_SkPathOp);
    if(newPath.has_value()) {
        d.meshPath = newPath.value();
        if(d.meshPath.isEmpty())
            return CanvasComponentEraseDetailResult::REMOVED;
        return CanvasComponentEraseDetailResult::CHANGED;
    }
    return CanvasComponentEraseDetailResult::NO_CHANGE;
}

SCollision::AABB<float> MeshCanvasComponent::get_obj_coord_bounds() const {
    return d.meshPath.getBounds();
}