CG-project/3d_lsystems.cpp at master · KobeDB/CG-project · GitHub

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//
// Created by kobedb on 20.05.22.
//

#include "3d_lsystems.h"

#include <iostream>
#include <stack>
#include <fstream>
#include "l_parser.h"

using namespace std;

namespace KDBRenderUtils {

    struct PenState {
        Vector3D pos;

        Vector3D H; // look at
        Vector3D L; // left
        Vector3D U; // up

        double angleDelta{};

        PenState() : pos{Vector3D::point(0,0,0)}, H{Vector3D::point(1,0,0)}, L{Vector3D::point(0,1,0)}, U{Vector3D::point(0,0,1)} {}
    };

    void generate3DLSystemFigureRecursive(
            int nrIterations,
            const std::string& penInstructions,
            Figure& fig,
            const LParser::LSystem3D& lSystem,
            PenState& curPenState,
            stack<PenState>& penStateStack
    )
    {
        for(char c : penInstructions) {
            if(lSystem.get_alphabet().find(c) != lSystem.get_alphabet().end()) {
                if(nrIterations <= 0) {
                    if(lSystem.draw(c)) {
                        auto next = curPenState.pos + curPenState.H;
                        fig.vertices.push_back(curPenState.pos); int prevPos_i = fig.vertices.size()-1;
                        fig.vertices.push_back(next); int next_i = fig.vertices.size()-1;
                        fig.faces.push_back(Face{{prevPos_i, next_i}});

                        curPenState.pos = next;
                    }
                    continue;
                }
                generate3DLSystemFigureRecursive(nrIterations-1, lSystem.get_replacement(c), fig, lSystem, curPenState, penStateStack);
                continue;
            }
            if( c == '(') {
                penStateStack.push(curPenState);
                continue;
            }
            if(c == ')') {
                curPenState = penStateStack.top();
                penStateStack.pop();
                continue;
            }
            double angle = curPenState.angleDelta;
            if(c == '-' || c == '&' || c == '/') {
                angle = -angle;
            }
            if(c == '+' || c == '-') {
                auto H_new = curPenState.H * cos(angle) + curPenState.L * sin(angle);
                auto L_new = -curPenState.H * sin(angle) + curPenState.L * cos(angle);

                curPenState.H = H_new;
                curPenState.L = L_new;
                continue;
            }
            if(c == '^' || c == '&') {
                auto H_new = (curPenState.H * cos(angle)) + (curPenState.U * sin(angle));
                auto U_new = (-curPenState.H * sin(angle)) + (curPenState.U * cos(angle));

                curPenState.H = H_new;
                curPenState.U = U_new;
                continue;
            }
            if(c == '\\' || c == '/') {
                auto L_new = curPenState.L * cos(angle) - curPenState.U * sin(angle);
                auto U_new = curPenState.L * sin(angle) + curPenState.U * cos(angle);

                curPenState.L = L_new;
                curPenState.U = U_new;
                continue;
            }
            if(c == '|') {
                angle = KDB_PI;
                curPenState.H = -curPenState.H;
                curPenState.L = -curPenState.L;
                continue;
            }
            cerr << "Unhandled symbol in 3d lsystem\n";
        }
    }

    Figure generate3DLSystemFigure(const std::string& inputFile)
    {
        std::stack<PenState> penStateStack{};
        PenState curPenState{};

        LParser::LSystem3D lSystem;
        std::ifstream ifs{inputFile};
        ifs >> lSystem;
        if(!ifs) std::cerr << "Couldn't read l-system\n";

        curPenState.angleDelta = rad(lSystem.get_angle());

        Figure fig;
        generate3DLSystemFigureRecursive(lSystem.get_nr_iterations(), lSystem.get_initiator(), fig, lSystem, curPenState, penStateStack);

        return fig;
    }

};