perspective.cpp

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

#include "perspective.h"

#include <vector>

using namespace std;

namespace KDBRenderUtils
{
    void doProjection(Figure& fig, double d = 1)
    {
        for(auto& v : fig.vertices) {
            v.x = d * v.x / -v.z;
            v.y = d * v.y / -v.z;
        }
    }

    std::vector<Line2D> toPerspectiveProjectedLines(const std::vector<Figure>& pFigures, PolarCoord eye, bool eyeCoordTransformationNeeded)
    {
        vector<Figure> figures = pFigures; // make a local copy of pFigures

        vector<Line2D> lines;

        for(auto& fig : figures) {
            if(eyeCoordTransformationNeeded) applyTransformation(fig, eyePointTransformation(eye));
            doProjection(fig);
            for(const auto& face : fig.faces) {
                for(int i = 0; i < face.point_indexes.size(); i++) {
                    int p0_i = face.point_indexes[i];
                    int p1_i = face.point_indexes[(i+1)%face.point_indexes.size()]; //This loops around to 0, to draw a line between the first and the last vertex
                    const Vector3D& p0 = fig.vertices[p0_i];
                    const Vector3D& p1 = fig.vertices[p1_i];
                    Point2D projP0 = {p0.x, p0.y};
                    Point2D projP1 = {p1.x, p1.y};
                    lines.push_back(Line2D{projP0, projP1, fig.color, p0.z, p1.z});
                }
            }
        }
        return lines;
    }
}