3D blbosti...

import java.awt.image.BufferedImage;

import transforms3D.Mat4;
import transforms3D.Mat4Identity;
import transforms3D.Mat4PerspRH;
import transforms3D.Mat4ViewRH;
import transforms3D.Point3D;
import transforms3D.Vec3D;


public class RendererGPU {
    private Mat4 model;
    private Mat4 view;
    private Mat4 persp; // mohla by byt i Mat4PerspRH, ale diky dedicnosti pouzijeme Mat4 a tim je pak mozne pouzit i jinou transformaci

    private BufferedImage img;


    public RendererGPU(BufferedImage img) {
        Vec3D e = new Vec3D(0, 0, 10);
        Vec3D v = new Vec3D(0, 0, -1);
        Vec3D u = new Vec3D(0, 1,  0);

        this.img = img;
        model = new Mat4Identity();
        view = new Mat4ViewRH(e, v, u);

        float k = img.getWidth() / (float) img.getHeight();
        persp = new Mat4PerspRH(Math.PI/2, k, 0.1, 100);
            // Mat4PerspRH(zorny uhel, pomer sirka/vyska okna, blizke z, vzdalene z);
            // vzdy pri deleni zkousmat definicni obor!!!!!
            // 180°je rybi oko - cely prostor polokoule, ale hodne deformuje objem
            // Math.PI/2 je 90°lze zapsat Math.toRadians();

    }

    public void drawLine(Point3D p1, Point3D p2) {
        Vec3D a;
        Vec3D b;

        p1 = p1.mul(model);
        p2 = p2.mul(model);
        // p1 = p1.mul(model).mul(view); // jednodussi zapis

        p1 = p1.mul(view);
        p2 = p2.mul(view);

        p1 = p1.mul(persp);
        p2 = p2.mul(persp);

        // dehomogenizace:
        a = p1.dehomog();
        b = p2.dehomog();

        a = a.mul(new Vec3D(1, -1, 1)); // oteceni y - uz neni nahoru, ale dolu
        a = a.add(new Vec3D(1, 1, 0));
        a.x = a.x * (img.getWidth() - 1);
        a.y = a.y * (img.getHeight() - 1);



        img.getGraphics().drawLine(0, 0, img.getWidth()-1, img.getHeight()-1);

    }



}