cscの作法 その22 レイトレース

概要

cscの作法、調べてみた。
練習問題やってみた。

練習問題

レイトレースを表示せよ。

参考にしたページ

写真

サンプルコード

using System;
using System.Windows.Forms;
using System.Drawing;

class form1: Form {
    form1() {
        Text = "ray";
        ClientSize = new Size(300, 300);
    }
    protected override void OnPaint(PaintEventArgs e) {
        Graphics g = e.Graphics;
        Color clrBackground = Color.Black;
        g.FillRectangle(new SolidBrush(clrBackground), new Rectangle(0, 0, 200, 200));
        Rectangle rect = new Rectangle(0, 0, 200, 200);
        System.Collections.ArrayList obj3dArrayList;
        obj3dArrayList = new System.Collections.ArrayList();
        obj3dArrayList.Add(new Sphere(0.0, 0.0, 90.0, 100.0, 0.0, 0.0, 255.0));
        obj3dArrayList.Add(new Sphere(-180.0, -130.0, -110.0, 15.0, 255.0, 0.0, 0.0));
        obj3dArrayList.Add(new Sphere(-140.0, -140.0, -150.0, 20.0, 255.0, 200.0, 0.0));
        Graphics graphics = g;
        double px = (double) 0,
            py = (double) 0,
            pz = (double) 500;
        double lpx = (double) 200,
            lpy = (double) 200,
            lpz = (double) 200;
        double lvx = (double) -1.0,
            lvy = (double) -1.0,
            lvz = (double) -1.0;
        double fMax = 200.0;
        for (int i = rect.Left; i <= rect.Right; i++)
        {
            double x = Sphere.GetCoord(rect.Left, rect.Right, -fMax, fMax, i);
            for (int j = rect.Top; j <= rect.Bottom; j++)
            {
                double y = Sphere.GetCoord(rect.Top, rect.Bottom, fMax, -fMax, j);
                double t = 1.0E10;
                double vx = x - px, vy = y - py, vz = -pz;
                double mod_v = Sphere.modv(vx, vy, vz);
                vx = vx / mod_v;
                vy = vy / mod_v;
                vz = vz / mod_v;
                bool bShadow = false;
                Sphere spherehit = null;
                for (int k = 0; k < (int) obj3dArrayList.Count; k++)
                {
                    Sphere sphn = (Sphere) obj3dArrayList[k];
                    double taux = Sphere.GetSphereIntersec(sphn.cx, sphn.cy, sphn.cz, sphn.radius, px, py, pz, vx, vy, vz);
                    if (taux < 0) continue;
                    if (taux > 0 && taux < t)
                    {
                        t = taux;
                        spherehit = sphn;
                    }
                }
                Color color = Color.FromArgb(10, 20, 10);
                if (spherehit != null)
                {
                    double itx = px + t * vx, ity = py + t * vy, itz = pz + t * vz;
                    double tauxla = Sphere.GetSphereIntersec(spherehit.cx, spherehit.cy, spherehit.cz, spherehit.radius, lpx, lpy, lpz, itx - lpx, ity - lpy, itz - lpz);
                    for (int k = 0; k < (int)obj3dArrayList.Count; k++)
                    {
                        Sphere sphnb = (Sphere)(obj3dArrayList[k]);
                        if (sphnb != spherehit)
                        {
                            double tauxlb = Sphere.GetSphereIntersec(sphnb.cx, sphnb.cy, sphnb.cz, sphnb.radius, lpx, lpy, lpz, itx - lpx, ity - lpy, itz - lpz);
                            if (tauxlb > 0 && tauxla < tauxlb)
                            {
                                bShadow = true;
                                break;
                            }
                        }
                    }
                    double cost = Sphere.GetCosAngleV1V2(lvx, lvy, lvz, itx - spherehit.cx, ity - spherehit.cy, itz - spherehit.cz);
                    if (cost < 0) cost = 0;
                    double fact = 1.0;
                    if (bShadow == true) fact = 0.5; else fact = 1.0;
                    double rgbR = spherehit.clR * cost * fact;
                    double rgbG = spherehit.clG * cost * fact;
                    double rgbB = spherehit.clB * cost * fact;
                    color = Color.FromArgb((int)rgbR, (int)rgbG, (int)rgbB);
                    Pen pen = new Pen(color);
                }
                Brush brs = new SolidBrush(color);
                graphics.FillRectangle(brs, i, j, 1, 1);
                brs.Dispose();
            }
        }
        base.OnPaint(e);
    }
    class Sphere {
    public Sphere(double x, double y, double z, double r, double clr, double clg, double clb) {
        cx = x;
        cy = y;
        cz = z;
        radius = r;
        clR = clr;
        clG = clg;
        clB = clb;
    }
    public static double GetCoord(double i1, double i2, double w1, double w2, double p) {
        return ((p - i1) / (i2 - i1)) * (w2 - w1) + w1;
    }
    public static double modv(double vx, double vy, double vz) {
        return System.Math.Sqrt(vx * vx + vy * vy + vz * vz);
    }
    void Move(double vx, double vy, double vz) {
        cx += vx;
        cy += vy;
        cz += vz;
    }
    void MoveTo(double vx, double vy, double vz) {
        cx = vx;
        cy = vy;
        cz = vz;
    }
    void RotX(double angle) {
        double y = cy * System.Math.Cos(angle) - cz * System.Math.Sin(angle);
        double z = cy * System.Math.Sin(angle) + cz * System.Math.Cos(angle);
        cy = y;
        cz = z;
    }
    void RotY(double angle) {
        double x = cx * System.Math.Cos(angle) - cz * System.Math.Sin(angle);
        double z = cx * System.Math.Sin(angle) + cz * System.Math.Cos(angle);
        cx = x;
        cz = z;
    }
    public static double GetSphereIntersec(double cx, double cy, double cz, double radius, double px, double py, double pz, double vx, double vy, double vz) {
        double A = (vx * vx + vy * vy + vz * vz);
        double B = 2.0 * (px * vx + py * vy + pz * vz - vx * cx - vy * cy - vz * cz);
        double C = px * px - 2 * px * cx + cx * cx + py * py - 2 * py * cy + cy * cy + pz * pz - 2 * pz * cz + cz * cz - radius * radius;
        double D = B * B - 4 * A * C;
        double t = -1.0;
        if (D >= 0)
        {
            double t1 = (-B - System.Math.Sqrt(D)) / (2.0 * A);
            double t2 = (-B + System.Math.Sqrt(D)) / (2.0 * A);
            if (t1 > t2) t = t1; else t = t2;
        }
        return t;
    }
    public static double GetCosAngleV1V2(double v1x, double v1y, double v1z, double v2x, double v2y, double v2z) {
        return (v1x * v2x + v1y * v2y + v1z * v2z) / (modv(v1x, v1y, v1z) * modv(v2x, v2y, v2z));
    }
    public double cx,
        cy,
        cz,
        radius,
        clR,
        clG,
        clB;
    }
    [STAThread]
    public static void Main() {
        Application.Run(new form1());
    }
}

以上。