⚠️ Warning: This is a draft ⚠️

This means it might contain formatting issues, incorrect code, conceptual problems, or other severe issues.

If you want to help to improve and eventually enable this page, please fork RosettaGit's repository and open a merge request on GitHub.

{{task|Constructive Solid Geometry}} {{requires|Graphics}} [[Category:Geometric Subtraction]] {{omit from|AWK|Does not have this functionality in the language}} {{omit from|Lotus 123 Macro Scripting}} {{omit from|ML/I}} {{omit from|Modula-2}} {{omit from|Retro}} {{omit from|SQL PL|It does not handle GUI}}

[[File:Deathstar-tcl.gif|400px|thumb]]

;Task: Display a region that consists of a large sphere with part of a smaller sphere removed from it as a result of geometric subtraction.

(This will basically produce a shape like a "death star".)

;Related task:

  • [[Draw a sphere]]

AutoHotkey

{{libheader|GDIP}}

#NoEnv
SetBatchLines, -1
#SingleInstance, Force

; Uncomment if Gdip.ahk is not in your standard library
#Include, Gdip.ahk

; Settings
X := 200, Y := 200, Width := 200, Height := 200 ; Location and size of sphere
rotation := 60 ; degrees
ARGB := 0xFFFF0000 ; Color=Solid Red

If !pToken := Gdip_Startup() ; Start gdi+
{
	MsgBox, 48, gdiplus error!, Gdiplus failed to start. Please ensure you have gdiplus on your system
	ExitApp
}
OnExit, Exit

Gui, -Caption +E0x80000 +LastFound +AlwaysOnTop +ToolWindow +OwnDialogs ; Create GUI
Gui, Show, NA ; Show GUI
hwnd1 := WinExist() ; Get a handle to this window we have created in order to update it later
hbm := CreateDIBSection(A_ScreenWidth, A_ScreenHeight) ; Create a gdi bitmap drawing area
hdc := CreateCompatibleDC() ; Get a device context compatible with the screen
obm := SelectObject(hdc, hbm) ; Select the bitmap into the device context
pGraphics := Gdip_GraphicsFromHDC(hdc) ; Get a pointer to the graphics of the bitmap, for use with drawing functions
Gdip_SetSmoothingMode(pGraphics, 4) ; Set the smoothing mode to antialias = 4 to make shapes appear smother

Gdip_TranslateWorldTransform(pGraphics, X, Y)
Gdip_RotateWorldTransform(pGraphics, rotation)

; Base ellipse
pBrush := Gdip_CreateLineBrushFromRect(0, 0, Width, Height, ARGB, 0xFF000000)
Gdip_FillEllipse(pGraphics, pBrush, 0, 0, Width, Height)

; First highlight ellipse
pBrush := Gdip_CreateLineBrushFromRect(Width*0.1, Height*0.01, Width*0.8, Height*0.6, 0x33FFFFFF, 0x00FFFFFF)
Gdip_FillEllipse(pGraphics, pBrush, Width*0.1, Height*0.01, Width*0.8, Height*0.6)

; Second highlight ellipse
pBrush := Gdip_CreateLineBrushFromRect(Width*0.3, Height*0.02, Width*0.3, Height*0.2, 0xBBFFFFFF, 0x00FFFFFF)
Gdip_FillEllipse(pGraphics, pBrush, Width*0.3, Height*0.02, Width*0.3, Height*0.2)


; Reset variables for smaller subtracted sphere
X-=150
Y-=10
Width*=0.5
Height*=0.4
rotation-=180

Gdip_TranslateWorldTransform(pGraphics, X, Y)
Gdip_RotateWorldTransform(pGraphics, rotation)

; Base ellipse
pBrush := Gdip_CreateLineBrushFromRect(0, 0, Width, Height, ARGB, 0xFF000000)
Gdip_FillEllipse(pGraphics, pBrush, 0, 0, Width, Height)

; First highlight ellipse
pBrush := Gdip_CreateLineBrushFromRect(Width*0.1, Height*0.01, Width*0.8, Height*0.6, 0x33FFFFFF, 0x00FFFFFF)
Gdip_FillEllipse(pGraphics, pBrush, Width*0.1, Height*0.01, Width*0.8, Height*0.6)

; Second highlight ellipse
pBrush := Gdip_CreateLineBrushFromRect(Width*0.3, Height*0.02, Width*0.3, Height*0.2, 0xBBFFFFFF, 0x00FFFFFF)
Gdip_FillEllipse(pGraphics, pBrush, Width*0.3, Height*0.02, Width*0.3, Height*0.2)


UpdateLayeredWindow(hwnd1, hdc, 0, 0, A_ScreenWidth, A_ScreenHeight)
SelectObject(hdc, obm) ; Select the object back into the hdc
Gdip_DeletePath(Path)
Gdip_DeleteBrush(pBrush)
DeleteObject(hbm) ; Now the bitmap may be deleted
DeleteDC(hdc) ; Also the device context related to the bitmap may be deleted
Gdip_DeleteGraphics(G) ; The graphics may now be deleted
Return

Exit:
; gdi+ may now be shutdown on exiting the program
Gdip_Shutdown(pToken)
ExitApp

Brlcad

# We need a database to hold the objects
opendb deathstar.g y

# We will be measuring in kilometers
units km

# Create a sphere of radius 60km centred at the origin
in sph1.s sph 0 0 0 60

# We will be subtracting an overlapping sphere with a radius of 40km
# The resultant hole will be smaller than this, because we only
# only catch the edge
in sph2.s sph 0 90 0 40

# Create a region named deathstar.r which consists of big minus small sphere
r deathstar.r u sph1.s - sph2.s

# We will use a plastic material texture with rgb colour 224,224,224
# with specular lighting value of 0.1 and no inheritance
mater deathstar.r "plastic sp=0.1" 224 224 224 0

# Clear the wireframe display and draw the deathstar
B deathstar.r

# We now trigger the raytracer to see our finished product
rt

C

Primitive ray tracing.

#include <stdio.h>
#include <math.h>
#include <unistd.h>

const char *shades = ".:!*oe&#%@";

double light[3] = { -50, 0, 50 };
void normalize(double * v)
{
	double len = sqrt(v[0]*v[0] + v[1]*v[1] + v[2]*v[2]);
	v[0] /= len; v[1] /= len; v[2] /= len;
}

double dot(double *x, double *y)
{
	double d = x[0]*y[0] + x[1]*y[1] + x[2]*y[2];
	return d < 0 ? -d : 0;
}

typedef struct { double cx, cy, cz, r; } sphere_t;

/* positive shpere and negative sphere */
sphere_t pos = { 20, 20, 0, 20 }, neg = { 1, 1, -6, 20 };

/* check if a ray (x,y, -inf)->(x, y, inf) hits a sphere; if so, return
   the intersecting z values.  z1 is closer to the eye */
int hit_sphere(sphere_t *sph, double x, double y, double *z1, double *z2)
{
	double zsq;
	x -= sph->cx;
	y -= sph->cy;
	zsq = sph->r * sph->r - (x * x + y * y);
	if (zsq < 0) return 0;
	zsq = sqrt(zsq);
	*z1 = sph->cz - zsq;
	*z2 = sph->cz + zsq;
	return 1;
}

void draw_sphere(double k, double ambient)
{
	int i, j, intensity, hit_result;
	double b;
	double vec[3], x, y, zb1, zb2, zs1, zs2;
	for (i = floor(pos.cy - pos.r); i <= ceil(pos.cy + pos.r); i++) {
		y = i + .5;
		for (j = floor(pos.cx - 2 * pos.r); j <= ceil(pos.cx + 2 * pos.r); j++) {
			x = (j - pos.cx) / 2. + .5 + pos.cx;

			/* ray lands in blank space, draw bg */
			if (!hit_sphere(&pos, x, y, &zb1, &zb2))
				hit_result = 0;

			/* ray hits pos sphere but not neg, draw pos sphere surface */
			else if (!hit_sphere(&neg, x, y, &zs1, &zs2))
				hit_result = 1;

			/* ray hits both, but pos front surface is closer */
			else if (zs1 > zb1) hit_result = 1;

			/* pos sphere surface is inside neg sphere, show bg */
			else if (zs2 > zb2) hit_result = 0;

			/* back surface on neg sphere is inside pos sphere,
			   the only place where neg sphere surface will be shown */
			else if (zs2 > zb1) hit_result = 2;
			else		    hit_result = 1;

			switch(hit_result) {
			case 0:
				putchar('+');
				continue;
			case 1:
				vec[0] = x - pos.cx;
				vec[1] = y - pos.cy;
				vec[2] = zb1 - pos.cz;
				break;
			default:
				vec[0] = neg.cx - x;
				vec[1] = neg.cy - y;
				vec[2] = neg.cz - zs2;
			}

			normalize(vec);
			b = pow(dot(light, vec), k) + ambient;
			intensity = (1 - b) * (sizeof(shades) - 1);
			if (intensity < 0) intensity = 0;
			if (intensity >= sizeof(shades) - 1)
				intensity = sizeof(shades) - 2;
			putchar(shades[intensity]);
		}
		putchar('\n');
	}
}

int main()
{
	double ang = 0;

	while (1) {
		printf("\033[H");
		light[1] = cos(ang * 2);
		light[2] = cos(ang);
		light[0] = sin(ang);
		normalize(light);
		ang += .05;

		draw_sphere(2, .3);
		usleep(100000);
	}
	return 0;
}

D

{{trans|C}}

import std.stdio, std.math, std.numeric, std.algorithm;

struct V3 {
    double[3] v;

    @property V3 normalize() pure nothrow const @nogc {
        immutable double len = dotProduct(v, v).sqrt;
        return [v[0] / len, v[1] / len, v[2] / len].V3;
    }

    double dot(in ref V3 y) pure nothrow const @nogc {
        immutable double d = dotProduct(v, y.v);
        return d < 0 ? -d : 0;
    }
}


const struct Sphere { double cx, cy, cz, r; }

void drawSphere(in double k, in double ambient, in V3 light) nothrow {
    /** Check if a ray (x,y, -inf).(x, y, inf) hits a sphere; if so,
    return the intersecting z values.  z1 is closer to the eye.*/
    static bool hitSphere(in ref Sphere sph,
                          in double x0, in double y0,
                          out double z1,
                          out double z2) pure nothrow @nogc {
        immutable double x = x0 - sph.cx;
        immutable double y = y0 - sph.cy;
        immutable double zsq = sph.r ^^ 2 - (x ^^ 2 + y ^^ 2);
        if (zsq < 0)
            return false;
        immutable double szsq = zsq.sqrt;
        z1 = sph.cz - szsq;
        z2 = sph.cz + szsq;
        return true;
    }

    immutable shades = ".:!*oe&#%@";
    // Positive and negative spheres.
    immutable pos = Sphere(20, 20, 0, 20);
    immutable neg = Sphere(1, 1, -6, 20);

    foreach (immutable int i; cast(int)floor(pos.cy - pos.r) ..
                              cast(int)ceil(pos.cy + pos.r) + 1) {
        immutable double y = i + 0.5;
    JLOOP:
        foreach (int j; cast(int)floor(pos.cx - 2 * pos.r) ..
                        cast(int)ceil(pos.cx + 2 * pos.r) + 1) {
            immutable double x = (j - pos.cx) / 2.0 + 0.5 + pos.cx;

            enum Hit { background, posSphere, negSphere }

            double zb1, zs2;
            immutable Hit hitResult = {
                double zb2, zs1;

                if (!hitSphere(pos, x, y, zb1, zb2)) {
                    // Ray lands in blank space, draw bg.
                    return Hit.background;
                } else if (!hitSphere(neg, x, y, zs1, zs2)) {
                    // Ray hits pos sphere but not neg one,
                    // draw pos sphere surface.
                    return Hit.posSphere;
                } else if (zs1 > zb1) {
                    // ray hits both, but pos front surface is closer.
                    return Hit.posSphere;
                } else if (zs2 > zb2) {
                    // pos sphere surface is inside neg sphere,
                    // show bg.
                    return Hit.background;
                } else if (zs2 > zb1) {
                    // Back surface on neg sphere is inside pos
                    // sphere, the only place where neg sphere
                    // surface will be shown.
                    return Hit.negSphere;
                } else {
                    return Hit.posSphere;
                }
            }();

            V3 vec_;
            final switch (hitResult) {
                case Hit.background:
                    ' '.putchar;
                    continue JLOOP;
                case Hit.posSphere:
                    vec_ = [x - pos.cx, y - pos.cy, zb1 - pos.cz].V3;
                    break;
                case Hit.negSphere:
                    vec_ = [neg.cx - x, neg.cy - y, neg.cz - zs2].V3;
                    break;
            }
            immutable nvec = vec_.normalize;

            immutable double b = light.dot(nvec) ^^ k + ambient;
            immutable intensity = cast(int)((1 - b) * shades.length);
            immutable normInt = min(shades.length, max(0, intensity));
            shades[normInt].putchar;
        }

        '\n'.putchar;
    }
}


void main() {
    immutable light = [-50, 30, 50].V3.normalize;
    drawSphere(2, 0.5, light);
}

The output is the same of the C version.

DWScript

{{trans|C}}

const cShades = '.:!*oe&#%@';

type TVector = array [0..2] of Float;

var light : TVector = [-50.0, 30, 50];

procedure Normalize(var v : TVector);
begin
   var len := Sqrt(v[0]*v[0] + v[1]*v[1] + v[2]*v[2]);
   v[0] /= len; v[1] /= len; v[2] /= len;
end;

function Dot(x, y : TVector) : Float;
begin
   var d :=x[0]*y[0] + x[1]*y[1] + x[2]*y[2];
   if d<0 then
      Result:=-d
   else Result:=0;
end;

type
   TSphere = record
      cx, cy, cz, r : Float;
   end;

const big : TSphere = (cx: 20; cy: 20; cz: 0; r: 20);
const small : TSphere = (cx: 7; cy: 7; cz: -10; r: 15);

function HitSphere(sph : TSphere; x, y : Float; var z1, z2 : Float) : Boolean;
begin
   x -= sph.cx;
   y -= sph.cy;
   var zsq = sph.r * sph.r - (x * x + y * y);
   if (zsq < 0) then Exit False;
   zsq := Sqrt(zsq);
   z1 := sph.cz - zsq;
   z2 := sph.cz + zsq;
   Result:=True;
end;

procedure DrawSphere(k, ambient : Float);
var
   i, j, intensity : Integer;
   b : Float;
   x, y, zb1, zb2, zs1, zs2 : Float;
   vec : TVector;
begin
   for i:=Trunc(big.cy-big.r) to Trunc(big.cy+big.r)+1 do begin
      y := i + 0.5;
      for j := Trunc(big.cx-2*big.r) to Trunc(big.cx+2*big.r) do begin
         x := (j-big.cx)/2 + 0.5 + big.cx;

         if not HitSphere(big, x, y, zb1, zb2) then begin
            Print(' ');
            continue;
         end;
         if not HitSphere(small, x, y, zs1, zs2) then begin
            vec[0] := x - big.cx;
            vec[1] := y - big.cy;
            vec[2] := zb1 - big.cz;
         end else begin
            if zs1 < zb1 then begin
               if zs2 > zb2 then begin
                  Print(' ');
                  continue;
               end;
               if zs2 > zb1 then begin
                  vec[0] := small.cx - x;
                  vec[1] := small.cy - y;
                  vec[2] := small.cz - zs2;
               end else begin
                  vec[0] := x - big.cx;
                  vec[1] := y - big.cy;
                  vec[2] := zb1 - big.cz;
               end;
            end else begin
               vec[0] := x - big.cx;
               vec[1] := y - big.cy;
               vec[2] := zb1 - big.cz;
            end;
         end;

         Normalize(vec);
         b := Power(Dot(light, vec), k) + ambient;
         intensity := Round((1 - b) * Length(cShades));
         Print(cShades[ClampInt(intensity+1, 1, Length(cShades))]);
      end;
      PrintLn('');
   end;
end;

Normalize(light);

DrawSphere(2, 0.3);

Go

[[file:GoDstar.png|right|thumb|Output png]] {{trans|C}}

package main

import (
    "fmt"
    "image"
    "image/color"
    "image/png"
    "math"
    "os"
)

type vector [3]float64

func (v *vector) normalize() {
    invLen := 1 / math.Sqrt(dot(v, v))
    v[0] *= invLen
    v[1] *= invLen
    v[2] *= invLen
}

func dot(x, y *vector) float64 {
    return x[0]*y[0] + x[1]*y[1] + x[2]*y[2]
}

type sphere struct {
    cx, cy, cz int
    r          int
}

func (s *sphere) hit(x, y int) (z1, z2 float64, hit bool) {
    x -= s.cx
    y -= s.cy
    if zsq := s.r*s.r - (x*x + y*y); zsq >= 0 {
        zsqrt := math.Sqrt(float64(zsq))
        return float64(s.cz) - zsqrt, float64(s.cz) + zsqrt, true
    }
    return 0, 0, false
}

func deathStar(pos, neg *sphere, k, amb float64, dir *vector) *image.Gray {
    w, h := pos.r*4, pos.r*3
    bounds := image.Rect(pos.cx-w/2, pos.cy-h/2, pos.cx+w/2, pos.cy+h/2)
    img := image.NewGray(bounds)
    vec := new(vector)
    for y, yMax := pos.cy-pos.r, pos.cy+pos.r; y <= yMax; y++ {
        for x, xMax := pos.cx-pos.r, pos.cx+pos.r; x <= xMax; x++ {
            zb1, zb2, hit := pos.hit(x, y)
            if !hit {
                continue
            }
            zs1, zs2, hit := neg.hit(x, y)
            if hit {
                if zs1 > zb1 {
                    hit = false
                } else if zs2 > zb2 {
                    continue
                }
            }
            if hit {
                vec[0] = float64(neg.cx - x)
                vec[1] = float64(neg.cy - y)
                vec[2] = float64(neg.cz) - zs2
            } else {
                vec[0] = float64(x - pos.cx)
                vec[1] = float64(y - pos.cy)
                vec[2] = zb1 - float64(pos.cz)
            }
            vec.normalize()
            s := dot(dir, vec)
            if s < 0 {
                s = 0
            }
            lum := 255 * (math.Pow(s, k) + amb) / (1 + amb)
            if lum < 0 {
                lum = 0
            } else if lum > 255 {
                lum = 255
            }
            img.SetGray(x, y, color.Gray{uint8(lum)})
        }
    }
    return img
}

func main() {
    dir := &vector{20, -40, -10}
    dir.normalize()
    pos := &sphere{0, 0, 0, 120}
    neg := &sphere{-90, -90, -30, 100}

    img := deathStar(pos, neg, 1.5, .2, dir)
    f, err := os.Create("dstar.png")
    if err != nil {
        fmt.Println(err)
        return
    }
    if err = png.Encode(f, img); err != nil {
        fmt.Println(err)
    }
    if err = f.Close(); err != nil {
        fmt.Println(err)
    }
}

J

{{Trans|Python}}


load'graphics/viewmat'
mag =: +/&.:*:"1
norm=: %"1 0 mag
dot =: +/@:*"1

NB. (pos;posr;neg;negr) getvec (x,y)
getvec =: 4 :0 "1
  pt =. y
  'pos posr neg negr' =. x
  if. (dot~ pt-}:pos) > *:posr do.
    0 0 0
  else.
    zb =. ({:pos) (-,+)  posr -&.:*: pt mag@:- }:pos
    if. (dot~ pt-}:neg) > *:negr do.
      (pt,{:zb) - pos
    else.
      zs =. ({:neg) (-,+) negr -&.:*: pt mag@:- }:neg
      if. zs >&{. zb do. (pt,{:zb) - pos
      elseif. zs >&{: zb do. 0 0 0
      elseif. ({.zs) < ({:zb) do. neg - (pt,{.zs)
      elseif. do. (pt,{.zb) - pos end.
    end.
  end.
)


NB. (k;ambient;light) draw_sphere (pos;posr;neg;negr)
draw_sphere =: 4 :0
  'pos posr neg negr' =. y
  'k ambient light' =. x
  vec=. norm y getvec ,"0// (2{.pos) +/ i: 200 j.~ 0.5+posr

  b=. (mag vec) * ambient + k * 0>. light dot vec
)

togray =: 256#. 255 255 255 <.@*"1 0 (%>./@,)

env=.(2; 0.5; (norm _50 30 50))
sph=. 20 20 0; 20;   1 1 _6; 20
'rgb' viewmat togray  env draw_sphere sph

Java



import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.geometry.Point3D;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyEvent;
import javafx.scene.shape.MeshView;
import javafx.scene.shape.TriangleMesh;
import javafx.scene.transform.Rotate;
import javafx.stage.Stage;
public class DeathStar extends Application {

	private static final int DIVISION = 200;// the bigger the higher resolution
	float radius = 300;// radius of the sphere

	@Override
	public void start(Stage primaryStage) throws Exception {
		Point3D otherSphere = new Point3D(-radius, 0, -radius * 1.5);
		final TriangleMesh triangleMesh = createMesh(DIVISION, radius, otherSphere);
		MeshView a = new MeshView(triangleMesh);

		a.setTranslateY(radius);
		a.setTranslateX(radius);
		a.setRotationAxis(Rotate.Y_AXIS);
		Scene scene = new Scene(new Group(a));
//		uncomment if you want to move the other sphere

//		scene.setOnKeyPressed(new EventHandler<KeyEvent>() {
//			Point3D sphere = otherSphere;
//
//			@Override
//			public void handle(KeyEvent e) {
//				KeyCode code = e.getCode();
//				switch (code) {
//				case UP:
//					sphere = sphere.add(0, -10, 0);
//					break;
//				case DOWN:
//					sphere = sphere.add(0, 10, 0);
//					break;
//				case LEFT:
//					sphere = sphere.add(-10, 0, 0);
//					break;
//				case RIGHT:
//					sphere = sphere.add(10, 0, 0);
//					break;
//				case W:
//					sphere = sphere.add(0, 0, 10);
//					break;
//				case S:
//					sphere = sphere.add(0, 0, -10);
//					break;
//				default:
//					return;
//				}
//				a.setMesh(createMesh(DIVISION, radius, sphere));
//
//			}
//		});

		primaryStage.setScene(scene);
		primaryStage.show();
	}

	static TriangleMesh createMesh(final int division, final float radius, final Point3D centerOtherSphere) {
		Rotate rotate = new Rotate(180, centerOtherSphere);
		final int div2 = division / 2;

		final int nPoints = division * (div2 - 1) + 2;
		final int nTPoints = (division + 1) * (div2 - 1) + division * 2;
		final int nFaces = division * (div2 - 2) * 2 + division * 2;

		final float rDiv = 1.f / division;

		float points[] = new float[nPoints * 3];
		float tPoints[] = new float[nTPoints * 2];
		int faces[] = new int[nFaces * 6];

		int pPos = 0, tPos = 0;

		for (int y = 0; y < div2 - 1; ++y) {
			float va = rDiv * (y + 1 - div2 / 2) * 2 * (float) Math.PI;
			float sin_va = (float) Math.sin(va);
			float cos_va = (float) Math.cos(va);

			float ty = 0.5f + sin_va * 0.5f;
			for (int i = 0; i < division; ++i) {
				double a = rDiv * i * 2 * (float) Math.PI;
				float hSin = (float) Math.sin(a);
				float hCos = (float) Math.cos(a);
				points[pPos + 0] = hSin * cos_va * radius;
				points[pPos + 2] = hCos * cos_va * radius;
				points[pPos + 1] = sin_va * radius;

				final Point3D point3D = new Point3D(points[pPos + 0], points[pPos + 1], points[pPos + 2]);
				double distance = centerOtherSphere.distance(point3D);
				if (distance <= radius) {
					Point3D subtract = centerOtherSphere.subtract(point3D);
					Point3D transform = rotate.transform(subtract);
					points[pPos + 0] = (float) transform.getX();
					points[pPos + 1] = (float) transform.getY();
					points[pPos + 2] = (float) transform.getZ();

				}
				tPoints[tPos + 0] = 1 - rDiv * i;
				tPoints[tPos + 1] = ty;
				pPos += 3;
				tPos += 2;
			}
			tPoints[tPos + 0] = 0;
			tPoints[tPos + 1] = ty;
			tPos += 2;
		}

		points[pPos + 0] = 0;
		points[pPos + 1] = -radius;
		points[pPos + 2] = 0;
		points[pPos + 3] = 0;
		points[pPos + 4] = radius;
		points[pPos + 5] = 0;
		pPos += 6;

		int pS = (div2 - 1) * division;

		float textureDelta = 1.f / 256;
		for (int i = 0; i < division; ++i) {
			tPoints[tPos + 0] = rDiv * (0.5f + i);
			tPoints[tPos + 1] = textureDelta;
			tPos += 2;
		}

		for (int i = 0; i < division; ++i) {
			tPoints[tPos + 0] = rDiv * (0.5f + i);
			tPoints[tPos + 1] = 1 - textureDelta;
			tPos += 2;
		}

		int fIndex = 0;
		for (int y = 0; y < div2 - 2; ++y) {
			for (int x = 0; x < division; ++x) {
				int p0 = y * division + x;
				int p1 = p0 + 1;
				int p2 = p0 + division;
				int p3 = p1 + division;

				int t0 = p0 + y;
				int t1 = t0 + 1;
				int t2 = t0 + division + 1;
				int t3 = t1 + division + 1;

				// add p0, p1, p2
				faces[fIndex + 0] = p0;
				faces[fIndex + 1] = t0;
				faces[fIndex + 2] = p1 % division == 0 ? p1 - division : p1;
				faces[fIndex + 3] = t1;
				faces[fIndex + 4] = p2;
				faces[fIndex + 5] = t2;
				fIndex += 6;

				// add p3, p2, p1
				faces[fIndex + 0] = p3 % division == 0 ? p3 - division : p3;
				faces[fIndex + 1] = t3;
				faces[fIndex + 2] = p2;
				faces[fIndex + 3] = t2;
				faces[fIndex + 4] = p1 % division == 0 ? p1 - division : p1;
				faces[fIndex + 5] = t1;
				fIndex += 6;
			}
		}

		int p0 = pS;
		int tB = (div2 - 1) * (division + 1);
		for (int x = 0; x < division; ++x) {
			int p2 = x, p1 = x + 1, t0 = tB + x;
			faces[fIndex + 0] = p0;
			faces[fIndex + 1] = t0;
			faces[fIndex + 2] = p1 == division ? 0 : p1;
			faces[fIndex + 3] = p1;
			faces[fIndex + 4] = p2;
			faces[fIndex + 5] = p2;
			fIndex += 6;
		}

		p0 = p0 + 1;
		tB = tB + division;
		int pB = (div2 - 2) * division;

		for (int x = 0; x < division; ++x) {
			int p1 = pB + x, p2 = pB + x + 1, t0 = tB + x;
			int t1 = (div2 - 2) * (division + 1) + x, t2 = t1 + 1;
			faces[fIndex + 0] = p0;
			faces[fIndex + 1] = t0;
			faces[fIndex + 2] = p1;
			faces[fIndex + 3] = t1;
			faces[fIndex + 4] = p2 % division == 0 ? p2 - division : p2;
			faces[fIndex + 5] = t2;
			fIndex += 6;
		}

		TriangleMesh m = new TriangleMesh();
		m.getPoints().setAll(points);
		m.getTexCoords().setAll(tPoints);
		m.getFaces().setAll(faces);

		return m;
	}

	public static void main(String[] args) {

		launch(args);
	}

}

JavaScript

Layer circles and gradients to achieve result similar to that of the Wikipedia page for the [http://en.wikipedia.org/wiki/Death_Star Death Star].


<!DOCTYPE html>
<html>
<body style="margin:0">
  <canvas id="myCanvas" width="250" height="250" style="border:1px solid #d3d3d3;">
    Your browser does not support the HTML5 canvas tag.
  </canvas>
  <script>
    var c = document.getElementById("myCanvas");
    var ctx = c.getContext("2d");
    //Fill the canvas with a dark gray background
    ctx.fillStyle = "#222222";
    ctx.fillRect(0,0,250,250);

    // Create radial gradient for large base circle
    var grd = ctx.createRadialGradient(225,175,190,225,150,130);
    grd.addColorStop(0,"#EEEEEE");
    grd.addColorStop(1,"black");
    //Apply gradient and fill circle
    ctx.fillStyle = grd;
    ctx.beginPath();
    ctx.arc(125,125,105,0,2*Math.PI);
    ctx.fill();

    // Create linear gradient for small inner circle
    var grd = ctx.createLinearGradient(75,90,102,90);
    grd.addColorStop(0,"black");
    grd.addColorStop(1,"gray");
    //Apply gradient and fill circle
    ctx.fillStyle = grd;
    ctx.beginPath();
    ctx.arc(90,90,30,0,2*Math.PI);
    ctx.fill();

    //Add another small circle on top of the previous one to enhance the "shadow"
    ctx.fillStyle = "black";
    ctx.beginPath();
    ctx.arc(80,90,17,0,2*Math.PI);
    ctx.fill();
  </script>
</body>
</html>


Julia

# run in REPL
using Makie

function deathstar()
    n = 60
    θ = [0; (0.5: n - 0.5) / n; 1]
    φ = [(0: 2n - 2) * 2 / (2n - 1); 2]
    # if x is +0.9 radius units, replace it with the coordinates of sphere surface
    # at (1.2,0,0) center, radius 0.5 units
    x = [(x1 = cospi(φ)*sinpi(θ)) > 0.9 ? 1.2 - x1 * 0.5 : x1 for θ in θ, φ in φ]
    y = [sinpi(φ)*sinpi(θ) for θ in θ, φ in φ]
    z = [cospi(θ) for θ in θ, φ in φ]
    scene = Scene(backgroundcolor=:black)
    surface!(scene, x, y, z, color = rand(RGBAf0, 124, 124), show_axis=false)
end

deathstar()

LSL

Rez a box on the ground, raise it up a few meters, add the following as a New Script.

default {
    state_entry() {
        llSetPrimitiveParams([PRIM_NAME, "RosettaCode DeathStar"]);
        llSetPrimitiveParams([PRIM_DESC, llGetObjectName()]);
        llSetPrimitiveParams([PRIM_TYPE, PRIM_TYPE_SPHERE, PRIM_HOLE_CIRCLE, <0.0, 1.0, 0.0>, 0.0, <0.0, 0.0, 0.0>, <0.12, 1.0, 0.0>]);
        llSetPrimitiveParams([PRIM_ROTATION, <-0.586217, 0.395411, -0.586217, 0.395411>]);
        llSetPrimitiveParams([PRIM_TEXTURE, ALL_SIDES, TEXTURE_BLANK, ZERO_VECTOR, ZERO_VECTOR, 0.0]);
        llSetPrimitiveParams([PRIM_TEXT, llGetObjectName(), <1.0, 1.0, 1.0>, 1.0]);
        llSetPrimitiveParams([PRIM_COLOR, ALL_SIDES, <0.5, 0.5, 0.5>, 1.0]);
        llSetPrimitiveParams([PRIM_BUMP_SHINY, ALL_SIDES, PRIM_SHINY_HIGH, PRIM_BUMP_NONE]);
        llSetPrimitiveParams([PRIM_SIZE, <10.0, 10.0, 10.0>]);
        llSetPrimitiveParams([PRIM_OMEGA, <0.0, 0.0, 1.0>, 1.0, 1.0]);
    }
}

Output: [[File:Death_Star_LSL.jpg|200px|Death Star]]

Maple

with(plots):
with(plottools):
plots:-display(
   implicitplot3d(x^2 + y^2 + z^2 = 1, x = -1..0.85, y = -1..1, z = -1..1, style = surface, grid = [50,50,50]),
   translate(rotate(implicitplot3d(x^2 + y^2 + z^2 = 1, x = 0.85..1, y = -1..1, z = -1..1, style = surface, grid = [50,50,50]), 0, Pi, 0), 1.70, 0, 0),
axes = none, scaling = constrained, color = gray)

=={{header|Mathematica}} / {{header|Wolfram Language}}==

RegionPlot3D[x^2 + y^2 + z^2 < 1 && (x + 1.7)^2 + y^2 + z^2 > 1,
{x, -1, 1}, {y, -1, 1}, {z, -1, 1},
Boxed -> False, Mesh -> False, Axes -> False, Background -> Black, PlotPoints -> 100]

Openscad

// We are performing geometric subtraction

difference() {

  // Create the primary sphere of radius 60 centred at the origin

  translate(v = [0,0,0]) {
    sphere(60);
  }

  /*Subtract an overlapping sphere with a radius of 40
     The resultant hole will be smaller than this, because we only
     only catch the edge
  */

  translate(v = [0,90,0]) {
    sphere(40);
  }
}

Perl

[[file:death-star-perl.png|thumb]] Writes a PGM to stdout.

use strict;

sub sq {
	my $s = 0;
	$s += $_ ** 2 for @_;
	$s;
}

sub hit {
	my ($sph, $x, $y) = @_;
	$x -= $sph->[0];
	$y -= $sph->[1];

	my $z = sq($sph->[3]) - sq($x, $y);
	return	if $z < 0;

	$z = sqrt $z;
	return $sph->[2] - $z, $sph->[2] + $z;
}

sub normalize {
	my $v = shift;
	my $n = sqrt sq(@$v);
	$_ /= $n for @$v;
	$v;
}

sub dot {
	my ($x, $y) = @_;
	my $s = $x->[0] * $y->[0] + $x->[1] * $y->[1] + $x->[2] * $y->[2];
	$s > 0 ? $s : 0;
}

my $pos = [ 120, 120, 0, 120 ];
my $neg = [ -77, -33, -100, 190 ];
my $light = normalize([ -12, 13, -10 ]);
sub draw {
	my ($k, $amb) = @_;
	binmode STDOUT, ":raw";
	print "P5\n", $pos->[0] * 2 + 3, " ", $pos->[1] * 2 + 3, "\n255\n";
	for my $y (($pos->[1] - $pos->[3] - 1) .. ($pos->[1] + $pos->[3] + 1)) {
		my @row = ();
		for my $x (($pos->[0] - $pos->[3] - 1) .. ($pos->[0] + $pos->[3] + 1)) {
			my ($hit, @hs) = 0;
			my @h = hit($pos, $x, $y);

			if (!@h) { $hit = 0 }
			elsif (!(@hs = hit($neg, $x, $y))) { $hit = 1 }
			elsif ($hs[0] > $h[0]) { $hit = 1 }
			elsif ($hs[1] > $h[0]) { $hit = $hs[1] > $h[1] ? 0 : 2 }
			else { $hit = 1 }

			my ($val, $v);
			if ($hit == 0) { $val = 0 }
			elsif ($hit == 1) {
				$v = [	$x - $pos->[0],
					$y - $pos->[1],
					$h[0] - $pos->[2] ];
			} else {
				$v = [	$neg->[0] - $x,
					$neg->[1] - $y,
					$neg->[2] - $hs[1] ];
			}
			if ($v) {
				normalize($v);
				$val = int((dot($v, $light) ** $k + $amb) * 255);
				$val = ($val > 255) ? 255 : ($val < 0) ? 0 : $val;
			}
			push @row, $val;
		}
		print pack("C*", @row);
	}
}

draw(2, 0.2);

Perl 6

{{trans|C}}Reimplemented to output a .pgm image. {{works with|Rakudo|2018.10}} [[File:Deathstar-perl6.png|thumb]]

class sphere {
   has $.cx; # center x coordinate
   has $.cy; # center y coordinate
   has $.cz; # center z coordinate
   has $.r;  # radius
}

my $depth = 255;     # image color depth

my $width = my $height = 255; # dimensions of generated .pgm; must be odd

my $s = ($width - 1)/2;  # scaled dimension to build geometry

my @light = normalize([ 4, -1, -3 ]);

# positive sphere at origin
my $pos = sphere.new(
    cx => 0,
    cy => 0,
    cz => 0,
    r  => $s.Int
);

# negative sphere offset to upper left
my $neg = sphere.new(
    cx => (-$s*.90).Int,
    cy => (-$s*.90).Int,
    cz => (-$s*.3).Int,
    r  => ($s*.7).Int
);

sub MAIN ($outfile = 'deathstar-perl6.pgm') {
    spurt $outfile, ("P5\n$width $height\n$depth\n"); # .pgm header
    my $out = open( $outfile, :a, :bin ) orelse .die;
    say 'Working...';
    $out.write( Blob.new( |draw_ds(3, .15) ) );
    say 'File written.';
    $out.close;
}

sub draw_ds ( $k, $ambient ) {
    my @pixels[$height];

    (($pos.cy - $pos.r) .. ($pos.cy + $pos.r)).race.map: -> $y {
        my @row[$width];
        (($pos.cx - $pos.r) .. ($pos.cx + $pos.r)).map: -> $x {
            # black if we don't hit positive sphere, ignore negative sphere
            if not hit($pos, $x, $y, my $posz) {
                @row[$x + $s] = 0;
                next;
            }
            my @vec;
            # is front of positive sphere inside negative sphere?
            if hit($neg, $x, $y, my $negz) and $negz.min < $posz.min < $negz.max {
                # make black if whole positive sphere eaten here
                if $negz.min < $posz.max < $negz.max { @row[$x + $s] = 0; next; }
                # render inside of negative sphere
                @vec = normalize([$neg.cx - $x, $neg.cy - $y, -$negz.max - $neg.cz]);
            }
            else {
                # render outside of positive sphere
                @vec = normalize([$x - $pos.cx, $y - $pos.cy,  $posz.max - $pos.cz]);
            }
            my $intensity = dot(@light, @vec) ** $k + $ambient;
            @row[$x + $s] = ($intensity * $depth).Int min $depth;
        }
         @pixels[$y + $s] = @row;
    }
    flat |@pixels.map: *.list;
}

# normalize a vector
sub normalize (@vec) { @vec »/» ([+] @vec »*« @vec).sqrt }

# dot product of two vectors
sub dot (@x, @y) { -([+] @x »*« @y) max 0 }

# are the coordinates within the radius of the sphere?
sub hit ($sphere, $x is copy, $y is copy, $z is rw) {
    $x -= $sphere.cx;
    $y -= $sphere.cy;
    my $z2 = $sphere.r * $sphere.r - $x * $x - $y * $y;
    return 0 if $z2 < 0;
    $z2 = $z2.sqrt;
    $z = $sphere.cz - $z2 .. $sphere.cz + $z2;
    1;
}

Phix

{{trans|Go}} {{libheader|pGUI}}

--
-- demo\rosetta\DeathStar.exw
--
include pGUI.e

Ihandle dlg, canvas
cdCanvas cddbuffer, cdcanvas

function dot(sequence x, sequence y)
    return sum(sq_mul(x,y))
end function

function normalize(sequence v)
    atom len = sqrt(dot(v, v))
    if len=0 then return {0,0,0} end if
    return sq_mul(v,1/len)
end function

enum X,Y,Z

function hit(sequence s, atom x, y, atom r)
    x -= s[X]
    y -= s[Y]
    atom zsq := r*r - (x*x + y*y)
    if zsq >= 0 then
        atom zsqrt := sqrt(zsq)
        return {s[Z] - zsqrt, s[Z] + zsqrt, true}
    end if
    return {0, 0, false}
end function

procedure deathStar(integer width, height, atom k, atom amb, sequence direction)
integer lum
sequence vec
integer r = floor((min(width,height)-40)/2)
integer cx = floor(width/2)
integer cy = floor(height/2)
sequence pos = {0,0,0},
         neg = {r*-3/4,r*-3/4,r*-1/4}

    for y = pos[Y]-r to pos[Y]+r do
        for x = pos[X]-r to pos[X]+r do
            atom {zb1, zb2, hit1} := hit(pos, x, y, r)
            if hit1 then
                atom {zs1, zs2, hit2} := hit(neg, x, y, r/2)
                if not hit2 or zs2<=zb2 then
                    if hit2 and zs1<=zb1 then
                        vec = {neg[X] - x, neg[Y] - y, neg[Z] - zs2}
                    else
                        vec = {x - pos[X], y - pos[Y], zb1 - pos[Z]}
--                      vec = {x, y, zb1}
                    end if
                    atom s = dot(direction, normalize(vec))
                    lum = and_bits(#FF,255*(iff(s<0?0:power(s,k))+amb)/(1+amb))
                    lum += lum*#100+lum*#10000
                    cdCanvasPixel(cddbuffer, cx+x, cy-y, lum)
                end if
            end if
        end for
    end for
end procedure

function redraw_cb(Ihandle /*ih*/, integer /*posx*/, integer /*posy*/)
integer {width, height} = IupGetIntInt(canvas, "DRAWSIZE")
    cdCanvasActivate(cddbuffer)
    cdCanvasClear(cddbuffer)
    deathStar(width, height, 1.5, 0.2, normalize({20, -40, -10}))
    cdCanvasFlush(cddbuffer)
    return IUP_DEFAULT
end function

function map_cb(Ihandle ih)
    cdcanvas = cdCreateCanvas(CD_IUP, ih)
    cddbuffer = cdCreateCanvas(CD_DBUFFER, cdcanvas)
    cdCanvasSetBackground(cddbuffer, CD_BLACK)
    return IUP_DEFAULT
end function

function esc_close(Ihandle /*ih*/, atom c)
    if c=K_ESC then return IUP_CLOSE end if
    return IUP_CONTINUE
end function

procedure main()
    IupOpen()

    canvas = IupCanvas(NULL)
    IupSetAttribute(canvas, "RASTERSIZE", "340x340") -- initial size
    IupSetCallback(canvas, "MAP_CB", Icallback("map_cb"))

    dlg = IupDialog(canvas)
    IupSetAttribute(dlg, "TITLE", "Draw a sphere")
    IupSetCallback(dlg, "K_ANY",     Icallback("esc_close"))
    IupSetCallback(canvas, "ACTION", Icallback("redraw_cb"))

    IupMap(dlg)
    IupSetAttribute(canvas, "RASTERSIZE", NULL) -- release the minimum limitation
    IupShowXY(dlg,IUP_CENTER,IUP_CENTER)
    IupMainLoop()
    IupClose()
end procedure

main()

=={{header|POV-Ray}}== camera { perspective location <0.0 , .8 ,-3.0> look_at 0 aperture .1 blur_samples 20 variance 1/100000 focal_point 0}

light_source{< 3,3,-3> color rgb 1}

sky_sphere { pigment{ color rgb <0,.2,.5>}}

plane {y,-5 pigment {color rgb .54} normal {hexagon} }

difference { sphere { 0,1 } sphere { <-1,1,-1>,1 } texture { pigment{ granite } finish { phong 1 reflection {0.10 metallic 0.5} } } }


[[image:PovRay-deathstar.jpg]]


## Python

{{trans|C}}

```python
import sys, math, collections

Sphere = collections.namedtuple("Sphere", "cx cy cz r")
V3 = collections.namedtuple("V3", "x y z")

def normalize((x, y, z)):
    len = math.sqrt(x**2 + y**2 + z**2)
    return V3(x / len, y / len, z / len)

def dot(v1, v2):
    d = v1.x*v2.x + v1.y*v2.y + v1.z*v2.z
    return -d if d < 0 else 0.0

def hit_sphere(sph, x0, y0):
    x = x0 - sph.cx
    y = y0 - sph.cy
    zsq = sph.r ** 2 - (x ** 2 + y ** 2)
    if zsq < 0:
        return (False, 0, 0)
    szsq = math.sqrt(zsq)
    return (True, sph.cz - szsq, sph.cz + szsq)

def draw_sphere(k, ambient, light):
    shades = ".:!*oe&#%@"
    pos = Sphere(20.0, 20.0, 0.0, 20.0)
    neg = Sphere(1.0, 1.0, -6.0, 20.0)

    for i in xrange(int(math.floor(pos.cy - pos.r)),
                    int(math.ceil(pos.cy + pos.r) + 1)):
        y = i + 0.5
        for j in xrange(int(math.floor(pos.cx - 2 * pos.r)),
                        int(math.ceil(pos.cx + 2 * pos.r) + 1)):
            x = (j - pos.cx) / 2.0 + 0.5 + pos.cx

            (h, zb1, zb2) = hit_sphere(pos, x, y)
            if not h:
                hit_result = 0
            else:
                (h, zs1, zs2) = hit_sphere(neg, x, y)
                if not h:
                    hit_result = 1
                elif zs1 > zb1:
                    hit_result = 1
                elif zs2 > zb2:
                    hit_result = 0
                elif zs2 > zb1:
                    hit_result = 2
                else:
                    hit_result = 1

            if hit_result == 0:
                sys.stdout.write(' ')
                continue
            elif hit_result == 1:
                vec = V3(x - pos.cx, y - pos.cy, zb1 - pos.cz)
            elif hit_result == 2:
                vec = V3(neg.cx-x, neg.cy-y, neg.cz-zs2)
            vec = normalize(vec)

            b = dot(light, vec) ** k + ambient
            intensity = int((1 - b) * len(shades))
            intensity = min(len(shades), max(0, intensity))
            sys.stdout.write(shades[intensity])
        print

light = normalize(V3(-50, 30, 50))
draw_sphere(2, 0.5, light)

Q

write an image in BMP format:


/ https://en.wikipedia.org/wiki/BMP_file_format
/ BITMAPINFOHEADER / RGB24

/ generate a header

genheader:{[w;h]
   0x424d, "x"$(f2i4[54+4*h*w],0,0,0,0,54,0,0,0,40,0,0,0,
                f2i4[h],f2i4[w],1,0,24,0,0,0,0,0,
                f2i4[h*((w*3)+((w*3)mod 4))],
                19,11,0,0,19,11,0,0,0,0,0,0,0,0,0,0)};

/ generate a raster line at a vertical position

genrow:{[w;y;fcn]
    row:enlist 0i;xx:0i;do[w;row,:fcn[xx;y];xx+:1i];row,:((w mod 4)#0i);1_row};

/ generate a bitmap

genbitmap:{[w;h;fcn]
    ary:enlist 0i;yy:0i;do[h;ary,:genrow[w;yy;fcn];yy+:1i];"x"$1_ary};

/ deal with endianness
/ might need to reverse last line if host computer is not a PC

f2i4:{[x] r:x;
  s0:r mod 256;r-:s0; r%:256;
  s1:r mod 256;r-:s1; r%:256;
  s2:r mod 256;r-:s2; r%:256;
  s3:r mod 256;
  "h"$(s0,s1,s2,s3)}

/ compose and write a file

writebmp:{[w;h;fcn;fn]
    fn 1: (genheader[h;w],genbitmap[w;h;fcn])};

/ / usage example:
/ w:400;
/ h:300;
/ fcn:{x0:x-w%2;y0:y-h%2;r:175;$[(r*r)>((x0*x0)+(y0*y0));(0;0;255);(0;255;0)]};
/ fn:`:demo.bmp;
/ writebmp[w;h;fcn;fn];

Create the death star image:


w:400; h:300; r:150; l:-0.5 0.7 0.5
sqrt0:{$[x>0;sqrt x;0]};

/ get x,y,z position of point on sphere given x,y,r

z:{[x;y;r]sqrt0((r*r)-((x*x)+(y*y)))};

/ get diffused light at point on sphere

is:{[x;y;r]
   z0:z[x;y;r];
   s:(x;y;z0)%r;
   $[z0>0;i:0.5*1+(+/)(s*l);i:0];
   i};

/ get pixel value at given image position

fcn:{[xpx;ypx]
   x:xpx-w%2;
   y:ypx-h%2;
   z1:z[x;y;r];
   x2:x+190;
   z2:170-z[x2;y;r];
   $[(r*r)<((x*x)+(y*y));
      $[y>-50;
          i:3#0;
          i:200 100 50];
      $[z2>z1;
         i:3#is[x;y;r]*140;
         i:3#is[(-1*x2);(-1*y);r]*120]
   ];
   "i"$i};

/ do it ...

\l bmp.q
fn:`:demo.bmp;
writebmp[w;h;fcn;fn];


(converted to JPG ...)

[[image:qdstar.jpg]]

Racket


#lang racket
(require plot)
(plot3d (polar3d (λ (φ θ) (real-part (- (sin θ) (sqrt (- (sqr 1/3) (sqr (cos θ)))))))
                 #:samples 100 #:line-style 'transparent #:color 9)
        #:altitude 60 #:angle 80
        #:height  500 #:width 400
        #:x-min  -1/2 #:x-max 1/2
        #:y-min  -1/2 #:y-max 1/2
        #:z-min     0 #:z-max 1)

[[File:death-star.png]]

REXX

{{trans|D}}

(Apologies for the comments making the lines so wide, but it was easier to read and compare to the original '''D''' source.)

/*REXX program displays a sphere with another sphere subtracted where it's superimposed.*/
call deathStar   2,   .5,   v3('-50  30  50')
exit                                             /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
dot:   #=0;  do j=1  for words(x);  #=# + word(x,j)*word(y,j);  end; return #
dot.:  procedure; parse arg x,y; d=dot(x,y); if d<0  then return -d; return 0
ceil:  procedure; parse arg x;   _=trunc(x);                         return _+(x>0)*(x\=_)
floor: procedure; parse arg x;   _=trunc(x);                         return _-(x<0)*(x\=_)
v3:    procedure; parse arg a b c;      #=sqrt(a**2 + b**2 + c**2);  return a/#  b/#  c/#
/*──────────────────────────────────────────────────────────────────────────────────────*/
sqrt:  procedure; parse arg x; if x=0  then return 0;  d=digits();  h= d+6; numeric digits
       m.=9; numeric form; parse value format(x,2,1,,0) 'E0' with g 'E' _ .; g=g*.5'e'_%2
         do j=0  while h>9;      m.j= h;              h= h % 2 + 1;    end /*j*/
         do k=j+5  to 0  by -1;  numeric digits m.k;  g= (g +x/g)* .5; end /*k*/; return g
/*──────────────────────────────────────────────────────────────────────────────────────*/
hitSphere: procedure expose !.; parse arg xx yy zz r,x0,y0;  z= r*r -(x0-xx)**2-(y0-yy)**2
           if z<0  then return 0;  _= sqrt(z);  !.z1= zz - _;    !.z2= zz + _;    return 1
/*──────────────────────────────────────────────────────────────────────────────────────*/
deathStar: procedure; parse arg k,ambient,sun    /* [↓]  display the deathstar to screen*/
parse var  sun   s1 s2 s3                        /*identify the light source coördinates*/
if 5=="f5"x  then shading= '.:!*oe&#%@'          /*dithering chars for an EBCDIC machine*/
             else shading= '·:!ºoe@░▒▓'          /*    "       "    "   "  ASCII    "   */
shadingL= length(shading)                        /*the number of dithering characters.  */
shades.= ' ';            do i=1  for shadingL;    shades.i= substr(shading, i, 1)
                         end   /*i*/
ship=  20   20  0 20  ;           parse var  ship    shipX  shipY  shipZ  shipR
hole= ' 1    1 -6 20' ;           parse var  hole    holeX  holeY  holeZ  .

  do   i=floor(shipY-shipR  )  to ceil(shipY+shipR  )+1;    y= i +.5;   @= /*@   is a single line of the deathstar to be displayed.*/
    do j=floor(shipX-shipR*2)  to ceil(shipX+shipR*2)+1;    !.= 0
    x=.5 * (j-shipX+1) + shipX;       $bg= 0;    $pos= 0;    $neg= 0       /*$BG,  $POS,  and  $NEG  are boolean values.           */
    ?= hitSphere(ship, x, y);                    b1= !.z1;   b2= !.z2      /*?  is boolean,  "true"  indicates ray hits the sphere.*/
                                                                           /*$BG:  if 1, its background;  if zero, it's foreground.*/
    if \? then $bg= 1                                                      /*ray lands in blank space, so draw the background.     */
          else do; ?= hitSphere(hole, x, y);     s1= !.z1;   s2= !.z2
               if \? then $pos= 1                                          /*ray hits ship but not the hole, so draw ship surface. */
                     else if s1>b1 then $pos=1                             /*ray hits both, but ship front surface is closer.      */
                                   else if s2>b2 then $bg= 1               /*ship surface is inside hole,  so show the background. */
                                                 else if s2>b1 then $neg=1 /*hole back surface is inside ship;  the only place ··· */
                                                               else $pos=1 /*························ a hole surface will be shown.*/
               end
        select
        when $bg   then do;   @= @' ';    iterate j;     end               /*append a blank character to the line to be displayed. */
        when $pos  then vec_= v3(x-shipX  y-shipY  b1-shipZ)
        when $neg  then vec_= v3(holeX-x  holeY-y  holeZ-s2)
        end    /*select*/

    b=1 +min(shadingL, max(0, trunc((1 - (dot.(sun, v3(vec_))**k + ambient)) * shadingL)))
    @=@ || shades.b                                 /*B:  the ray's intensity│brightness*/
    end      /*j*/                                  /* [↑]  build a line for the sphere.*/

  if @\=''  then say strip(@, 'T')                  /*strip trailing blanks from line.  */
  end        /*i*/                                  /* [↑]  show all lines for sphere.  */
return

{{out|output|text= when using the internal default input:}} (Shown at '''1/2''' size.)

                                    eeeee:::::::
                                eeeeeeeee··············
                             ooeeeeeeeeee··················
                           ooooeeeeeeeee······················
                        oooooooeeeeeeee··························
                      ooooooooooeeeee······························
                    ººooooooooooeeee·································
                  ººººooooooooooee·····································
                !ºººººooooooooooe·······································
              !!!ºººººooooooooo:··········································
            :!!!!ºººººooooooo:::···········································
          :::!!!!ºººººooooo!:::::···········································
        ::::!!!!!ºººººooo!!!!::::············································
       ·::::!!!!ºººººooº!!!!!::::············································
     ···::::!!!!ººººººººº!!!!:::::············································
    ···::::!!!!ººººoººººº!!!!!::::············································
  ····::::!!!!ºººoooºººººº!!!!!::::············································
 ····::::!!!!ºoooooooººººº!!!!!:::::···········································
···::::!!!!!ooooooooooººººº!!!!!:::::··········································
:::::!!!!eeoooooooooooºººººº!!!!!:::::·········································
!!!!!eeeeeeeoooooooooooºººººº!!!!!:::::········································
eeeeeeeeeeeeooooooooooooºººººº!!!!!:::::·······································
eeeeeeeeeeeeeooooooooooooºººººº!!!!!!:::::·····································
eeeeeeeeeeeeeeooooooooooooºººººº!!!!!!:::::····································
 eeeeeeeeeeeeeeooooooooooooººººººº!!!!!!:::::·································
 eeeeeeeeeeeeeeeoooooooooooooºººººº!!!!!!::::::······························:
  eeeeeeeeeeeeeeeoooooooooooooººººººº!!!!!!:::::::··························:
  eeeeeeeeeeeeeeeeooooooooooooooººººººº!!!!!!!:::::::·····················::!
   eeeeeeeeeeeeeeeeeoooooooooooooºººººººº!!!!!!!:::::::::··············::::!
    eeeeeeeeeeeeeeeeeooooooooooooooºººººººº!!!!!!!!::::::::::::::::::::::!º
     eeeeeeeeeeeeeeeeeeoooooooooooooooºººººººº!!!!!!!!!!:::::::::::::!!!!º
       eeeeeeeeeeeeeeeeeooooooooooooooooºººººººººº!!!!!!!!!!!!!!!!!!!!!º
        eeeeeeeeeeeeeeeeeeoooooooooooooooooºººººººººººº!!!!!!!!!!!!ºººº
          eeeeeeeeeeeeeeeeeeooooooooooooooooooººººººººººººººººººººººo
            eeeeeeeeeeeeeeeeeeeoooooooooooooooooooooººººººººººººooo
              eeeeeeeeeeeeeeeeeeeeooooooooooooooooooooooooooooooo
                 eeeeeeeeeeeeeeeeeeeeooooooooooooooooooooooooo
                    eeeeeeeeeeeeeeeeeeeeeoooooooooooooooooo
                        eeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
                               eeeeeeeeeeeeeeeee

```



## Set lang

set ! 32
set ! 32
set ! 46
set ! 45
set ! 126
set ! 34
set ! 34
set ! 126
set ! 45
set ! 46
set ! 10
set ! 46
set ! 39
set ! 40
set ! 95
set ! 41
set ! 32
set ! 32
set ! 32
set ! 32
set ! 32
set ! 39
set ! 46
set ! 10
set ! 124
set ! 61
set ! 61
set ! 61
set ! 61
set ! 61
set ! 61
set ! 61
set ! 61
set ! 61
set ! 61
set ! 124
set ! 10
set ! 39
set ! 46
set ! 32
set ! 32
set ! 32
set ! 32
set ! 32
set ! 32
set ! 32
set ! 32
set ! 46
set ! 39
set ! 10
set ! 32
set ! 32
set ! 126
set ! 45
set ! 46
set ! 95
set ! 95
set ! 46
set ! 45
set ! 126
```

Outputs:

```txt
  .-~""~-.
.'(_)     '.
|
### ====
|
'.        .'
  ~-.__.-~
```

(it's the best I could do!)


## Sidef

{{trans|Perl}}
Writes a PGM to stdout.

```ruby
func hitf(sph, x, y) {
    x -= sph[0]
    y -= sph[1]

    var z = (sph[3]**2 - (x**2 + y**2))

    z < 0 && return nil

    z.sqrt!
    [sph[2] - z, sph[2] + z]
}

func normalize(v) {
    v / v.abs
}

func dot(x, y) {
    max(0, x*y)
}

var pos = [120, 120, 0, 120]
var neg = [-77, -33, -100, 190]
var light = normalize(Vector(-12, 13, -10))

func draw(k, amb) {
    STDOUT.binmode(':raw')
    print ("P5\n", pos[0]*2 + 3, " ", pos[1]*2 + 3, "\n255\n")

    for y in ((pos[1] - pos[3] - 1) .. (pos[1] + pos[3] + 1)) {
        var row = []
        for x in ((pos[0] - pos[3] - 1) .. (pos[0] + pos[3] + 1)) {

            var hit = 0
            var hs = []
            var h = hitf(pos, x, y)

            if    (!h)                      { hit = 0; h  = [0, 0] }
            elsif (!(hs = hitf(neg, x, y))) { hit = 1; hs = [0, 0] }
            elsif (hs[0] > h[0])            { hit = 1 }
            elsif (hs[1] > h[0])            { hit = (hs[1] > h[1] ? 0 : 2) }
            else                            { hit = 1 }

            var (val, v)

            given(hit) {
                when (0) { val = 0}
                when (1) { v = Vector(x-pos[0], y-pos[1], h[0]-pos[2]) }
                default  { v = Vector(neg[0]-x, neg[1]-y, neg[2]-hs[1]) }
            }

            if (defined(v)) {
                v = normalize(v)
                val = int((dot(v, light)**k + amb) * 255)
                val = (val > 255 ? 255 : (val < 0 ? 0 : val))
            }
            row.append(val)
        }
        print 'C*'.pack(row...)
    }
}

draw(2, 0.2)
```

Output image: [https://github.com/trizen/rc/blob/master/img/death_star_sidef.png here].


## Tcl

{{trans|C}}
Note that this code has a significant amount of refactoring relative to the C version, including the addition of specular reflections and the separation of the scene code from the raytracing from the rendering.

```tcl
package require Tcl 8.5

proc normalize vec {
    upvar 1 $vec v
    lassign $v x y z
    set len [expr {sqrt($x**2 + $y**2 + $z**2)}]
    set v [list [expr {$x/$len}] [expr {$y/$len}] [expr {$z/$len}]]
    return
}

proc dot {a b} {
    lassign $a ax ay az
    lassign $b bx by bz
    return [expr {-($ax*$bx + $ay*$by + $az*$bz)}]
}

# Intersection code; assumes that the vector is parallel to the Z-axis
proc hitSphere {sphere x y z1 z2} {
    dict with sphere {
	set x [expr {$x - $cx}]
	set y [expr {$y - $cy}]
	set zsq [expr {$r**2 - $x**2 - $y**2}]
	if {$zsq < 0} {return 0}
	upvar 1 $z1 _1 $z2 _2
	set zsq [expr {sqrt($zsq)}]
	set _1 [expr {$cz - $zsq}]
	set _2 [expr {$cz + $zsq}]
	return 1
    }
}

# How to do the intersection with our scene
proc intersectDeathStar {x y vecName} {
    global big small
    if {![hitSphere $big $x $y zb1 zb2]} {
	# ray lands in blank space
	return 0
    }
    upvar 1 $vecName vec
    # ray hits big sphere; check if it hit the small one first
    set vec [if {
	![hitSphere $small $x $y zs1 zs2] || $zs1 > $zb1 || $zs2 <= $zb1
    } then {
	dict with big {
	    list [expr {$x - $cx}] [expr {$y - $cy}] [expr {$zb1 - $cz}]
	}
    } else {
	dict with small {
	    list [expr {$cx - $x}] [expr {$cy - $y}] [expr {$cz - $zs2}]
	}
    }]
    normalize vec
    return 1
}

# Intensity calculators for different lighting components
proc diffuse {k intensity L N} {
    expr {[dot $L $N] ** $k * $intensity}
}
proc specular {k intensity L N S} {
    # Calculate reflection vector
    set r [expr {2 * [dot $L $N]}]
    foreach l $L n $N {lappend R [expr {$l-$r*$n}]}
    normalize R
    # Calculate the specular reflection term
    return [expr {[dot $R $S] ** $k * $intensity}]
}

# Simple raytracing engine that uses parallel rays
proc raytraceEngine {diffparms specparms ambient intersector shades renderer fx tx sx fy ty sy} {
    global light
    for {set y $fy} {$y <= $ty} {set y [expr {$y + $sy}]} {
	set line {}
	for {set x $fx} {$x <= $tx} {set x [expr {$x + $sx}]} {
	    if {![$intersector $x $y vec]} {
		# ray lands in blank space
		set intensity end
	    } else {
		# ray hits something; we've got the normalized vector
		set b [expr {
		    [diffuse {*}$diffparms $light $vec]
		    + [specular {*}$specparms $light $vec {0 0 -1}]
		    + $ambient
		}]
		set intensity [expr {int((1-$b) * ([llength $shades]-1))}]
		if {$intensity < 0} {
		    set intensity 0
		} elseif {$intensity >= [llength $shades]-1} {
		    set intensity end-1
		}
	    }
	    lappend line [lindex $shades $intensity]
	}
	{*}$renderer $line
    }
}

# The general scene settings
set light {-50 30 50}
set big   {cx 20 cy 20 cz 0   r 20}
set small {cx 7  cy 7  cz -10 r 15}
normalize light

# Render as text
proc textDeathStar {diff spec lightBrightness ambient} {
    global big
    dict with big {
	raytraceEngine [list $diff $lightBrightness] \
	    [list $spec $lightBrightness] $ambient intersectDeathStar \
	    [split ".:!*oe&#%@ " {}] {apply {l {puts [join $l ""]}}} \
	    [expr {$cx+floor(-$r)}] [expr {$cx+ceil($r)+0.5}] 0.5 \
	    [expr {$cy+floor(-$r)+0.5}] [expr {$cy+ceil($r)+0.5}] 1
    }
}
textDeathStar 3 10 0.7 0.3
```

Output:

```txt

                                #######&eeeeeeeee
                         ee&&&&&&########%eeoooooooooooe
                     **oooee&&&&&&########%ooooo**********oo
                  !!!***oooee&&&&&&########%********!!!!!!!!***
               !!!!!!!****ooee&&&&&&#######%*****!!!!!!!!!!!!!!!**
             ::::!!!!!!***oooee&&&&&&######***!!!!!!!::::::::::::!!*
           :::::::!!!!!!***ooeee&&&&&&#####**!!!!!!:::::::::::::::::!*
         ::::::::::!!!!!***oooee&&&&&&####*!!!!!!::::::::.........::::!*
        ::::::::::!!!!!!***oooeee&&&&&&###!!!!!!:::::::..............:::!
      ..:::::::::!!!!!!****oooeee&&&&&&##!!!!!!::::::..................::!*
     ...::::::::!!!!!!****ooooeee&&&&&&!!!!!!:::::::....................::!*
    ....::::::!!!!!!*****ooooeeee&&&&&!!!!!!:::::::......................::!*
   ....::::::!!!!!*****oooooeeeee&&&&!!!!!!::::::::.......................::!*
   ...::::::!!!!!*****oooooeeeee&&&!!!!!!:::::::::.........................::!
  ...:::::!!!!!*****oooooeeeeee&&!!!!!!!:::::::::..........................::!*
  ..:::::!!!!!****oooooeeeeee&&&!!!!!!!::::::::::..........................::!!
 .::::::!!!!*****ooooeeeeee&&*!!!!!!!::::::::::::.........................:::!!*
 :::::!!!!!****oooooeeeee&&**!!!!!!!::::::::::::::.......................::::!!*
 !!!!!!!!****oooooeeeee&****!!!!!!!::::::::::::::::::..................::::::!!*
 #!!!******oooooeeeeeoo*****!!!!!!!:::::::::::::::::::::::::::::::::::::::::!!!*
 ##oooooooooooeeeeeeoooo****!!!!!!!:::::::::::::::::::::::::::::::::::::::!!!!**
 %#####eeee&&&&&&&eeeooo****!!!!!!!!:::::::::::::::::::::::::::::::::::!!!!!!**o
 %#########&&&&&&&&eeeooo****!!!!!!!!!::::::::::::::::::!!!!!!!!!!!!!!!!!!!****o
 %##########&&&&&&&&eeeooo****!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!****ooe
  %##########&&&&&&&&eeeooo*****!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!**********ooo
  %%##########&&&&&&&&eeeoooo*****!!!!!!!!!!!!!!!!!!!*********************ooooe
   %%##########&&&&&&&&eeeoooo***************************************oooooooee
   @%###########&&&&&&&&&eeeooooo*************************ooooooooooooooooeee&
    @%###########&&&&&&&&&eeeeoooooo*************ooooooooooooooooooooooeeeee&
     @%%##########&&&&&&&&&&eeeeoooooooooooooooooooooooooooooooeeeeeeeeeee&&
      @%%###########&&&&&&&&&&eeeeeoooooooooooooooooooeeeeeeeeeeeeeeeeee&&&
        %%############&&&&&&&&&&eeeeeeeeeeooeeeeeeeeeeeeeeeeeeeeeeee&&&&&
         @%%###########&&&&&&&&&&&&eeeeeeeeeeeeeeeeeeeeeeeeee&&&&&&&&&&&
           %%############&&&&&&&&&&&&&&eeeeeeeeeeeeeee&&&&&&&&&&&&&&&&
             %%############&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
               %%#############&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
                  %%#############&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
                     %##############&&&&&&&&&&&&&&&&&&&&&&&&
                         %##############&&&&&&&&&&&&&&&&
                                #################

```

To render it as an image, we just supply different code to map the intensities to displayable values:
{{libheader|Tk}}
[[File:Deathstar-tcl.gif|200px|thumb|Rendering of the Death Star by the Tcl solution.]]

```tcl
# Render as a picture (with many hard-coded settings)
package require Tk
proc guiDeathStar {photo diff spec lightBrightness ambient} {
    set row 0
    for {set i 255} {$i>=0} {incr i -1} {
	lappend shades [format "#%02x%02x%02x" $i $i $i]
    }
    raytraceEngine [list $diff $lightBrightness] \
	[list $spec $lightBrightness] $ambient intersectDeathStar \
	$shades {apply {l {
	    upvar 2 photo photo row row
	    $photo put [list $l] -to 0 $row
	    incr row
	    update
	}}} 0 40 0.0625 0 40 0.0625
}
pack [label .l -image [image create photo ds]]
guiDeathStar ds 3 10 0.7 0.3
```



## Yabasic


```Yabasic
open window 100,100
window origin "cc"
backcolor 0,0,0
clear window

tonos = 100
interv = int(255 / tonos)
dim shades(tonos)

shades(1) = 255
for i = 2 to tonos
	shades(i) = shades(i-1) - interv
next i

dim light(3)

light(0) = 30
light(1) = 30
light(2) = -50


sub normalize(v())
    local long

    long = sqrt(v(0)*v(0) + v(1)*v(1) + v(2)*v(2))
    v(0) = v(0) / long
    v(1) = v(1) / long
    v(2) = v(2) / long
end sub


sub punto(x(), y())
    local d

    d = x(0)*y(0) + x(1)*y(1) + x(2)*y(2)
    if d < 0 then
    	return -d
    else
    	return 0
    end if
end sub


//* positive shpere and negative sphere */
dim pos(3)
dim neg(3)

// x, y, z, r

pos(0) = 10
pos(1) = 10
pos(2) = 0
pos(3) = 20

neg(0) = 0
neg(1) = 0
neg(2) = -5
neg(3) = 15


sub hit_sphere(sph(), x, y)
	local zsq

	x = x - sph(0)
	y = y - sph(1)
	zsq = sph(3) * sph(3) - (x * x + y * y)
	if (zsq < 0) then
		return 0
	else
		return sqrt(zsq)
	end if
end sub


sub draw_sphere(k, ambient)
    local i, j, intensity, hit_result, result, b, vec(3), x, y, zb1, zb2, zs1, zs2, ini1, fin1, ini2, fin2

    ini1 = int(pos(1) - pos(3))
    fin1 = int(pos(1) + pos(3) + .5)
    for i = ini1 to fin1
        y = i + .5
        ini2 = int(pos(0) - 2 * pos(3))
        fin2 = int(pos(0) + 2 * pos(3) + .5)
        for j = ini2 to fin2
            x = (j - pos(0)) / 2 + .5 + pos(0)

            // ray lands in blank space, draw bg
            result = hit_sphere(pos(), x, y)

            if not result then
		hit_result = 0

		//* ray hits pos sphere but not neg, draw pos sphere surface */
	    else
		zb1 = pos(2) - result
		zb2 = pos(2) + result
		result = hit_sphere(neg(), x, y)
		if not result then
		    hit_result = 1
		else
		    zs1 = neg(2) - result
		    zs2 = neg(2) + result
		    if (zs1 > zb1) then
			hit_result = 1
		    elseif (zs2 > zb2) then
			hit_result = 0
		    elseif (zs2 > zb1) then
			hit_result = 2
		    else
			hit_result = 1
		    end if
		end if
	    end if

  	    if not hit_result then
  	        color 0,0,0
  	        dot x, y
  	    else
	        switch(hit_result)
	        case 1:
		    vec(0) = x - pos(0)
		    vec(1) = y - pos(1)
		    vec(2) = zb1 - pos(2)
		    break
	        default:
		    vec(0) = neg(0) - x
		    vec(1) = neg(1) - y
		    vec(2) = neg(2) - zs2
	        end switch

                normalize(vec())
                b = (punto(light(), vec())^k) + ambient
                intensity = (1 - b) * tonos
                if (intensity < 1) intensity = 1
                if (intensity > tonos) intensity = tonos
                color shades(intensity),shades(intensity),shades(intensity)
                dot x,y
            end if
        next j
    next i
end sub


ang = 0

while(true)
	//clear window
	light(1) = cos(ang * 2)
	light(2) = cos(ang)
	light(0) = sin(ang)
	normalize(light())
	ang = ang + .05

	draw_sphere(2, .3)
wend

```