Death Star
You are encouraged to solve this task according to the task description, using any language you may know.
Death Star is a task to 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".)
Brlcad
<lang 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</lang>
C
<lang C>
- include <stdio.h>
- include <stdlib.h>
- include <math.h>
char shades[] = ".:!*oe&#%@";
double light[3] = { -50, 30, 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; sphere_t big = { 20, 20, 0, 20 }, small = { 7, 7, -10, 15 };
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;
double b;
double vec[3], x, y, zb1, zb2, zs1, zs2;
for (i = floor(big.cy - big.r); i <= ceil(big.cy + big.r); i++) {
y = i + .5;
for (j = floor(big.cx - 2 * big.r); j <= ceil(big.cx + 2 * big.r); j++) {
x = (j - big.cx) / 2. + .5 + big.cx;
if (!hit_sphere(&big, x, y, &zb1, &zb2)) { putchar(' '); continue; } if (!hit_sphere(&small, x, y, &zs1, &zs2)) { vec[0] = x - big.cx; vec[1] = y - big.cy; vec[2] = zb1 - big.cz; } else { if (zs1 < zb1) { if (zs2 > zb2) { putchar(' '); continue; } if (zs2 > zb1) { vec[0] = small.cx - x; vec[1] = small.cy - y; vec[2] = small.cz - zs2; } else { vec[0] = x - big.cx; vec[1] = y - big.cy; vec[2] = zb1 - big.cz; } } else { vec[0] = x - big.cx; vec[1] = y - big.cy; vec[2] = zb1 - big.cz; } }
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() {
normalize(light);
draw_sphere(2, .3);
return 0;
}</lang>Output:<lang> #######ooo*******
&&&&&###########!!!!!!!!:::!!!
&&&&&&&&&###########!:::::::......:::
eee&&&&&&&&&&###########:::...............:
oooeeeee&&&&&&&&&##########:....................:
**ooooeeeee&&&&&&&&&########.........................
!!***ooooeeeee&&&&&&&&########...........................
:!!!!***ooooeeeee&&&&&&&&######..............................
.::::!!!***ooooeeee&&&&&&&&######...............................
...:::!!!!***ooooeeee&&&&&&&&####..................................
......:::!!!****oooeeee&&&&&&&&##:::..................................
........:::!!!***ooooeeee&&&&&&&#::::...................................
.........:::!!!****oooeeee&&&&&&&!::::....................................
...........:::!!!***oooeeee&&&&&!!!:::::...................................
............:::!!!***oooeeee&&&**!!!!::::....................................
............:::!!!***oooeeee&&***!!!!!::::...................................
............:::!!!***ooooeeeooo****!!!!:::::................................... ............:::!!!***oooeeooooo*****!!!!:::::.................................. ...........:::!!!***oooeeeeooooo*****!!!!:::::.................................
- ........:::!!!!***o&&eeeeeeooooo*****!!!!:::::................................
- !!!!***&&&&&&eeeeeeooooo*****!!!!!:::::.............................:
- &&&&&&&&&&&&eeeeeeooooo*****!!!!!::::::...........................:
- &&&&&&&&&&&&eeeeeeoooooo*****!!!!!::::::........................:!
- &&&&&&&&&&&&eeeeeeoooooo*****!!!!!!::::::.....................::!
- &&&&&&&&&&&&eeeeeeoooooo*****!!!!!::::::........................:!
##############&&&&&&&&&&&&eeeeeeeoooooo*****!!!!!!:::::::................:::!
###############&&&&&&&&&&&&&eeeeeeoooooo******!!!!!!!::::::::::.....::::::!!*
###############&&&&&&&&&&&&&eeeeeeeoooooo*******!!!!!!!::::::::::::::::!!!*
################&&&&&&&&&&&&&&eeeeeeeooooooo*******!!!!!!!!!!!!!!!!!!!!!**o
#################&&&&&&&&&&&&&eeeeeeeeooooooo*********!!!!!!!!!!!!!!****o
#################&&&&&&&&&&&&&&eeeeeeeeoooooooo**********************oe
##################&&&&&&&&&&&&&&&eeeeeeeeoooooooooo*************ooooe
#################&&&&&&&&&&&&&&&&eeeeeeeeeeoooooooooooooooooooooe
##################&&&&&&&&&&&&&&&&&eeeeeeeeeeeeooooooooooooeeee
##################&&&&&&&&&&&&&&&&&&eeeeeeeeeeeeeeeeeeeeee&
###################&&&&&&&&&&&&&&&&&&&&&eeeeeeeeeeee&&&
####################&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
####################&&&&&&&&&&&&&&&&&&&&&&&&&
#####################&&&&&&&&&&&&&&&&&&
###############################
#################
</lang>
DWScript
Translation of C version.
<lang delphi>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);</lang>
Openscad
<lang 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);
}
}</lang>
POV-Ray
<lang 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} }
}
} </lang>
