Initial data commit

Task/Draw-a-sphere/Java/draw-a-sphere.java

@@ -0,0 +1,43 @@
+public class Sphere{
+    static char[] shades = {'.', ':', '!', '*', 'o', 'e', '&', '#', '%', '@'};
+
+    static double[] light = { 30, 30, -50 };
+    private static void normalize(double[] v){
+        double len = Math.sqrt(v[0]*v[0] + v[1]*v[1] + v[2]*v[2]);
+        v[0] /= len; v[1] /= len; v[2] /= len;
+    }
+
+    private static 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;
+    }
+
+    public static void drawSphere(double R, double k, double ambient){
+        double[] vec = new double[3];
+        for(int i = (int)Math.floor(-R); i <= (int)Math.ceil(R); i++){
+            double x = i + .5;
+            for(int j = (int)Math.floor(-2 * R); j <= (int)Math.ceil(2 * R); j++){
+                double y = j / 2. + .5;
+                if(x * x + y * y <= R * R) {
+                    vec[0] = x;
+                    vec[1] = y;
+                    vec[2] = Math.sqrt(R * R - x * x - y * y);
+                    normalize(vec);
+                    double b = Math.pow(dot(light, vec), k) + ambient;
+                    int intensity = (b <= 0) ?
+                                shades.length - 2 :
+                                (int)Math.max((1 - b) * (shades.length - 1), 0);
+                    System.out.print(shades[intensity]);
+                } else
+                    System.out.print(' ');
+            }
+            System.out.println();
+        }
+    }
+
+    public static void main(String[] args){
+        normalize(light);
+        drawSphere(20, 4, .1);
+        drawSphere(10, 2, .4);
+    }
+}