📝 add new test file feigenbaum.nas

test/feigenbaum.nas

@@ -0,0 +1,48 @@
+import.std.process_bar;
+
+var ppm=func(filename, width, height, RGB){
+    # P3 use ASCII number
+    # P6 use binary character
+    var fd = io.open(filename, "wb");
+    io.write(fd, "P6\n"~width~" "~height~"\n255\n");
+    for(var i = 0; i<height; i+=1) {
+        for(var j = 0; j<width; j+=1) {
+            io.write(fd, RGB(i, j));
+        }
+    }
+    io.close(fd);
+}
+
+var width = 1600;
+var height = 900;
+var bar=(os.platform()=="windows")?
+    process_bar.bar(front:"sharp",back:"point",sep:"line",length:50):
+    process_bar.high_resolution_bar(50);
+
+var RGB = func(h, w) {
+    var r = 2+w*2/width;
+    var x = (height-h)/height;
+
+    var res = 0;
+    var tmp = 0.5;
+    for(var i = 0; i<50; i+=1) {
+        tmp = r*tmp*(1-tmp);
+    }
+    for(var i = 0; i<100; i+=1) {
+        tmp = r*tmp*(1-tmp);
+        if (math.abs(tmp-x)<0.001) {
+            res = 255;
+            break;
+        }
+    }
+
+    var progress = (h*width+w+1)/(width*height);
+    if(progress*100-int(progress*100)==0){
+        print(bar.bar(progress), " ", progress*100, "%          \r");
+    }
+
+    var c = char(res);
+    return c~c~c;
+}
+ppm("feigenbaum.ppm", width, height, RGB);
+println();