duktape-nspire/examples/mandelbrot.js.tns

// Mandelbrot demo
//
// Copyright (C) 2015 Legimet
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

// Based on Micro Python demo by Fabian Vogt

var t = require('nsp/texture');
var k = require('nsp/keys');

function mandel(x, y, max_iters) {
    var zr = 0;
    var zi = 0;
    var tmp;
    for (var i = 0; i < max_iters; i++) {
	tmp = zr * zr - zi * zi + x;
	zi = 2 * zr * zi + y;
	zr = tmp;
	if (zr * zr + zi * zi >= 4) {
	    return i;
	}
    }
    return max_iters;
}

var screen = new t.Texture(320, 240);
screen.fill(0x0000);

var width = 320;
var height = 240;
var iter = 16;

var min_x = -2.0;
var max_x = 1.0;
var min_y = -1.0;
var max_y = 1.0;
var pixel_size_x = (max_x - min_x) / width;
var pixel_size_y = (max_y - min_y) / height;

var time_start = Date.now();

var real, imag, color;

for (var x = 0; x < height; x++) {
    real = min_x + x * pixel_size_x;
    for (var y = 0; y < width; y++) {
	imag = min_y + y * pixel_size_y;
	color = mandel(real, imag, iter);
	screen.setPx(y, x, color << 14 | color << 8 | color << 3);
    }
    screen.display();
}

print(width+"x"+height+" ("+iter+" iters) in "+(Date.now()-time_start)/1000+" seconds");
k.waitKeyPressed();