Created pommicket.github.io

1 files changed, 179 insertions, 0 deletions

diff --git a/js/mandelbrot.js b/js/mandelbrot.js
new file mode 100644
index 0000000..cdfc467
--- /dev/null
+++ b/js/mandelbrot.js
@@ -0,0 +1,179 @@
+var increment = 0.01;
+var iterations = 30;
+var startI = -2.5;
+var startJ = -2.5;
+var power = 2;
+var canvas = document.getElementById("canvas");
+var ctx = canvas.getContext("2d");
+var width = canvas.width;
+var height = canvas.height;
+function reciprocal(re, im)
+{
+	return [re/(re*re+im*im), -im/(im*im+re*re)];
+}
+
+function add(re1, im1, re2, im2)
+{
+	return [re1+re2, im1+im2];
+}
+
+function multiply(re1, im1, re2, im2)
+{
+	return [re1*re2-im1*im2, re1*im2+re2*im1];
+}
+
+function cpower(re, im, power)
+{
+	if (power < 0)
+	{
+		var r = reciprocal(re, im);
+		return cpower(r[0], r[1], -power);
+	}
+	var x = [re, im];
+	var i = 1;
+	while (i < power)
+	{
+		x = multiply(x[0], x[1], re, im);
+		i++;
+	}
+	return x;
+	
+}
+
+function iterate(z, power, c)
+{
+	var x = cpower(z[0], z[1], power);
+	return add(x[0], x[1], c[0], c[1]);
+}
+
+function cabs(z)
+{
+	return Math.sqrt(z[0]*z[0]+z[1]*z[1]);
+}
+
+function num_iterations(power, c, max_iterations)
+{
+	var iterations = 0;
+	var z = [0, 0];
+	while (iterations < max_iterations && cabs(z) < 2)
+	{
+		z = iterate(z, power, c);
+		iterations++;
+	}
+	return iterations;
+}
+
+function draw_mandelbrot()
+{
+	var size = width*increment;
+	
+	
+	
+	var endI = startI+size;
+	var endJ = startJ+size;
+	
+	var imgData = ctx.createImageData(width, height);
+	
+	for (var i = startI; i < endI; i+=increment)
+	{
+		for (var j = startJ; j < endJ; j+=increment)
+		{
+			var ipos = i*(1.0/increment)-startI*(1.0/increment);
+			var jpos = j*(1.0/increment)-startJ*(1.0/increment);
+			jpos = Math.floor(Math.round(jpos));
+			ipos = Math.floor(Math.round(ipos));
+			
+			var x = num_iterations(power, [i, j], iterations)/iterations * 255
+			imgData.data[4*(jpos*width+ipos)] = x;
+			imgData.data[1+4*(jpos*width+ipos)] = x;
+			imgData.data[2+4*(jpos*width+ipos)] = x;
+			imgData.data[3+4*(jpos*width+ipos)] = 255;
+			
+			
+		}
+	}
+	ctx.putImageData(imgData, 0, 0);
+}
+
+function draw()
+{
+
+}
+
+function map(val, startA, endA, startB, endB)
+{
+	return (endB-startB)*((val-startA)/(endA-startA))+startB;
+}
+
+function mousePressed(e)
+{
+	var x;
+	var y;
+	if (e.pageX || e.pageY) { 
+	  x = e.pageX;
+	  y = e.pageY;
+	}
+	else { 
+	  x = e.clientX; 
+	  y = e.clientY; 
+	} 
+	x -= canvas.offsetLeft;
+	y -= canvas.offsetTop;
+	if (x < 0 || x > width || y < 0 || y > height)
+		return;
+		
+	if (e.button == 0)
+	{
+		increment /= 2;
+		startI = map(x, 0, width, startI, startI+width*increment);
+		startJ = map(y, 0, height, startJ, startJ+width*increment);
+	 
+		draw_mandelbrot();
+	}
+}
+
+function keyPressed(e)
+{
+
+	var key = String.fromCharCode(e.keyCode);
+	if (key == "A")
+	{
+		increment /= 2;
+		startI = startI+width*increment/2;
+		startJ = startJ+height*increment/2;
+		
+		draw_mandelbrot();
+	}
+	if (key == "Q")
+	{
+		increment *= 2;
+		startI = startI-width*increment/2;
+		startJ = startJ-height*increment/2;
+		draw_mandelbrot();
+	}
+	if (key == "P")
+	{
+		power++;
+		draw_mandelbrot();
+	}
+	if (key == "L")
+	{
+		power--;
+		draw_mandelbrot();
+	}
+	if (key == "I")
+	{
+		iterations = Math.floor(iterations*1.5);
+		draw_mandelbrot();
+	}
+	if (key == "K")
+	{
+		iterations = Math.floor(iterations/1.5);
+		draw_mandelbrot();
+	}
+}
+canvas.addEventListener("mousedown", mousePressed);
+document.body.addEventListener("keydown", keyPressed);
+
+draw_mandelbrot();
+	
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