enjalot/.block

## .block
license: gpl-3.0

## README.md

      
    Raw
  

              README.md
            
          
    Playing with varying the radius of the poisson disc as it generates
Based on Jason Davies’ implementation of Bridson’s algorithm. See the related explanation.
forked from mbostock's block: Poisson-Disc

  
## index.html
<!DOCTYPE html>
<meta charset="utf-8">
<style>
  body: {
    position:fixed;
    top:0; bottom: 0;
    left: 0; right: 0;
  }
  canvas {
    width: 100%;
    height: 100%;
    position:absolute;
    top:0;
    left: 0;
  }
  path {
    fill: #fff;
    stroke: #de4459;
  }
  path:nth-child(2n+1) {

    fill: #de4459;
  }
</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>

  <canvas></canvas>
<script>

var bbox = d3.select("body").node().getBoundingClientRect();
var width = bbox.width,
    height = bbox.height;

var r = 8;
var sample = poissonDiscSampler(width, height, r);

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

var grid;
var points = [[width/2, height/2]];

var voronoi = d3.geom.voronoi();

d3.timer(function(elapsed) {
  var mod = -2
    + 100 * Math.sin(elapsed * Math.PI*2)
    - 5 * Math.cos(elapsed * Math.PI)
  ;
  for (var i = 0; i < 10; ++i) {
    var s = sample(r + mod);
    if (!s) {

      renderVoronoi();
      svg.selectAll("circle")
      .remove()
      return true;
    }
    svg.append("circle")
        .attr("cx", s[0])
        .attr("cy", s[1])
        .attr("r", 0)
      .transition()
        .attr("r", 2);
  }
  //console.log(elapsed)
});

function renderVoronoi() {
  var canvas = d3.select("canvas").node();
  canvas.width = width;
  canvas.height = height;
  var context = canvas.getContext('2d');

  var noids = voronoi(points);
  /*
  for (var i = 1, n = noids.length; i < n; ++i) {
    draw(noids[i]);
    context.stroke();
  }
  */
  console.log("noids",noids)
  var cells = svg.selectAll("path.cell").data(noids)
  cells.enter().append("path")
  .attr("d", function(d) {
    if(!d) return;
    return "M" + d.join("L") + "Z";
  })

  function draw(cell) {
    if (cell) {
      context.beginPath();
      context.moveTo(cell[0][0], cell[0][1]);
      for (var j = 1, m = cell.length; j < m; ++j) {
        context.lineTo(cell[j][0], cell[j][1]);
      }
      context.closePath();
      return true;
    }
  }
}

// Based on https://www.jasondavies.com/poisson-disc/
function poissonDiscSampler(width, height, radius) {
  var k = 30; // maximum number of samples before rejection
  var radius2 = radius * radius;
  var R = 3 * radius2
  var cellSize = radius * Math.SQRT1_2
  var gridWidth = Math.ceil(width / cellSize)
  var gridHeight = Math.ceil(height / cellSize)
  grid = new Array(gridWidth * gridHeight)
  var queue = []
  var queueSize = 0
  var sampleSize = 0

  return function(newRadius) {
    radius2 = newRadius * newRadius;
  	R = 3 * radius2
  	cellSize = radius * Math.SQRT1_2;

    if (!sampleSize) return sample(Math.random()*width,Math.random()*height);

    // Pick a random existing sample and remove it from the queue.
    while (queueSize) {
      var i = Math.random() * queueSize | 0,
          s = queue[i];

      // Make a new candidate between [radius, 2 * radius] from the existing sample.
      for (var j = 0; j < k; ++j) {
        var a = 2 * Math.PI * Math.random(),
            rad = Math.sqrt(Math.random() * R + radius2),
            x = s[0] + rad * Math.cos(a) * Math.random(),
            y = s[1] + rad * Math.sin(a) * Math.random();

        // Reject candidates that are outside the allowed extent,
        // or closer than 2 * radius to any existing sample.
        if (0 <= x && x < width && 0 <= y && y < height && far(x, y)) {
          points.push([x,y])
          return sample(x, y);
        }
      }

      queue[i] = queue[--queueSize];
      queue.length = queueSize;
    }
  };

  function far(x, y) {
    var i = x / cellSize | 0,
        j = y / cellSize | 0,
        i0 = Math.max(i - 2, 0),
        j0 = Math.max(j - 2, 0),
        i1 = Math.min(i + 3, gridWidth),
        j1 = Math.min(j + 3, gridHeight);

    for (j = j0; j < j1; ++j) {
      var o = j * gridWidth;
      for (i = i0; i < i1; ++i) {
        if (s = grid[o + i]) {
          var s,
              dx = s[0] - x,
              dy = s[1] - y;
          if (dx * dx + dy * dy < radius2) return false;
        }
      }
    }

    return true;
  }

  function sample(x, y) {
    var s = [x, y];
    queue.push(s);
    grid[gridWidth * (y / cellSize | 0) + (x / cellSize | 0)] = s;
    ++sampleSize;
    ++queueSize;
    return s;
  }
}

</script>

## thumbnail.png

      
    Raw
  

              thumbnail.png
	<!DOCTYPE html>
	<meta charset="utf-8">
	<style>
	body: {
	position:fixed;
	top:0; bottom: 0;
	left: 0; right: 0;
	}
	canvas {
	width: 100%;
	height: 100%;
	position:absolute;
	top:0;
	left: 0;
	}
	path {
	fill: #fff;
	stroke: #de4459;
	}
	path:nth-child(2n+1) {

	fill: #de4459;
	}
	</style>
	<body>
	<script src="//d3js.org/d3.v3.min.js"></script>

	<canvas></canvas>
	<script>

	var bbox = d3.select("body").node().getBoundingClientRect();
	var width = bbox.width,
	height = bbox.height;

	var r = 8;
	var sample = poissonDiscSampler(width, height, r);

	var svg = d3.select("body").append("svg")
	.attr("width", width)
	.attr("height", height);

	var grid;
	var points = [[width/2, height/2]];

	var voronoi = d3.geom.voronoi();

	d3.timer(function(elapsed) {
	var mod = -2
	+ 100 * Math.sin(elapsed * Math.PI*2)
	- 5 * Math.cos(elapsed * Math.PI)
	;
	for (var i = 0; i < 10; ++i) {
	var s = sample(r + mod);
	if (!s) {

	renderVoronoi();
	svg.selectAll("circle")
	.remove()
	return true;
	}
	svg.append("circle")
	.attr("cx", s[0])
	.attr("cy", s[1])
	.attr("r", 0)
	.transition()
	.attr("r", 2);
	}
	//console.log(elapsed)
	});

	function renderVoronoi() {
	var canvas = d3.select("canvas").node();
	canvas.width = width;
	canvas.height = height;
	var context = canvas.getContext('2d');

	var noids = voronoi(points);
	/*
	for (var i = 1, n = noids.length; i < n; ++i) {
	draw(noids[i]);
	context.stroke();
	}
	*/
	console.log("noids",noids)
	var cells = svg.selectAll("path.cell").data(noids)
	cells.enter().append("path")
	.attr("d", function(d) {
	if(!d) return;
	return "M" + d.join("L") + "Z";
	})

	function draw(cell) {
	if (cell) {
	context.beginPath();
	context.moveTo(cell[0][0], cell[0][1]);
	for (var j = 1, m = cell.length; j < m; ++j) {
	context.lineTo(cell[j][0], cell[j][1]);
	}
	context.closePath();
	return true;
	}
	}
	}

	// Based on https://www.jasondavies.com/poisson-disc/
	function poissonDiscSampler(width, height, radius) {
	var k = 30; // maximum number of samples before rejection
	var radius2 = radius * radius;
	var R = 3 * radius2
	var cellSize = radius * Math.SQRT1_2
	var gridWidth = Math.ceil(width / cellSize)
	var gridHeight = Math.ceil(height / cellSize)
	grid = new Array(gridWidth * gridHeight)
	var queue = []
	var queueSize = 0
	var sampleSize = 0

	return function(newRadius) {
	radius2 = newRadius * newRadius;
	R = 3 * radius2
	cellSize = radius * Math.SQRT1_2;

	if (!sampleSize) return sample(Math.random()width,Math.random()height);

	// Pick a random existing sample and remove it from the queue.
	while (queueSize) {
	var i = Math.random() * queueSize \| 0,
	s = queue[i];

	// Make a new candidate between [radius, 2 * radius] from the existing sample.
	for (var j = 0; j < k; ++j) {
	var a = 2 * Math.PI * Math.random(),
	rad = Math.sqrt(Math.random() * R + radius2),
	x = s[0] + rad * Math.cos(a) * Math.random(),
	y = s[1] + rad * Math.sin(a) * Math.random();

	// Reject candidates that are outside the allowed extent,
	// or closer than 2 * radius to any existing sample.
	if (0 <= x && x < width && 0 <= y && y < height && far(x, y)) {
	points.push([x,y])
	return sample(x, y);
	}
	}

	queue[i] = queue[--queueSize];
	queue.length = queueSize;
	}
	};

	function far(x, y) {
	var i = x / cellSize \| 0,
	j = y / cellSize \| 0,
	i0 = Math.max(i - 2, 0),
	j0 = Math.max(j - 2, 0),
	i1 = Math.min(i + 3, gridWidth),
	j1 = Math.min(j + 3, gridHeight);

	for (j = j0; j < j1; ++j) {
	var o = j * gridWidth;
	for (i = i0; i < i1; ++i) {
	if (s = grid[o + i]) {
	var s,
	dx = s[0] - x,
	dy = s[1] - y;
	if (dx * dx + dy * dy < radius2) return false;
	}
	}
	}

	return true;
	}

	function sample(x, y) {
	var s = [x, y];
	queue.push(s);
	grid[gridWidth * (y / cellSize \| 0) + (x / cellSize \| 0)] = s;
	++sampleSize;
	++queueSize;
	return s;
	}
	}

	</script>
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