inertia slightly off [UNLISTED]

By changing the scale and clip angle of an orthographic projection, this example creates two concentric spheres to give the appearance of floating landmasses. Inspired by Derek Watkin’s Faux-3D Arcs.

forked from mbostock's block: Floating Landmasses

Now also using d3-inertia.

forked from Fil's block: Floating Landmasses in d3v4

forked from enjalot's block: inertia slightly off

<!DOCTYPE html>
<meta charset="utf-8">
<style>

body {
  background: #fcfcfa;
}

canvas {
  position: absolute;
  top: 0;
  left: 0;
  cursor: move;
  cursor: drag;
}

.blur {
  -webkit-filter: blur(6px);
  filter: blur(6px);
}

</style>
<body>
<script src="https://unpkg.com/d3"></script>
<script src="https://unpkg.com/topojson"></script>
<script src="https://unpkg.com/versor"></script>
<script src="https://unpkg.com/d3-inertia"></script>
<script>

var width = 960,
    height = 960,
    speed = -1e-2,
    start = Date.now();

var sphere = {type: "Sphere"};

var projection = d3.geoOrthographic()
    .translate([width / 2, height / 2])
    .precision(.5)
.rotate([-70, -25]);
  
var projection2 = d3.geoOrthographic()
    .translate([width / 2, height / 2])
    .precision(.5)
.rotate([-70, -25])

var graticule = d3.geoGraticule();

var canvas1 = d3.select("body").append("canvas"),
    canvas2 = d3.select("body").append("canvas").attr("class", "blur"),
    canvas3 = d3.select("body").append("canvas");

d3.selectAll("canvas")
    .attr("width", width)
    .attr("height", height);

var context1 = canvas1.node().getContext("2d"),
    context2 = canvas2.node().getContext("2d"),
    context3 = canvas3.node().getContext("2d");

var path = d3.geoPath()
  .projection(projection);

projection.scale(width / 2.3).clipAngle(90);
projection2.scale(width / 2.3).clipAngle(90);

context1.beginPath();
path.context(context1)(sphere);
context1.lineWidth = 3;
context1.strokeStyle = "#000";
context1.stroke();

context1.beginPath();
path(sphere);
context1.fillStyle = "#fff";
context1.fill();

context2.fillStyle = "rgba(0,0,0,.4)";
context3.strokeStyle = "rgba(0,0,0,.2)";

var render = function(){};

function draw() {
  render();
}
  
d3.json("https://unpkg.com/world-atlas/world/110m.json", function(error, topo) {
  if (error) throw error;

var land = topojson.feature(topo, topo.objects.land),
      grid = graticule();

render = function() {
    var r = projection.rotate();
    if (inertia.t) {
      var t = inertia.t * (1-inertia.t);
      projection.rotate([r[0] + 90 * t, r[1] + 90 * t, r[2]]); 
    }
    context2.clearRect(0, 0, width, height);
    context3.clearRect(0, 0, width, height);
    
    projection.scale(width / 2.3).clipAngle(90);
    // shadow
    context2.beginPath();
    path.context(context2)(land);
    context2.fill();

//grid
    context3.beginPath();
    path.context(context3)(grid);
    context3.lineWidth = .5;
    context3.stroke();

projection.scale(width / 2.2).clipAngle(106.3);

context3.beginPath();
    // underside
    projection.rotate(r);
    path(land);
    context3.fillStyle = "#737368";
    context3.fill();

projection.scale(width / 2.2).clipAngle(90);
    
    context3.beginPath();
    //topside 
    path(land);
    context3.fillStyle = "#dadac4";
    context3.fill();
    
  };
  
  render();
});

var inertia = d3.geoInertiaDrag(canvas3, draw, projection);

d3.timer(function(e){
    if (inertia.timer) return;
    draw();
  })
  
d3.select(self.frameElement).style("height", height + "px");

</script>

https://unpkg.com/d3

https://unpkg.com/topojson

https://unpkg.com/versor

https://unpkg.com/d3-inertia