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@ptvans
Created August 4, 2012 06:23
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just another inlet to tributary
//laser math
//http://spot.colorado.edu/~lessley/pdf%20stuff/lasermath2.pdf
d3.select("#header").style("background-color","#000000")
var x0 = 394;
var y0 = 340;
var a = 489;
var b = 98;
//var b = (n-1)/(n+10);
var hx = -1155;
var hy = -352;
var fbase = 317.06738;
var omega0 = 23 * Math.PI * fbase;
var om = omega0 * 0.32721;
var tempo = 0.001;
var erasing = 0.1;
var linen = 190;
var cs = d3.interpolateHsl("#3F4DEC", "#0CE97F");
var sopacity = 0.32032;
var cf = d3.interpolateHsl("#004FF8", "#FF1F00");
var fopacity = 0.9;
var radius = 23;
var nt = 200;
var to = 0.296;
function x(t, o) {
//return (a - b) * Math.cos(omega0*t) + h * Math.cos(omega0*t*(a/b-1));
return (a - b) * Math.tan(o*t) + hx * Math.cos(o*t*(a-b)/b);
//return h * Math.cos(t*Math.PI);
}
function y(t, o) {
//return (a - b) * Math.sin(omega0*t) - h * Math.sin(omega0*t*(a/b-1));
return (a - b) * Math.tan(o*t) - hy * Math.cos(o*t*(a-b)/b);
//return h * Math.sin(t*Math.PI);
}
function circle(ctx, p) {
//ctx.fillStyle = 'hsla(0,0%,' + 70 +'%,' + 1 + ')';
ctx.beginPath();
ctx.arc(p[0],p[1],radius,0,2*Math.PI);
ctx.fill();
}
function line(ctx) {
ctx.beginPath();
var i;
for(i=0;i<linen;i++) {
//ctx.strokeStyle = c(i/linen);
ctx.lineTo(x0 + x(i/linen, omega0), y0 + y(i/linen, omega0));
}
ctx.stroke();
}
tributary.init = function(ctx) {
d3.select("#display").style("background-color", "#000000")
ctx.globalCompositeOperation = 'source-over';
};
tributary.run = function(ctx,t) {
//tributary.clear(); //helper function to clear the canvas
ctx.fillStyle = "rgba(9,9,9," + erasing + ")";
ctx.fillRect(0,0,tributary.sw,tributary.sh);
var tt = (t % 10)/tempo;
var p;
ctx.strokeStyle = cs(tt);
line(ctx);
p = [x0 + x(tt, om), y0 + y(tt, om)];
ctx.fillStyle = cf(tt);
circle(ctx, p);
var i = 0;
for(i = 0; i < nt; i++) {
//p = [x0 + x(tt+i*tt/2, om), y0 + y(tt+i*tt/2, om)];
p = [x0 + x(tt+i*to, om), y0 + y(tt+i*to, om)];
ctx.fillStyle = cf(tt);
circle(ctx, p);
}
};
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