rollerderby-track/track.js

282 lines
7.3 KiB
JavaScript

/*
* LADD Roller Derby Track
* Copyright © 2012 Neale Pickett <neale@woozle.org>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
var canvas;
var ctx;
var scale;
var tau = Math.PI * 2;
// Measurements from Appendix B, 2010 rulebook
var ri = 12.5;
var ro = 26.5;
var halflen = 17.5;
var offset = 1.0; // How far off-center the outer circle is
var curve_d = 7 + (0.5/12); // Distance between lines in curves
var theta = Math.acos(1 - (curve_d * curve_d) / (2 * ri * ri));
var rp = 1; // Radius of a piece
var JAMMER = 0;
var PIVOT = 1;
var players = [];
function debug(msg) {
var e = document.getElementById("debug");
e.innerHTML = msg;
}
var b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.,';
function aenc(i) {
var neg = i < 0;
i = Math.max(Math.min(i, 127), -127);
i = Math.round(Math.abs(i) * 16);
var al = i & 0x3f;
var ah = (i >> 6) | (neg?0x20:0);
return b64.charAt(ah) + b64.charAt(al);
}
function adec(s) {
var ah = b64.indexOf(s[0]);
var al = b64.indexOf(s[1]);
var neg = (ah & 0x20);
var i = ((ah & 0x1f) << 6) | al;
return i * (neg?-1:1) / 16;
}
function player(color, pos) {
var e = document.createElement("canvas");
var ctx = e.getContext("2d");
var body = document.getElementsByTagName("body")[0];
var midpoint = rp + 0.5;
e.enc = function() {
return aenc(e.pos[0]) + aenc(e.pos[1]);
}
e.dec = function(s) {
var x = adec(s.substr(0, 2));
var y = adec(s.substr(2, 2));
e.moveTo(x, y);
}
e.moveTo = function(x, y) {
var wx = ((x - midpoint) * scale) + window.innerWidth/2;
var wy = (y - midpoint) * scale + canvas.height/2;
e.pos = [x, y];
e.style.left = wx + "px";
e.style.top = wy + "px";
}
var moved = false;
function mouseMove(evt) {
var x = (evt.pageX - window.innerWidth/2) / scale;
var y = (evt.pageY - canvas.height/2) / scale;
e.moveTo(x, y);
moved = true;
}
function drop() {
if (! moved) {
e.onmouseup = null;
e.onmousedown = null;
e.onclick = drop;
return;
}
var l = document.getElementById("link");
var positions = '';
for (var i = 0; i < players.length; i += 1) {
positions += players[i].enc();
}
l.href = "#" + positions;
e.style.backgroundColor = "inherit";
window.onmousemove = null;
e.onmousedown = lift;
e.onclick = null;
}
function lift() {
moved = false;
window.onmousemove = mouseMove;
e.style.backgroundColor = "rgba(255, 255, 0, 0.5)";
e.onmouseup = drop;
}
e.onmousedown = lift;
players.push(e);
body.appendChild(e);
e.style.position = "absolute";
e.moveTo(0, 0);
// Draw it
e.width = scale * (midpoint*2);
e.height = scale * (midpoint*2);
ctx.scale(scale, scale);
ctx.translate(midpoint, midpoint);
ctx.lineWidth = 2/12;
ctx.strokeStyle = "#fff";
ctx.fillStyle = color;
ctx.beginPath();
ctx.arc(0, 0, rp, 0, tau);
ctx.closePath();
ctx.fill();
ctx.stroke();
if (pos == PIVOT) {
ctx.fillStyle = "#fff";
ctx.beginPath();
ctx.arc(0, 0, rp, tau*31/32, tau* 1/32);
ctx.arc(0, 0, rp, tau*15/32, tau*17/32);
ctx.closePath();
ctx.fill();
} else if (pos == JAMMER) {
ctx.save();
ctx.fillStyle = "#fff";
ctx.beginPath();
ctx.rotate(tau/2);
ctx.moveTo(0, rp);
for (var i = 0; i < 5; i += 1) {
ctx.rotate(tau/10);
ctx.lineTo(0, rp * 0.4);
ctx.rotate(tau/10);
ctx.lineTo(0, rp);
}
ctx.fill();
ctx.restore();
} else {
// android doesn't scale text :<
ctx.scale(1/scale, 1/scale);
ctx.fillStyle = "#fff";
ctx.font = (scale) + "px sans-serif";
ctx.fillText(pos, -0.25 * scale, 0.25 * scale);
}
return e;
}
function drawTrack(ctx) {
ctx.beginPath();
ctx.arc( halflen, -offset, ro, tau*3/4, tau*1/4);
ctx.arc(-halflen, offset, ro, tau*1/4, tau*3/4);
ctx.lineTo( halflen, -offset - ro);
ctx.moveTo( halflen, -ri);
ctx.lineTo(-halflen, -ri);
ctx.arc(-halflen, 0, ri, tau*3/4, tau*1/4, true);
ctx.arc( halflen, 0, ri, tau*1/4, tau*3/4, true);
ctx.closePath();
}
function start() {
canvas = document.getElementById("canvas");
ctx = canvas.getContext("2d");
scale = Math.min(window.innerWidth / 100, (window.innerHeight - 20) / 60);
canvas.width = scale * 100;
canvas.height = scale * 60;
// Set things up so all measurements are in feet.
// This gives a 6-foot vertical border on each side,
// and a 2.5-foot horizontal border on each side.
ctx.scale(scale, scale);
ctx.translate(50, 30);
// Draw track according to WFTDA 2010 rulebook, Appendix B
// Fill in track area
ctx.fillStyle = "#888";
drawTrack(ctx);
ctx.fill();
// A bunch of lines
ctx.lineWidth = 1/12;
ctx.strokeStyle = "rgba(0, 0, 0, 0.4)";
ctx.beginPath();
for (var i = 0; i < 4; i += 1) {
ctx.moveTo(halflen - i*10, ri);
ctx.lineTo(halflen - i*10, ro + offset);
ctx.moveTo(i*10 - halflen, -ri);
ctx.lineTo(i*10 - halflen, -ro - offset);
}
for (var j = 0; j < 2; j += 1) {
ctx.save();
ctx.translate(halflen * (j?-1:1), 0);
ctx.rotate(j*tau/2);
for (var i = 0; i < 5; i += 1) {
ctx.rotate(-theta);
ctx.moveTo(0, ri);
ctx.lineTo(0, 12.5 + 15.0);
}
ctx.restore();
}
ctx.stroke();
// Pivot and Jammer lines
ctx.lineWidth = 4/12;
ctx.strokeStyle = "#000";
ctx.beginPath();
ctx.moveTo(halflen , ri);
ctx.lineTo(halflen , ro - offset);
ctx.moveTo(halflen - 30, ri);
ctx.lineTo(halflen - 30, ro + offset);
ctx.stroke();
// Now draw track boundaries
ctx.lineWidth = 4/12;
ctx.strokeStyle = "#ff0";
ctx.fillStyle = "#000";
drawTrack(ctx);
ctx.stroke();
var positions = location.hash.substr(1);
for (var team = 0; team < 2; team += 1) {
for (var pos = 0; pos < 5; pos += 1) {
var p = player(team?"#080":"#f0f", pos);
if (positions) {
var s = positions.substr(4*(team*5 + pos), 4);
p.dec(s)
} else if (pos == JAMMER) {
p.moveTo(halflen - 30 - rp, ri + rp*(team*4 + 4));
} else {
p.moveTo(halflen-rp - team * (rp*3), ri + rp*(2.5*pos));
}
}
}
}
window.onload = start;