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Refactored and optimized magic

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This commit is contained in:
Tyler Hallada
2014-07-19 22:42:43 -04:00
parent 2fa00b2929
commit 208a20f06f
3 changed files with 143 additions and 122 deletions
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256
js/magic.js
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@@ -1,5 +1,11 @@
window.onload = function () {
// Array to hold all active spells being drawn
var spells = [];
// Save this query here now that the page is loaded
var canvas = document.getElementById("magic");
/* Get the height and width of full document. To avoid browser
* incompatibility issues, choose the maximum of all height/width values.
*
@@ -37,7 +43,10 @@ window.onload = function () {
If the red, green, or blue value of the color is at 0 or 255 and the
gradient for that value is not zero, then the gradient for that value
will change signs. */
will change signs.
Unused for now. It turns out that changing the canvas stroke color is a
costly operation and slows things down a lot. */
function nextColor(color, gradient) {
var values = ["r", "g", "b"];
@@ -66,7 +75,7 @@ window.onload = function () {
"b": Math.floor(Math.random() * (255 + 1))};
}
function drawSplineSegment(branch, t, context) {
function drawSplineSegment(branch, context) {
var ax = (-branch.points[0].x + 3*branch.points[1].x - 3*branch.points[2].x + branch.points[3].x) / 6;
var ay = (-branch.points[0].y + 3*branch.points[1].y - 3*branch.points[2].y + branch.points[3].y) / 6;
var bx = (branch.points[0].x - 2*branch.points[1].x + branch.points[2].x) / 2;
@@ -76,16 +85,18 @@ window.onload = function () {
var dx = (branch.points[0].x + 4*branch.points[1].x + branch.points[2].x) / 6;
var dy = (branch.points[0].y + 4*branch.points[1].y + branch.points[2].y) / 6;
context.moveTo(
ax*Math.pow(t, 3) + bx*Math.pow(t, 2) + cx*t + dx,
ay*Math.pow(t, 3) + by*Math.pow(t, 2) + cy*t + dy
ax*Math.pow(branch.t, 3) + bx*Math.pow(branch.t, 2) + cx*branch.t + dx,
ay*Math.pow(branch.t, 3) + by*Math.pow(branch.t, 2) + cy*branch.t + dy
);
context.lineTo(
ax*Math.pow(t+0.2, 3) + bx*Math.pow(t+0.2, 2) + cx*(t+0.2) + dx,
ay*Math.pow(t+0.2, 3) + by*Math.pow(t+0.2, 2) + cy*(t+0.2) + dy
ax*Math.pow(branch.t+0.2, 3) + bx*Math.pow(branch.t+0.2, 2) + cx*(branch.t+0.2) + dx,
ay*Math.pow(branch.t+0.2, 3) + by*Math.pow(branch.t+0.2, 2) + cy*(branch.t+0.2) + dy
);
branch.t += 0.2;
}
function splitBranch(branch, new_branches) {
function splitBranch(branch) {
var newBranches = [];
// Replace with 2 new branches
for (var k = 0; k < 2; k++) {
@@ -100,7 +111,7 @@ window.onload = function () {
var y2 = branch.points[3].y - Math.cos(Math.PI * angle / 180) * length;
// Add to new branch array
new_branches.push({
newBranches.push({
points:new Array(
branch.points[1],
branch.points[2],
@@ -108,124 +119,54 @@ window.onload = function () {
{x:x2, y:y2}
),
angle:angle,
t:0,
});
}
return newBranches;
}
function createNewBranches(branches) {
// Create array to store next iteration of branchces
var new_branches = [];
// Iterate over each branch
for (var j in branches) {
splitBranch(branches[j], new_branches);
function cast(x, y, angle) {
// Find random position if not defined
if (x === undefined) {
x = Math.floor(Math.random() * (canvas.width + 1));
}
if (y === undefined) {
y = Math.floor(Math.random() * (canvas.height + 1));
}
if (angle === undefined) {
angle = Math.random() * 360;
}
return new_branches;
var color = pickRandomColor();
var colorString = "rgb(" + color.r + "," + color.g + "," + color.b + ")";
// Create new spell (branch)
spells.push({
branches:new Array({
points:new Array({x:x, y:y}, {x:x, y:y}, {x:x, y:y}, {x:x, y:y}),
angle:angle,
t:0,
}),
color:colorString,
duration:Math.floor(Math.random() * (600 - 50 + 1)) + 50,
});
}
/* Most of this funtion is provided by Maissan Inc. in their tutorial:
http://www.maissan.net/articles/simulating-vines */
function drawTendrils(context, x, y, iterations, sort, prune, prune_to) {
// Set stroke colour
function drawSpells(context, sort, prune, prune_to) {
var AnimationFrame = window.AnimationFrame;
AnimationFrame.shim();
var animationFrame = new AnimationFrame(30),
timeCounter = 0,
waitTime = 80,
lastCast = 0,
color,
gradient;
context.lineWidth = 0.5;
var color = pickRandomColor();
context.strokeStyle = "rgb(" + color.r + "," + color.g + "," + color.b + ")";
// Create initial branch
var branches = [];
branches.push({
points:new Array({x:x, y:y}, {x:x, y:y}, {x:x, y:y}, {x:x, y:y}),
angle:(Math.random() * 360),
});
// Start drawing splines at t=0
var t = 0;
// Drawing interval
var interval = setInterval(function() {
var gradient = pickGradient();
// Set stroke color
var newColor = nextColor(color, gradient);
color = newColor.color;
gradient = newColor.gradient;
context.strokeStyle = "rgb(" + color.r + "," + color.g + "," + color.b + ")";
context.beginPath();
// Draw branches
for (var i in branches) {
drawSplineSegment(branches[i], t, context);
}
context.stroke();
context.closePath();
// Advance t
t += 0.2;
// When finished drawing splines, create a new set of branches
if (t >= 1) {
var new_branches = createNewBranches(branches);
// If over 10 branches, prune the branches
if (prune) {
if (sort) {
while (new_branches.length > 20) new_branches.pop();
} else {
while (new_branches.length > prune_to) {
new_branches.splice(Math.floor(Math.random() * new_branches.length), 1);
}
}
}
// Replace old branch array with new
branches = new_branches;
// Restart drawing splines at t=0
t = 0;
}
// Count interations
iterations--;
if (iterations < 0) clearInterval(interval);
}, 32);
// Return interval
return interval;
}
function canvasClickHandler(event) {
var x = event.pageX;
var y = event.pageY;
var duration = Math.floor(Math.random() * (600 - 50 + 1)) + 50;
var canvas = document.getElementById("magic");
var context = canvas.getContext("2d");
var interval = drawTendrils(context, x, y, duration, false, true, 15);
}
function draw() {
var interval_time = 2000;
var metaInterval;
function cast() {
console.log(interval_time);
clearInterval(metaInterval);
// Go slower once started
if (interval_time === 2000) {
interval_time = 4000;
} else if (interval_time > 20000) {
return; // stop drawing
} else {
interval_time = interval_time * 1.1;
}
function animate(time) {
// resize canvas if document size changed
dimensions = getDocumentDimensions();
if ((dimensions.height !== canvas.height) ||
@@ -234,18 +175,89 @@ window.onload = function () {
canvas.width = dimensions.width;
}
// Find random position
var x = Math.floor(Math.random() * (canvas.width + 1));
var y = Math.floor(Math.random() * (canvas.height + 1));
var duration = Math.floor(Math.random() * (600 - 50 + 1)) + 50;
var interval = drawTendrils(context, x, y, duration, false, true, 15);
// if enough time has passed, cast another spell to draw
if ((timeCounter - lastCast) >= waitTime) {
if (waitTime > 500) {
return; // stop drawing
} else if (waitTime === 80){
waitTime = 125;
} else {
waitTime = waitTime * 1.1;
}
metaInterval = setInterval(cast, interval_time);
console.log("cast: " + waitTime);
lastCast = timeCounter;
if (waitTime === 125) {
cast(5, 5, 270); // start position
} else {
cast(undefined, undefined, undefined); // random spell position
}
}
// Draw branches
for (var i in spells) {
context.beginPath();
context.strokeStyle = spells[i].color;
if (spells[i].duration > 0) {
for (var j in spells[i].branches) {
drawSplineSegment(spells[i].branches[j], context);
// When finished drawing splines, create a new set of branches
if (spells[i].branches[j].t >= 1) {
var newBranches = splitBranch(spells[i].branches[j]);
// Replace old branch with two new branches
spells[i].branches.splice(j, 1);
spells[i].branches = spells[i].branches.concat(newBranches);
}
}
// If over 10 branches, prune the branches
if (prune) {
if (sort) {
while (spells[i].branches.length > prune_to) {
spells[i].branches.pop();
}
} else {
while (spells[i].branches.length > prune_to) {
spells[i].branches.splice(
Math.floor(Math.random() * spells[i].branches.length),
1);
}
}
}
context.stroke();
context.closePath();
spells[i].duration--;
} else {
spells.splice(i, 1); // spell is done now
}
}
timeCounter++;
frameId = animationFrame.request(animate);
}
// Drawing interval
var frameId = animationFrame.request(animate);
return frameId;
}
function canvasClickHandler(event) {
var x = event.pageX;
var y = event.pageY;
cast(x, y, undefined);
}
function draw() {
var interval_time = 2000;
// Initialize canvas
console.log("draw");
var canvas = document.getElementById("magic");
var dimensions = getDocumentDimensions();
console.log(dimensions.height);
console.log(dimensions.width);
@@ -259,7 +271,7 @@ window.onload = function () {
var context = canvas.getContext("2d");
// Cast magic spells
metaInterval = setInterval(cast, interval_time);
var frameId = drawSpells(context, false, true, 30);
}
}