metanohi-misc-subsites/nohix/videocanvas3.js

58 lines
1.4 KiB
JavaScript

// Code layout taken from http://www.mozbox.org/pub/green/main.js
var processor = {
doLoad: function() {
this.video = document.getElementById("video");
this.c1 = document.createElement("canvas");
this.c1.width = "160"
this.c1.height = "96"
this.ctx1 = this.c1.getContext("2d");
this.c2 = document.getElementById("c2");
this.ctx2 = this.c2.getContext("2d");
var self = this;
this.video.addEventListener("play", function() {
self.width = self.video.videoWidth / 2;
self.height = self.video.videoHeight / 2;
self.len = self.width * self.height;
self.video.addEventListener('timeupdate', function(event) {
self.computeFrame()
}, true);
}, false);
},
computeFrame: function() {
var frame, data, i, j, rgba
this.ctx1.drawImage(this.video, 0, 0, this.width, this.height);
frame = this.ctx1.getImageData(0, 0, this.width, this.height);
data = frame.data;
for (i = 0; i < this.len; i++) {
rgba = data.getPixel(i);
for (j = 0; j < 3; j++) {
data.setPixel(i, j, rgba[Math.floor(Math.random()*3)]);
}
}
this.ctx2.putImageData(frame, 0, 0);
return;
}
};
Array.prototype.getPixel = function(number) {
var real = number * 4;
return this.slice(real, real + 4);
};
Array.prototype.setPixel = function(number, rgba, val) {
var real = number * 4 + rgba;
if (number < 0 || real > this.length)
return;
this[real] = val;
};