3D Basics - HTML5 Animation with JavaScript - page 356

trees = [],
numTrees = 100,
fl = 250,
vpX = canvas.width / 2,
vpY = canvas.height / 2,
floor = 50,
ax = 0,
ay = 0,
az = 0,
vx = 0,
vy = 0,
vz = 0,
gravity = 0.3,
friction = 0.95;
for (var tree, i = 0; i < numTrees; i++) {
tree = new Tree();
tree.xpos = Math.random() * 2000 - 1000;
tree.ypos = floor;
tree.zpos = Math.random() * 10000;
trees.push(tree);
}
window.addEventListener('keydown', function (event) {
switch (event.keyCode) {
case 38: //up
az = -1;
break;
case 40: //down
az = 1;
break;
case 37: //left
ax = 1;
break;
case 39: //right
ax = -1;
break;
case 32: //space
ay = 1;
break;
}
}, false);
window.addEventListener('keyup', function (event) {
switch (event.keyCode) {
case 38: //up
case 40: //down
az = 0;
break;
case 37: //left
case 39: //right
ax = 0;
break;