function P(b,e){c[e?'stroke':'fill'](c.arc(b[0]+=(b[0]>W?-W:b[0]<0?W:0)+b[3],b[1]+=(b[1]>H?-H:b[1]<0?H:0)+b[4],b[5],e?0:b[2]-2,e?6.3:b[2]+2,c.beginPath()))}function T(b,e){return M.sqrt(M.pow(b[0]-a[0],2)+M.pow(b[1]-a[1],2))<a[5]+b[5]}function L(){c.clearRect(0,0,W,H);i=u?.2:d?-.08:0;p[3]=p[3]*.986+X(t=p[2]+=l?-.12:r?.12:0)*i;p[4]=p[4]*.986+Y(t)*i;P(p);for(i=7;i--;x|=T(p)){P(a=A[i]=A[i]||[p[0]+W/4+R()*W/2,p[1]+H/4+R()*H/2,t=R()*6.3,X(t),Y(t),R()*40+20],1);for(n in G)T(g=G[n])?s+=g[6]|G.splice(n,1)|A.splice(i,1):i?0:--g[6]?P(g):G.shift()}c.fillText("Score: "+s,5,14);x?alert("GameOver"):setTimeout(L,17)}L(D=document,C=D.body.children[0],C.style.position='fixed',C.width=W=innerWidth,C.height=H=innerHeight,c=C.getContext('2d'),M=Math,R=M.random,X=M.cos,Y=M.sin,p=[W/2,H/2,0,0,0,10],A=[],G=[],a=g=l=u=r=d=z=i=n=t=x=s=0,D.onkeyup=K=function(b,e){t=b.keyCode-32;t?t-5?t-6?t-7?t-8?0:d=e:r=e:u=e:l=e:z=z|!e?e:G.push([p[0],p[1],t=p[2],p[3]+X(t)*14,p[4]+Y(t)*14,4,30])},D.onkeypress=D.onkeydown=function(b){K(b,1);return!1})
/**
* move and draw an object to the canvas
*/
function P(o/*object*/, a/*isAsteroid=false*/)
{
c[a ? 'stroke' : 'fill'](
c.arc(
o[0] += (o[0] > W ? -W : o[0] < 0 ? W : 0) + o[3],
o[1] += (o[1] > H ? -H : o[1] < 0 ? H : 0) + o[4],
o[5],
a ? 0 : o[2] - 2,
a ? 6.3 : o[2] + 2,
c.beginPath()
)
)
}
/**
* hittest object against Asteroid(which is 'a')
*/
function T(o/*object*/, r/*objectRadius*/)
{
return M.sqrt(M.pow(o[0] - a[0], 2) + M.pow(o[1] - a[1], 2)) < a[5] + o[5]
}
//main loop
function L()
{
//clear the canvas
c.clearRect(0, 0, W, H);
//update the Player
i = u ? .2 : d ? -.08 : 0;
p[3] = p[3] * .986 + X(t = p[2] += l ? -.12 : r ? .12 : 0) * i;
p[4] = p[4] * .986 + Y(t) * i;
//draw the Player
P(p);
//loop through the Asteroids
for (i = 7; i--; /*hittest Asteroid against the Player*/ x |= T(p))
{
//draw an Asteroid
P(
//create an Asteroid if there are less than 7 alive
a = A[i] = A[i] || [
p[0] + W/4 + R() * W/2, //posX (1/4 to 3/4 of the stage away from the player)
p[1] + H/4 + R() * H/2, //posY (1/4 to 3/4 of the stage away from the player)
t = R() * 6.3, //direction
X(t), //deltaX
Y(t), //deltaY
R() * 40 + 20 //radius (20-60)
],
1
);
//loop through the Bullets for hittests
for (n in G)
//hittest Asteroid against the Bullet
T(g = G[n]) ?
//if true
s += g[6] | //add score
G.splice(n, 1) | //remove Bullet
A.splice(i, 1) //remove Asteroid
:
//if false check if we are 'not' in the last loop of Asteroids
i ?
//if true do nothing
0
:
//if false check if frames are left
--g[6] ?
//if true draw the Bullet
P(g)
:
//if false remove the Bullet
G.shift()
}
//draw the score
c.fillText("Score: " + s, 5, 14);
//check for gameover
x ? alert("GameOver") : setTimeout(L, 17)
}
L(
//init vars
D = document,
C = D.body.children[0], //canvas
C.style.position = 'fixed',
C.width = W = innerWidth,
C.height = H = innerHeight,
c = C.getContext('2d'), //context
M = Math,
R = M.random,
X = M.cos,
Y = M.sin,
p = [W/2, H/2, 0, 0, 0, 10],//Player [posX, posY, direction, deltaX, deltaY, radius]
A = [], //Asteroids [[posX, posY, direction, deltaX, deltaY, radius]]
G = [], //Bullets [[posX, posY, direction, deltaX, deltaY, radius, framesleft]]
a = //single Asteroid
g = //single Bullet
l = u = r = d = z = //keyflags l=left, u=up, r=right, d=down
i = n = t = //tmp vars
x = //gameover flag
s = 0, //score
//init key events
D.onkeyup = K = function(e, f)
{
t = e.keyCode - 32;
//update the pressed key flag
t ?
t - 5 ?
t - 6 ?
t - 7 ?
t - 8 ? 0 : d = f
: r = f
: u = f
: l = f
: z =
z | !f ?
f
://fire a Bullet
G.push([
p[0], //posX
p[1], //posY
t = p[2], //direction
p[3] + X(t) * 14, //deltaX
p[4] + Y(t) * 14, //deltaY
4, //radius
30 //framesleft
])
},
D.onkeypress = D.onkeydown = function(e)
{
//update the pressed key flag to true
K(e, 1);
//return false for opera
return !1
}
)
