The full version of the bullet tracking aircraft is provided here. The bullet will keep tracking until it hits the plane. After the call, a message is displayed, indicating a few seconds of persistence.
There is a small bug. After hitting it, It is prompted first and then red. You can change it to red first, and then prompt again.
In addition, it can be changed to a bullet that automatically disappears after 10 s of flight (re-start again)
You can also change the speed to + 1 per second;
<! Doctype HTML>
<HTML>
<Head>
<Title> full version of smart bullets </title>
<SCRIPT type = "text/JavaScript" src = "jquery-1.6.1.js"> </SCRIPT>
<SCRIPT type = "text/JavaScript">
VaR x = 225;
Var y = 450;
VaR mousex, Mousey;
VaR canvas;
VaR CTX;
VaR C = 0;
VaR Zidan = new object ();
$ (Document). Ready (function (){
Canvas = $ (document). Get (0). getelementbyid ("mycanvas ");
If (canvas. getcontext ){
CTX = canvas. getcontext ("2D ");
Zidan. x = 245;
Zidan. Y = 10;
Zidan. jiaodu = math. Pi * 0.5;
Zidan. Sudu = 10;
Zidan. dadao = 0; // 0 indicates that no call is made, and 1 indicates that no call is made.
Animate ();
}
});
Zidan. Move = function (){
If (Y-Zidan. Y> 0)
{
Zidan. Y = Zidan. Y + math. Abs (Zidan. Sudu * Math. Cos (Zidan. jiaodu ));
}
Else
{
Zidan. Y = Zidan. Y-math. Abs (Zidan. Sudu * Math. Cos (Zidan. jiaodu ));
}
If (X-Zidan. x> 0)
{
Zidan. x = Zidan. x + math. Abs (Zidan. Sudu * Math. Sin (Zidan. jiaodu ));
}
Else
{
Zidan. x = Zidan. X-math. Abs (Zidan. Sudu * Math. Sin (Zidan. jiaodu ));
}
// Exceeds the bottom boundary
If (zidan. y> 500)
Zidan. Y = 10;
// Add a judgment that exceeds the upper left and right boundary
// If (Zidan. Y = 10)
Zidan. jiaodu = math. atan (X-Zidan. X)/(Y-Zidan. y ));
};
Function animate ()
{
CTX. clearrect (0, 0,500,500 );
// The square controlled by the keyboard
If (Zidan. dadao = 1)
CTX. fillstyle = "red ";
CTX. fillrect (X, Y, 50, 50 );
CTX. fillstyle = "black ";
CTX. beginpath ();
CTX. ARC (Zidan. X, Zidan. Y, 10, 0, math. Pi * 2, false );
CTX. closepath ();
CTX. Fill ();
If (Zidan. dadao = 0)
SetTimeout (animate, 100 );
// Animation logic. If the bullet is in a straight line and beyond the range, set it to 10 again.
Zidan. Move ();
// Collision detection. If hit, the square turns red and the game stops.
If (Zidan. y> Y) & (Zidan. Y <Y + 50) & (Zidan. x> X) & (Zidan. x <X + 50 ))
{
Zidan. dadao = 1;
Alert (C/10 );
}
C = C + 1;
};
</SCRIPT>
</Head>
<Body>
<Div>
<Canvas id = "mycanvas" width = "500" Height = "500"> </canvas>
</Div>
</Body>
<SCRIPT type = "text/JavaScript">
// Note that this is document, and canvas should be able to capture the keydown event. Try again later.
$ (Document). keydown (function (e ){
VaR K = E. keycode;
// If you do not know the key code, use alert to output it.
// Alert (k );
If (k = 37)
X = x-10;
If (k = 39)
X = x + 10;
If (k = 38)
Y = Y-10;
If (k = 40)
Y = Y + 10;
});
</SCRIPT>
</Html>
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