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Use transformvertices rather than creating array each time

pull/2983/head
Gordon Williams 2023-09-11 15:08:34 +01:00 committed by GitHub
parent 648cc11fdc
commit 1cec511879
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1 changed files with 11 additions and 10 deletions
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21
apps/astroid/asteroids.js
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@ -23,7 +23,16 @@ var SL = W/15; // ship side length
var AS = W/18; // asteroid radius
// radius of ship, assumed a circle inside equilateral traingle of side SS
// r = a / root 3 where a is length of equilateral triangle
var SR = SS / Math.sqrt(3);
var SR = SS / Math.sqrt(3);
var AST = [ // asteroid polygon as X/Y pairs
0 ,-1.5,
1 , 0,
0.5, 0,
0.5, 0.5,
0 , 1,
-1 , 0,
-1 , -1
];
g.clear().setFontAlign(0,-1);
@ -148,15 +157,7 @@ function onFrame() {
a.y += a.vy*d;
//g.drawCircle(a.x, a.y, a.rad);
// a 7 point asteroid with rough circle radius of scale 2
g.drawPoly([
a.x , a.y - 1.5 * a.rad,
a.x + a.rad , a.y ,
a.x + a.rad/2 , a.y ,
a.x + a.rad/2 , a.y + a.rad/2 ,
a.x , a.y + a.rad ,
a.x - a.rad , a.y ,
a.x - a.rad , a.y - a.rad
],true);
g.drawPoly(g.transformVertices(AST,{x:a.x,y:a.y,scale:a.rad,rotate:t}),true);
if (a.x<0) a.x+=W;
if (a.y<0) a.y+=H;