{"id":358,"date":"2009-07-26T15:31:24","date_gmt":"2009-07-26T22:31:24","guid":{"rendered":"https:\/\/actionsnippet.com\/?p=1845"},"modified":"2009-07-26T15:31:24","modified_gmt":"2009-07-26T22:31:24","slug":"quick-pixel-sphere","status":"publish","type":"post","link":"https:\/\/actionsnippet.com\/?p=358","title":{"rendered":"Quick Pixel Sphere"},"content":{"rendered":"<pre class=\"brush: as3; title: ; notranslate\" title=\"\">\r\nvar pointNum:int = 20000;\r\nvar radius:int = 150;\r\n\r\nvar canvas:BitmapData = new BitmapData(400,400,false, 0x000000);\r\naddChild(new Bitmap(canvas));\r\nvar verts:Vector.&lt;Number&gt;  = new Vector.&lt;Number&gt;();\r\nvar pVerts:Vector.&lt;Number&gt; = new Vector.&lt;Number&gt;();\r\nvar uv:Vector.&lt;Number&gt; = new Vector.&lt;Number&gt;();\r\n\r\nfor (var i:int = 0; i&lt;pointNum; i+=3){\r\n\tvar xp:Number = Math.random() * 400 - 200;\r\n\tvar yp:Number = Math.random() * 400 - 200;\r\n\tvar zp:Number = Math.random() * 400 - 200;\r\n\tvar dist:Number = Math.sqrt(xp * xp + yp * yp + zp * zp);\r\n\t\/\/ normalize and scale x,y,z \r\n\tverts&#x5B;i] = xp \/ dist * radius;\r\n\tverts&#x5B;i+1] = yp \/ dist * radius;\r\n\tverts&#x5B;i+2] = zp \/ dist * radius;\r\n}\r\n\r\nvar m:Matrix3D = new Matrix3D();\r\nvar dx:Number = 0, dy:Number = 0;\r\naddEventListener(Event.ENTER_FRAME, onLoop);\r\nfunction onLoop(evt:Event):void {\r\n       m.identity();\r\n\t   dx += (mouseX - dx) \/ 4;\r\n\t   dy += (mouseY - dy) \/ 4;\r\n\t   m.appendRotation(dx, Vector3D.X_AXIS);\r\n\t   m.appendRotation(dy, Vector3D.Y_AXIS);\r\n\t   m.appendTranslation(200,200,0);\r\n\t   Utils3D.projectVectors(m, verts, pVerts, uv);\r\n\t   canvas.fillRect(canvas.rect, 0x000000);\r\n\t   for (var i:int = 0; i&lt;pVerts.length; i+=2){\r\n\t     canvas.setPixel(pVerts&#x5B;i], pVerts&#x5B;i + 1], 0xFFFFFF);\r\n\t   }\r\n}\r\n<\/pre>\n<p>This snippet shows a quick way to randomly place a bunch of xyz coordinates on the surface of a sphere. I saw this trick in an OpenGL book a few years back &#8211; dug around my books but couldn&#8217;t find it&#8230; If I find it I&#8217;ll update this post.<\/p>\n<p>The trick is achieved by <a href=\"http:\/\/www.fundza.com\/vectors\/normalize\/index.html\" target=\"blank\">normalizing the vector<\/a> defined by each 3D coordinate&#8230;<\/p>\n<p><a data-asruffle-linked=\"true\" href=\"http:\/\/www.actionsnippet.com\/swfs\/pix_sphere.html\" target=\"blank\"><br \/>\nHave a look at the swf&#8230;<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/actionsnippet.com\/wp-content\/pix_sphere.jpg\" \/><\/a> <span class=\"asruffle-link\" data-swf=\"{&quot;url&quot;:&quot;https:\\\/\\\/actionsnippet.com\\\/swfs\\\/pix_sphere.swf&quot;,&quot;title&quot;:&quot;pix sphere&quot;,&quot;width&quot;:800,&quot;height&quot;:600,&quot;missing&quot;:false,&quot;allowScriptAccess&quot;:false,&quot;backgroundColor&quot;:&quot;#ffffff&quot;}\"><button type=\"button\" hidden aria-expanded=\"false\">Play demo<span class=\"screen-reader-text\">: pix sphere<\/span><\/button><\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>var pointNum:int = 20000; var radius:int = 150; var canvas:BitmapData = new BitmapData(400,400,false, 0x000000); addChild(new Bitmap(canvas)); var verts:Vector.&lt;Number&gt; = new Vector.&lt;Number&gt;(); var pVerts:Vector.&lt;Number&gt; = new Vector.&lt;Number&gt;(); var uv:Vector.&lt;Number&gt; = new Vector.&lt;Number&gt;(); for (var i:int = 0; i&lt;pointNum; i+=3){ var xp:Number = Math.random() * 400 &#8211; 200; var yp:Number = Math.random() * 400 &#8211; 200; var [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101,24,121,118,26],"tags":[3,14,4],"class_list":["post-358","post","type-post","status-publish","format-standard","hentry","category-3d","category-bitmapdata","category-math","category-matrix","category-setpixel","tag-actionscript","tag-as3","tag-flash"],"_links":{"self":[{"href":"https:\/\/actionsnippet.com\/index.php?rest_route=\/wp\/v2\/posts\/358","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/actionsnippet.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/actionsnippet.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/actionsnippet.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/actionsnippet.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=358"}],"version-history":[{"count":0,"href":"https:\/\/actionsnippet.com\/index.php?rest_route=\/wp\/v2\/posts\/358\/revisions"}],"wp:attachment":[{"href":"https:\/\/actionsnippet.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=358"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/actionsnippet.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=358"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/actionsnippet.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=358"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}