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Groups > comp.lang.javascript > #34845
| From | Joao Rodrigues <groups_jr-1@yahoo.com.br> |
|---|---|
| Newsgroups | comp.lang.javascript |
| Subject | Re: Triying to do 3D in Javascript |
| Date | 2018-04-16 10:16 -0300 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <pb27mu$1mcd$1@gioia.aioe.org> (permalink) |
| References | <f268863c-f1a9-4337-8012-08454b2a639f@googlegroups.com> |
bit-naughty@hotmail.com wrote:
> Hi,
> I'm just trying to do some 3D in JS.
>
> All I want is for a triangle to rotate in 3D.
> Here is my code, what am I doing wrong?: (I'm just drawing a poly, rotating it around the Y axis, perspective projecting it,...and repeat..)
>
>
> Is this code even *right*? I'm not sure....
>
>
> <html>
>
>
> <head>
> <style>
>
> canvas {
> border: 1px solid black;
> }
> </style>
>
> <script>
>
>
>
> window.onload = function() {
> var canvas = document.getElementById("drawingCanvas");
> var context = canvas.getContext("2d");
>
> function drawpoly (twodpoly) {
>
> context.moveTo (twodpoly[0].x,twodpoly[0].y);
> context.lineTo (twodpoly[1].x,twodpoly[1].y);
> context.lineTo (twodpoly[2].x,twodpoly[2].y);
> context.closePath();
>
>
> context.fill();
>
>
> }
>
>
>
>
> var threedpoly = [
> {
> x:250,
> y:50,
> z:1
> },
>
> {
> x:50,
> y:250,
> z:1
> },
>
> {
> x:450,
> y:250,
> z:1
> }
> ];
>
>
>
>
> function perspproject(threedpoly) {
>
>
> var twodpoly = [{
> x:0,
> y:0
> },
>
> {
> x:0,
> y:0
> },
>
> {
> x:0,
> y:0
>
> }]
>
>
>
> for (var i=0; i<3; i++) {
>
>
> twodpoly[i].x = threedpoly[i].x/threedpoly[i].z ;
> twodpoly[i].y = (threedpoly[i].y/threedpoly[i].z) * -1 ;
>
> };
>
> return twodpoly;
>
> };
>
> function rotatethreedpoly(threedpoly, angle) {
>
> var rotatedthreedpoly = [
> {
> x:0,
> y:0,
> z:0
> },
>
> {
> x:0,
> y:0,
> z:0
> },
>
> {
> x:0,
> y:0,
> z:0
> }
> ];
>
>
> for (var i=0; i<3; i++) {
> rotatedthreedpoly[i].x = (Math.cos(angle) * threedpoly[i].x) + (Math.sin(angle) * threedpoly[i].z) ;
> rotatedthreedpoly[i].y = threedpoly[i].y ;
> rotatedthreedpoly[i].z = (Math.sin(angle) * threedpoly[i].x) + (Math.cos(angle) * threedpoly[i].z) ;
>
> }
>
> return rotatedthreedpoly ;
>
> };
>
>
>
>
> // DRAW SHIT - MAIN LOOP
>
>
> for (var i=1; i<360; i++) {
>
> var rad = i * 0.017453293;
>
>
> var foo = rotatethreedpoly(threedpoly, rad);
>
> var bar = perspproject(foo);
>
> drawpoly(bar);
>
> //context.clearRect(0, 0, canvas.width, canvas.height);
>
> }
>
>
>
>
> }
>
> </script>
> </head>
>
> <body>
> <canvas id = "drawingCanvas" width="500" height="300">
> </canvas>
> </body>
>
> </html>
>
Hopefully Mr. Know It All Thomas 'PointedEars' Lahn will answer your
question, after he stops bugging other participants LOL
--
Joao Rodrigues
Back to comp.lang.javascript | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Triying to do 3D in Javascript bit-naughty@hotmail.com - 2018-04-13 00:13 -0700
Re: Triying to do 3D in Javascript "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2018-04-13 14:07 -0700
Re: Triying to do 3D in Javascript bit-naughty@hotmail.com - 2018-04-14 07:34 -0700
Re: Triying to do 3D in Javascript Joao Rodrigues <groups_jr-1@yahoo.com> - 2018-04-14 15:01 -0300
Re: Triying to do 3D in Javascript "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-04-14 15:58 -0700
Re: Triying to do 3D in Javascript Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-04-15 01:06 +0200
Re: Triying to do 3D in Javascript "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2018-04-15 11:09 +0200
Re: Triying to do 3D in Javascript bit-naughty@hotmail.com - 2018-04-16 00:03 -0700
Re: Triying to do 3D in Javascript "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2018-04-16 11:14 +0200
Re: Triying to do 3D in Javascript Joao Rodrigues <groups_jr-1@yahoo.com> - 2018-04-15 11:11 -0300
Re: Triying to do 3D in Javascript Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-04-16 02:08 +0200
Re: Triying to do 3D in Javascript Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2018-04-16 10:02 -0300
Re: Triying to do 3D in Javascript Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-04-17 17:57 +0200
Re: Triying to do 3D in Javascript Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2018-04-17 14:19 -0300
Re: Triying to do 3D in Javascript Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-04-17 19:44 +0200
Re: Triying to do 3D in Javascript Gene Wirchenko <genew@telus.net> - 2018-04-17 11:22 -0700
Re: Triying to do 3D in Javascript Julio Di Egidio <julio@diegidio.name> - 2018-04-17 11:42 -0700
Re: Triying to do 3D in Javascript Jon Ribbens <jon+usenet@unequivocal.eu> - 2018-04-18 13:48 +0000
Re: Triying to do 3D in Javascript John G Harris <niam@jghnorth.org.uk.invalid> - 2018-04-17 19:27 +0100
Re: Triying to do 3D in Javascript Jon Ribbens <jon+usenet@unequivocal.eu> - 2018-04-18 13:48 +0000
Re: Triying to do 3D in Javascript "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2018-04-20 11:52 -0700
Re: Triying to do 3D in Javascript bit-naughty@hotmail.com - 2018-04-16 00:00 -0700
Re: Triying to do 3D in Javascript Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2018-04-16 10:16 -0300
Re: Triying to do 3D in Javascript Julio Di Egidio <julio@diegidio.name> - 2018-05-24 06:35 -0700
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