Comments on: Beginning WebGL step-by-step tutorial

By: SoHotCall

SoHotCall — Mon, 12 Dec 2011 03:12:40 +0000

Wow, needs so many lines of code just to draw a triangle..
Nice tutorial, anyway.
Next tutorial should be adding image texture to the triangle,
and then making simple animation..
—
@BabyRaptor: The code that is displayed here is not the complete code.
It is just the part, and you will need to add the etc.
The [complete] source file for this tutorial can be found at http://www.rozengain.com/files/webgl/tutorial/WebGLTutorial.html

By: Dennis

Dennis — Fri, 09 Dec 2011 10:49:58 +0000

@BabyRaptor: … and thank you for your constructive criticism. I create tutorials and I build free, open source frameworks exactly for this kind of glorious recognition.

I tested this on Chrome & Firefox and on Mac OS & Windows. Next time tell me what platform & browser you’re working on and what error you get before calling it a pile of crap.

By: BabyRaptor

BabyRaptor — Fri, 09 Dec 2011 10:38:06 +0000

Thank you for posting a pile of crap…
I copy your entire code and it doesn’t run at all…

By: Philip Schlup

Philip Schlup — Tue, 30 Aug 2011 20:45:23 +0000

Thank you for posting this. I’m not a big fan of external libraries, so it’s great that you’ve written it without dependencies.

By: Arul Jeeva Gaspar

Arul Jeeva Gaspar — Tue, 30 Aug 2011 08:53:35 +0000

this is good site those who are starting with webgl.
you have done good work here. thank you

By: Paul

Paul — Thu, 28 Jul 2011 13:49:16 +0000

Thanks, this is a really great tutorial. Nice to see how it’s done without extra js libraries.

One small thing… I’m still a newbie to this, so correct me if I’m wrong, but I think on lines 225 and 226 of your code, the use of the perspectiveMatrix and modelViewMatrix variables are swapped. I think that what you have as…

gl.uniformMatrix4fv(uModelViewMatrix, false, new Float32Array(perspectiveMatrix));
gl.uniformMatrix4fv(uPerspectiveMatrix, false, new Float32Array(modelViewMatrix));

… should be …

gl.uniformMatrix4fv(uModelViewMatrix, false, new Float32Array(modelViewMatrix));
gl.uniformMatrix4fv(uPerspectiveMatrix, false, new Float32Array(perspectiveMatrix));

… maybe it works anyway, in the example, because the modelview is the identity transformation. When I started playing around with the modelview, I think this correction made things work a little better.

By: Dominic

Dominic — Tue, 19 Jul 2011 16:09:04 +0000

A great intro, but there’s a couple of bugs in your implementation.

- When failing to link the program, you’re deleting the shaders with a call to deleteProgram.

- When setting the perspective and modelView matrices you’ve mixed them up:
gl.uniformMatrix4fv(uModelViewMatrix, false,
new Float32Array(perspectiveMatrix));
gl.uniformMatrix4fv(uPerspectiveMatrix, false,
new Float32Array(modelViewMatrix));

should be:
gl.uniformMatrix4fv(uModelViewMatrix, false,
new Float32Array(modelViewMatrix));
gl.uniformMatrix4fv(uPerspectiveMatrix, false,
new Float32Array(perspectiveMatrix));

By: 10 adımda WebGL ile ilgili bilmek istediğiniz herşey | Kliknete

10 adımda WebGL ile ilgili bilmek istediğiniz herşey | Kliknete — Sat, 07 May 2011 11:52:56 +0000

[...] Adım Adım WebGL [...]

By: Lukas

Lukas — Thu, 24 Mar 2011 10:15:30 +0000

Hi I just have a question. I did OpenGL years ago. What I see now you are using shaders etc to render even primitive objects. I m used to use a gl_begin and draw_list…

Is it still possible to use it or only shaders are supported now (in webgl)?

By: Dennis

Dennis — Fri, 30 Apr 2010 15:38:17 +0000

@DLabz: Thanks, I’ve updated the documentation