601629 - Anti-aliasing in WebGL

Status: RESOLVED DUPLICATE of bug 539771

(Core :: Graphics: CanvasWebGL, defect)

Description

[Jayesh]

User-Agent:       Mozilla/5.0 (X11; U; Linux x86_64; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/7.0.536.2 Safari/534.10
Build Identifier: 4.0b7pre

WebGL does not yet seem to support Anti aliasing, the way it does in Canvas 2D. Please follow following steps to see how same wireframe cube is rendered differently with WebGL and Canvas2D w.r.t. anti-aliasing. Note that, I am explicitly mentioning antialiasing while getting WebGL context, as follows:

gl = canvas.getContext("experimental-webgl", {antialias : true});


Reproducible: Always

Steps to Reproduce:
1. Make sure Minefield is running with WebGL enabled
2. Visit http://www.3dtin.com, Click on the pencil tool, move the mouse around. You will see a wireframe cube following the mouse pointer. Note the aliasing of the edges of this cube.
3. Run Minefield with WebGL disabled
4. Visit http://www.3dtin.com. Since WebGL is disabled, the website will automatically fallback to Canvas 2D. Click the pencil tool as before, move around the mouse and note the edges of the wireframe cube. They are better antialiased, than in WebGL.

[To verify if the backend is WebGL or Canvas 2D, click on info button in top tool bar and check the "using" string near bottom right corner]
Actual Results:  
The wireframe cube edges are aliased with WebGL

Expected Results:  
The wireframe cube edges should be antialiased as they are with Canvas2D

Attaching screenshots in comments. I am filing this against Linux platform, but I am not sure if it holds for other platforms or not.

Comment 1

[Jayesh]

Attachment: Wireframe cube rendered with WebGL backend

Comment 2

[Jayesh]

Attachment: Wireframe cube rendered with Canvas2D backend

Comment 3

[Benoit Jacob [:bjacob] (mostly away)]

Yes, we know about this issue, which is part of the bigger issue that we don't support canvas context attribs. Antialiasing is one of the context attribs. This is bug 539771.