Sergey Reporter
	Description • 9 years ago

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.99 Safari/537.36

Steps to reproduce:

open https://dev.alisgames.com:8081/hero/data-single_test/hero_test.html
click on video to skip, wait until game is loading


Actual results:

text are not draw correct (some text are not draw at all). Firefox 34 works fine. Chrome and Safari works fine


Expected results:

text must be drawn as on attached image (from chrome, in safari works too)

	Sergey Reporter
	Comment 1 • 9 years ago

forget to write, all texts are rendered into texture and then texture with whole text is drawn to screen. It seems that first batch is not drawn correct the second one seems to draw correct

	Sergey Reporter
	Comment 2 • 9 years ago

that is how it works in firefox

	Sergey Reporter
	Comment 3 • 9 years ago

porbably the cause is that I'm using alpha texture (i.e. texture that has only alpha channel
glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, (GLsizei)image.getWidth(), (GLsizei)image.getHeight(), 0, GL_ALPHA, GL_UNSIGNED_BYTE, image.getData());

	Alice0775 White
	Comment 4 • 9 years ago

Could you provide minimal testcase?
And could you try using mozregression tool to find regression? 
( http://mozilla.github.io/mozregression/ )

	Sergey Reporter
	Comment 5 • 9 years ago

from mozregression

11:21.94 LOG: MainThread Bisector INFO Last good revision: 14665b1de5ee
11:21.94 LOG: MainThread Bisector INFO First bad revision: 5d6ec4dddf14

11:21.94 LOG: MainThread Bisector INFO Narrowed nightly regression window from [2014-09-30, 2014-10-02] (2 days) to [2014-10-01, 2014-10-02] (1 days) (~0 steps left)

creating more minimal test require for me quite a lot of time. If mozreggression info is not enough tell me.

	Alice0775 White
	Comment 6 • 9 years ago

Pushlog in accordance with comment #5
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=14665b1de5ee&tochange=5d6ec4dddf14

Suspect: Bug 1048108

	Alice0775 White
	Comment 7 • 9 years ago

Disable ANGLE helps. (however, another Bug 1123573 will raise)
user_pref("webgl.disable-angle", true);
user_pref("webgl.force-enabled", true);

	Sergey Reporter
	Comment 8 • 9 years ago

these changes

user_pref("webgl.disable-angle", true);
user_pref("webgl.force-enabled", true);

helps.

I found workaroud without changing prefs. I need to explicitly define when initialize webgl context.
alpha:true

e.g. 
var webGLContextAttributes = {alpha:true};
ctx = canvas.getContext("webgl", webGLContextAttributes) || canvas.getContext("experimental-webgl", webGLContextAttributes);

However this is default value

	Alon Zakai (:azakai)
	Comment 9 • 9 years ago

This might be a windows-specific regression, I can't reproduce it on linux on firefox 35.

	Andre Weissflog
	Comment 10 • 9 years ago

Related bug from AlteredQualia: https://bugzilla.mozilla.org/show_bug.cgi?id=1124187