Comments on: Adding Font support in OpenGL

By: George

George — Mon, 11 Apr 2011 10:56:04 +0000

Hi argelast,

The basic idea in OpenGL ES v2.0 is similar, although a lot of the setup code is different. I’m in the process of moving over to v2.0 at the moment, although it’s taking some time. When I get a chance I’ll post an updated version.

By: argelast

argelast — Mon, 11 Apr 2011 10:48:38 +0000

Does anyone know How to do it in Opengl ES 2.0?
Thanks.

By: JustinB

JustinB — Wed, 24 Nov 2010 05:40:42 +0000

Hi George.
A few months ago I found this tutorial while I was learning how to program on the Android alongside OpenGL (I’m not one to do it easy, I guess…) Anyway, I translated your code into Java and got it working on my Cliq; you have probably the easiest and most elegant method I’ve seen (along with Paul Nettle’s program) to get text into OpenGL.

I really just wanted to say thanks for the great tip, and thank you for sharing this code!

By: Alex

Alex — Fri, 04 Jun 2010 12:57:22 +0000

Hi,

this is really a nice way to use fonts in an OpenGL application. Thanks for publishing it.

I tried writing some international characters and when rendering the CGLString it stopps rendering when the special character should be appear. I tried that Windows Tool to create a new binary font file but again when rendering the CGLString the special characters are not beeing rendered.

Does anyone has an idea to make it possible to use chars like the german umlaut “ä, ö, ü, ß” ???

Any help would be much appreciated

Alex

By: Al

Al — Thu, 15 Apr 2010 22:34:56 +0000

Thanks for the quick response. Yes the test app works just fine. I am even using one of the pre converted font files from your example for my test app. But in my test app when I swap the y values the text is right side up, but the lowercase letters are too high, and other letters too low

Thanks for any info.

By: George

George — Thu, 15 Apr 2010 21:37:29 +0000

Hi Al,

If the characters are in the correct place, just upside down, then you need to swap the y texture coordinates. IS the sample project working for you?

By: Al

Al — Thu, 15 Apr 2010 19:30:23 +0000

Hello,

I saw it mentioned above that Brandon had fixed the “rendering upside down” issue. I was wondering if you could let me know how? I have been looking at the opengl code, and everything I change the top / bottom vars, I just get very odd results.

Thanks

By: Brandon Mantzey

Brandon Mantzey — Tue, 09 Mar 2010 08:32:09 +0000

Yes, that does make sense. Thanks for breaking it down. You’re converting it to a percentage essentially but instead of per 100, it’s per 1. .9 = 90%, just like OpenGL scaling is 0-1. I get it now. lol

I had to crank that padding variable up to 15 to make those artifacts go away.

Well, it looks like I’ve got it rocking now. Thank you so much again for your help. I’ve learned a lot from this.

By: George

George — Tue, 09 Mar 2010 08:06:52 +0000

Hi Brandon,

widthScale is measuring the size of 1 pixel in texture coordinates, which range from 0 to 1. Think of, say, an 8 x 8 texture. The distance from one grid point to the adjacent grid point is the ‘size’ of one pixel in texture coordinates. So, rather than counting the number of pixels in the texture (textureWidth), we use one less (textureWidth – 1) because we’re interested in the spaces between the grid points, and there’s one less of those.

I hope that makes some sense. There’s a character padding variable used when the font is created that adds some extra clear space around each character in the texture. Make sure this is at least 4 to get enough clear space between characters. It may help fix the issues you’re seeing.

By: Brandon Mantzey

Brandon Mantzey — Tue, 09 Mar 2010 08:04:52 +0000

Back again, here’s the finished product:

http://i76.photobucket.com/albums/j18/brandhey/Work/FontwithArtifacts2.png

The artifacts are really noticeable.