3D graph OpenGL

3D graph is program for drawing mathematical equations in form of 3D graph. You can write whatever equation you like and use variables x and y as you like. You enter equation in text box at the top of the screen and press Draw button to draw it. You can then rotate 3D graph by moving finger across the screen and zoom in and out with + and - buttons at the bottom of the screen. There are some predefined great looking equations available by opening menu and select Favorites option. You can add equation to list of favorites with star button, and take picture of it with camera button which will be saved to 3DGraph folder on SD card. You can use settings menu option to fine tune your 3D graph. Home page: http://goo.gl/mldKM

Version 1.3.4
- added input values range chacking
- optimized performance

Version 1.3.3
- fixed bug while taking screen-shot
- fixed equation wrapping in favorites dialog
- enable move to SD-card option

Version 1.3
- switched to min3d OpenGL library (hopefuly lights will work now as they should)
- added option to make lights visible
- added option to draw graph with lines or dots
- optimized icons for all resolutions
- added X,Y,Z axes
- added version selector to choose between notification or classical ads
- optimized screen capturing code
- minor UI optimizations

Version 1.2.1
- added option to disable notification bar push Ads

Version 1.2
- minor bug fixes
- improved ad display module
- added Chinese translation
- added Taiwanese translation

Version 1.1
- fixed error when drawing functions like 1/(x*y)
- fixed uppercase/lovercase error with equations
- added contact and home page in about box