Creating texture with varying alpha values for drawing anti-aliased lines in OpenGL-ES

Question

I am working on drawing anti-aliased lines in OpenGL-ES on iPhone. I am using an approach outlined in iPhone 3D Programming, called "Rendering Anti-Aliased Lines with Textures". The basis idea is to iterate through the line creating a bounding rectangle for each line segment (pair of vertices). This bounding rectangle can be represented by 6 triangles - and these can be filled with a texture. A texture (dot.png) comes with sample code, but I would like to experiment with other textures to see if I can get a more 3 dimensional affect.

So, I am wondering if there is a tool that would help me create these texture images. I have tried using Photoshop - but my skills there are rudimentary. I have seen "GIMP" mentioned, but I have no experience with it. I am guessing/hoping that there is some app out there that is designed for this purpose. Any pointers would be most welcome.

Thanks

Answer 1

Hi If you mean, to create some blurry circles you can try to generate some using imagemagick. Some examples are here for blurring www.imagemagick.org/Usage/blur/ and here for radial gradients: http://www.imagemagick.org/Usage/canvas/#radial-gradient and www.imagemagick.org/script/fx.php