Rendering SVG with OpenGL (and OpenGL ES)

Question

I am currently investigating the possibility of rendering vector graphics from an SVG file using OpenGL and OpenGL ES. I intend to target Windows and Android. My ideal solution

Answer 1

I am currently investigating the possibility of rendering vector graphics from an SVG file > using OpenGL and OpenGL ES. I intend to target Windows and Android. My ideal solution would be to have a minimal C library that generates a polygon triangulation from a given SVG file. This would then generate standard OpenGL or OpenGL ES calls, and use a display list or vbo for optimization when redrawing. I would simply draw a display list to draw the vector image after translating and rotating, allowing me to mix this with other OpenGL > calls.

If you only want to transform SVG vector shapes into OpenGL|ES, then I suggest to do the parser and the logic yourself. Note that SVG is a huge spec, with different features like paint servers (gradients, patterns ...), references, filters, clipping, font handling, animations, scripting, linking, etc, etc.

If you want full svg support, then there's a library on http://code.google.com/p/enesim called egueb (and particularly esvg) which uses enesim (a rendering library that has software and opengl backends) for the drawing. In most cases it uses shaders and everything is rendered into a texture, the library is very flexible allowing you to adapt to your particular needs like modifying the rendered scene, transform it, etc. Because the gl drawing is done always into a texture.

So far I see that the suggestions are to firstly use QT or Cairo. - This is not an option given that I wish to manage my own OpenGL context without bloated libraries (in the context of what I am trying to achieve). Nor is this suitable for Android.

Second option is to use libraries that render to a texture. While this might be ok for static vector graphics, it's not an efficient or feasible option for games where scaling and rotations occur frequently.

In the particular case of the gl backend, enesim does not create a GLX (or any other window dependent context), you have to provide it, so it adapts perfectly to your situation as it only uses GL calls.

The only drawback is that the library is not complete yet in terms of gl support or full SVG spec support, but depending on your needs, seems to me like a good option.