What about OpenGL ES?
http://www.khronos.org/opengles/
It is designed to scale across a wide range of hardware capabilites
"The embedded space varies widely, ranging from 400Mhz PDAs with 64MB RAM to 50MHz mobile phones with 1 MB RAM. OpenGL ES is designed to accommodate these differences by requiring a minimum footprint with minimum data storage requirements, minimized instruction/data traffic, and is both integer and floating point friendly."