I've been tinkering with software techniques for emulation of obsolete analog instant photography for about 5 years. The early solutions consisted of Quartz Composer patches containing sampled art and OpenGL GLSL shaders. FotoRoid 100 runs on early iOS devices that do not have programmable shader pipelines. Because the image synthesis techniques I've developed cannot be effectively realized on the OpenGLES 1.0 fixed function pipeline, I coded the image processing routines in C++. Once iOS went multi-core, I parallelized the routines. It's still much slower than GPU implementations, but the aim was accurate synthesis of 'roid camera technologies, not speed.
"The thing about Fotoroid 100 is that when it works well, the results are amazing. There is no other polaroid app out there that looks so realistic." - Satisfied Customer