Apple deliberately designed their custom GPU to have the same performance characteristics as the PowerVR gpus that early iphones used. Apple GPUs support the p

Apple deliberately designed their custom GPU to have the same performance characteristics as the PowerVR gpus that early iphones used. Apple GPUs support the proprietary IMGTEC compressed texture format that nobody else uses and they use the same deferred rendering method. Apple's deception was good that nobody realised they were shipping custom GPUs. Even with hindsight, nobody can really tell when apple shipped their first custom GPU. Apple may have even shipped GPUs which were a mixture of IMG and Apple RTL. But at this point the internals are far enough appart that I doubt much code can be shared.