hierarchical systems, no calculations need to be made to determine what a polygon looks like in an area where it is obscured by other geometry. It also allows for correct rendering of partially transparent polygons, independent of the order in which they are processed by the polygon producing application. (This capability was only implemented in Series 2 including Dreamcast and one MBX variant. It is generally not included for lack of API support and cost reasons.) More importantly, as the rendering is limited to one tile at a time, the whole tile can be in fast on-chip memory, which is flushed to video memory before processing the next tile. Under normal circumstances, each tile is visited just once per frame. PowerVR is a pioneer of tile based deferred rendering. Microsoft also conceptualized the idea with their abandoned Talisman project. Gigapixel, a company that developed IP for tile-based 3D graphics, was purchased by 3dfx, which in turn was subsequently purchased by Nvidia. Nvidia has now been shown to use tile rendering in the Maxwell and Pascal microarchitectures for a limited amount of geometry. ARM began developing another major tile based architecture known as Mali after their acquisition of Falanx. Intel uses a similar concept in their integrated graphics products. However, its method, called zone rendering, does not perform full hidden surface removal (HSR) and deferred texturing, therefore wasting fillrate and texture bandwidth on pixels that are not visible in the final image. Recent advances in hierarchical Z-buffering have effectively incorporated ideas previously only used in deferred rendering, including the idea of being able to split a scene into tiles and of potentially being able to accept or reject tile sized pieces of polygon. Today, the PowerVR software and hardware suite has ASICs for video encoding, decoding and associated image processing. It also has virtualisation, and DirectX, OpenGL ES, OpenVG, and OpenCL acceleration. Newest PowerVR Wizard GPUs have fixed-function Ray Tracing Unit (RTU) hardware and support hybrid rendering. PowerVR Graphics Series1 (NEC) The first series of PowerVR cards was mostly designed as 3D-only accelerator boards that would use the main 2D video card's memory as framebuffer over PCI. Videologic's first PowerVR PC product to market was the 3-chip Midas3, which saw very limited availability in some OEM Compaq PCs. This card had very poor compatibility with all but the first Direct3D games, and even most SGL games did not run. However, its