PowerVR is a division of Imagination Technologies (formerly VideoLogic) that develops hardware and software for 2D and 3D rendering, and for video encoding, decoding, associated image processing and DirectX, OpenGL ES, OpenVG, and OpenCL acceleration. PowerVR also develops AI accelerators called Neural Network Accelerator (NNA). The PowerVR product line was originally introduced to compete in the desktop PC market for 3D hardware accelerators with a product with a better price–performance ratio than existing products like those from 3dfx Interactive. Rapid changes in that market, notably with the introduction of OpenGL and Direct3D, led to rapid consolidation. PowerVR introduced new versions with low-power electronics that were aimed at the laptop computer market. Over time, this developed into a series of designs that could be incorporated into system-on-a-chip architectures suitable for handheld device use. PowerVR accelerators are not manufactured by PowerVR, but instead their integrated circuit designs and patents are licensed to other companies, such as Texas Instruments, Intel, NEC, BlackBerry, Renesas, Samsung, Sony, STMicroelectronics, Freescale, Apple, NXP Semiconductors (formerly Philips Semiconductors), and many others. Technology The PowerVR chipset uses a method of 3D rendering known as tile-based deferred rendering (often abbreviated as TBDR) which is tile-based rendering combined with PowerVR's proprietary method of Hidden Surface Removal (HSR) and Hierarchical Scheduling Technology (HST). As the polygon generating program feeds triangles to the PowerVR (driver), it stores them in memory in a triangle strip or an indexed format. Unlike other architectures, polygon rendering is (usually) not performed until all polygon information has been collated for the current frame. Furthermore, the expensive operations of texturing and shading of pixels (or fragments) is delayed, whenever possible, until the visible surface at a pixel is determined — hence rendering is deferred. In order to render, the display is split into rectangular sections in a grid pattern. Each section is known as a tile. Associated with each tile is a list of the triangles that visibly overlap that tile. Each tile is rendered in turn to produce the final image. Tiles are rendered using a process similar to ray-casting. Rays are numerically simulated as if cast onto the triangles associated with the tile and a pixel is rendered from the triangle closest to the camera. The PowerVR hardware typically calculates the depths associated with each polygon for one tile row in 1 cycle. This method has the advantage that, unlike a more traditional early Z rejection based