The evolution of the modern graphics processor begins with the introduction of the first 3D add-in cards in 1995, followed by the widespread adoption of the 32-bit operating systems and the affordable personal computer.
The graphics industry that existed before that largely consisted of a more prosaic 2D, non-PC architecture, with graphics boards better known by their chip’s alphanumeric naming conventions and their huge price tags. 3D gaming and virtualization PC graphics eventually coalesced from sources as diverse as arcade and console gaming, military, robotics and space simulators, as well as medical imaging.
The early days of 3D consumer graphics were a Wild West of competing ideas. From how to implement the hardware, to the use of different rendering techniques and their application and data interfaces, as well as the persistent naming hyperbole. The early graphics systems featured a fixed function pipeline (FFP), and an architecture following a very rigid processing path utilizing almost as many graphics APIs as there were 3D chip makers.
While 3D graphics turned a fairly dull PC industry into a light and magic show, they owe their existence to generations of innovative endeavour. Over the next few weeks (this is the first installment on a series of four articles) we’ll be taking an extensive look at the history of the GPU, going from the early days of 3D consumer graphics, to the 3Dfx Voodoo game-changer, the industry’s consolidation at the turn of the century, and today’s modern GPGPU.
1976 – 1995: The Early Days of 3D Consumer Graphics
The first true 3D graphics started with early display controllers, known as video shifters and video address generators. They acted as a pass-through between the main processor and the display. The incoming data stream was converted into serial bitmapped video output such as luminance, color, as well as vertical and horizontal composite sync, which kept the line of pixels in a display generation and synchronized each successive line along with the blanking interval (the time between ending one scan line and starting the next).
A flurry of designs arrived in the latter half of the 1970s, laying the foundation for 3D graphics as we know them.
Atari 2600 released in September 1977
RCA’s “Pixie” video chip (CDP1861) in 1976, for instance, was capable of outputting a NTSC compatible video signal at 62×128 resolution, or 64×32 for the ill-fated RCA Studio II console.
The video chip was quickly followed a year later by the Television Interface Adapter (TIA) 1A, which was integrated into the Atari 2600 for generating the screen display, sound effects, and reading input controllers. Development of the TIA was led by Jay Miner, who also led the design of the custom chips for the Commodore Amiga computer later on.
In 1978, Motorola unveiled the MC6845 video address generator. This became the basis for the IBM PC’s Monochrome and Color Display Adapter (MDA/CDA) cards of 1981, and provided the same functionality for the Apple II. Motorola added the MC6847 video display generator later the same year, which made its way into a number of first generation personal computers, including the Tandy TRS-80.
IBM PC’s Monochrome Display Adapter
A similar solution from Commodore’s MOS Tech subsidiary, the VIC, provided graphics output for 1980-83 vintage Commodore home computers.
In November the following year, LSI’s ANTIC (Alphanumeric Television Interface Controller) and CTIA/GTIA co-processor (Color or Graphics Television Interface Adaptor), debuted in the Atari 400. ANTIC processed 2D display instructions using direct memory access (DMA). Like most video co-processors, it could generate playfield graphics (background, title screens, scoring display), while the CTIA generated colors and moveable objects. Yamaha and Texas Instruments supplied similar IC’s to a variety of early home computer vendors.
The next steps in the graphics evolution were primarily in the professional fields.
Intel used their 82720 graphics chip as the basis for the $1000 iSBX 275 Video Graphics Controller Multimode Board. It was capable of displaying eight color data at a resolution of 256×256 (or monochrome at 512×512). Its 32KB of display memory was sufficient to draw lines, arcs, circles, rectangles and character bitmaps. The chip also had provision for zooming, screen partitioning and scrolling.
SGI quickly followed up with their IRIS Graphics for workstations — a GR1.x graphics board with provision for separate add-in (daughter) boards for color options, geometry, Z-buffer and Overlay/Underlay.
Full Story: The History of the Modern Graphics Processor – TechSpot.