When I think about what it was like to use a computer in the sixties compared to using a computer today it makes all those little problems we deal with every day seem kind of small. For instance, in '64 we had stroke writer displays, and computers that were built with magnetic core memory and integrated circuits that had only simple flip-flops. Graphics were only line drawings and were created either with tedious assembly language or with arcane Fortran. Only the elite had computer graphics, the primary applications being CAD and weapons simulation. The systems were time-shared (one main computer, several terminals); there was (at least one) operator of the main computer plus tech support for the terminal users. The main computer was as large as four to six refrigerators; the terminals looked like giant radar screens and they sat on a special table.
The screens were monochromatic (white or green), had simple text (dot matrix style) and only lines for graphicsno images, no fill. A main computer cost $100,000 to $250,000 (in 1964 dollarsabout $2 million in today's money). The ARPANET (forerunner to the Internet) wasn't developed yet and data was exchanged over distance by a stack of punch cards or a reel of magnetic tape. Conversational graphics consoles were developed by General Motors (DAC-1) and MIT Lincoln Laboratories (Sketchpad), resulting in computer-aided design (CAD). Sketchpad used the first light pen, developed by Ivan Sutherland, and the IBM 7094 (the first commercial computer to use semiconductors) dominated scientific computing at the time; and researchers in England created the first computer with virtual memory. This computer was capable of 200 KFlops (your mobile phone is about 100 times more powerful).
Today, on a $1,500 portable PC we can create cinematic-quality graphics and produce images that are so lifelike they have to be studied to discern whether they are a photograph or not. These great advances are due to several influences including the semiconductor revolution driven by Moore's Law; the explosion in sales of PCs and associated devices; the shrinkage in the physical size and price of hard drives as they simultaneously quadruple in capacity; the abundance of cheap memory; the widespread use of high-level programming languages like C++; and the deployment of common user interfaces like Windows and Apple OS. Today programs and data travel at near the speed of light from and to anywhere in the world, and even our grandmothers are enjoying high-quality computer graphics such as games and email animations.
Now of that what is the most significant CG event? Assuming all of the infrastructure was a given (i.e., we all have low-cost powerful computers with high-level programming languages, plenty of memory, and great displays), then the one thing that gave CG a big kick was texture mapping. It spawned, or enabled mipmapping, anisotropic filtering, bi- and tri-linear filtering, full-scene anti-aliasing, and new exploitations of alpha plane techniques. If you asked the graphics chip producers the question they would, without hesitation, say programmable shaders.
So I guess the answer is two-fold: texture mapping and shaders. In addition to the super-duper graphics available today to the masses, we also have video and amazing audio at our disposal. I'm sitting in the redwoods on the north central coast of California writing this with just electricity and water as modern conveniences available, yet I'm not lacking for modern entertainment because I have my trusty Evo N800w mobile workstation (talk about prying it from my cold, dead fingers)I'm playing a CD on it whilst I type, and later we're going to watch a DVD movie on a ZD 7000 HP mobile media center. The screen is a super-wide, high-res, 17 inches, and I can remember as a kid watching TV on a black-and-white 15-inch screen, so don't give me that snotty lean-back argumentthis will be just fine, thank you. And, the scalers in the GPU on this machine will de-interlace and make the movie look great and run smoothly, and if the electricity goes out we'll run it on its batteries. We brought our entire music collection on a Creative Zen portable audio player and we'll run it through the boombox up here. I'm telling you, life ain't bad; take a moment and appreciate how far we've come and what we've accomplished.