Unlike the PSX, though, the N64 also had an FPU installed as COP1 (coprocessor 1). The N64 had a similar configuration to the PSX, except that the equivalent to GTE was called RSP there – also installed as COP2 (coprocessor 2). Polygons will snap into place until one of the vertices moves enough to snap into a different pixel. At the very end when the GTE has done its processing, it will output the results of the perspective transform to the GPU as integer pixel coordinates. It deals mainly in fixed point math, and because of the rotate and translation transformations involved that occur on the GTE side, precision errors will build up and this will result in the ‘wobbling’ effect you can see manifested onscreen. The PSX had no floating point unit installed as COP1 (coprocessor 1), and neither did the GTE have any float support. Without this coprocessor, the paltry 33MHz main CPU would have been unable to render most of the graphics at full speed performance. ![]() Being able to do this at nearly zero cost was the envy of many a PC around that time period. ![]() It’s a coprocessor (attached to COP2) which has fixed-function functionality allowing the programmer to do perspective transforms, rotations, light sourcing, depth cuing, etc. What made it special at the time was the coprocessor attached to it which made it very adequate at 3D rendering: the Geometry Transfer Engine. The PlayStation’s MIPS R3000A processor was a very barebones MIPS CPU, very outdated even by 1994 standards. Geometry Transfer engine and integer precision math Lack of time/effort and optimizing specifically around the PSX’s limitations are probably a reason for developers taking shortcuts even on far more capable hardware. The issues were fixed for Final Fantasy VII but Final Fantasy VIII’s PC port featured the same subpixel precision issues as the PSX version. A similar thing happened with the Final Fantasy series. For instance, the aforementioned issues were fixed in Resident Evil 1 PC but then by the time we get to Resident Evil 3: Nemesis for PC, we can spot wobbling polygons again on the character models. Most PlayStation-to-PC ports didn’t put the extra effort in to fix these issues either. This, combined with the lack of subpixel precision, can result in a very glitchy look in many a PlayStation game. In addition to this, other games (like Ridge Racer Revolution, or Tomb Raider 2) can also sometimes show random color outlines around texture maps while the camera is moving.Īll of the aforementioned issues can be traced back to the lack of perspective correct texturing. See the video above for an example of what we are talking about.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |