Path: news1.icaen!news.uiowa.edu!news.physics.uiowa.edu!math.ohio-state.edu!cs.utexas.edu!howland.erols.net!nntprelay.mathworks.com!portc04.blue.aol.com!audrey01.news.aol.com!not-for-mail From: supertimer@aol.com (Supertimer) Newsgroups: comp.sys.apple2 Subject: Re: CMD products for GS (NTSC->RGB?, Scan Doublers, 20MHz) Date: 9 Mar 1998 05:34:45 GMT Lines: 154 Message-ID: <19980309053400.AAA17377@ladder03.news.aol.com> NNTP-Posting-Host: ladder03.news.aol.com X-Admin: news@aol.com Organization: AOL http://www.aol.com References: <19980302031001.WAA15556@ladder03.news.aol.com> Xref: news1.icaen comp.sys.apple2:131137 Someone said that if CMD was interested in tapping the GS market, it would be more interested if there was a product already designed that they could build with no additional R&D. There is also talk that the Second Sight card is not the best that the GS can do. Presenting the TurboRez GS card, by RezTek. TurboRez is a fully designed graphics accelerator card for the GS. After spending years designing and redesigning the card, the designer shelved the project because the Second Sight beat them to the market. Today, many people express distain for the Second Sight's performance. The designer of the TurboRez had misjuged the market. They had the better card and had the TurboRez been made, it would be the dominant card today. Many people still yearn for a better graphics card. CMD (or Alltech or others) has a chance to pick up this fully designed, ready to manufacture card and provide the GS community with a new product. This card offers new capabilities and has a market in the GS community where many users want better video but reject the Second Sight for its limitations. CMD has shown that a market still exist in an orphaned platform like the Commodore 64 and 128. The GS community is a similar group of hackers, waiting to be wowed. If you are interested in building for us, there is a market here. PRESENTING THE TURBOREZ GS AN OVERVIEW The TurboRez GS card is a circuit board that plugs into one of the 7 peripheral slots inside the IIGS. It's RGB video output (Turbo HiRes or THR) is merged with the SHR video on the GS motherboard. They both leave on the standard RGB video port at the rear of the GS. Until the TurboRez card is activated by an application that's aware of its presence, it stays in the background and doesn't interfere with normal GS operations. Which brings up the question: Are existing applications automatically enhanced by the TurboRez card? The answer is no and the main reason is that when those applications were originally written, cards like the TurboRez didn't yet exist. TurboRez can generate a 256 color display (That is, it can display up to 256 colors on a line versus the stock GS's 16 color per line limitation). This applies to both the 320 and the 640 display modes. There's also an extended palette feature that allows up to 7000+ colors onscreen. This is done in a somewhat similar fashion as the "3200" color mode used on the stock SHR display, except that with TurboRez it's totally handled by the hardware (so no software loading). Here, you have the advantage of additional shading capability and yet retain the ability to do palette-cycling for "cheap but fast" animation (Something you give up when using a "True-Color" display). In addition to the standard 200 line (vertical) display mode, there's also an interlaced 400 line mode available. This works on a stock GS RGB monitor. There's also the ability to switch into a true Overscan mode. This makes it possible to extend the display to fill up the monitor screen completely (Extra pixels are added to do this). Note: A 640 mode VGA adaptor is available separately. MULTIPLANE TECHNOLOGY On a typical Single Plane display system, animated "sprites" or "shapes" pass over or under each other, or in front of or behind fixed scenery in the background image. To make all of this appear seamless, the application software has to stay very busy not only erasing and redrawing the sprite of interest every time it's to be moved, but also any other sprite or scene element that it happens to overlap (even if those other objects are not due to be moved during this frame). As you might imagine, all of this activity slows the CPU down tremendously On a MultiPlane display, there can be several separate images that overlay one another. Modifying one of them doesn't affect the contents of the others. This reduces or eliminates the duplicated and timewasting gyrations necessary on a single plane system. A BLITTER, YOU SAY? The term "blitter" comes from an obscure acronym used on earlier graphic hardware. It's commonly accepted meaning is basically the act of efficiently moving groups of pixel data from from one place in memory to another. During this process, the pixel data can be modified if needed. For instance, "transparent" pixels could be detected and not written, or the source bitmap could be scaled as it's being read. The key is to move image data as fast as possible. A higher transfer speed means larger shapes can be drawn and/or higher animation frame rates can be maintained (i.e. "smoother" motion). Now, a CPU chip can execute code and operate as a "software blitter" but, as is the case with other functions, dedicated hardware can easily outperform it. As an example, the Second Sight's onboard CPU is capable of software blitting at about 4 megapixels/sec (1 pixel=1 byte). On a TurboRez card with .5 meg of ram, the hardware blitter can transfer at 16 megapixels/sec, about 4 times faster. On a TurboRez with 1 meg of ram, the blitter can achieve 32 megapixels/sec, or about 8 times as fast. In the above example, we're only dealing with straight blitting. That is, we're only talking about reading pixels from one place and writing them to another without doing any kind of modifications. For a software blitter, this is as good as it gets because, to modily the pixel data as we "blit" it, means adding more instructions for the CPU to execute (per pixel). In the case of the transparent source pixel detect or in the process of scaling a source bitmap (shrinking or expanding it), the software blitter takes a big hit in performance. Now, instead of 4 megapixels/sec, we drop to about .5 megapixels/sec (with the software blitter). Ah, but even while performing scaling or transparent pixel detect operations, the TurboRez's hardware blitter still operates at its normal speed, it doesn't suffer from the "extra" workload. So comparisons now reveal TurboRez performance as being anywhere from 32(16/.5) to 64(32/.5) times faster than the Second Sight, under these conditions. LINE DRAWING, SCALING AND ROTATION The TurboRez's hardware line drawing feature shares the blitter circuitry and so it has similar performance specifications. Again, this is because the process of drawing a sloped line involves a heavier workload for a software blitter, whereas a hardware blitter takes it in stride. Because the TurboRez line drawing hardware can scale (shrink/expand) a source bitmap as it drwws, we gain the ability to Scale with Rotation. This is extremely useful for many drawing and animation tasks. It allows us to use a master set of bitmaps and then modify them in "real time" as they're being drawn. Say, for instance, a spinning object that approaches and recedes. This Scaling and Rotation capability also comes in handy for "texture mapping" operations. This is a process where a source bitmap is applied to the face of an onscreen object, much like sticking a decal on a plastic model. In this way, a pseudo 3D scene can be built up onscreen in a very rapid manner. Many popular games on the PC ("Doom", for one) use techniques similar to this to generate virtual worlds for gameplayers to explore and interact with. With TurboRez's fast hardware drawing power, GS users will be able to experience full-screen, high frame-rate, texture mapped environments. Why the overiding concern with drawing speed? Think about it: A 320 by 200 byte-per-pixel display is about 60K in size. A 640 by 400 display is 4 times that, a whopping 240K! Since realistic animation demands frame rates of 15 per second and higher, dealing with display memory buffers this big requires some pixel moving muscle. And that's where TurboRez comes in.... CONTACT INFORMATION: RezTek owns the design to the TurboRez card. RezTek 2301 Cotton Ct Santa Rosa, Ca 95401 707-573-9257 Last known email address: REZTEK@GENIE.COM