How are video games projected on screen?

May be...

I know that we aren't actually looking at a constant moving video game and that all we are seeing are multiple frames per second. But how is it done? I'm just curious how they do it. And are video games only projected at 30 frames and 60 frames per second, or are there other # of frames that can be shown in a given second?

The numbers 30 and 60 are a side effect of the NTSC format of television. Even back in the black-and-white days of TV, NTSC was a 640X480 image, interlaced (draws all the odd lines in one pass, then draws all the even lines on the next), and operating at 60 Hz. It wasn't until about 10 years ago that consumers started seeing any change to this, when EDTVs came on the scene and changed the interlaced to Progressive Scan (all lines are drawn sequentially on each pass), and then HDTVs changing the image resolution. Very recently, sets that can do 120 Hz have come onto the market. In Europe, they uses the PAL format, which ran at 50 Hz, but switched to 60 Hz for HDTV to simplify things for TV manufacturers (who had started to sell sets in Europe that could handle both 50 Hz and 60 Hz).



So for the longest time, TVs were displaying 60 half-frames (due to interlacing). As such, having a game run at 60 Hz would result in slightly smoother animation, but a lot more processing power which could otherwise be used to enhance the detail. So typically 60 frames games were smoother, but 30 frames games were much more detailed. Any other rate, and you the smoothness will vary, which is rather jarring to the immersiveness factor.



All of this only applies to consoles, though, since PCs have always had monitors that could do a variety of framerates, and therfore their games always strived for the highest framerate possible (and where 60 Hz is on the far low end) and don't really worry about the framerate dipping at times. High end modern monitors can typically do at least 140 Hz, and some older games on new hardware can actually create several hundred frames per second if certain settings are disabled.



Regardless of PC or console, the same programming technique is used for creating the frames and managing the process of sending them to the screen. Each object is placed in position in a virtual 3D space in RAM, textures are applied (only if they are facing the virtual camera's location), the view from the virtual camera is established, and the objects that the camera can see are flattened into a 2D image. This whole process is called rendering.



Then, the rendered image is put into a piece of memory (usually in the graphics chip itself) that has been designated as a "frame". This frame is then sent to the TV/monitor, and as it is being sent, a second image is being rendered and put into a second "frame". Once the first frame has been sent to the screen completely, the second frame is designated as the primary frame, and a third image is rendered and overwrites the first frame. This process is called Frame Buffering.



PCs (and maybe HDMI TV connections, I'm not sure) have the capability of the monitor being able to send a signal back to the game program and tell it when a frame is done being drawn. This allows the game to not switch frames while it is being sent to the screen (vertical synch), preventing a top section of an image and a bottom section of the same image displayed not matching up, refered to as "tearing". Since consoles know what frequency the TV is operating at based on the region (or more recently in Europe, through an option in the settings for either the game or the system), they can simply use an internal timer as an artificial vertical synch.

There are two target FPS that game developers commonly try to make their games run at. 30 FPS is the most common. 60 FPS is less common and provides an increase in smoothness of the animations on screen compared to 30 FPS.



That being said, there are games that experience a drop in FPS in processor/graphics intensive moments. Ideally, these moments wouldn't exist, but they still do in some games as they're pushing the hardware too much to keep the animation smooth.



If you play games on a computer and get a FPS display for the game you're playing you will notice it generally stays around a constant area with a few fluctuations. If you upgrade your hardware you will notice the FPS increase. Adjusting the graphics quality in the options for the game will also change the FPS you get while playing.



It's a direct relation on how much power the game is asking from the hardware and how much the hardware can put out at a certain rate.



Kurt

http://www.myinternetmarketinggroup.com

The FPS is the constant speed that games run at, most games run at 30 FPS. This means that there are 30 frames being shown in any given second. There are a few games however that run at 60 FPS, an example would be Call of Duty 4. Games that run at 60 FPS generally have better frame rates and look clearer and smoother.

thats a good question i don't know but i guess the disc is already predetermined with functions and different ways to get to the finish using the controls thats why there are glitches but no clue about frames