XBOXとGAMECUBEはどちらが性能いい？ Vol１９
889 ：名無信者さん：
Lighting
GameCube's basic lighting features support per-vertex lighting much in the vein of OpenGL＠｀ if you're familiar with the standard. The model supports lights with ambient＠｀ specular＠｀ diffuse＠｀ and spotlight effects. This also supports local lights with distance attenuation via the hardware. In particular＠｀ the graphics processor only supports four lights at a time. However＠｀ GameCube utilizes the concept of light channels in which a vertex color component can be associated with one or more lights. This allows for up to four channels and can be used as the vertex color or can be pushed through the pipeline to use in per-pixel calculations. In general＠｀ though＠｀ GameCube combines the capabilities of
per-vertex lighting and texture lighting to make a more hefty lighting model. It also allows for CPU-computer lights along with pre-lighting to be merged with the lighting in the Graphics Processor. This gives developers the power to use a massive number of lights.
GameCube's basic lighting features support per-vertex lighting much in the vein of OpenGL＠｀ if you're familiar with the standard. The model supports lights with ambient＠｀ specular＠｀ diffuse＠｀ and spotlight effects. This also supports local lights with distance attenuation via the hardware. In particular＠｀ the graphics processor only supports four lights at a time. However＠｀ GameCube utilizes the concept of light channels in which a vertex color component can be associated with one or more lights. This allows for up to four channels and can be used as the vertex color or can be pushed through the pipeline to use in per-pixel calculations. In general＠｀ though＠｀ GameCube combines the capabilities of
per-vertex lighting and texture lighting to make a more hefty lighting model. It also allows for CPU-computer lights along with pre-lighting to be merged with the lighting in the Graphics Processor. This gives developers the power to use a massive number of lights.
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890 ：名無信者さん：2001/04/29(日) 11:47
Texturing
The graphics processor textures four pixels per clock at 200MHz＠｀ which results in a mip-mapped texture rate of 800 million pixels/second. GameCube also supports many powerful texture mapping features＠｀ including single-cycle mip-mapping＠｀ compressed color texture and color index textures＠｀ anisotropic texture filtering＠｀ multi-texture support (in multiple cycles)＠｀ and more. Textures are pre-fetched in parallel with rendering＠｀ and in terms of multi-texturing the processor can store up to eight active textures at once. This multi-texturing is performed by processing a square block of four pixels＠｀ a quad＠｀ through the pipeline over multiple cycles. This is one of GameCube's most powerful advantages＠｀ but it will affect the fill rate. Also＠｀ to eliminate getting textures for parts of the screen that are not visible＠｀ the hardware can be configured to Z-buffer before texturing. All these and many other features maximize the processor efficiency.
The graphics processor textures four pixels per clock at 200MHz＠｀ which results in a mip-mapped texture rate of 800 million pixels/second. GameCube also supports many powerful texture mapping features＠｀ including single-cycle mip-mapping＠｀ compressed color texture and color index textures＠｀ anisotropic texture filtering＠｀ multi-texture support (in multiple cycles)＠｀ and more. Textures are pre-fetched in parallel with rendering＠｀ and in terms of multi-texturing the processor can store up to eight active textures at once. This multi-texturing is performed by processing a square block of four pixels＠｀ a quad＠｀ through the pipeline over multiple cycles. This is one of GameCube's most powerful advantages＠｀ but it will affect the fill rate. Also＠｀ to eliminate getting textures for parts of the screen that are not visible＠｀ the hardware can be configured to Z-buffer before texturing. All these and many other features maximize the processor efficiency.
891 ：名無信者さん：2001/04/29(日) 11:50
Anti-aliasing
One of the biggest qualms with the PS2 was its anti-aliasing and deflickering capabilities. It's slowly overcoming those issues＠｀ but it requires a lot of work. Does GameCube have similar problems? No＠｀ its graphics processor performs anti-aliasing in a number of ways. The sub-pixel anti-aliasing is a method of anti-aliasing that samples the pixel in three different locations. These locations can be varied as per the programmers request＠｀ and are averaged to produce the final pixel color. This is an intense form of super-sampling anti-aliasing that reduces the jaggies on edges of polygons＠｀ and also improves the overall visual quality. However＠｀ it takes a hit on performance and requires use of the embedded frame buffer (eFB) memory.
One of the biggest qualms with the PS2 was its anti-aliasing and deflickering capabilities. It's slowly overcoming those issues＠｀ but it requires a lot of work. Does GameCube have similar problems? No＠｀ its graphics processor performs anti-aliasing in a number of ways. The sub-pixel anti-aliasing is a method of anti-aliasing that samples the pixel in three different locations. These locations can be varied as per the programmers request＠｀ and are averaged to produce the final pixel color. This is an intense form of super-sampling anti-aliasing that reduces the jaggies on edges of polygons＠｀ and also improves the overall visual quality. However＠｀ it takes a hit on performance and requires use of the embedded frame buffer (eFB) memory.
892 ：名無信者さん：2001/04/29(日) 11:50
Furthermore＠｀ the eFB can only handle a sub-pixel anti-aliased frame at a max resolution of 640x264 (Note: the vertical resolution of 264＠｀ is half of 528＠｀ which is the standard PAL resolution -- PAL is the European/Australian standard as opposed to the American/Japanese standard called NTSC). What this means is it requires two rendering passes to perform. Whether or not the visual upgrade is beneficial enough to make it worth the performance hit＠｀ is up to them. It will certainly vary from developer to developer.
893 ：名無信者さん：2001/04/29(日) 11:51
By now if you understood all that techno-babble you're assuming GameCube can't perform anti-aliasing without taking a huge hit＠｀ right? Not true. That is the super-sampling technique＠｀ but if developers prefer they can use a more simpler form of anti-aliasing＠｀ much like the Dreamcast＠｀ via a hardware deflickering filter mode. This is essentially a two-sample super-sampling technique. Judging from the demonstrations IGNcube saw at Space World＠｀ there shouldn't be any issues with GameCube's anti-aliasing techniques.
以上、IGNinsiderからの情報だそうです。
以上、IGNinsiderからの情報だそうです。