I have implemented something in OpenGL and tested this on different PC with different graphic-cards. During my testing session i recognized that the FPS (=Performance) is very different from one graphic-card to the other. I think this has also to do with the memory of the graphic card. But now on to the problem: How can i hold the performance constant on any PC with any different video-card (of course not for the oldest ones)? For example how creates the developers of some well-known 3D-Action Games like Half-Life to run on PC with a bad graphic-card just as good as on a PC with a better graphic-card(for example with more graphics memory)? Exists there common techniques to achieve that? Hope anybody can help me.
the techniques used in half-life and quake2/3 are actually pretty simple. they use a LOD (level of detail) system to moderate the stress put on the video card. For example, if you go into quake3, go into the settings and you should be able to find a menu with the LOD options (filtering options, lighting options, geometric detail options, etc.). if you want to try this out for yourself, go onto one of those slower computers, and boot up half life. but before playing, go into the settings and set it on software rendering. then if you play the game, you''ll notice its not in full detail. the textures will be all blocky, weapons wont look as smooth, things look really ugly from far away, ladder''s may not show up right. same goes for quake3, just screw around with the settings and you''ll see what i mean. Unreal Tournament is a bad example, because even in software mode UT doesnt lose much detail and runs at a high framerate (UT ROX! ). If you want to implement your own LOD system, just make sure your app supports multiple rendering techniques and such. Stuff like if the system is sluggish, you can resize the textures smaller before using them, this will put less stress on the system. If the system has alot of memory but not alot of speed, try MIP mapping. if its a high end system, you could use effects like Bilinear or Trilinear filtering to make the textures look good from a distance. these are just examples with textures, theres plenty of other things that could have a LOD system implemented.