
Originally Posted by
Cloofoofoo
It's the way dc is arranged , makes things like depth of field , bloom hard to do. Basically Dreamcast access to vram is slow , storing copies of rendered to texture that you plan to work on wouldn't be wise so they usually store in the main ram and either dma or sq copy to the vram. While faster that doesn't mean it's a speed demon. There's other things like fillrate that gets eaten up from multiple renders or bad performance from multiple large overlayed full screen polygons. This is a simplification as there might other issues( framebuffer it self might be an issue since I think you can't use the back buffer directly and have to copy it to main ram to manipulate it) . All this overhead piles up as you can imagine. It's even evident when you look at ps1 games that used things like cloaking , motion blur , radial blur , full screen warping/wave. Even ps1 games that did depth of field ( 2 definitely) . Heck someone I know , that was a hardcore soul calibur 1 player brought to my attention that soul calibur 1 ( super up ps1 that ran tekken) had a time released refraction mode instead of metal mode. So think about that for a second , the dc being magnitudes faster actually had to settle for a simple metal environment map mode for the costume instead of the framebuffer refraction effect of the ps1-esque the arcade machine did years prior.
It really doesn't seem a question of knowing how to do these effects but the struggle of doing it effectively on hw that doesn't mesh well with them