is there any way to display water caustics on terrain (like in aquanox) with shaders (only pixel or vertex shader if it has to be, i would like to run the game also on old machines or machines without ps&vs shaders)? i currently use 2 terrains, 1 terrain with the ground texture and one with caustic texture. the "caustic-terrain" above the first. that looks quite nice, but i have to use the same terrain twice, which brings me to an fps of min. 45 and max.80 fps ( 60 is Average). without these caustics i achieve framerates from 60-80 fps ( 70 is Average ). so there is a big performance loss on lower machines. is there any script to do such caustics or do i have to do it this way ?

Here is a screen of it with 2 terrains , one as caustic overlay:


since iam a shader n00b, i would be pleased if you would have an idea


Edit: Hier ist noch ein link zu dem quellcode von dem DolphinTween von der ATI Page wo genau dieser effekt drin vorkommt. leider weiss ich nicht wie man den code so "umwandelt" (bzw. umschreibt) das der auch bei 3DGS funktioniert, vielleicht kann ja einer mit ahnung sich das viech mal ansehen

DolphinTween.CPP

Use a multitexture effect (There are a couple here on the forums) with one layer as the regular terrain skin, then a layer over that with the caustic texture. Then blend them with an alpha channel. If you were really ambitious, you could make 2 caustic layers, and scroll them in opposite directions. With some effort you could get this effect to work without vrtex/pixel shaders.

but how do i do that? cause iam a complete shader/material n00b or i leave the effect the way it is and change it in a few months when iam capable of programming material/shader effects ...

Well start off with grabbing SteamPipe's FFP multitexturer, no shaders required. Edit the textures so that the top 2 textures are water caustics, and the bottom is your actual terrain texture. Then edit the alpha channel accordingly. That shouldn't require any coding Then examine his code.. and research texture scrolling... and that should give you a pretty good start. Look at other effects as well to see how they achieve the movement.

ok, thank you nadester you were a great help thats N#1 on my ToDo list for tomorrow, now ill upload a video and then i catch some sleep thx again ^^