“I'm not sure if flexible float buffers fall into the same catagory, but I will look into it.” MRT are much more the theorytical idea, you can choose to render to multiple places at teh same time.” MET have to be special cases where MRT can be used much more like any render target.īoth are handy but MRT is the perferred route (AFAIK MET were added to Dx9 to try and cope with the GFFX style pack/unpack render targets). MRT are much better as you can mix and match standard render targets as you like. It may be possible in MET's are different formats for each 'logical' texture. RGBA), MET aren't really anything special there just >4 channel textures (RGBAXYZW). MET are special textures that are wider than usual (usual being upto 4 channels (i.e. “MRT are a lot more flexible, effectively upto 4 render-target can be rendered to simulatously, the only real restrictions are same size and for some chipsets (ATI but not AFAIK PowerVR) same format. I asked a developer about the difference between MRT’s and MET’s and this was his reply:
The FX series would probably need the driver to support MRT’s by packing and unpacking instructions. “I know (as do many who were present when David Kirk was speaking about the issue) that the FX hardware supports Multiple Render Targets.”įX natively supports MET’s, not MRT’s. Regardless of whether NVIDIA are closer to PS3.0 or not that doesn’t mean that ATI will have issues support it – ATI hadn’t support true multisampling FSAA before R300 and yet leapfrogged NVIDIA in this respect, NVIDIA hadn’t supported PS1.4 before the FX series and yet they went to PS2.0 Extended – what they currently support doesn’t necessarily have much bearing on what they are going to support.
We need to fill in the gap between DX9 PS/VS2.0 and DX10 PS/VS4.0, being the update to DX9.0 that will allow hardware targets for PS/VS3.0. Please read out DirectX Next article to gain an understanding of the directions DX10 is taking I will definitely give the Meltdown presentations some more in depth study time though.”ĭerek – As I said, PS3.0 is already part of *DX9*, DX10 will be PS/VS4.0.
The difference in filtering methods causes the flickering effect by which we have been bothered, and could be fixed via a patch from EIDOS though, ATI reports that EIDOS is unwilling to do so. Since TRAOD only requests anisotropic filtering be done on texture minification, NVIDIA does anisotropic filtering just fine while ATI doesn't do anisotropic filtering on magnification. NVIDIA hardware requires that magnification be done using the same filtering method as minification. ATI supports using a separate filtering scheme for texture magnification (filtering when the screen pixels are smaller than texels) and minification (filtering when the screen pixels are larger than texels). We can see the same thing in the frame with anisotropic filtering and antialiasing turned on.Īgain, ATI does a better job at antialiasing in this game than the NVIDIA card.Īlso, ATI has helped us track down the motion issue that we've been seeing on their cards. We can see, however, that the ground on the ATI card has more lighting effects. Tests here were too tricky to get close enough to the same frame on both cards for a difference image.