   terrain texturing
  hi,currently i render my terrain through multipass texturing and a shader.i have a blend map, each color channel is encoded with how much of each texture to blendand i have 3 textures that are tiled and blendedso red = 255 would mean texture a would be 100% visiblered = 120blue = 120green = 15 would result in roughly 50/50 of texture a and b with a small bit og texture c showing through....is there a way i can do this with out a shader in a single pass using dx blend operations? 
  Yes, but unfortunately, you would need a separate texture for each blending map. The pixel shader approach is what I do and it works pretty well . You can use the alpha channel in the textures (not the blend map) as a detail map and scale its texture coordinates up (so it repeats more) and then combine it with the unscaled value for super-detail. ;  hrmm i was thinking of the detail map or maybe a clouds moving across the terrain image:| hard choice ;p ;  You can do it without a shader, but it wont be in a single pass. You have to use the dot3 texture operation to extract a color channel to use for blending. On most hardware it will take 2 or 3 passes.;  hrmm maybe i should divide my terrain up, so only 2 textures can be on 1 poly at once? that way i dont rely on shaders so it works on older hardware...this would be hard to work out tho especially as im currently exporting from 3d MAX :-/ 