   Draw on texture in HLSL
  Im new to xna and dont understand some of it so bare with me :P i have a project where i need to draw a road on some terrain. i tried just creating some triangles with a road texture but it didnt work very well because the terrain would poke through in some places, so i decided the best approach would be to draw the road right onto the terrain. i tried setting the render target to a texture and drawing the terrain and road to that, and then setting the terrain texture to that texture... but it didnt work. I want to know if its possible to draw the road to the texture in the HLSL code, and if it is i would like to know how. Any help would be awesome!   