Hello, I have been trying to apply more then one effect to a primitive and after many failures I have decided to seek help here, lets say there are two effect files written in HLSL, one that applies grayscale and another that does some simple blurring, how would I apply that to a square made up of two polygons with a texture that are made with such code:

verts = new VertexPositionTexture[4];
verts[0] = new VertexPositionTexture(new Vector3(-1, 1, 0), new Vector2(0, 0));
verts[1] = new VertexPositionTexture(new Vector3(1, 1, 0), new Vector2(1, 0));
verts[2] = new VertexPositionTexture(new Vector3(-1, -1, 0), new Vector2(0, 1));
verts[3] = new VertexPositionTexture(new Vector3(1, -1, 0), new Vector2(1, 1));

so with that verts array for example, would it be possible to apply more then one texture? (this is of course in a 3d space)

What I have been trying is just drawing it to a rendertarget with a blur effect, then getting the texture of the rendertarget and applying grayscale to that, however I feel that is just a cheat because what I want to achieve is two effects on the square itself not the whole screen if you get my meaning...

Can't you just create a technique with 2 passes. The first would apply blurring and the second grayscale? Or combine the two into a single pass. Or why would you need to have 2 different HLSL files?

I was just using those two shaders as an example, it doesn't have to be them exactly. Having a technique with two passes is possible for simple shaders like the blur and greyscale, but I would prefer to know how to apply two in the form of two files in the event that I can't just put them in one shader, as I would prefer to be able to stick in the lowest shader model version possible(so as to be more accessible) and since they have a limit on the number of instructions(shader model 2.0 is my target) I can't just chuck them all in the same file once they reach a certain complexity...