Uniform shader parameters

float4 PS_Foo(float4 pos : SV_Position, float2 uv : TEXCOORD, uniform float2 dir) {
//blur in the direction defined by dir
}

technique Bar {
    pass X {
        VertexShader = PostProcessVS;
        PixelShader = PS_Foo(float2(1.0, 0.0));
    }
    pass Y {
        VertexShader = PostProcessVS;
        PixelShader = PS_Foo(float2(0.0, 1.0));
    }
}

float4 PS_Foo(float4 pos : SV_Position, float2 uv : TEXCOORD, float2 dir) {
//blur in the direction defined by dir
}

float4 PS_FooX(float4 pos : SV_Position, float2 uv : TEXCOORD) { return PS_Foo(pos, uv, float2(1.0, 0.0)); }
float4 PS_FooY(float4 pos : SV_Position, float2 uv : TEXCOORD) { return PS_Foo(pos, uv, float2(0.0, 1.0)); }

technique Bar {
    pass X {
        VertexShader = PostProcessVS;
        PixelShader = PS_FooX;
    }
    pass Y {
        VertexShader = PostProcessVS;
        PixelShader = PS_FooY;
    }
}