void ShowDepth_fp
(
    in float2 iTexCoord: TEXCOORD0, 
    
    out float4 oColor0 : COLOR0,

    uniform sampler mrt1: register(s0),
    uniform sampler tex : register(s1)
)
{
    float depth = tex2D(mrt1, iTexCoord).w;
    oColor0 = float4(tex2D(tex, float2(depth*20, 0)).rgb, 1);
}