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

    uniform sampler mrt1: register(s0)
)
{
    float depth = tex2D(mrt1, iTexCoord).w;
    depth = pow(depth, 0.3);
    oColor0 = float4(depth, depth, depth, 1);
}