Load HLSL intrinsic

/*Using Effect syntax*/

struct PixelShader_INPUT
{
    float4 p : SV_POSITION;
};

float4 PixelMain(PixelShader_INPUT input) : SV_TARGET
{
    uint3 index = uint3(input.p.x, input.p.y, 0);
    float val = tex0.Load(index).r;
    float4 output = float4(val, val, val, 1);
    return output;
}