sRGB to Linear RGB (approximation)

#include "ReShade.fxh"

float4 LinearisePass(float4 vpos : SV_Position, float2 texcoord : TexCoord) : SV_Target
{

float4 c0=tex2D(ReShade::BackBuffer, texcoord);

c0.rgb=(c0.rgb > 0.0404482362771082)?pow(abs((c0.rgb+0.055)/1.055),2.4):c0.rgb/12.92;
	
return c0;
}

float4 sRGBPass(float4 vpos : SV_Position, float2 texcoord : TexCoord) : SV_Target
{

float4 c0=tex2D(ReShade::BackBuffer, texcoord);

c0.rgb=( c0.rgb > 0.00313066844250063 )?1.055 * pow(abs(c0.rgb),1/2.4) - 0.055:12.92 *c0.rgb;

return c0;
}

technique sRGB_to_Linear
{
	pass
	{
		VertexShader = PostProcessVS;
		PixelShader = LinearisePass;
	}
}

technique Linear_to_sRGB
{
	pass
	{
		VertexShader = PostProcessVS;
		PixelShader = sRGBPass;
	}
}