brightness contrast Options

[nbac]

hi

can someone give me a hint on a correct contrast function for my pixelshader?

thx

[nbac]

in case somebody wants to know

float3 diff = tex2D(diffuseSampler,IN.TexCoord).rgb;
float3 diffBrightnessContrast = (diff.rgb - 0.5) * Contrast + 0.5 + Brightness;