// Standard lift/gamma/gain color correction tools. // // We do lift in a nonlinear (gamma-2.2) space since that looks a lot better // than in linear (blacks stay a lot closer to black). The two others don't // really care; they are (sans some constants) commutative with the x^2.2 // operation. // These are calculated in the host code to save some arithmetic. uniform vec3 PREFIX(gain_pow_inv_gamma); // gain^(1/gamma). uniform vec3 PREFIX(inv_gamma_22); // 2.2 / gamma. vec4 FUNCNAME(vec2 tc) { vec4 x = LAST_INPUT(tc); x.rgb = pow(x.rgb, vec3(1.0/2.2)); x.rgb += PREFIX(lift) * (vec3(1) - x.rgb); x.rgb = pow(x.rgb, PREFIX(inv_gamma_22)); x.rgb *= PREFIX(gain_pow_inv_gamma); return x; }