LYGIA Shader Library

Use:

blendNegation(<float|vec3> base, <float|vec3> blend [, <float> opacity])

Check it on Github

#ifndef FNC_BLENDNEGATION
#define FNC_BLENDNEGATION
float blendNegation(in float base, in float blend) {
    return 1. - abs(1. - base - blend);
}

vec3 blendNegation(in vec3 base, in vec3 blend) {
    return vec3(1.) - abs(vec3(1.) - base - blend);
}

vec3 blendNegation(in vec3 base, in vec3 blend, in float opacity) {
    return (blendNegation(base, blend) * opacity + base * (1. - opacity));
}
#endif

Use:

blendNegation(<float|float3> base, <float|float3> blend [, <float> opacity])

Check it on Github

#ifndef FNC_BLENDNEGATION
#define FNC_BLENDNEGATION
float blendNegation(in float base, in float blend) {
    return 1. - abs(1. - base - blend);
}

float3 blendNegation(in float3 base, in float3 blend) {
    return float3(1., 1., 1.) - abs(float3(1., 1., 1.) - base - blend);
}

float3 blendNegation(in float3 base, in float3 blend, in float opacity) {
    return (blendNegation(base, blend) * opacity + base * (1. - opacity));
}
#endif