LYGIA Shader Library

Dependencies:

• lygia/math/saturate.glsl

Use:

lineSDF(<vec2> st, <vec2> A, <vec2> B)

Check it on Github

#ifndef FNC_LINESDF
#define FNC_LINESDF
float lineSDF( in vec2 st, in vec2 a, in vec2 b ) {
    vec2 b_to_a = b - a;
    vec2 to_a = st - a;
    float h = saturate(dot(to_a, b_to_a)/dot(b_to_a, b_to_a));
    return length(to_a - h * b_to_a );
}

float lineSDF(vec3 p, vec3 a, vec3 b) {
    //https://mathworld.wolfram.com/Point-LineDistance3-Dimensional.html
    return length(cross(p - a, p - b))/length(b - a);
}
#endif

Use:

lineSDF(<float2> st, <float2> A, <float2> B)

Check it on Github

#ifndef FNC_LINESDF
#define FNC_LINESDF
float lineSDF( in float2 st, in float2 a, in float2 b ) {
    float2 b_to_a = b - a;
    float2 to_a = st - a;
    float h = saturate(dot(to_a, b_to_a)/dot(b_to_a, b_to_a));
    return length(to_a - h * b_to_a );
}
#endif