Summary:
I have an triangle with points at specified positions, they all have F signed distance field value, this field is lineary interpolated between each other point and used to get the distance by D = 1.0 - sqrt(F.x * F.x + F.y * F.y) function that evaluated for each pixel in that triangle. There's also SDF limits variables, S=thickness/radius - start cutoff distance, E=0.5/(thickness+radius) - end cutoff distance, where thickness=1.0; radius=25.0. If D >= S && D <= E color of pixel is red, otherwise it's discarded. The green line is quadratic bezier curve with same points positions as triangles just for showcase.
Issue: How do I can compute 'F' variable of points to adjust red line near the green? It is also possible to add points to triangle and/or translate their positions if required.