This is Godot, purely GDScript implementation of Resolution independent rendering technique described by Charles Loop & Jim Blinn here. Original code prepared by Mirco Müller, can be found here.
Implemented simple shape, no antialiasing yet:
This shape drawn with just only 7 trianlges, some calculations required to provide resulting simple shader with params. The shader itself it really lightweight:
shader_type canvas_item;
void fragment(){
if (COLOR.a <= 0.0){
float v = COLOR.x;
float w = COLOR.y;
float t = COLOR.z;
if (v*v*v - w*t + 0.000001 > 0.0){
COLOR.rgb = vec3(1.0, 0.0, 0.0);
} else {
COLOR.rgb = vec3(0.0, 1.1, 0.0);
}
COLOR.a = 0.5;
}
}
There is also no curve splitting for edge cases yet, so there are possible some artefacts:
Tested with godot 3.1.alpha3.