## cylinderSDF (`lygia`/`sdf`/`cylinderSDF`)

generate the SDF of a cylinder

Use:

``````<float> cylinderSDF( in <vec3> pos, in <vec2|float> h [, <float> r] )
``````
``````<float> cylinderSDF( <vec3> p, <vec3> a, <vec3> b, <float> r)
``````

Check it on Github

``````
#ifndef FNC_CYLINDERSDF
#define FNC_CYLINDERSDF

// vertical
float cylinderSDF( vec3 p, vec2 h ) {
vec2 d = abs(vec2(length(p.xz),p.y)) - h;
return min(max(d.x,d.y),0.0) + length(max(d,0.0));
}

float cylinderSDF( vec3 p, float h ) {
return cylinderSDF( p, vec2(h) );
}

float cylinderSDF( vec3 p, float h, float r ) {
vec2 d = abs(vec2(length(p.xz),p.y)) - vec2(h,r);
return min(max(d.x,d.y),0.0) + length(max(d,0.0));
}

// arbitrary orientation
float cylinderSDF(vec3 p, vec3 a, vec3 b, float r) {
vec3 pa = p - a;
vec3 ba = b - a;
float baba = dot(ba,ba);
float paba = dot(pa,ba);

float x = length(pa*baba-ba*paba) - r*baba;
float y = abs(paba-baba*0.5)-baba*0.5;
float x2 = x*x;
float y2 = y*y*baba;
float d = (max(x,y)<0.0)?-min(x2,y2):(((x>0.0)?x2:0.0)+((y>0.0)?y2:0.0));
return sign(d)*sqrt(abs(d))/baba;
}

#endif
``````

Use:

``````<float> cylinderSDF( in <float3> pos, in <float2|float> h [, <float> r] )
``````
``````<float> cylinderSDF( <float3> p, <float3> a, <float3> b, <float> r)
``````

Check it on Github

``````
#ifndef FNC_CYLINDERSDF
#define FNC_CYLINDERSDF

// vertical
float cylinderSDF( float3 p, float2 h ) {
float2 d = abs(float2(length(p.xz),p.y)) - h;
return min(max(d.x,d.y),0.0) + length(max(d,0.0));
}

float cylinderSDF( float3 p, float h ) {
return cylinderSDF( p, float2(h, h) );
}

float cylinderSDF( float3 p, float h, float r ) {
float2 d = abs(float2(length(p.xz),p.y)) - float2(h,r);
return min(max(d.x,d.y),0.0) + length(max(d,0.0));
}

// arbitrary orientation
float cylinderSDF(float3 p, float3 a, float3 b, float r) {
float3 pa = p - a;
float3 ba = b - a;
float baba = dot(ba,ba);
float paba = dot(pa,ba);

float x = length(pa*baba-ba*paba) - r*baba;
float y = abs(paba-baba*0.5)-baba*0.5;
float x2 = x*x;
float y2 = y*y*baba;
float d = (max(x,y)<0.0)?-min(x2,y2):(((x>0.0)?x2:0.0)+((y>0.0)?y2:0.0));
return sign(d)*sqrt(abs(d))/baba;
}

#endif
``````