How to increase line depth in shader?

I drew a line using this as the shader:

void setEndpointMarkerBorderColor(vec4 rgba);
void setLineWidth(float widthInScreenPixels);
void setEndpointMarkerSize(float diameter);
void main() {
setColor(defaultColor());
setEndpointMarkerSize(3.0);
setLineWidth(3.0);
setEndpointMarkerBorderColor(vec4(0,0,0,0));
}

Is there a way increase the depth/height of the line? Basically, whenever I'm scrolling along the z-axis, the line I drew starts disappearing the further from the original z-point I am, but I just want the line to always appear. I can't seem to find anything in line.ts