GLSL shader example
Warp-Speed Star Trails
Angle fixes trail direction while reciprocal radius and time create radial motion. Trails stretch toward the perimeter.
Live example
Edit the code and the preview updates as you type.
What to observe
Warp-Speed Star Trails.
Mechanism
Angle fixes trail direction while reciprocal radius and time create radial motion. Trails stretch toward the perimeter.
The controlling code
float a=atan(p.y,p.x),r=max(length(p),.01);float sector=floor(a*130.),phase=fract(1./r*.5+u_time*(.5+u_parameter*3.)+hash(vec2(sector)));float line=pow(.5+.5*cos(a*130.),24.)*pow(phase,15.);c+=vec3(.5,.7,1.)*line*smoothstep(.08,.3,r);
Experiment
Set u_parameter to 0 and then 1, changing phase speed .5+u_parameter*3. from 0.5 to 3.5. Radial streaks move faster while their angular sectors stay fixed.
Debugging and cost
The reciprocal radius is bounded by max(length(p),.01) and the central fade uses smoothstep(.08,.3,r). Increase .08 to .2 to clear a larger center; these streaks are computed per pixel without particle buffers.