OpenGL strokeCap(ROUND) and strokeJoin should account for scale when computing the number of arc points

Created by: scudly

The default renderer very smoothly supports zooming in on ROUND line endcaps and joins while maintaining their roundness. P2D and P3D, however, assume that any strokeWeight less than one won't have visible endcaps even when the scale factor blows them up to many pixels in size.

The following code runs fine with s = 600, i.e., no scaling. Change to s = 1, however, and the endcaps and joins disappear. Remove the P2D and both cases will stay smooth.

float s = 600;
void setup() {
  size( 600, 600, P2D );
  noFill();
  scale( height/s );
  strokeWeight( 0.2*s );
  point( 0.3*s, 0.3*s );
  strokeJoin( ROUND );
  beginShape();
  vertex( 0.6*s, 0.2*s );
  vertex( 0.8*s, 0.8*s );
  vertex( 0.2*s, 0.6*s );
  endShape();
}

Empieza ejecutando el sketch proporcionado con P2D en s = 600 y s = 1, y luego compáralo sin P2D. Rastrea cómo P2D y P3D manejan los extremos y las uniones de trazo ROUND, centrándote en cómo el recuento de puntos del arco usa strokeWeight y scale. Se considera terminado cuando los trazos reducidos conservan extremos y uniones redondos, suaves y visibles.