processing/processing4

Issue when using a transparent stroke with vertex()

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#675 opened on Feb 20, 2023

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Description

Created by: finerrecliner

Description

I'm running into a possible bug when using vertex() with a stroke that has transparency/alpha. I would expect the color to be consistent from the beginning to the end of the drawn line. Instead there are "dots" that appear at the vertices. Here is an example:

size(400, 400, P2D);
smooth(8);
background(0);
stroke(255, 60);
noFill();
strokeWeight(1.9);
beginShape();
for (int x = 100, y = 100; x < 300; x+=20, y+=20) {
  vertex(x, y);
}
endShape();

Screenshot 2023-02-20 123627

I'd like to use a strokeWeight of 1 in my project, but the issue is easier to visualize at 1.9. The issue goes away if using a strokeWeight >= 2.0, as seen here:

Screenshot 2023-02-20 130203

The issue also goes away if using the default renderer instead of P2D, but I need to use P2D for my project for additional reasons. I've tried using different strokeJoin options but it doesn't seem to change the result here.

My Environment

  • Processing v4.1.2
  • Windows 10
  • Nvidia RTX 2060 Super

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