Drawing java.awt.Shape

Processing Coding Questions
1

I’m using the java.awt.Shape class for collision detection with intersects() and contains(). However, this means that I’m duplication code, and in particular, magic numbers, when drawing vs checking collisions.

an Example:
a bit of the collider code

  public boolean contains(float x, float y, float facing, float checkX, float checkY) {
    AffineTransform at = new AffineTransform();
    at.translate(x,y);
    at.rotate(facing);
    Shape collider = at.createTransformedShape(collision);
    return collider.contains(checkX,checkY);
  }

the code to create the collider:

  protected Shape createCollision() {
    int[] xPoints = new int[3];
    int[] yPoints = new int[3];
    for(int vertex=0; vertex<3; vertex++) {
      float angle=vertex*TWO_PI/3;
      xPoints[vertex]=int(20*cos(angle));
      yPoints[vertex]=int(20*sin(angle));
    }
    Polygon collision = new Polygon(xPoints,yPoints,3);
    return collision;
  }

and the render code

  public void render(float x, float y, float facing) {
    pushMatrix();
    translate(x,y);
    rotate(facing);
    fill(110,82,255);
    beginShape();
    for(int vertex=0; vertex<3; vertex++) {
      float angle=vertex*TWO_PI/3;
      vertex(20*cos(angle),20*sin(angle));
    }
    endShape(CLOSE);
    popMatrix();
  }

so as you can see, there’s quit a bit of code duplication there.
To fix this, I’d like to either:

  • Draw the awt Shape directly (this is preferable)
    or
  • Create the Vertices/PShape based on the collider (or the inverse, create the collider from the render shape during construction)

Unfortunately, I know how to do neither of those using processing functions.

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2

I have some code to draw Shape in Processing inside PraxisLIVE.

Some of the code in this class might be helpful https://github.com/praxis-live/praxis/blob/master/praxis.video.pgl/src/org/praxislive/video/pgl/ops/PGLShapeRenderOp.java

PGLGraphics is basically PGraphics.

EDIT : incidentally, I’m using this with OpenGL. If you’re using the Java2D renderer, you can cast to PGraphicsJava2D, access the Graphics2D and do the same as https://github.com/processing/processing/blob/master/core/src/processing/awt/PGraphicsJava2D.java#L1358

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