Hi.

I am a new user interested in computational fluid dynamics.

while trying to run this simple script:

void setup()
{
 size(500,500);
 framerate(30);
}

void draw()
{
 background(204);

 //create grid
 for(float i=1; i<500; i=i+20) {
   for(float j=1; j<500; j=j+20) {


 pushMatrix();
 

//find slope, then rotate
translate(i,j);
float slope =(j-mouseY)/(i-mouseX);

rotate(slope);
 line(0, 0, 10, 10);
 popMatrix();
 
}
}


}

I get the following error codes:
java.lang.InternalError: Unable to Stroke shape (setPenT4: invalid pen transformation (singular))


at sun.java2d.pipe.LoopPipe.getStrokeSpans(Unknown Source)


at sun.java2d.pipe.LoopPipe.draw(Unknown Source)


at sun.java2d.pipe.ValidatePipe.draw(Unknown Source)


at sun.java2d.SunGraphics2D.draw(Unknown Source)


at processing.core.PGraphics2.stroke_shape(PGraphics2.java:383)


at processing.core.PGraphics2.line(PGraphics2.java:411)


at processing.core.PApplet.line(PApplet.java:5827)


at Temporary_9210_1234.draw(Temporary_9210_1234.java:27)


at processing.core.PApplet.display(PApplet.java:1116)


at processing.core.PGraphics.requestDisplay(PGraphics.java:362)


at processing.core.PApplet.run(PApplet.java:951)


at java.lang.Thread.run(Unknown Source)

From reading the documentation, it seems as if this should work. Am I doing something wrong??

Thanks,
Meg
UMCP
http://www.megmitchell.com/eyecandy/