Various Starship effects

Programming Questions

leam_h

in Programming Questions • 3 years ago

My expectation is that I'll have a lot of questions as I learn, don't want to clog the forum. :)

Current issue is that I'm trying to build a file to hold Starship effects as objects. I've done okay with the Turrent, with help from forumites, but now 'm not sure why my blinking light isn't showing up on the sketch at all.

The running light is called with numbers for it's X, Y, diameter, R, G, and B color.

myRunningLight = new RunningLight(50, 50, 5, 100, 100, 255);

However, nothing shows up on the screen. The file is in the same sketchbook directory as the ship file and the turrent file.

RunningLight myRunningLight;

class RunningLight {

// Place these first so the other parts of the ship
// overset them and block the "blink" that would
// be on the hull.

float xpos;
float ypos;
int dia;
int cR;
int cG;
int cB;

RunningLight(float xpos, float ypos, int dia, int cR, int cG, int cB ) {

}

void display() {

    fill(cR, cB, cG);
    ellipseMode(CENTER);
    ellipse(xpos, ypos, dia, dia);
    stroke(cR, cG, cB);
    line(xpos, ypos, xpos, ypos + ( 2 * dia) );
}
}

One bit of confusion I have is the empty "RunningLight" stanza that just takes the parameters. In the Turrent program There were just a few assignments in there. They don't seem to be needed in this one, or am I missing something?

Thanks!

Leam

Replies(4)

leam_h

Re: Various Starship effects

3 years ago

Okay, so this fixes the issue, but I have no idea why...

RunningLight(float tmpXpos, float tmpYpos, int tmpDia, int tmpCR, int tmpCG, int tmpCB ) {
    xpos = tmpXpos;
    ypos = tmpYpos;
    dia = tmpDia;
    cR = tmpCR;
    cG = tmpCG;
    cB = tmpCB;
}

And I'm still confused on how to make it blink. Oh well, it's been a long day at work and night-night time is upon me. I'll cogitate a bit while I snore and see if anything comes to me.

bjordal

Re: Re: Various Starship effects

3 years ago

Okay, so this fixes the issue, but I have no idea why...

really?... someone needs go back to the basic-basics.

the constructors arguments are local to the constructor and will not override the classes members. Generally all the class members should be initialized (or have something assigned to them) in the constructor.

leam_h

Re: Various Starship effects

3 years ago

Really? C'mon, I've spent almost 8-10 hours learning the language so far! ;)

Yeah, I thought about that afterwards. "Variable Scope" in other languages.

Also, fixed my "blinking lights" issue by adding another couple variables:

float dia_multiple;
int count = 0;
...
    frameRate(3);
    fill(cR, cB, cG);
    ellipseMode(CENTER);
    ellipse(xpos, ypos, dia, dia);
    stroke(cR, cG, cB);
    count = count + 1;
    if ( count%2 == 1 ) {
      dia_multiple = 2;
    } else {
      dia_multiple = 1;
    }

    line(xpos, ypos - ( dia_multiple * dia), xpos, ypos + ( dia_multiple * dia) );
    line(xpos - (dia_multiple * dia), ypos, xpos + (dia_multiple * dia), ypos );
    line(xpos - ( dia_multiple * dia), ypos - ( dia_multiple * dia), xpos + ( dia_multiple * dia), ypos + ( dia_multiple * dia) );
    line(xpos + ( dia_multiple * dia), ypos - ( dia_multiple * dia), xpos - ( dia_multiple * dia), ypos + ( dia_multiple * dia) );
}

blindfish

Re: Various Starship effects

3 years ago

Yeah, I thought about that afterwards. "Variable Scope" in other languages.

Well, not really: an empty constructor isn't going to do much! The system isn't going to assume that because the parameter names match class properties the values should be assigned to them... You have to do that yourself ;)

Note that another approach is to use the 'this' keyword to distinguish between a class property and a constructor parameter. Just a matter of personal taste really; but I find the 'someString + ParameterName' jars with my aesthetic sensibilities :)

RunningLight(float xpos, float ypos, int dia, int cR, int cG, int cB ) {
this.xpos = xpos;
this ypos = ypos;
this.dia = dia;
this.cR = cR;
this.cG = cG;
this.cB = cB;
}