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Topic: NullPointerException (Read 320 times) |
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Jordan J
 
 
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NullPointerException
« on: Feb 10th, 2003, 12:18am » |
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I seem to get getting a NullPointerException in this code. Could someone perhaps tell me why?
int W = 640;
int H = 480;
float Scale = 10;
float sub = 0.5;
float num = 1;
float substep = 0.01;
float numstep = 0.01;
float sunx = 0;
float suny = 0;
Planet roger = new Planet();
void setup()
{
size(W, H);
noBackground();
noStroke();
fill(color(0, 0, 0));
rect(0, 0, W, H);
stroke(#FFFFFF);
translate(W, H);
}
void loop()
{
//stroke(roger.colour);
//point(roger.x, roger.y);
//point(sunx, suny);
}
class Planet
{
float x, y;
float xdelta, ydelta;
color colour = color(90, 70, 120);
Planet()
{
x = random(0-(W/2), W);
y = random(0-(H/2), H);
xdelta = 0;
ydelta = 0;
}
void Calcdelta(float xdist, float ydist, float xdelta, float ydelta)
{
float delta = 0;
float dist = sqrt(pow(xdist, 2) + pow(ydist, 2));
if (dist != 0)
{
delta = (num / (1 + dist)) - sub;
xdelta = (xdist / dist) * delta;
ydelta = (ydist / dist) * delta;
}
}
}
void checkKeys()
{
if (keyPressed)
{
//Subtractor
if (key == 'T' || key == 't')
sub += substep;
if (key == 'G' || key == 'g')
sub -= substep;
//Numerator
if (key == 'Y' || key == 'y')
num += numstep;
if (key == 'H' || key == 'h')
num -= numstep;
//Scale
if (key == 'U' || key == 'u')
Scale += 0.01;
if (key == 'J' || key == 'j')
{
Scale -= 0.01;
if (Scale <= 0)
Scale = 0.01;
}
//Randomize
if (key == 'F' || key == 'f')
//randomize();
//Stop
if (key == 'Q' || key == 'q')
stop();
}
}
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Glen Murphy
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Re: NullPointerException
« Reply #1 on: Feb 10th, 2003, 1:44am » |
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One thing, you can't use size(W, H); - you have to put actual integers in there (size(640,480); for example), this is a limitation of P5.
Also, you have random() inside your constructor for Planet - at the moment, you can't have P5 functions inside constructors.
Using a process of commenting stuff out until it works, your NPE is caused by this line:
Code:
color colour = color(90, 70, 120);
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Which is a bit weird, because that line in a P5 by itself runs fine, but whereever I put it in your code, it fails.
After playing with this for a while, I get a P5 error while compiling, which is even a bit more odd. Perhaps this should be moved to bugs?
Don't have time to investigate further, sorry.
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