Duta wrote ...
2012/3/10
Here's a challenge for someone! :)
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I've only just found both of the versions have an extra feature I didn't notice before. Hold down the mouse button while moving it - it has different effects between the 2 versions
Very interesting, no idea how to go about it :D.
here's what i got so far.
for 1, i get a null pointer exception if i actually try to call the mouseDraw() method. for testing purposes (not included here) i created an actor that moves around a bit and then calls, essentially, the mousedraw method on its own xy position, instead of using mouse xy position.
i notice he's followed by a white pixel that disappears almost immediately.
my next step is to change the fadeout code from setting the background color to black, to setting the background color incrementally less than it's current value.
but i'm not sure yet how to get a number value from java.awt.Color. I'm still working on it.
public class Black_Background extends World
{
/**
* Constructor for objects of class Black_Background.
*
*/
public Black_Background()
{
// Create a new world with 600x400 cells with a cell size of 1x1 pixels.
super(600, 400, 1);
addObject (new Test_Drawer(), 100,100);
}
public void act()
{
// mouseDraw();
fadeOut();
}
public void mouseDraw()
{
getBackground().setColorAt(Greenfoot.getMouseInfo().getX(),
Greenfoot.getMouseInfo().getY(), Color.WHITE);
}
public void fadeOut()
{
for (int i = 0; i < getWidth(); i++)
{
for (int j = 0; j < getHeight(); j++)
{
if (getBackground().getColorAt(i,j) != Color.BLACK)
{
getBackground().setColorAt(i,j, Color.BLACK);
}
}
}
}
}
@matt.milan To get around that exception, here's one way:
Also enclose your code that you post on here with tags - it makes it easier to read :)
public void mouseDraw()
{
MouseInfo m = Greenfoot.getMouseInfo();
if(m == null) return;
getBackground().setColorAt(m.getX(),
m.getY(), Color.WHITE);
}You get a color value by color.getBlue() for blue, color.getGreen() for green, etc.
thanks for the instruction duta, that fixed it alright.
here's my modified mouseDraw code, i put in a check to see if the x/y values are out of range, beucase it was crashing me out.
and here's the code for fadeout, at first it was crashing out because i was reaching negative values for color which is no good,
public void mouseDraw()
{
MouseInfo m = Greenfoot.getMouseInfo();
if (m == null) return;
if (!(m.getX() > getWidth() || m.getY() > getHeight()))
{
getBackground().fillOval(m.getX(), m.getY(), 10,10);
}
}
public void fadeOut()
{
for (int i = 0; i < getWidth(); i++)
{
for (int j = 0; j < getHeight(); j++)
{
fadeColor = getBackground().getColorAt(i,j);
int r = fadeColor.getRed();
int b = fadeColor.getBlue();
int g = fadeColor.getGreen();
if (r > 5)
{
r-=5;
}
if (b > 5)
{
b-=5;
}
if (g > 5)
{
g-=5;
}
if (getBackground().getColorAt(i,j) != baseColor)
{
getBackground().setColorAt(i,j, new Color(r,b,g));
}
}
}
}
after reflecting on my code for a bit, i think i'm supposed to be writing it differently
instead of the mouse painting the background, the mouse should "shoot" objects that paint the background as they move. they should have a lifespan relative to their velocity. they should get the color at each pixel and modify it slightly based on different behavior.
about done for the night... so far we got this
I think my math is wrong in calculateMouseSpeed and calculateMouseDirection.
i am also experiencing a divide by zero error on my calculateMouseSlope if the mouse isn't moving enough, or is moving too much.
import java.awt.Color;
import greenfoot.*
public class Black_Background extends World
{
private MouseInfo mouseNew;
private MouseInfo mouseOld;
private Color fadeColor = new Color(0,0,0);
private Color baseColor = new Color(0,0,0);
private Color myColor = new Color (0,200,200);
private int r;
private int b;
private int g;
public void act()
{
mouseShootParticle();
fadeOut();
}
public void mouseShootParticle()
{
mouseNew = Greenfoot.getMouseInfo();
if (mouseNew == null ) return;
if (mouseOld != mouseNew)
{
if (!(mouseNew.getX() > getWidth() || mouseNew.getY() > getHeight()))
{
addObject(new ColorParticle(calculateMouseSpeed(),
calculateMouseDirection()),
mouseNew.getX(), mouseNew.getY());
//addObject(new ColorParticle(10, 10),mouseNew.getX(), mouseNew.getY());
}
mouseOld = mouseNew;
} else
if (mouseOld == mouseNew)
{
//idleMouseParticles();
}
}
public void fadeOut()
{
for (int i = 0; i < getWidth(); i++)
{
for (int j = 0; j < getHeight(); j++)
{
if (getBackground().getColorAt(i,j) != baseColor)
{
fadeColor = getBackground().getColorAt(i,j);
r = fadeColor.getRed();
b = fadeColor.getBlue();
g = fadeColor.getGreen();
if (r > 10)
{
r-=5;
} else
if (r <= 10)
{
r = 0;
}
if (b > 10)
{
b-=5;
} else
if (b <= 10)
{
b = 0;
}
if (g > 10)
{
g-=5;
} else
if (g <= 10)
{
g = 0;
}
getBackground().setColorAt(i,j, new Color(r,b,g));
}
}
}
}
public int calculateMouseSpeed()
{
return (int)(calculateMouseDistance() / 1);
}
public int calculateMouseDirection()
{
return (int)(Math.tan(calculateMouseSlope()));
}
public double calculateMouseDistance()
{
return Math.sqrt(Math.pow(mouseOld.getX() - mouseNew.getX(),2)
+ Math.pow(mouseOld.getY() - mouseNew.getY(),2));
}
public double calculateMouseSlope()
{
if (Greenfoot.mouseMoved(null))
{
return (mouseOld.getY() - mouseNew.getY() / (mouseOld.getX() - mouseNew.getX()));
}
else
{
return 1;
}
}
For calculateMouseDirection I think something like this might work (haven't tested it though):
Also once you have that you can basically remove calculateMouseSlope().
To call this method do:
public int calculateMouseDirection() throws Exception
{
(int)(180 * Math.atan2(mouseNew.getY() - mouseOld.getY(), mouseNew.getX() - mouseOld.getX()) / Math.PI)
}try {
addObject(new ColorParticle(calculateMouseSpeed(),
calculateMouseDirection()),
mouseNew.getX(), mouseNew.getY());
} catch(Exception e) {}it does feel slow, i wonder if there's a limit to how far we can optimize this in greenfoot.
duta, take a look at this (this is in world)
and then when the mouse fires a particle you call shapesize
that's how i made it so that when you drag, only new particles get big, the old ones stay small
public void grow()
{
if (Greenfoot.mousePressed(null))
{
shapeSize= 150;
}
if (Greenfoot.mouseClicked(null))
{
shapeSize = 20;
}
}
if (!(mouseNew.getX() > getWidth() || mouseNew.getY() > getHeight()))
{
try {
addObject(new ColorParticle(calculateMouseSpeed(),
calculateMouseDirection(), shapeSize),
mouseNew.getX() - (shapeSize / 2), mouseNew.getY() - (shapeSize / 2));
} catch(Exception e) {}
}
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