I continue to work with Phys2D
For exclusion, i use bitmask :
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| public static final long MASK_NONE = 0;
public static final long MASK_ROAD_CAR = 1;
public static final long MASK_CAR_CAR = 2;
public static final long MASK_OPTION_CAR = 4; |
For "road" body, i use MASK_ROAD_CAR.
For "car" body, i use MASK_ROAD_CAR | MASK_CAR_CAR | MASK_OPTION_CAR
...
It work fine. But i came accros another problem
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| for(int i=0;i<NB_V;i++)
{
cars[i].step();
}
world.step();
for(int i=0;i<NB_V;i++)
{
int val = map.crossStart(cars[i]);
if (val != 0) { System.out.println("Start : "+val); }
} |
In Map.crossStart, I test if a car cross the start line.
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| public int crossStart(Car car)
{
float cx1 = car.getPosition().getX();
float cy1 = car.getPosition().getY();
float cx2 = car.getLastPosition().getX();
float cy2 = car.getLastPosition().getY();
Line l = (Line)start.getShape();
float sx1 = l.getX1();
float sy1 = l.getY1();
float sx2 = l.getX2();
float sy2 = l.getY2();
float nx = (sx2-sx1);
float ny = (sy2-sy1);
int signe1 = (int)Math.signum((cx1-sx1)*(ny)-(cy1-sy1)*(nx));
int signe2 = (int)Math.signum((cx2-sx1)*(ny)-(cy2-sy1)*(nx));
if (signe1 == signe2) { return 0; }
float ln = (float)(Math.sqrt(nx*nx+ny*ny));
nx = nx/ln;
ny = ny/ln;
float dist = (cx1-sx1)*nx+(cy1-sy1)*ny;
if ((dist<0)||(dist>ln)) { return 0; }
return signe1;
} |
If i use the Body.getLastPosition to do the test, it didn't work.
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| class Car
{
[...]
public ROVector2f getPosition()
{
return body.getPosition();
}
public ROVector2f getLastPosition()
{
return body.getLastPosition();
} |
If i store the current possition before World.step(), it work.
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| class Car
{
[...]
public ROVector2f getPosition()
{
return body.getPosition();
}
public void step()
{
lastPosition.set(body.getPosition().getX(),body.getPosition().getY());
}
public ROVector2f getLastPosition()
{
return lastPosition;
}
} |
Body.getLastPosition didn't mean to return the position of the body before the world.step() ?
