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Bug
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Resolution: Fixed
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Minor
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None
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None
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None
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Tested on both Windows 10 (64bit) and Ubuntu 16.04 (64bit)
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CraftBukkit version git-Spigot-e7dc2f5-a8ec1d6 (MC: 1.15.2) (Implementing API version 1.15.2-R0.1-SNAPSHOT)
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Yes
When using setDirection(Vector) on a fireball, it will start to move at 10 times the intended velocity.
This can be tested by using the following code: (Also attached in Jar with source)
@EventHandler public void test(ProjectileLaunchEvent event){ if(event.getEntity() instanceof Fireball){ Fireball fireball = (Fireball) event.getEntity(); fireball.setDirection(fireball.getDirection()); } }
After some investigation it appears that the original EntityFireball in the Vanilla Server uses the following method to set the direction.
public void setDirection(double d0, double d1, double d2) { d0 += this.random.nextGaussian() * 0.4D; d1 += this.random.nextGaussian() * 0.4D; d2 += this.random.nextGaussian() * 0.4D; double d3 = (double) MathHelper.sqrt(d0 * d0 + d1 * d1 + d2 * d2); this.dirX = d0 / d3 * 0.1D; this.dirY = d1 / d3 * 0.1D; this.dirZ = d2 / d3 * 0.1D; }
While the CraftFireball seems to miss the last step after normalizing the vector (multiplying the direction values by 0.1D)
@Override public void setDirection(Vector direction) { Validate.notNull(direction, "Direction can not be null"); double x = direction.getX(); double y = direction.getY(); double z = direction.getZ(); double magnitude = (double) MathHelper.sqrt(x * x + y * y + z * z); getHandle().dirX = x / magnitude; getHandle().dirY = y / magnitude; getHandle().dirZ = z / magnitude; }
By adding the final step (* 0.1D) to the CraftBukkit class and compiling the server from the fixed source I was able to fix the bug.
I am however currently unable to submit a PR for this bug fix on Git.
