On Saturday, 13 April 2013 at 11:59:12 UTC, Simen Kjaeraas wrote:
On Sat, 13 Apr 2013 08:07:39 +0200, Jeremy DeHaan
<dehaan.jerem...@gmail.com> wrote:
In debug mode this works as expected. Let's say the radius is
50. getPoint(0) returns a vector that prints X: 50 Y: 0. For
some reason, the same function will return a vector that
prints X: 50 Y: 4.77673e-14. Now, 4.77673e-14 is a crazy small
number that might as well be 0, but why the difference?
Sounds to me like a bug. I've tried recreating the problem on
my machine
(Win7, dmd 2.062 32-bit, no flags other than debug/release),
but can't see
it happen here. My (perceived) version of your code:
import std.stdio : writeln;
import std.math : sin, cos;
struct Vector2f {
float x,y;
}
int m_pointCount = 25;
float m_radius = 50;
Vector2f getPoint(uint index)
{
static const(float) pi = 3.141592654f;
float angle = index * 2 * pi / m_pointCount - pi / 2;
float x = cos(angle) * m_radius;
float y = sin(angle) * m_radius;
return Vector2f(m_radius + x, m_radius + y);
}
void main( string[] args ) {
writeln( getPoint( 0 ) );
}
Could you please post here the minimum code necessary to get the
behavior you describe, as well as the platform and compiler
flags
you're using?
After playing around I discovered that Mono-D automatically uses
-O for release builds and it looks like that is what is causing
this. After compiling using that switch just from the command
line I reproduced the problem.
I'm on Windows, and I my compilation was nothing more than "dmd
-O -release main.d" to get the issue I described.
