On 03.06.2012 01:47, Christopher Night wrote:
On Sat, Jun 2, 2012 at 1:50 PM, DR0ID <dr...@bluewin.ch
<mailto:dr...@bluewin.ch>> wrote:
On 02.06.2012 16:46, Christopher Night wrote:
On Fri, Jun 1, 2012 at 2:29 PM, DR0ID <dr...@bluewin.ch
<mailto:dr...@bluewin.ch>> wrote:
On 01.06.2012 15:29, Sagie Maoz wrote:
2. Setting a sprite's anchor points for handling in
movement, animation, collision etc.
5. New visual attributes for sprites:
- Rotation angle
- Scale
2. the sprites anchor point should be just an offset, not
limited to 'topleft', 'midtop', 'topright',... and the other
rect attributes
I want to be able to specify "center" or "midbottom" for the
sprite anchor without knowing the image's dimensions. And I want
that anchor point to remain in the appropriate place even if the
image is rotated, scaled, or flipped. I'm not sure that an offset
would accomplish this, but if so, then that's okay.
-Christopher
Hi
I agree, what I suggested is that both things should be possible:
a general offset and/or specifying 'center' or 'midbottom' or....
I'm not sure right now how the math to maintain the point at the
appropriate place. Maybe this needs some more specification for
the different transformations (rotation, flip, scale).
Well the desired behavior is pretty straightforward to me. Say I
specify a sprite's anchor as "midbottom", and the sprite's image has a
single orange pixel at its mid-bottom. Then if I ask to draw the
sprite at (200, 100), then that orange pixel should wind up at (200,
100) no matter how the sprite is transformed (maybe one pixel off
because of rounding). The math shouldn't be too hard to work out from
that.
-Christopher
Hi once again
In the mean time, I have implemented such a system that leaves the
anchor where it is, but I run into a problem: the order of applying the
transformations. It's not exactly the same if you first flip and then
rotate or the other way around, first rotate and then flip. To see
better what I'm talking about: http://imagebin.org/215001
What is more useful?
As for now my implementation does first rotate and then flip, because
that looks like the behavior I would want if I write a platformer or
similar game. I then have thought about how many cases a flip and
rotation would be used on the same sprite at the same time and I think
there are not that man occasions. But maybe I'm wrong.
As for scaling it does not matter when it occurs, although I use
rotozoom (which has an annoying black border when rotate by a multiple
of 90 degrees, which looks like the entire image is shifted by 1 or 2
pixels for whatever reason, bug! bug!, also not sure how transparency is
handled by it).
~DR0ID