Sidescroll camera has inverted view transform

I was using nphysics testbed which uses kiss3d under the hood to display some objects and the look_at method isn't doing what I expected (related issue dimforge/nphysics#243 (comment)). In order to look at (30,20) for example I needed to call the method with negatives (-30,-20). After a bit of digging it seems like the method is a straight pass through to the Sidescroll camera look_at method.

I think this line in the sidecroll.rs file:

    fn update_projviews(&mut self) {
        self.view = Translation2::new(self.at.x, self.at.y).to_homogeneous();

should actually be:

    fn update_projviews(&mut self) {
        self.view = Translation2::new(-self.at.x, -self.at.y).to_homogeneous();

kiss3d/src/planar_camera/sidescroll.rs

Line 109 in cde25c3

self.view = Translation2::new(self.at.x, self.at.y).to_homogeneous();

If that seems right I'm happy to create a PR for the change.

You are right, there should be negative signs in there.

If that seems right I'm happy to create a PR for the change.

That would be great!