change mouse control from ArcBall-like to orbiting-camera-like

Author: mohawk2

Changes

@@ -1,5 +1,6 @@
 - non-trivial tests added
 - add overloads of ::Quaternion
+- change mouse control from ArcBall-like to orbiting-camera-like
 
 2.100 2025-01-16
 - adjust MathGraph and Labels so Debian packaging is happy

lib/PDL/Graphics/TriD/ArcBall.pm

@@ -106,4 +106,26 @@ sub get_z {
   cos($dist*PI/2);
 }
 
+package PDL::Graphics::TriD::Orbiter;
+
+use base qw/PDL::Graphics::TriD::QuaterController/;
+BEGIN { *PI = \&PDL::Graphics::TriD::QuaterController::PI; }
+
+# we rotate about our space's "Z" because that's what we made vertical
+# this is different from the OpenGL Z axis which is towards the viewer
+sub mouse_moved {
+  my($this,$x0,$y0,$x1,$y1) = @_;
+  $this->SUPER::mouse_moved($x0,$y0,$x1,$y1);
+  my ($dx, $dy) = ($x1-$x0, $y1-$y0);
+  $dx /= $this->{W}/2; $dy /= $this->{H}/2; # scale to whole window not SC
+  my ($x_rad, $y_rad) = map PI*$_, $dx, $dy;
+  my $q_horiz = PDL::Graphics::TriD::Quaternion->new(cos $x_rad/2, 0, 0, sin $x_rad/2);
+  my $q_vert = PDL::Graphics::TriD::Quaternion->new(cos $y_rad/2, sin $y_rad/2, 0, 0);
+  if ($this->{Inv}) {
+    $_->invert_rotation_this for $q_horiz, $q_vert;
+  }
+  $this->{Quat} .= $q_vert * $this->{Quat} * $q_horiz;
+  1;  # signals a refresh
+}
+
 1;

lib/PDL/Graphics/TriD/Window.pm

@@ -67,7 +67,7 @@ sub new_viewport {
 	 my $cont = $options->{Transformer} // PDL::Graphics::TriD::SimpleController->new;
 	 $vp->transformer($cont);
 	 if (ref($ev)){
-		$ev->set_button(0,PDL::Graphics::TriD::ArcCone->new( $vp, 0, $cont->{WRotation}));
+		$ev->set_button(0,PDL::Graphics::TriD::Orbiter->new( $vp, 0, $cont->{WRotation}));
 		$ev->set_button(2,PDL::Graphics::TriD::SimpleScaler->new( $vp, \$cont->{CDistance}));
 		$ev->set_button(3,PDL::Graphics::TriD::ScrollButtonScaler->new( $vp, \$cont->{CDistance}, 0.9));
 		$ev->set_button(4,PDL::Graphics::TriD::ScrollButtonScaler->new( $vp, \$cont->{CDistance}, 1.1));

t/arcball.t

@@ -62,4 +62,12 @@ is_qua $arcbowl->xy2qua(75,75), [0,0.598834,-0.598834,0.531784];
 mousemove $arcbowl, 50, 50, 50, 50, [1,0,0,0];
 mousemove $arcbowl, 50, 50, 25, 25, [0.531784,-0.598834,-0.598834,0];
 
+my $orbiter = PDL::Graphics::TriD::Orbiter->new($win);
+isa_ok $orbiter, 'PDL::Graphics::TriD::Orbiter';
+$orbiter->set_wh(100,100);
+mousemove $orbiter, 50, 50, 50, 50, [1,0,0,0];
+mousemove $orbiter, 25, 25, 25, 25, [1,0,0,0];
+mousemove $orbiter, 50, 50, 25, 25, [0.5,-0.5,-0.5,-0.5];
+mousemove $orbiter, 25, 25, 0, 0, [0.5,-0.5,-0.5,-0.5];
+
 done_testing;