Lattice to pre-calculate and pass FaceNormals

Author: mohawk2

demos/test5.p

@@ -18,7 +18,7 @@ my @objs = (
   ['Lattice', {Shading=>0}],
   ['Lattice', {Shading=>1}],
   ['Lattice', {Shading=>2}],
-  ['Lattice', {Shading=>3, Lighting => 1}],
+  ['Lattice', {Shading=>3, Lighting => 1, ShowNormals => 1}],
   ['Lattice', {Shading=>3, Lighting => 1, ShowNormals => 1, Smooth=>1}],
 );
 my $i = 0;

lib/PDL/Graphics/TriD/GL.pm

@@ -194,24 +194,39 @@ sub PDL::Graphics::TriD::Lattice::gdraw {
     if grep $_->ndims < 3, $points, $this->{Colors};
   my $options = $this->{Options};
   my $shading = $options->{Shading};
+  my $faces = !defined $this->{Faceidx} ? undef : $points->clump(1..$points->ndims-1)->dice_axis(1,$this->{Faceidx}->flat)->splitdim(1,3);
+  my $colours = !defined $this->{Faceidx} ? undef : $this->{Colors}->clump(1..$this->{Colors}->ndims-1)->dice_axis(1,$this->{Faceidx}->flat)->splitdim(1,3);
   if ($shading == 0) {
     $this->_lattice_lines($points,$this->{Colors});
   } else {
     glShadeModel($shading == 1 ? GL_FLAT : GL_SMOOTH);
     my $f = 'PDL::gl_triangles';
-    $f .= '_' . ($this->{Options}{Smooth} ? 'w' : '') . 'n' if $shading > 2;
+    $f .= '_wn' if $shading > 2;
     { no strict 'refs'; $f = \&$f; }
     if ($shading > 2) { glColorMaterial(GL_FRONT_AND_BACK,GL_DIFFUSE); glEnable(GL_COLOR_MATERIAL); }
-    _lattice_slice($f, $points, $this->{Options}{Smooth} ? $this->{VertexNormals} : (), $this->{Colors});
+    my $tmpn = $shading <= 2 ? undef : $options->{Smooth}
+      ? $this->{VertexNormals}->dice_axis(1,$this->{Faceidx}->flat)
+                    ->splitdim(1,$this->{Faceidx}->dim(0)) : $this->{FaceNormals}->dummy(1,3);
+    $f->(map $_->mv(1,-1)->dog, $faces, $shading > 2 ? $tmpn : (), $colours);
     if ($shading > 2) { glDisable(GL_COLOR_MATERIAL); }
-    $this->_lattice_lines($points) if $this->{Options}{Lines};
+    $this->_lattice_lines($points) if $options->{Lines};
   }
   if ($options->{ShowNormals}) {
-    die "No normals to show!" if !defined $this->{VertexNormals};
-    my $arrows = $points->append($points + $this->{VertexNormals}*0.1)->splitdim(0,3);
-    glDisable(GL_LIGHTING);
-    glColor3d(1,1,1);
-    PDL::Graphics::OpenGLQ::gl_arrows($arrows, 0, 1, 0.5, 0.02);
+    die "No normals to show!" if !grep defined $this->{$_}, qw(FaceNormals VertexNormals);
+    if (defined $this->{VertexNormals}) {
+      my $points_clumped = $points->clump(1..$points->ndims-1);
+      my $arrows = $points_clumped->append($points_clumped + $this->{VertexNormals}*0.1)->splitdim(0,3);
+      glDisable(GL_LIGHTING);
+      glColor3d(1,1,1);
+      PDL::Graphics::OpenGLQ::gl_arrows($arrows, 0, 1, 0.5, 0.02);
+    }
+    if (defined $this->{FaceNormals}) {
+      my $facecentres = $faces->transpose->avgover;
+      my $facearrows = $facecentres->append($facecentres + $this->{FaceNormals}*0.1)->splitdim(0,3);
+      glDisable(GL_LIGHTING);
+      glColor3d(0.5,0.5,0.5);
+      PDL::Graphics::OpenGLQ::gl_arrows($facearrows, 0, 1, 0.5, 0.02);
+    }
   }
 }
 

lib/PDL/Graphics/TriD/Objects.pm

@@ -163,9 +163,13 @@ sub get_valid_options { +{
 }}
 sub cdummies { $_[1]->dummy(1,$_[2]->getdim(1)); }
 
+# lattice -> triangle vertices:
+# 4  5  6  7  ->  formula: origin coords + sequence of orig size minus top+right
+# 0  1  2  3      4,0,1,1,5,4  5,1,2,2,6,5    6,2,3,3,7,6
 package PDL::Graphics::TriD::Lattice;
+use PDL::Graphics::OpenGLQ;
 use base qw/PDL::Graphics::TriD::GObject/;
-use fields qw/VertexNormals/;
+use fields qw/VertexNormals Faceidx FaceNormals/;
 sub cdummies {
   my $shading = $_[0]{Options}{Shading};
   !$shading ? $_[1]->dummy(1)->dummy(1) :
@@ -184,34 +188,18 @@ sub get_valid_options { +{
 sub new {
   my ($class,$points,$colors,$options) = @_;
   my $this = $class->SUPER::new($points,$colors,$options);
-  $this->{VertexNormals} //= $this->smoothn($this->{Points}) if $this->{Options}{Smooth};
+  ($points, $options) = @$this{qw(Points Options)};
+  if ($options->{Shading} or $options->{ShowNormals}) {
+    my (undef, $x, $y, @extradims) = $points->dims;
+    my $inds = PDL::ulong(0,1,$x,$x+1,$x,1)->slice(',*'.($x-1).',*'.($y-1));
+    $inds = $inds->dupN(1,1,@extradims) if @extradims;
+    my $indadd = PDL->sequence($x,$y,@extradims)->slice('*1,:-2,:-2');
+    my $faceidx = $this->{Faceidx} = ($inds + $indadd)->splitdim(0,3)->clump(1..3+@extradims);
+    my ($fn, $vn) = triangle_normals($points->clump(1..2+@extradims), $faceidx);
+    $this->{VertexNormals} = $vn if $options->{Smooth} or $options->{ShowNormals};
+    $this->{FaceNormals} = $fn if !$options->{Smooth} or $options->{ShowNormals};
+  }
   $this;
 }
-# calculate smooth normals
-sub smoothn {
-  my ($this,$p) = @_;
-  # coords of parallel sides (left and right via 'lags')
-  my $trip = $p->lags(1,1,2)->slice(':,:,:,1:-1') -
-		$p->lags(1,1,2)->slice(':,:,:,0:-2');
-  # coords of diagonals with dim 2 having original and reflected diags
-  my $trid = ($p->slice(':,0:-2,1:-1')-$p->slice(':,1:-1,0:-2'))
-		    ->dummy(2,2);
-  # $ortho is a (3D,x-1,left/right triangle,y-1) array that enumerates
-  # all triangles
-  my $ortho = $trip->crossp($trid);
-  $ortho->norm($ortho); # normalise inplace
-  # now add to vertices to smooth
-  my $aver = ref($p)->zeroes(PDL::float(), $p->dims);
-  # step 1, upper right tri0, upper left tri1
-  $aver->lags(1,1,2)->slice(':,:,:,1:-1') += $ortho;
-  # step 2, lower right tri0, lower left tri1
-  $aver->lags(1,1,2)->slice(':,:,:,0:-2') += $ortho;
-  # step 3, upper left tri0
-  $aver->slice(':,0:-2,1:-1') += $ortho->slice(':,:,(0)');
-  # step 4, lower right tri1
-  $aver->slice(':,1:-1,0:-2') += $ortho->slice(':,:,(1)');
-  $aver->norm($aver);
-  return $aver;
-}
 
 1;