Update bw_shader.rb

Use tap to avoid temporary variable shape

shaders/bw_shader.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'picrate'
 
 class BwShader < Processing::App
@@ -21,29 +23,29 @@ def setup
   def draw
     background(0)
     shader(bw_shader)
-    translate(width/2, height/2)
+    translate(width / 2, height / 2)
     rotate_y(angle)
     shape(can)
     @angle += 0.01
   end
 
   def create_can(r, h, detail, tex)
     texture_mode(NORMAL)
-    sh = create_shape
-    sh.begin_shape(QUAD_STRIP)
-    sh.no_stroke
-    sh.texture(tex)
-    (0..detail).each do |i|
-      angle = TAU / detail
-      x = sin(i * angle)
-      z = cos(i * angle)
-      u = i.to_f / detail
-      sh.normal(x, 0, z)
-      sh.vertex(x * r, -h/2, z * r, u, 0)
-      sh.vertex(x * r, +h/2, z * r, u, 1)
+    create_shape.tap do |sh|
+      sh.begin_shape(QUAD_STRIP)
+      sh.no_stroke
+      sh.texture(tex)
+      (0..detail).each do |i|
+        angle = TAU / detail
+        x = sin(i * angle)
+        z = cos(i * angle)
+        u = i.to_f / detail
+        sh.normal(x, 0, z)
+        sh.vertex(x * r, -h / 2, z * r, u, 0)
+        sh.vertex(x * r, +h / 2, z * r, u, 1)
+      end
+      sh.end_shape
     end
-    sh.end_shape
-    sh
   end
 end