fix camera tutorial

Author: peteroupc

tutorials/camera.md

@@ -1,15 +1,15 @@
 ## The "Camera" and the Projection and View Transforms
 
-The `Scene3D` class has a concept of a "projection transform" and a "view transform". If we use the concept of a "camera", the projection is like setting the camera's focus and lens, and the view transform is like setting its position and orientation. `Scene3D` has methods for setting all these attributes of this abstract "camera". Two of them are `setPerspective()` and `setLookAt(), which are shown in the example below.
+The `Scene3D` class has a concept of a "projection transform" and a "view transform". If we use the concept of a "camera", the projection is like setting the camera's focus and lens, and the view transform is like setting its position and orientation. `Scene3D` has methods for setting all these attributes of this abstract "camera". Two of them are `setPerspective()` and `setLookAt()`, which are shown in the example below.
 
-  // Set the perspective view.  Camera has a 45-degree field of view
-  // and will see objects from 0.1 to 100 units away.
-  scene.setPerspective(45,scene.getAspect(),0.1,100);
-  // Move the camera back 40 units.
-  scene.setLookAt([0,0,40]);
-  // Move the camera back 30 units instead, and turn it so it
-  // points at (0, 2, 0), that is, up 2 units.
-  scene.setLookAt([0,0,30], [0,2,0]);
+    // Set the perspective view.  Camera has a 45-degree field of view
+    // and will see objects from 0.1 to 100 units away.
+    scene.setPerspective(45,scene.getAspect(),0.1,100);
+    // Move the camera back 40 units.
+    scene.setLookAt([0,0,40]);
+    // Move the camera back 30 units instead, and turn it so it
+    // points at (0, 2, 0), that is, up 2 units.
+    scene.setLookAt([0,0,30], [0,2,0]);
 
 In 3D graphics, the two most commonly used projections are the perspective projection and the orthographic projection.  Both are described in detail below.