Subchapters: integrating review feedback

Author: hollasch

books/RayTracingInOneWeekend.html

@@ -116,7 +116,7 @@
      corner to be yellow.
 
 
-Creating An Image File
+Creating an Image File
 -----------------------
 <div class='together'>
 Because the file is written to the program output, you'll need to redirect it to an image file.
@@ -221,8 +221,8 @@
 have a good point, but we’re going to always take the “less code” route when not obviously wrong.
 
 
-Main Class
------------
+Variables and Methods
+----------------------
 <div class='together'>
 Here’s the top part of my `vec3` class:
 
@@ -423,7 +423,7 @@
 </div>
 
 
-Sending Rays Into The Scene
+Sending Rays Into the Scene
 ----------------------------
 Now we are ready to turn the corner and make a ray tracer. At the core, the ray tracer sends rays
 through pixels and computes the color seen in the direction of those rays. The involved steps are
@@ -640,7 +640,7 @@
 ====================================================================================================
 
 
-Shading With Surface Normals
+Shading with Surface Normals
 -----------------------------
 First, let’s get ourselves a surface normal so we can shade. This is a vector that is perpendicular
 to the surface at the point of intersection. There are two design decisions to make for normals.
@@ -709,8 +709,8 @@
 </div>
 
 
-Improving the Ray-Sphere Intersection Code
--------------------------------------------
+Simplifying the Ray-Sphere Intersection Code
+---------------------------------------------
 Let’s revisit the ray-sphere equation:
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
@@ -988,8 +988,8 @@
 </div>
 
 
-Lists of Hittable Objects
---------------------------
+A List of Hittable Objects
+---------------------------
 <div class='together'>
 We add a list of objects:
 
@@ -1282,7 +1282,7 @@
 </div>
 
 
-Generating Pixels With Multiple Samples
+Generating Pixels with Multiple Samples
 ----------------------------------------
 <div class='together'>
 For a given pixel we have several samples within that pixel and send rays through each of the
@@ -1512,7 +1512,7 @@
 </div>
 
 
-Limiting The Number of Child Rays
+Limiting the Number of Child Rays
 ----------------------------------
 <div class='together'>
 There's one potential problem lurking here. Notice that the `ray_color` function is recursive. When
@@ -1582,7 +1582,7 @@
 </div>
 
 
-Using Gamma Correction For Accurate Color Intensity
+Using Gamma Correction for Accurate Color Intensity
 ----------------------------------------------------
 <div class='together'>
 Note the shadowing under the sphere. This picture is very dark, but our spheres only absorb half the
@@ -1722,8 +1722,8 @@
 </div>
 
 
-Even Truer Lambertian Reflection
----------------------------------
+An Alternative Diffuse Formulation
+-----------------------------------
 <div class='together'>
 The initial hack presented in this book lasted a long time before it was proven to be an incorrect
 approximation of ideal Lambertian diffuse. A big reason that the error persisted for so long is
@@ -1806,7 +1806,7 @@
 Metal
 ====================================================================================================
 
-An Abstract Class For Materials
+An Abstract Class for Materials
 --------------------------------
 If we want different objects to have different materials, we have a design decision. We could have a
 universal material with lots of parameters and different material types just zero out some of those
@@ -1832,7 +1832,7 @@
 </div>
 
 
-A Data Structure To Describe Ray-Object Intersections
+A Data Structure to Describe Ray-Object Intersections
 ------------------------------------------------------
 <div class='together'>
 The `hit_record` is to avoid a bunch of arguments so we can stuff whatever info we want in there.
@@ -1946,7 +1946,7 @@
 </div>
 
 
-Modeling Light Scatter And Reflectance
+Modeling Light Scatter and Reflectance
 ---------------------------------------
 <div class='together'>
 For the Lambertian (diffuse) case we already have, it can either scatter always and attenuate by its
@@ -2056,7 +2056,7 @@
 </div>
 
 
-A Scene With Metal Spheres
+A Scene with Metal Spheres
 ---------------------------
 <div class='together'>
 Now let’s add some metal spheres to our scene:
@@ -2603,7 +2603,7 @@
 </div>
 
 
-Positioning and Orienting The Camera
+Positioning and Orienting the Camera
 -------------------------------------
 To get an arbitrary viewpoint, let’s first name the points we care about. We’ll call the position
 where we place the camera _lookfrom_, and the point we look at _lookat_. (Later, if you want, you

books/RayTracingTheNextWeek.html

@@ -49,8 +49,8 @@
 interval that we want.
 
 
-Updating The Ray Class to Track Time
--------------------------------------
+Introduction of SpaceTime Ray Tracing
+--------------------------------------
 We can get a random estimate by sending each ray at some random time when the shutter is open. As
 long as the objects are where they should be at that time, we can get the right average answer with
 a ray that is at exactly a single time. This is fundamentally why random ray tracing tends to be
@@ -96,7 +96,7 @@
 </div>
 
 
-Updating the Camera To Simulate Motion Blur
+Updating the Camera to Simulate Motion Blur
 --------------------------------------------
 Now we need to modify the camera to generate rays at a random time between `time1` and `time2`.
 Should the camera keep track of `time1` and `time2` or should that be up to the user of camera when
@@ -166,8 +166,8 @@
     [Listing [time-camera]: <kbd>[camera.h]</kbd> Camera with time information]
 
 
-Moving Objects
----------------
+Adding Moving Spheres
+----------------------
 We also need a moving object. I’ll create a sphere class that has its center move linearly from
 `center0` at `time0` to `center1` at `time1`. Outside that time interval it continues on, so those
 times need not match up with the camera aperture open and close.
@@ -251,7 +251,7 @@
 </div>
 
 
-Tracking The Time Of Ray Intersection
+Tracking the Time of Ray Intersection
 --------------------------------------
 <div class='together'>
 Be sure that in the materials you have the scattered rays be at the time of the incident ray.
@@ -377,8 +377,8 @@
 models.
 
 
-Creating Bounding Volumes
---------------------------
+The Key Idea
+-------------
 <div class='together'>
 The key idea of a bounding volume over a set of primitives is to find a volume that fully encloses
 (bounds) all the objects. For example, suppose you computed a bounding sphere of 10 objects. Any ray
@@ -493,11 +493,10 @@
 </div>
 
 
-Determining If a Ray Intersects an AABB
-----------------------------------------
+Ray Intersection with an AABB
+------------------------------
 <div class='together'>
-What the question “do the t intervals in the slabs overlap?” would look like in code is something
-like this:
+The following pseudocode determines whether the $t$ intervals in the slab overlap:
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     compute (tx0, tx1)
@@ -637,7 +636,7 @@
 </div>
 
 
-Constructing Bounding Boxes For Hittables
+Constructing Bounding Boxes for Hittables
 ------------------------------------------
 <div class='together'>
 We now need to add a function to compute the bounding boxes of all the hittables. Then we will make
@@ -1055,7 +1054,7 @@
 </div>
 
 
-Rendering A Scene With A Checkered Texture
+Rendering a Scene with a Checkered Texture
 -------------------------------------------
 <div class='together'>
 If we add a new scene:
@@ -1283,7 +1282,7 @@
 </div>
 
 
-Smoothing Out The Result
+Smoothing out the Result
 -------------------------
 <div class='together'>
 To make it smooth, we can linearly interpolate:
@@ -1342,8 +1341,8 @@
 </div>
 
 
-Another Approach to Smoothing
-------------------------------
+Improvement with Hermitian Smoothing
+-------------------------------------
 <div class='together'>
 Smoothing yields an improved result, but there are obvious grid features in there. Some of it is
 Mach bands, a known perceptual artifact of linear interpolation of color. A standard trick is to use
@@ -1419,7 +1418,7 @@
 </div>
 
 
-Using Random Vectors On The Lattice Points
+Using Random Vectors on the Lattice Points
 -------------------------------------------
 <div class='together'>
 This is still a bit blocky looking, probably because the min and max of the pattern always lands
@@ -1669,7 +1668,7 @@
 record.
 
 
-Texture Coordinates For Spheres
+Texture Coordinates for Spheres
 --------------------------------
 For spheres, this is usually based on some form of longitude and latitude, _i.e._, spherical
 coordinates. So if we have a $(\theta,\phi)$ in spherical coordinates, we just need to scale
@@ -1787,20 +1786,22 @@
     [Listing [incl-stb-img]: Including the STB image package]
 </div>
 
+
+Using an Image Texture
+-----------------------
 <div class='together'>
+I just grabbed a random earth map from the web -- any standard projection will do for our purposes.
 
   <div class="render">
 
   ![earthmap.jpg](../images/earthmap.jpg)
 
   </div>
 
+</div>
 
-Using An Image Texture
------------------------
-To read an image from a file earthmap.jpg (I just grabbed a random earth map from the web -- any
-standard projection will do for our purposes), and then assign it to a diffuse material, the code
-is:
+<div class='together'>
+Here's the code to read an image from a file and then assign it to a diffuse material:
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
     hittable_list earth() {
@@ -1836,6 +1837,11 @@
 
 Rectangles and Lights
 ====================================================================================================
+Lighting is a key component of raytracing. Early simple raytracers used abstract light sources, like
+points in space, or directions. Modern approaches have more physically-based lights, which have
+position and size. To create such light sources, we need to be able to take any regular object and
+turn it into something that emits light into our scene.
+
 
 Emissive Materials
 -------------------
@@ -1888,7 +1894,7 @@
 </div>
 
 
-Adding Background Color to The Ray Color Function
+Adding Background Color to the Ray Color Function
 --------------------------------------------------
 <div class='together'>
 Next, we want a pure black background so the only light in the scene is coming from the emitters. To
@@ -2013,7 +2019,7 @@
 </div>
 
 
-Turning Objects Into Lights
+Turning Objects into Lights
 ----------------------------
 <div class='together'>
 If we set up a rectangle as a light:
@@ -2154,7 +2160,7 @@
 </div>
 
 
-Creating An Empty “Cornell Box”
+Creating an Empty “Cornell Box”
 --------------------------------
 <div class='together'>
 The “Cornell Box” was introduced in 1984 to model the interaction of light between diffuse surfaces.
@@ -2740,7 +2746,7 @@
 handles arbitrary shapes, but we'll leave that as an exercise for the reader.
 
 
-Rendering a Cornell Box With Smoke and Fog Boxes
+Rendering a Cornell Box with Smoke and Fog Boxes
 -------------------------------------------------
 <div class='together'>
 If we replace the two blocks with smoke and fog (dark and light particles) and make the light bigger