Merge pull request #409 from RayTracing/new-figures

New figures

Author: hollasch

books/RayTracingInOneWeekend.html

@@ -802,6 +802,8 @@
 
     ![Figure [normal-directions]: Possible directions for sphere surface-normal geometry](../images/fig.normal-possibilities.jpg)
 
+</div>
+
 We need to choose one of these possibilities because we will eventually want to determine which
 side of the surface that the ray is coming from. This is important for objects that are rendered
 differently on each side, like the text on a two-sided sheet of paper, or for objects that have an
@@ -883,6 +885,7 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     [Listing [hittable-time-side]: <kbd>[hittable.h]</kbd> The hittable class with time and side]
 
+<div class='together'>
 And then we add the surface side determination to the class:
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
@@ -1026,7 +1029,7 @@
 
 ## Common Constants and Utility Functions
 
-<div class='together'></div>
+<div class='together'>
 We need some math constants that we conveniently define in their own header file. For now we only
 need infinity, but we will also throw our own definition of pi in there, which we will need later.
 There is no standard portable definition of pi, so we just define our own constant for it. We'll
@@ -1360,12 +1363,13 @@
 the chapter.)
 
 <div class='together'>
-There are two unit radius spheres tangent to the hit point $p$ of a surface. These two spheres
-have a center of $(p + N)$ and $(p - N)$, where $N$ is the normal of the surface. The sphere with a
-center at $(p - N)$ is considered _inside_ the surface, whereas the sphere with center $(p + N)$ is
-considered _outside_ the surface. Select the tangent unit radius sphere that is on the same side of
-the surface as the ray origin. Pick a random point $s$ inside this unit radius sphere and send a
-ray from the hit point $p$ to the random point $s$:
+There are two unit radius spheres tangent to the hit point $p$ of a surface. These two spheres have
+a center of $(p + \vec{N})$ and $(p - \vec{N})$, where $\vec{N}$ is the normal of the surface. The
+sphere with a center at $(p - \vec{N})$ is considered _inside_ the surface, whereas the sphere with
+center $(p + \vec{N})$ is considered _outside_ the surface. Select the tangent unit radius sphere
+that is on the same side of the surface as the ray origin. Pick a random point $s$ inside this unit
+radius sphere and send a ray from the hit point $p$ to the random point $s$ (this is the vector
+$(s-p)$):
 
   ![Figure [rand-vector]: Generating a random diffuse bounce ray](../images/fig.rand-vector.jpg)
 
@@ -2757,6 +2761,7 @@
 
   - Dave Hart
   - Jean Buckley
+</div>
 
 <div class="credit-list"> **Web Release**
 

books/RayTracingTheNextWeek.html

@@ -2686,6 +2686,7 @@
 
   - Dave Hart
   - Jean Buckley
+</div>
 
 <div class="credit-list"> **Web Release**
 

books/RayTracingTheRestOfYourLife.html

@@ -2364,6 +2364,7 @@
 
   - Dave Hart
   - Jean Buckley
+</div>
 
 <div class="credit-list"> **Web Release**