Merge pull request #702 from rjkilpatrick/rtweekend-include

Rtweekend include missing from listing 29

Author: hollasch

CHANGELOG.md

@@ -6,6 +6,7 @@ Change Log -- Ray Tracing in One Weekend
 ### _In One Weekend_
   - Delete: remove premature `cstdlib` include; not needed until we use `rand()` (#687)
   - Fix: replace old anti-alias result image with before-and-after image (#679)
+  - Fix: Listing 29: Added missing `rtweekend.h` include (#691)
   - Fix: undefined `vup` variable in camera definition (#686)
 
 ### _The Next Week_

books/RayTracingTheNextWeek.html

@@ -1422,6 +1422,8 @@
     #ifndef PERLIN_H
     #define PERLIN_H
 
+    #include "rtweekend.h"
+
     class perlin {
         public:
             perlin() {