Fix missing GLM_ENABLE_EXPERIMENTAL

Overv · Overv · commit 5a3e53c55358 · 2017-11-30T22:08:50.000+01:00
diff --git a/08_Loading_models.md b/08_Loading_models.md
@@ -303,7 +303,7 @@ namespace std {
     template<> struct hash<Vertex> {
         size_t operator()(Vertex const& vertex) const {
             return ((hash<glm::vec3>()(vertex.pos) ^
-                   (hash<glm::vec3>()(vertex.color) << 1)) >> 1) ^ 
+                   (hash<glm::vec3>()(vertex.color) << 1)) >> 1) ^
                    (hash<glm::vec2>()(vertex.texCoord) << 1);
         }
     };
@@ -314,9 +314,15 @@ This code should be placed outside the `Vertex` struct. The hash functions for
 the GLM types need to be included using the following header:
 
 ```c++
+#define GLM_ENABLE_EXPERIMENTAL
 #include <glm/gtx/hash.hpp>
 ```
 
+The hash functions are defined in the `gtx` folder, which means that it is
+technically still an experimental extension to GLM. Therefore you need to define
+`GLM_ENABLE_EXPERIMENTAL` to use it. It means that the API could change with a
+new version of GLM in the future, but in practice the API is very stable.
+
 You should now be able to successfully compile and run your program. If you
 check the size of `vertices`, then you'll see that it has shrunk down from
 1,500,000 to 265,645! That means that each vertex is reused in an average number
@@ -345,4 +351,4 @@ Vulkan's explicitness, many concepts still work the same.
 
 [C++ code](/code/model_loading.cpp) /
 [Vertex shader](/code/shader_depth.vert) /
-[Fragment shader](/code/shader_depth.frag)
+[Fragment shader](/code/shader_depth.frag)
diff --git a/code/model_loading.cpp b/code/model_loading.cpp
@@ -3,6 +3,7 @@
 
 #define GLM_FORCE_RADIANS
 #define GLM_FORCE_DEPTH_ZERO_TO_ONE
+#define GLM_ENABLE_EXPERIMENTAL
 #include <glm/glm.hpp>
 #include <glm/gtc/matrix_transform.hpp>
 #include <glm/gtx/hash.hpp>
