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cirosantilli · cirosantilli · commit c66716cb707f · 2017-03-11T07:33:12.000Z
diff --git a/bullet/alternatives.md b/bullet/alternatives.md
@@ -21,9 +21,19 @@ Proprietary:
 
 2D:
 
-- Box2D
 - <http://brm.io/matter-js/> JavaScript on browser
 
+## Box2D
+
+AngryBirds used Box2D physics engine which does not require even attribution, and never gave anything back to its creator (Blizzard employee):
+
+- <http://www.geek.com/games/box2d-creator-asks-rovio-for-angry-birds-credit-at-gdc-1321779/>
+- <http://www.neogaf.com/forum/showthread.php?t=472319>
+- impressive chain and watch demos with RUBE (closed source) editor <https://www.youtube.com/watch?v=WqLR4dFn1qE>
+- destructible terrain as in Worms:
+    - https://www.youtube.com/watch?v=Qkh8PMwOgQ4
+- gas internal combustion engine!!! <https://www.youtube.com/watch?v=8kZRpouZ3OQ>
+
 ## Fluids
 
 -   https://github.com/rchoetzlein/fluids3
diff --git a/cpp/functional.cpp b/cpp/functional.cpp
@@ -9,7 +9,39 @@
 
 #include "common.hpp"
 
+int overload(int i){ return i + 1; }
+int overload(int i, int j){ return i + j; }
+
+int default_(int i, int j = 1){ return i + j; }
+
 int main() {
+    // # function
+    {
+        // Disambiguate overload.
+        // http://stackoverflow.com/questions/12500411/setting-a-stdfunction-variable-to-refer-to-the-stdsin-function
+        {
+            std::function<int(int)> f = (int(*)(int))&overload;
+            assert(f(1) == 2);
+            std::function<int(int, int)> g = (int(*)(int, int))&overload;
+            assert(g(1, 2) == 3);
+        }
+
+        // Default vaues without bind.
+        // TODO possible?
+        {
+            // Fails. j seems to contain trash.
+            //std::function<int(int)> f = (int(*)(int))&default_;
+            //assert(f(1) == 2);
+
+            // Lambda workaround.
+            std::function<int(int)> f = [](int i){ return default_(i); };
+            assert(f(1) == 2);
+
+            std::function<int(int, int)> g = (int(*)(int, int))&default_;
+            assert(g(1, 2) == 3);
+        }
+    }
+
     /*
     # bind2nd
 
@@ -31,9 +63,7 @@ int main() {
         */
     }
 
-    /*
-    # plus
-    */
+    // # plus
     {
         assert(std::plus<int>()(1, 2) == 3);
     }
diff --git a/cpp/map.cpp b/cpp/map.cpp
@@ -121,13 +121,33 @@ int main() {
             {1, "one"},
         };
 
-
         auto found = m.find(0);
         assert(found != m.end());
         assert(found->second == "zero");
 
         assert(m.find(2) == m.end());
         assert(m.size() == 2);
+
+        /*
+        Get default provided value if key not present
+
+        TODO: any less verbose way than finding and check != end? Like:
+
+            m.get(key, default)
+
+        I know I can define a helper, but come on...
+        */
+        {
+            std::map<int,int> m{};
+            int default_ = 42;
+            int result;
+            auto f = m.find(1);
+            if (f == m.end()) {
+                result = default_;
+            } else {
+                result = f->second;
+            }
+        }
     }
 
     /*
@@ -225,4 +245,34 @@ int main() {
             assert((m == std::map<int,std::string>{{1, "one"}}));
         }
     }
+
+    // # Range switch case.
+    // http://stackoverflow.com/questions/9432226/how-do-i-select-a-range-of-values-in-a-switch-statement/42331563#42331563
+#if 0
+    {
+        for (auto i = -1; i < 8; ++i) {
+            std::cout << i << std::endl;
+            std::map<int,std::function<void()>> m;
+            m.emplace(0, [](){
+                std::cout << "too small" << std::endl;
+            });
+            m.emplace(2, [](){
+                std::cout << "zero" << std::endl;
+            });
+            m.emplace(5, [](){
+                std::cout << "two" << std::endl;
+            });
+            m.emplace(7, [](){
+                std::cout << "five" << std::endl;
+            });
+            auto it = m.upper_bound(i);
+            if (it == m.end()) {
+                std::cout << "too large" << std::endl;
+            } else {
+                it->second();
+            }
+            std::cout << std::endl;
+        }
+    }
+#endif
 }
diff --git a/cpp/random.cpp b/cpp/random.cpp
@@ -9,8 +9,9 @@ int main() {
         http://stackoverflow.com/questions/322938/recommended-way-to-initialize-srand/13004555#13004555
     */
     {
-        std::random_device r;
-        std::mt19937 prng(r());
+        std::random_device dev;
+        unsigned int seed = dev();
+        std::mt19937 prng(seed);
         std::uniform_int_distribution<> dist(1, 10);
         for (unsigned int i = 0; i < 10; ++i) {
             // std::cout << dist(prng) << std::endl;
diff --git a/cpp/set.cpp b/cpp/set.cpp
@@ -81,8 +81,6 @@ int main() {
     /*
     # insert
 
-        Like for std::vector, insert makes copies.
-
         Return is a pair conatining:
 
         - if the item was not present, an iterator to the item inserted and true
@@ -177,8 +175,6 @@ int main() {
         Else, returns `map::end()`
 
         find is `log n` time since the container is ordered.
-
-        log n time complexity since always sorted
     */
     {
         std::set<int> s = {0, 1, 2};
diff --git a/opengl/vulkan.md b/opengl/vulkan.md
@@ -17,6 +17,7 @@ TODO software implementations: <https://www.quora.com/unanswered/Is-there-a-Vulk
 - <https://github.com/SaschaWillems/Vulkan>
 - <https://github.com/LunarG/VulkanSamples>
 - <https://github.com/Overv/VulkanTutorial>
+- <https://gist.githubusercontent.com/sheredom/523f02bbad2ae397d7ed255f3f3b5a7f/raw/7c33ee6136ae1f7c03741ba7ad6e02e8de9f9802/VkComputeSample> Codeplay employee writes SPIR-V shader by hand! :-) The absolute minimal example?
 
 ## Hardware support
 
