implementing trace class.

game/CMakeLists.txt

@@ -15,6 +15,8 @@ set(GAME_SRC
     util.cpp
     game.cpp
     state/object.cpp
+    state/explosion.cpp
+    state/trace.cpp
     state/state.cpp
     state/player.cpp
     state/planet.cpp

game/state/explosion.hpp

@@ -1,5 +1,8 @@
 #pragma once
 
+#include <glm/vec2.hpp>
+
+namespace game {
     /**
      * Explosion: just an effect which looks good.
      */
@@ -24,5 +27,6 @@ public:
         // anymore and will disappear afterwards
         const float     maxAge;
     };
+}
 
 #endif

game/state/trace.hpp

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <glm/vec2.hpp>
+
+namespace game {
+    /*
+     * Trace of a missile through the space.
+     * Useful for rendering sth. like a smoke trail to follow the rocket.
+     */
+    class Trace {
+        public:
+            Trace(const glm::vec2 &startPoint)
+            {
+                points.push_back(startPoint);
+            }
+
+            void addPoint(const glm::vec2 &p)
+            {
+                points.push_back(p);
+            }
+
+            std::vector<glm::vec2> points;
+    };
+}