src/main.cpp

@@ -34,39 +34,26 @@
 // stuff to a library, since it keeps input a separate concern from the physics model
 struct Input
 {
-    bool pauseTime;
+    bool cycleAnimation;
 } input;
 
-
 void keyCallback(GLFWwindow* window, int key, int scancode, int action, int mods)
 {
-    if (key == GLFW_KEY_SPACE && action == GLFW_PRESS)
+    if (key == GLFW_KEY_C && action == GLFW_PRESS)
     {
-        input.pauseTime = true;
+        input.cycleAnimation = true;
     }
 }
 
 void clearInput()
 {
-    input.pauseTime = false;
+    input.cycleAnimation = false;
 }
 
-// now should always increase linearly with real world time, this should not be modified by input
-// for animations etc
-struct Time
+double getTime()
 {
-    double now;
-    double dt;
-} engineTime;
-
-void updateTime()
-{
-    std::chrono::duration timeSinceEpoch = std::chrono::steady_clock::now().time_since_epoch();
-    double now = std::chrono::duration<double>(timeSinceEpoch).count();
-    double dt = now - engineTime.now;
-
-    engineTime.dt = dt;
-    engineTime.now = now;
+    auto now = std::chrono::steady_clock::now().time_since_epoch();
+    return std::chrono::duration<double>(now).count();
 }
 
 int main()
@@ -113,12 +100,11 @@ int main()
     glfwSetKeyCallback(window, keyCallback);
 
     // TODO: convert these to an enum
-    const int MODE_ORBIT     = 0;
-    const int MODE_MANEOUVRE = 1;
-    int mode = 0;
+    const int ANIM_ORBITING     = 0;
+    const int ANIM_ECCENTRICITY = 1;
+    int animation = 0;
 
-    // simulation time. this can be paused or whatever as animation demands.
-    double time = 0;
+    double time = getTime();
 
     // Main loop
     while (!glfwWindowShouldClose(window))
@@ -127,15 +113,14 @@ int main()
         // clearInput() needs to be called to clear input from previous frame
         clearInput();
         glfwPollEvents();
-        updateTime();
 
         // apply input
-        if (input.pauseTime)
+        if (input.cycleAnimation)
         {
-            mode++;
-            if (mode > MODE_MANEOUVRE)
+            animation++;
+            if (animation > ANIM_ECCENTRICITY)
             {
-                mode = 0;
+                animation = 0;
             }
         }
 
@@ -143,14 +128,15 @@ int main()
         // increase the speed of time by 60 * 60 * 24 to see 1 day per second.
         const double speed = 60 * 60 * 24;
 
-        // orbit modifications need to be instanteneous
-        if (mode == MODE_ORBIT)
+        // only update time if playing the orbiting animation
+        if (animation == ANIM_ORBITING)
         {
-            time += engineTime.dt * speed;
+            time = getTime() * speed;
         }
         else
         {
-            printf("maneouvre mode!\n");
+            double e = .25 + .2 * sin(getTime());
+            moonOrbit.setEccentricity(e);
         }
 
         // rendering