Sample solutions to A01 and A02 Theory.

solutions/assignment01/Assignment01_solution.cc

+
+/// Implement the mainLoop variant that is shown on screen
+/// You can get the current wall clock via:
+///     double secs = timeInSeconds();
+/// ============= STUDENT CODE BEGIN =============
+
+auto fixedTimestep = true;
+auto variableRendering = false;
+auto targetFPS = 25;
+auto frameSkip = 5;
+
+if (fixedTimestep && variableRendering)
+{
+    auto targetTimestep = 1.0 / targetFPS;
+    auto nextTime = timeInSeconds();
+
+    while (!shouldClose())
+    {
+        // fixed timestep
+        while (timeInSeconds() > nextTime)
+        {
+            // accumulate time
+            nextTime += targetTimestep;
+
+            // run simulation with fixed timestep
+            update(targetTimestep);
+            ++totalFrames; // we only count simulation FPS
+        }
+
+        // render with variable timestep
+        render();
+    }
+}
+else if (fixedTimestep /* && frameSkip */)
+{
+    auto targetTimestep = 1.0 / targetFPS;
+    auto nextTime = timeInSeconds();
+
+    while (!shouldClose())
+    {
+        // fixed timestep
+        auto framesLeft = frameSkip;
+        while (timeInSeconds() > nextTime && framesLeft > 0)
+        {
+            // accumulate time
+            nextTime += targetTimestep;
+
+            // run simulation AND rendering with fixed timestep
+            update(targetTimestep);
+            render();
+            ++totalFrames;
+            --framesLeft;
+
+            // comment in to see skipped frames
+            // sleepSeconds(0.1);
+        }
+
+        if (framesLeft <= 0)
+            glow::info() << "skipped some frames";
+    }
+}
+else // variable timestep
+{
+    auto targetTimestep = 1.0 / targetFPS;
+    auto prevTime = 0.0;
+    auto currTime = timeInSeconds();
+
+    while (!shouldClose())
+    {
+        // calculate elapsed time
+        prevTime = currTime;
+        currTime = timeInSeconds();
+        auto dt = currTime - prevTime;
+
+        // perform simulation AND rendering
+        update(dt);
+        render();
+        ++totalFrames;
+
+        // sleep such that dt is expected to be targetTimestep next frame
+        auto nextTime = currTime + targetTimestep;
+        sleepSeconds(nextTime - timeInSeconds());
+    }
+}
+
+/// ============= STUDENT CODE END =============
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