Fix delta time and FPS count calculation

rendering/src/main/java/de/staropensource/engine/rendering/RenderingSubsystemConfiguration.java

@@ -338,7 +338,7 @@ public final class RenderingSubsystemConfiguration extends Configuration {
 
         renderingAdapter = RenderingAdapter.ANY;
         vsyncMode = VsyncMode.OFF;
-        maximumFramesPerSecond = 0;
+        maximumFramesPerSecond = 60;
     }
 
     /** {@inheritDoc} */

rendering/src/main/java/de/staropensource/engine/rendering/renderer/Renderer.java

@@ -101,17 +101,22 @@ public final class Renderer {
     private static long frameCount = 0L;
 
     /**
-     * Contains the delta time, also
-     * known as the render time.
+     * Contains the delta time.
      * <p>
-     * Updated every second.
+     * Delta time is the time in seconds
+     * between the last and current frame.
+     * <p>
+     * Updated every frame.
      *
      * @since v1-alpha9
      * -- GETTER --
      * Returns the delta time, also
      * known as the render time.
      * <p>
-     * Updated every second.
+     * Delta time is the time in seconds
+     * between the last and current frame.
+     * <p>
+     * Updated every frame.
      *
      * @return delta time
      * @since v1-alpha9
@@ -140,6 +145,11 @@ public final class Renderer {
      * Contains the time it took
      * to calculate the last frame.
      * <p>
+     * <b>Note</b>: The {@code Waiting} count may be
+     * negative if the renderer is lagging behind.
+     * No waiting will be performed internally if
+     * this count is {@code <0}.
+     * <p>
      * Updated every frame.
      *
      * @since v1-alpha9
@@ -187,15 +197,22 @@ public final class Renderer {
             /** {@inheritDoc} */
             @Override
             public void run() {
-                int offset = 2;
+                int offset = 7;
 
                 bgfx_dbg_text_clear(0, false);
-                bgfx_dbg_text_printf(0, 0, 0x0f, "It's " + NumberUtil.padNumbers(LocalTime.now().getHour(), 2) + ":" + NumberUtil.padNumbers(LocalTime.now().getMinute(), 2) + ":" + NumberUtil.padNumbers(LocalTime.now().getSecond(), 2));
-                bgfx_dbg_text_printf(0, 1, 0x0f, "LFT.size(): " + lastFrameTime.size());
+                bgfx_dbg_text_printf(0, 0, 0x0f, "Time: " + NumberUtil.padNumbers(LocalTime.now().getHour(), 2) + ":" + NumberUtil.padNumbers(LocalTime.now().getMinute(), 2) + ":" + NumberUtil.padNumbers(LocalTime.now().getSecond(), 2));
+                bgfx_dbg_text_printf(0, 1, 0x0f, "Frames: " + Renderer.getFrameCount());
+                bgfx_dbg_text_printf(0, 2, 0x0f, "Frames/s: " + Renderer.getFramesPerSecond());
+                bgfx_dbg_text_printf(0, 3, 0x0f, "Delta: " + Renderer.getDeltaTime());
+                bgfx_dbg_text_printf(0, 4, 0x0f, "V-Sync mode: " + RenderingSubsystemConfiguration.getInstance().getVsyncMode().name());
+                bgfx_dbg_text_printf(0, 6, 0x0f, "Rendering time:");
                 for (String item : lastFrameTime.keySet()) {
                     bgfx_dbg_text_printf(0, offset, 0x0f, item + ": " + lastFrameTime.get(item) + "ms");
                     offset += 1;
                 }
+                try {
+                    Thread.sleep(0);
+                } catch (InterruptedException ignored) {}
             }
         });
 
@@ -272,7 +289,9 @@ public final class Renderer {
     @SuppressWarnings({ "InfiniteLoopStatement" })
     private static void render() throws Throwable {
         long previousFrameCount = 0L;                         // Frame count one second ago
-        LinkedList<Long> deltaTimeFractions = new LinkedList<>();             // Contains all delta time fractions
+        long systemTimeNow;                                   // Current system time
+        long systemTimePrevious = System.currentTimeMillis(); // Previous system time
+        LinkedList<Double> deltaTimes = new LinkedList<>();   // Contains all delta time fractions
         Map<String, Long> execTimes = new LinkedHashMap<>();  // Contains the amount of time of all rendering operations
         long timesWait;                                       // Time to wait until the next frame
         long timesPSO = System.currentTimeMillis() + 1000;    // Time to wait until invoking per-second operations
@@ -337,15 +356,17 @@ public final class Renderer {
             // Perform per-frame operations
             frameCount += 1;
             lastFrameTime = new HashMap<>(execTimes);
-            deltaTimeFractions.add(execTimes.get("Rendering") + execTimes.get("Waiting"));
             execTimes.clear();
+            systemTimeNow = System.currentTimeMillis();
+            deltaTime = (double) (systemTimeNow - systemTimePrevious) / 1000;
+            systemTimePrevious = systemTimeNow;
+            deltaTimes.add(deltaTime);
 
 
             // Perform per-second operations
             if (System.currentTimeMillis() >= timesPSO) {
-                // Calculate delta time and FPS count
-                deltaTime = NumberUtil.calculateMeanLong(deltaTimeFractions);
-                framesPerSecond = 1000 / deltaTime;
+                // Calculate FPS count
+                framesPerSecond = 1 / deltaTime;
 
                 // Log frame count
                 if (RenderingSubsystemConfiguration.getInstance().isDebugFrames())
@@ -376,7 +397,7 @@ public final class Renderer {
 
                 // Reset per-second variables
                 previousFrameCount = frameCount;
-                deltaTimeFractions.clear();
+                deltaTimes.clear();
                 timesPSO = System.currentTimeMillis() + 1000;
             }
         }

rendering/src/main/java/de/staropensource/engine/rendering/type/Window.java

@@ -503,7 +503,7 @@ public final class Window implements Closeable {
         glfwWindowHintString(GLFW_X11_INSTANCE_NAME, name);
 
         // Create window
-        internalWindowIdentifier = glfwCreateWindow(size.getX(), size.getY(), title, NULL, NULL);
+        internalWindowIdentifier = glfwCreateWindow(1, 1, "", NULL, NULL);
         if (internalWindowIdentifier == NULL)
             throw new WindowCreationFailureException();
 
@@ -849,6 +849,7 @@ public final class Window implements Closeable {
             return;
 
         this.title = title;
+        queuedPropertyUpdates.put("title", title);
     }
 
     /**