From 0a90b17ca15694ae2c31b5a839490b0cc5caeb2c Mon Sep 17 00:00:00 2001
From: Peter Wu <lekensteyn@gmail.com>
Date: Thu, 9 Jan 2014 23:31:00 +0100
Subject: RobotRace: implement pause functionality

---
 src/Camera.java    |  1 -
 src/RobotRace.java | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/src/Camera.java b/src/Camera.java
index a3e3a43..24ebbc9 100644
--- a/src/Camera.java
+++ b/src/Camera.java
@@ -186,7 +186,6 @@ class Camera {
             fastest_pos = Math.max(fastest_pos, robot.getTimePos());
         }
         double distance = Robot.racepost2meter(fastest_pos - slowest_pos);
-        System.err.println("dist+" + distance);
         // the helicopter view is more suitable if robots are more distant
         if (distance > 5) {
             setHelicopterMode();
diff --git a/src/RobotRace.java b/src/RobotRace.java
index 57e0a98..d84ce68 100644
--- a/src/RobotRace.java
+++ b/src/RobotRace.java
@@ -151,6 +151,21 @@ public class RobotRace extends Base {
      */
     boolean enableTextures;
 
+    /**
+     * Real animation time at which the game is paused (or -1 if not paused).
+     */
+    private float pausedSince = -1;
+
+    /**
+     * Total number of animation time that was spent in the paused state.
+     */
+    private float pausedTimeTotal;
+
+    /**
+     * Trigger a pause on the next frame update.
+     */
+    private boolean requestPauseToggle = false;
+
     /**
      * Constructs this robot race by initializing robots, camera, track, and
      * terrain.
@@ -289,6 +304,8 @@ public class RobotRace extends Base {
         // function), the FPS update is done in the first accessible function
         // (here, in setView)
         updateFPS();
+        // similarly, reset the time very early here when paused
+        applyPausedTime();
 
         // Select part of window.
         gl.glViewport(0, 0, gs.w, gs.h);
@@ -609,6 +626,10 @@ public class RobotRace extends Base {
                     System.err.println("Textures are " +
                             (state ? "enabled" : "disabled"));
                     return true;
+                case KeyEvent.VK_SPACE: /* pause time */
+                    System.err.println("Triggering pause...");
+                    robotRace.requestPauseToggle = true;
+                    return true;
                 default:
                     return false;
                 }
@@ -629,4 +650,35 @@ public class RobotRace extends Base {
         }
         return enableTextures;
     }
+
+    /**
+     * If pause toggle is requested, check state and update. Otherwise, adjust
+     * global animation time.
+     */
+    private void applyPausedTime() {
+        if (requestPauseToggle) {
+            if (pausedSince == -1) {
+                // just paused, store start time
+                pausedSince = gs.tAnim;
+                System.err.println("Paused since gs.tAnim=" + gs.tAnim);
+            } else {
+                // continuing, increase paused time and clear pause flag
+                float pausedTime = gs.tAnim - pausedSince;
+                pausedTimeTotal += pausedTime;
+                pausedSince = -1;
+                System.err.println("Continued at gs.tAnim=" + gs.tAnim
+                        + ". Paused for " + pausedTime + " secs (new total: "
+                        + pausedTimeTotal + " secs)");
+            }
+            requestPauseToggle = false;
+        }
+
+        // if paused, set clock back.
+        if (pausedSince != -1) {
+            gs.tAnim = pausedSince;
+        }
+
+        // always apply correction for time drift
+        gs.tAnim -= pausedTimeTotal;
+    }
 }
-- 
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