drawRobots: reduce push/pop and better commentssubmission-20131202

Now robots are drawn from left to right (gold, silver, brown, orange),
the direction is now explicitly documented.

1 files changed, 17 insertions, 7 deletions

diff --git a/src/RobotRace.java b/src/RobotRace.java
index a7fc2e7..5d5a99c 100644
--- a/src/RobotRace.java
+++ b/src/RobotRace.java
@@ -287,17 +287,27 @@ public class RobotRace extends Base {
      * Draw all four robots in the robots array on the scene
      */
     private void drawRobots() {
-        // Draw all four robots on the x-axis
-        for (int i = 0; i < 4; i++) {
-            gl.glPushMatrix();
+        // laziness, save current positions because of translations
+        gl.glPushMatrix();
 
-            // Place the robots on a line based on the current robot
-            gl.glTranslatef(-1.5f + i * 1f, 0f, 0f);
+        // Place the robots on a line based on the current robot. Robots are
+        // drawn with a distance of 1 meter between the middle of each robot,
+        // from left to right (seen from the robot's POV). First, set the
+        // starting point in a way such that the robot is drawn left of the
+        // axis (for an even number of robots).
+        gl.glTranslatef(.5f - robots.length / 2, 0f, 0f);
 
+        // Draw each robot on the X-axis
+        for (Robot robot: robots) {
             // Draw the current robot
-            robots[i].draw(gs.showStick);
-            gl.glPopMatrix();
+            robot.draw(gs.showStick);
+
+            // Position the next robot 1 meter away from the current one.
+            gl.glTranslatef(1f, 0f, 0f);
         }
+
+        // restore positions
+        gl.glPopMatrix();
     }
 
     /**