title: Box2d debug draw doesn't show sometimes, but bodies show as normal
body: <p>Inside a subclass of CCLayer, there're two methods below:</p>
  
  <pre><code>-(void)setupDebugDraw 
  {
      _debugDraw = new GLESDebugDraw(PTM_RATIO * [[CCDirector sharedDirector] contentScaleFactor]);
      world-&gt;SetDebugDraw(_debugDraw);
  
      uint32 flags = 0;
      flags += b2DebugDraw::e_shapeBit;
      flags += b2DebugDraw::e_jointBit;
      flags += b2DebugDraw::e_aabbBit;
      flags += b2DebugDraw::e_pairBit;
      flags += b2DebugDraw::e_centerOfMassBit;
      _debugDraw-&gt;SetFlags(flags);
  
      // (TEST CODE) BELOW DOESN'T SHOW!
      _debugDraw-&gt;DrawPoint(b2Vec2(0,0), 500.0f, b2Color(255, 255, 255));
  }
  
  -(void) draw {
      glDisable(GL_TEXTURE_2D);
      glDisableClientState(GL_COLOR_ARRAY);
      glDisableClientState(GL_TEXTURE_COORD_ARRAY);
  
      if (world) {
          // BODIES SHOW OK
          world-&gt;DrawDebugData();
  
          // (TEST CODE) BELOW DOESN'T SHOW EITHER!
          _debugDraw-&gt;DrawPoint(b2Vec2(0,0), 500.0f, b2Color(255, 255, 255));
      }
  
      glEnable(GL_TEXTURE_2D);
      glEnableClientState(GL_COLOR_ARRAY);
      glEnableClientState(GL_TEXTURE_COORD_ARRAY);    
  }
  </code></pre>
  
  <p>In above code, there're two test codes, both doesn't show anything.</p>
  
  <p>Xcode 4.3.2
  IOS Simulator 5.1
  Box2D 2.1.2</p>
  
  <p>After some try:
  _debugDraw->DrawPoint(b2Vec2(0,0), 50.0f, b2Color(255, 0, 0)); // NO DRAW
  _debugDraw->DrawPoint(b2Vec2(1,1), 50.0f, b2Color(255, 0, 0)); // HAVE DRAW!!</p>
  
  <p>seems draw point with one or more 0 will not draw at all! Even if the size is big enough!</p>
  
  <pre><code>void GLESDebugDraw::DrawPoint(const b2Vec2&amp; p, float32 size, const b2Color&amp; color)
  {
      glColor4f(color.r, color.g, color.b,1);
      glPointSize(size);
      GLfloat             glVertices[] = {
          p.x * mRatio, p.y * mRatio
      };
      glVertexPointer(2, GL_FLOAT, 0, glVertices);
      glDrawArrays(GL_POINTS, 0, 1);
      glPointSize(1.0f);
  }
  </code></pre>
  
  <p>Since I don't understand the openGL api, anything susipcious here?</p>