title: Drawing Individual Pixels in OpenGL
body: <p>I'm trying to highlight ("color #00FFFF") specific individual pixels in an image (already displayed in the background) using OpenGL/C++.  The pixel coordinates and the image exist in exact 2D space, but all the OpenGL code I'm seeing in the project so far - <code>glTranslatef()</code>, <code>glScalef()</code> - is 3D and float-based, and the positioning of the object appears to happen separately from the time it's drawn.</p>
  
  <p>I'm used to Java's Graphics2D package, where I can call something to the effect of </p>
  
  <pre><code>width = 1; height = 1;
  buffer.drawRect(width, height, xPosition, yPosition);
  </code></pre>
  
  <p>and it'll fill in a pixel at the specified location.  Is there anything similar to that syntax - where I can set size, set position, and draw all in one line - in OpenGL?  If not, how would I go about adapting my 2D+pixel input to OpenGL's float and 3D structure?</p>
  
  <p>I currently have this:</p>
  
  <pre><code>glPushMatrix();
  glTranslatef(0.0f, 0.0f, -5.0f);
  glColor3f(0, 1, 1);
  glPointSize(5.0f);
  glBegin(GL_POINTS);
  glVertex3f(1.0f, 1.0f, 1.0f);
  glPopMatrix();
  </code></pre>
  
  <p>which I pieced together from some Google searches and other parts of my code, but I don't see anything being draw.  I have no idea as to the units for the translate, vertex, or pointsize commands.  It'd be awesome if I could replace all of that with something like the Java command up above.  If not, is there some way I can guarantee whatever I draw here will be "on top" of everything else, but still not behind the camera.</p>