I'm writing a screenplay. The main character has suffered a major tragedy, but we don't know that yet. 
This, of course, hugely affects the way he acts, due to this tragedy he is now a broken man, looking for revenge.

A big part of the conflict of the story comes from this trauma. As of now, the major tragedy he suffered is revealed close to the midpoint of the story. Should I reveal the information when the story begins so that the viewers know exactly why this character is acting this particular way and can empathize with him from early on in the story? Or in other words:

**How should I reveal information in my story?**
More specifically:

**How do I determine what is the proper moment (and pacing) in which I reveal information key to the viewer's understanding of the character's actions?**