The player reads the signals and decides whether to shoot or not
A computer game designed by researchers at Abertay University could help to select and train Scotland's firearms officers.
In the game, an officer approaches a man who is searching a car boot. The man turns and the player has to read the signs to decide if there is a risk.
The officer then chooses whether to shoot the suspect, fire a warning shot, or hold fire.
The Shoot/No Shoot game could identify those who panic in tense situations.
PhD student, Paul Robertson, 24, told the BBC Scotland news website that the game was not like those shoot-out versions that are bought in the shops.
"It's more realistic and focussed around a fixed decision, which is whether or not you pull the trigger," he said.
"A lot of games become very 'arcadey', it's all big and when you shoot at people it takes eight shots to take them down, and everything explodes.
"This is more realistic, a single shot will take someone down."
The police have been involved in developing the scenario and different variables, such as lighting.
Lecturer, Dr James Bown, explained the complexities involved in creating such a game.
He said: "That character itself has it's own artificial intelligence, so it can respond to voice commands, it can respond to gunfire if you shoot with the intention to miss and that response can be immediate surrender, it can be running away, or if they are carrying a weapon - shooting back.
"The animation is very important, that we get as realistic as possible movements associated with the individual turning round because that's where the signals are going to be as to whether to shoot or not."
Also working on the project is psychology lecturer Dr Patrick Cronin, who is also the Associate Director of the Scottish Institute for Policing Research.
He said: "It [shooting a suspect] is probably the most difficult decision that you'd ever want to make, or perhaps you wouldn't want to make, because it obviously has consequences outwith the decision.
"So, for example, if you get the decision wrong, when it's clearly seen to be wrong, then obviously that can have profound implications for yourself and perhaps your family, and even perhaps going to prison.
"What we're particularly focused on is the psychological mechanisms behind that decision and why some people shoot and other people don't."
The Association of Chief Police Officers in Scotland (Acpos) has said such technology would have to be assessed by the Home Office Scientific Development Branch (HOSDB) before Acpos could consider it for training use.