while page

Author: x87

content/while.md

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-TBD
+Many things in the game are extended in time or depend on the player feedback. A car driving to a destination, a model file loading from the disk, a button awaiting to be pressed all require a specific condition to become true. Did the car reached the point, was the specific button pressed, is the model available for use? If not, wait and check again later. 
+
+We can validate certain condition continuosly, each frame, or with some delay. To achieve this in the code, a special construct exists: a loop.
+
+The most common type of loop is a while loop. It will execute a block of code as long as the condition is true.
+
+```
+while <condition>
+  <block of code>
+end
+```
+
+For example, if we want to do something while the player can play (i.e. not dead or caught by the police), we can write:
+
+```
+while is_player_playing 0
+  wait 0
+end
+
+terminate_this_script
+```
+
+The `wait 0` command is used to yield the execution for a frame, allowing the game to process other events and not freeze. It is crucial to have a `wait` command inside the loop body. 
+
+Once the condition becomes false, the loop stops and the execution moves to `terminate_this_script` command.
+
+The loop condition can be negated using the `not` operator. For example, if we want to wait until the model becomes available, we can write:
+
+```
+while not is_model_available 42
+  wait 250
+end
+```
+
+The script will be continuously checking if the model 42 is available, processing other game events between iterations.