Difference between revisions of "Sync"
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'''Sync''' must be used when creating a thread on a looping function. Examples are functions that wait more than one frame for a condition to occur, such as a room being cleared, a switch being pressed, or a register being set. Sync should be called at least once in such loops. Not using sync inside of these loops may cause the game to freeze. | '''Sync''' must be used when creating a thread on a looping function. Examples are functions that wait more than one frame for a condition to occur, such as a room being cleared, a switch being pressed, or a register being set. Sync should be called at least once in such loops. Not using sync inside of these loops may cause the game to freeze. | ||
| − | One sync equals one frame elapsed in game, and 30 frames equals one second. Sega sometimes used multiple syncs in a function to force a specific delay, such as displaying a | + | One sync equals one frame elapsed in game, and 30 frames equals one second. Sega sometimes used multiple syncs in a function to force a specific delay, such as displaying a [[window_msg]] some number of frames after zooming in the camera. |
| − | On more technical terms, sync will cause the current coroutine to yield, allowing other coroutines to run ([[thread]] actually creates a coroutine and not a thread, and they don't run parallelly). Special menus called through opcodes will yield on their own. | + | On more technical terms, sync will cause the current coroutine to yield, allowing other coroutines to run ([[thread]] actually creates a coroutine and not a thread, and they don't run parallelly). Special menus called through opcodes will yield on their own and do not require a sync inside their function. |
Opcodes that will automatically yield: | Opcodes that will automatically yield: | ||
Latest revision as of 05:39, 31 December 2022
Contents
Syntax
Syntax: sync
- None
Use
Sync must be used when creating a thread on a looping function. Examples are functions that wait more than one frame for a condition to occur, such as a room being cleared, a switch being pressed, or a register being set. Sync should be called at least once in such loops. Not using sync inside of these loops may cause the game to freeze.
One sync equals one frame elapsed in game, and 30 frames equals one second. Sega sometimes used multiple syncs in a function to force a specific delay, such as displaying a window_msg some number of frames after zooming in the camera.
On more technical terms, sync will cause the current coroutine to yield, allowing other coroutines to run (thread actually creates a coroutine and not a thread, and they don't run parallelly). Special menus called through opcodes will yield on their own and do not require a sync inside their function.
Opcodes that will automatically yield:
- ret
- exit
- window_msg
- message
- chat_box
- disp_msg_qb
- add_msg
- list
- fadein
- fadeout
- award_item_name
- award_item_select
- award_item_ok
- get_item_id
Example
100: call 101 //Call function 101
window_msg 'Okay. I've waited 1 second. Now what?'
winend
ret
101: sync //Pause for 1 frame
addi R1, 00000001 //Add 1 to register R1
jmpi_<= R1, 0000001E, 101 //If R1 is less then or equal to 30 jump to 101
clear R1 //Set R1 to 0
ret
