draw_clear_alpha(col, alpha);
| Argument | Description |
|---|---|
| col | The colour with which the screen will be cleared |
| alpha | The transparency of the colour with which the screen will be cleared |
Returns: N/A
This function can be used to clear the entire screen with a
given colour and the alpha component of the destination is set to
the value you have set - this function does not do any
blending as it works but any subsequent blend operations can be set
up to use the destination alpha that you have set. This is only for
use in the draw event of an instance (it will not show if used in
any other event), and it can also be very useful for clearing
surfaces when they are
newly created.
It is worth noting that when using the HTML5 module, you can use
this function to make the canvas background transparent, which will
then permit any images being used in the host HTML to be seen with
the game running over them. To achieve this effect you must first
go into the room editor and untick the "Draw Background colour"
option from the Background
Tab, then untick the option "Clear Background with Window
colour" found on the Views
Tab. Finally, you will need to make a new object, place it in
the first room of the game, and assign it a very low depth (for
example, -1000000). Then in the Pre Draw event use this
function to set the canvas alpha to the colour and transparency
that you wish it to have.
draw_clear_alpha(c_red, 0.5);
This will clear the screen with 50% (0.5) transparency with the colour red.