NAME
set_write_alpha_blender - Enables the special alpha-channel editing
mode. Allegro game programming library.
SYNOPSIS
#include <allegro.h>
void set_write_alpha_blender();
DESCRIPTION
Enables the special alpha-channel editing mode, which is used for
drawing alpha channels over the top of an existing 32-bit RGB sprite,
to turn it into an RGBA format image. After calling this function, you
can set the drawing mode to DRAW_MODE_TRANS and then write draw color
values (0-255) onto a 32-bit image. This will leave the color values
unchanged, but alter the alpha to whatever values you are writing.
After enabling this mode you can also use draw_trans_sprite() to
superimpose an 8-bit alpha mask over the top of an existing 32-bit
sprite.
SEE ALSO
set_alpha_blender(3alleg), draw_trans_sprite(3alleg),
drawing_mode(3alleg), exalpha(3alleg), extrans(3alleg)