.\" Generated by the Allegro makedoc utility
.TH extrans 3alleg4 "version 4.4.3" "Allegro" "Allegro manual"
.SH NAME
extrans \- Lighting and translucency effects. Allegro game programming library.\&
.SH SYNOPSIS
.B #include <allegro.h>

.sp
.B Example extrans
.SH DESCRIPTION
This program demonstrates how to use the lighting and
translucency functions. The first part of the example will
show a dark screen illuminated by a spotlight you can move
with your mouse. After a key press the example shows the full
bitmap and the spotlight changes to be a reduced version of
the background with 50% of translucency.

The translucency effect is easy to do in all color depths.
However, the lighting effect has to be performed in a different
way depending on whether the screen is in 8bit mode or another
color depth. This is because additive drawing mode uses a
different set of routines for truecolor modes.

.SH SEE ALSO
.BR BITMAP (3alleg4),
.BR COLOR_MAP (3alleg4),
.BR END_OF_MAIN (3alleg4),
.BR PALETTE (3alleg4),
.BR RGB (3alleg4),
.BR RGB_MAP (3alleg4),
.BR SCREEN_H (3alleg4),
.BR SCREEN_W (3alleg4),
.BR allegro_error (3alleg4),
.BR allegro_init (3alleg4),
.BR allegro_message (3alleg4),
.BR bitmap_color_depth (3alleg4),
.BR blit (3alleg4),
.BR circlefill (3alleg4),
.BR clear_bitmap (3alleg4),
.BR clear_keybuf (3alleg4),
.BR color_map (3alleg4),
.BR create_bitmap (3alleg4),
.BR create_bitmap_ex (3alleg4),
.BR create_light_table (3alleg4),
.BR create_rgb_table (3alleg4),
.BR create_trans_table (3alleg4),
.BR destroy_bitmap (3alleg4),
.BR draw_trans_sprite (3alleg4),
.BR drawing_mode (3alleg4),
.BR install_keyboard (3alleg4),
.BR install_mouse (3alleg4),
.BR install_timer (3alleg4),
.BR keypressed (3alleg4),
.BR load_bitmap (3alleg4),
.BR mouse_x (3alleg4),
.BR mouse_y (3alleg4),
.BR poll_mouse (3alleg4),
.BR rectfill (3alleg4),
.BR replace_filename (3alleg4),
.BR rest (3alleg4),
.BR rgb_map (3alleg4),
.BR screen (3alleg4),
.BR set_alpha_blender (3alleg4),
.BR set_gfx_mode (3alleg4),
.BR set_palette (3alleg4),
.BR set_trans_blender (3alleg4),
.BR set_write_alpha_blender (3alleg4),
.BR stretch_blit (3alleg4)