Provided by: allegro4-doc_4.4.3.1-1_all bug


       extrans - Lighting and translucency effects. Allegro game programming library.


       #include <allegro.h>

       Example extrans


       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.


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