extrans (3alleg4)

#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), stretch_blit(3alleg4)