Ring/教程/使用 RingAllegro 进行图形和 2D 游戏编程
< Ring
在本章中，我们将学习如何在我们的 Ring 应用程序中使用 allegro 游戏编程库。
我们有 gamelib.ring 文件，它加载包含 Allegro 函数包装器的 DLL 库。
Load "allegro.rh"
Loadlib("ring_allegro.dll")gamelib.ring 文件使用 Load 指令执行 allegro.rh 文件，该文件是包含要在我们的程序中使用的常量的 Ring 源代码文件。然后使用 LoadLib() 函数，我们可以加载 DLL 库 "ring_allegro.dll"。
为了编写可移植的代码，我们可以更改 gamelib.ring 以在加载 DLL/So 文件之前检查平台。
下面的示例使用 Allegro 库来绘制、在屏幕上移动对象以及从键盘和鼠标获取输入。
Load "gamelib.ring"
al_init()
al_init_image_addon()
display = al_create_display(640,480)
al_show_native_message_box(display, "Hello", "Welcome",
"Using Allegro from the Ring programming language",
"", 0);
al_clear_to_color(al_map_rgb(0,0,255))
BOUNCER_SIZE = 40
bouncer_x = 10
bouncer_y = 20
bouncer = al_create_bitmap(BOUNCER_SIZE, BOUNCER_SIZE)
al_set_target_bitmap(bouncer)
al_clear_to_color(al_map_rgb(255,0,255))
for x = 1 to 30
bouncer_x += x
bouncer_y += x
al_set_target_bitmap(al_get_backbuffer(display))
al_clear_to_color(al_map_rgb(0,0,0))
al_draw_bitmap(bouncer, bouncer_x, bouncer_y, 0)
al_draw_bitmap(bouncer, 200+bouncer_x,200+ bouncer_y, 0)
al_flip_display()
al_rest(0.1)
next
al_clear_to_color(al_map_rgb(255,255,255))
image = al_load_bitmap("man2.jpg")
al_draw_bitmap(image,200,200,0)
al_flip_display()
al_rest(2)
event_queue = al_create_event_queue()
al_register_event_source(event_queue, al_get_display_event_source(display))
ev = al_new_allegro_event()
timeout = al_new_allegro_timeout()
al_init_timeout(timeout, 0.06)
FPS = 60
timer = al_create_timer(1.0 / FPS)
al_register_event_source(event_queue, al_get_timer_event_source(timer))
al_start_timer(timer)
redraw = true
SCREEN_W = 640
SCREEN_H = 480
BOUNCER_SIZE = 32
bouncer_x = SCREEN_W / 2.0 - BOUNCER_SIZE / 2.0
bouncer_y = SCREEN_H / 2.0 - BOUNCER_SIZE / 2.0
bouncer_dx = -4.0
bouncer_dy = 4.0
al_install_mouse()
al_register_event_source(event_queue, al_get_mouse_event_source())
al_install_keyboard()
al_register_event_source(event_queue, al_get_keyboard_event_source())
KEY_UP = 1
KEY_DOWN = 2
KEY_LEFT = 3
KEY_RIGHT = 4
Key = [false,false,false,false]
while true
al_wait_for_event_until(event_queue, ev, timeout)
switch al_get_allegro_event_type(ev)
on ALLEGRO_EVENT_DISPLAY_CLOSE
exit
on ALLEGRO_EVENT_TIMER
# Animation
if bouncer_x < 0 or bouncer_x > SCREEN_W - BOUNCER_SIZE
bouncer_dx = -bouncer_dx
ok
if bouncer_y < 0 or bouncer_y > SCREEN_H - BOUNCER_SIZE
bouncer_dy = -bouncer_dy
ok
bouncer_x += bouncer_dx
bouncer_y += bouncer_dy
# Keyboard
if key[KEY_UP] and bouncer_y >= 4.0
bouncer_y -= 4.0
ok
if key[KEY_DOWN] and bouncer_y <= SCREEN_H - BOUNCER_SIZE - 4.0
bouncer_y += 4.0
ok
if key[KEY_LEFT] and bouncer_x >= 4.0
bouncer_x -= 4.0
ok
if key[KEY_RIGHT] and bouncer_x <= SCREEN_W - BOUNCER_SIZE - 4.0
bouncer_x += 4.0
ok
redraw = true
on ALLEGRO_EVENT_MOUSE_AXES
bouncer_x = al_get_allegro_event_mouse_x(ev)
bouncer_y = al_get_allegro_event_mouse_y(ev)
on ALLEGRO_EVENT_MOUSE_ENTER_DISPLAY
bouncer_x = al_get_allegro_event_mouse_x(ev)
bouncer_y = al_get_allegro_event_mouse_y(ev)
on ALLEGRO_EVENT_MOUSE_BUTTON_UP
exit
on ALLEGRO_EVENT_KEY_DOWN
switch al_get_allegro_event_keyboard_keycode(ev)
on ALLEGRO_KEY_UP
key[KEY_UP] = true
on ALLEGRO_KEY_DOWN
key[KEY_DOWN] = true
on ALLEGRO_KEY_LEFT
key[KEY_LEFT] = true
on ALLEGRO_KEY_RIGHT
key[KEY_RIGHT] = true
off
on ALLEGRO_EVENT_KEY_UP
switch al_get_allegro_event_keyboard_keycode(ev)
on ALLEGRO_KEY_UP
key[KEY_UP] = false
on ALLEGRO_KEY_DOWN
key[KEY_DOWN] = false
on ALLEGRO_KEY_LEFT
key[KEY_LEFT] = false
on ALLEGRO_KEY_RIGHT
key[KEY_RIGHT] = false
on ALLEGRO_KEY_ESCAPE
exit
off
off
if redraw and al_is_event_queue_empty(event_queue)
redraw = false
al_clear_to_color(al_map_rgb(0,0,0))
al_draw_bitmap(bouncer, bouncer_x, bouncer_y, 0)
al_flip_display()
ok
callgc()
end
al_destroy_timer(timer)
al_destroy_allegro_event(ev)
al_destroy_allegro_timeout(timeout)
al_destroy_event_queue(event_queue)
al_destroy_bitmap(bouncer)
al_destroy_bitmap(image)
al_destroy_display(display)
.. 注意：在前面的示例中，我们使用了函数 callgc()，它是 Ring 函数，用于强制在 While/End 循环内调用垃圾收集器。
程序输出
首先，程序显示一个消息框
然后，我们看到两个矩形在屏幕上移动
然后，我们看到一个图像显示在屏幕上
最后，我们有一个矩形，我们看到它一直在屏幕上移动，但我们可以使用鼠标和/或键盘控制它
在本示例中，我们将看到如何在我们的游戏中使用 TrueType 字体 *.ttf。
Load "gamelib.ring"
al_init()
al_init_font_addon()
al_init_ttf_addon()
display = al_create_display(800,600)
al_clear_to_color(al_map_rgb(0,0,255))
font = al_load_ttf_font("pirulen.ttf",14,0 )
al_draw_text(font, al_map_rgb(255,255,255), 10, 10,ALLEGRO_ALIGN_LEFT,
"Welcome to the Ring programming language")
al_flip_display()
al_rest(2)
al_destroy_display(display)屏幕截图
下面的示例播放一个声音文件
Load "gamelib.ring"
al_init()
al_install_audio()
al_init_acodec_addon()
al_reserve_samples(1)
sample = al_load_sample( "footstep.wav" )
sampleid = al_new_allegro_sample_id()
al_play_sample(sample, 1.0, 0.0,1.0,ALLEGRO_PLAYMODE_LOOP,sampleid)
display = al_create_display(640,480)
al_clear_to_color(al_map_rgb(0,0,255))
al_flip_display()
al_rest(10)
al_destroy_allegro_sample_id(sampleid)
al_destroy_sample(sample)
al_destroy_display(display)
al_exit()
下面的示例显示并旋转一个图像
Load "gamelib.ring"
al_init()
al_init_image_addon()
display = al_create_display(640,480)
al_set_target_bitmap(al_get_backbuffer(display))
al_clear_to_color(al_map_rgb(255,255,255))
image = al_load_bitmap("man2.jpg")
al_draw_rotated_bitmap(image,0,0,250,250,150,0)
al_draw_scaled_bitmap(image,0,0,250,250,20,20,400,400,0)
al_flip_display()
al_rest(2)
al_destroy_bitmap(image)
al_destroy_display(display)屏幕截图
下面的示例在另一个图像上显示具有白色背景的图像
Load "gamelib.ring"
al_init()
al_init_image_addon()
display = al_create_display(640,480)
imageback = al_load_bitmap("palace.jpg")
al_draw_bitmap(imageback,0,0,0)
image = al_load_bitmap("man4.png")
al_convert_mask_to_alpha(image,al_map_rgb(255,255,255))
al_draw_bitmap(image,0,0,0)
al_flip_display()
al_rest(10)
al_destroy_bitmap(image)
al_destroy_display(display)屏幕截图
在本示例中，我们将学习如何使用 Allegro 库中的用户线程
Load "gamelib.ring"
o1 = new mythreads
Func Main
al_init()
for k = 1 to 5
al_create_thread("o1.thread1()")
al_create_thread("o1.thread2()")
al_create_thread("o1.thread3()")
next
al_rest(2)
Class Mythreads
cAppName = "Threads Application"
Func Thread1
for x = 1 to 5
see x + nl
next
See 'Thread(1) : Application Name : ' + cAppName + nl
Func Thread2
for x = 1 to 5
see '*****' + x + nl
next
See 'Thread(2) : Application Name : ' + cAppName + nl
Func Thread3
for x = 1 to 5
see '!!!!' + x + nl
next
See 'Thread(3) : Application Name : ' + cAppName + nl输出
1
2
3
4
5
Thread(1) : Application Name : Threads Application
*****1
*****2
*****3
*****4
*****5
Thread(2) : Application Name : Threads Application
!!!!1
!!!!2
!!!!3
!!!!4
!!!!5
Thread(3) : Application Name : Threads Application
1
2
3
4
5
Thread(1) : Application Name : Threads Application
!!!!1
!!!!2
!!!!3
!!!!4
!!!!5
Thread(3) : Application Name : Threads Application
*****1
*****2
*****3
*****4
*****5
Thread(2) : Application Name : Threads Application
*****1
*****2
*****3
*****4
*****5
Thread(2) : Application Name : Threads Application
!!!!1
!!!!2
!!!!3
!!!!4
!!!!5
Thread(3) : Application Name : Threads Application
1
2
3
4
5
Thread(1) : Application Name : Threads Application
*****1
*****2
*****3
*****1
*****4
*****2
!!!!1
*****5
*****3
1
!!!!2
Thread(2) : Application Name : Threads Application
1
*****4
!!!!1
2
!!!!3
!!!!4
*****5
!!!!2
3
2
!!!!5
Thread(2) : Application Name : Threads Application
!!!!3
4
3
Thread(3) : Application Name : Threads Application
!!!!4
5
4
!!!!5
Thread(1) : Application Name : Threads Application
5
Thread(3) : Application Name : Threads Application
Thread(1) : Application Name : Threads Application