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| Blitting from bitmap to blitmap in Allegro 5 |
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TeaRDoWN
Member #8,518
April 2007
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I'm trying to get into how Allegro 5 works from using Allegro 4 for a couple of years now. One thing that has changed alot (if I understand it correctly) is how to draw what onto which bitmaps. 1// Create screen buffer
2BITMAP *new_screen = create_bitmap(screen->w,screen->h);
3clear_to_color(new_screen, makecol(0,0,0));
4
5// Load sprite
6BITMAP *sprite1 = load_bitmap("image.bmp", NULL);
7
8// Create secondary sprite
9BITMAP *sprite2 = create_bitmap(sprite1->w-10, sprite1->h-10);
10blit(sprite1, sprite2, 0,0, 5,5, sprite1->w-10, sprite1->h-10);
11
12// Draw secondary sprite centered on screen buffer
13draw_sprite(new_screen, sprite2, new_screen->w/2-sprite2->w/2, new_screen->h/2-sprite2->h/2);
14
15// Update screen
16draw_sprite(screen, new_screen, 0,0);
(I think I wrote it without build errors, didn't try in a compiler before |
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Matthew Leverton
Supreme Loser
January 1999
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The new_screen is not needed, because Allegro 5 gives you a back buffer. By default, that back buffer is the target of all drawing operations. To change the target to a bitmap, use al_set_target_bitmap(bmp). To change back to the back buffer, use al_set_target_backbuffer(display). Also, most structs are opaque, so you must use functions like al_get_bitmap_width(bmp) to retrieve information, as opposed to directly accessing struct members. If you read the manual, you should find it pretty obvious how the various drawing related functions work. |
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TeaRDoWN
Member #8,518
April 2007
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Ok, thanks. I've read the manual but the information is divided into different areas and not always followed by a simple example I thought it could be handly to have it here on the forum - "this is how you did it before, this is how you do it now". |
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Matthew Leverton
Supreme Loser
January 1999
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Why don't you write the Allegro 5 version and see how close you get? If you get stuck, then ask some questions. |
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