|
|
|
This thread is locked; no one can reply to it.
|
| [a5] rendering to display bitmap with multisampling in directx |
|
Mark Oates
Member #1,146
March 2001
 |
I'm trying to do the following:
I'm able to do this just fine, but when 1) multi-sampling is enabled and 2) it's in directx, somehow bitmap_a clears out (becomes transparent or something.) I'm using 5.0.5. Here's my example program: 1#include <allegro5/allegro.h>
2#include <allegro5/allegro_color.h>
3#include <allegro5/allegro_primitives.h>
4#include <allegro5/allegro_image.h>
5
6
7
8void main()
9{
10 int screen_w = 320;
11 int screen_h = 240;
12 float shape_size = screen_w/4;
13 bool save_renders = true;
14
15 al_init();
16 al_init_primitives_addon();
17 al_init_image_addon();
18
19
20 al_set_new_display_option(ALLEGRO_SAMPLE_BUFFERS, 2, ALLEGRO_SUGGEST); // works only in opengl
21 al_set_new_display_option(ALLEGRO_SAMPLES, 4, ALLEGRO_SUGGEST); // works only in opengl
22 //al_set_new_display_flags(ALLEGRO_OPENGL);
23
24
25 // create the display and 2 surfaces
26 ALLEGRO_DISPLAY *display = al_create_display(screen_w, screen_h);
27 ALLEGRO_BITMAP *surface_a = al_create_bitmap(screen_w, screen_h);
28 ALLEGRO_BITMAP *surface_b = al_create_bitmap(screen_w, screen_h);
29
30
31 // draw the content of surface_a
32 al_clear_to_color(al_color_name("orange"));
33 al_draw_filled_circle(screen_w/2, screen_h/2, shape_size, al_map_rgba_f(0.2, 0.2, 0.2, 0.2));
34
35 al_set_target_bitmap(surface_a);
36 al_draw_bitmap(al_get_backbuffer(display), 0, 0, NULL);
37
38 if (save_renders) al_save_bitmap("surface_a_first.png", surface_a);
39 if (save_renders) al_save_bitmap("surface_b_first.png", surface_b);
40
41
42 // reset the surface (oops! forgot to put this in)
44
45
46
47 // draw the content of surface_b
48 al_clear_to_color(al_color_name("dodgerblue"));
49 al_draw_filled_rectangle(screen_w/2-shape_size, screen_h/2-shape_size,
50 screen_w/2+shape_size, screen_h/2+shape_size, al_map_rgba_f(0.2, 0.2, 0.2, 0.2));
51
52 al_set_target_bitmap(surface_b);
53 al_draw_bitmap(al_get_backbuffer(display), 0, 0, NULL);
54
55 if (save_renders) al_save_bitmap("surface_a_second.png", surface_a);
56 if (save_renders) al_save_bitmap("surface_b_second.png", surface_b);
57
58
59
60 // draw surface_a and surface_b blended together
61 al_set_target_bitmap(al_get_backbuffer(display));
62
63 al_draw_bitmap(surface_a, 0, 0, NULL);
64 al_draw_tinted_bitmap(surface_b, al_map_rgba_f(0.5, 0.5, 0.5, 0.5), 0, 0, NULL);
65
66
67 if (save_renders) al_save_bitmap("surface_a_final.png", surface_a);
68 if (save_renders) al_save_bitmap("surface_b_final.png", surface_b);
69
70
71 // flip the dip!
72 al_flip_display();
73
74
75 al_rest(5);
76
77 return;
78}
Here's what surface_a should look like:
-- |
|
moric haega
Member #13,935
January 2012
|
I don't know much about DirectX or OpenGL, but I think this is what goes wrong: -You draw the orange stuff to the backbuffer. Reminds me of some program of mine. I read some names and numbers from a file, but forgot to clear the readbuffer between reads. You can guess what kind of mess that became. PS. I'm a new user, so if there is something wrong with my English or tone, please tell me.
|
|
J-Gamer
Member #12,491
January 2011
 |
Yes, you should have another al_set_target_bitmap(al_get_backbuffer(display)); between line 39 and 44. " There are plenty of wonderful ideas in The Bible, but God isn't one of them." - Derezo |
|
Mark Oates
Member #1,146
March 2001
|
Yeoops! Silly mistake there. That explains the weird bitmap-swapping. I added the reset on line 43. Thanks. The OpenGL/DirectX inconsistency is a little more obvious now. By commenting/uncommenting the OpenGL line (22) alone it changes the results. Both work as expected when muti-sampling is disabled (20, 21). So: This works as expected: al_set_new_display_option(ALLEGRO_SAMPLE_BUFFERS, 2, ALLEGRO_SUGGEST); al_set_new_display_option(ALLEGRO_SAMPLES, 4, ALLEGRO_SUGGEST); al_set_new_display_flags(ALLEGRO_OPENGL); This does not work as expected (defaults to DirectX): al_set_new_display_option(ALLEGRO_SAMPLE_BUFFERS, 2, ALLEGRO_SUGGEST); al_set_new_display_option(ALLEGRO_SAMPLES, 4, ALLEGRO_SUGGEST); //al_set_new_display_flags(ALLEGRO_OPENGL); This works as expected (also DirectX): //al_set_new_display_option(ALLEGRO_SAMPLE_BUFFERS, 2, ALLEGRO_SUGGEST); //al_set_new_display_option(ALLEGRO_SAMPLES, 4, ALLEGRO_SUGGEST); //al_set_new_display_flags(ALLEGRO_OPENGL); In the second case, all of the bitmaps from save_renders are blank. Also, the window only displays what appears in "surface_b." moric haega said: PS. I'm a new user, so if there is something wrong with my English or tone, please tell me.
[edit:] Hmm... no takers? -- |
|
Matthew Leverton
Supreme Loser
January 1999
 |
Your posts are too confusing with commented and struck out content. |
|
Mark Oates
Member #1,146
March 2001
|
It's a strange problem to describe and might take a little work to figure out. Ignore anything that is The example program exposes the problem clearly if you try it. Then with lines 20, 21, and 22, comment/uncomment them out as I did in this post. Each configuration should produce the same results, but they don't. -- |
|
|
