I tried to reproduce your problem, but the OpenGL and the Direct3D one look the same to me, and they both look aliased. Note that I used ALLEGRO_DIRECT3D, not 'ALLEGRO_DIRECT3D_INTERNAL' as that shouldn't be visible anyway. Why are you trying to use _INTERNAL?
Here's the code I used :
1
2#include <allegro5/allegro.h>
3#include <allegro5/allegro_color.h>
4#include <allegro5/allegro_primitives.h>
5#include <allegro5/allegro_direct3d.h>
6
7#include <cstdio>
8
9int main(int argc, char **argv) {
10
11 if (!al_init()) {return 1;}
12 al_init_primitives_addon();
13 al_install_keyboard();
14
15 ALLEGRO_EVENT_QUEUE* queue = al_create_event_queue();
16 if (!queue) {return 2;}
17 al_register_event_source(queue , al_get_keyboard_event_source());
18
19 al_set_new_display_option(ALLEGRO_SAMPLE_BUFFERS, 1, ALLEGRO_SUGGEST);
20 al_set_new_display_option(ALLEGRO_SAMPLES, 8, ALLEGRO_SUGGEST);
21
22 int use_opengl = 0;
23 if (argc > 1) {
24 if (1 == sscanf(argv[1] , "%i" , &use_opengl)) {
25
26 }
27 else {
28 use_opengl = 0;
29 }
30 }
31
32 if (use_opengl) {
33 al_set_new_display_flags(ALLEGRO_OPENGL);
34 }
35 else {
36 al_set_new_display_flags(ALLEGRO_DIRECT3D);
37 }
38
39 ALLEGRO_DISPLAY *display = al_create_display(1024, 600);
40 if (!display) {return 2;}
41 al_register_event_source(queue , al_get_display_event_source(display));
42
43 al_clear_to_color(al_color_name("black"));
44 al_draw_circle(500, 300, 200, al_color_name("white"), 5.0);
45 al_draw_line(200, 200, 700, 300, al_color_name("white"), 5.0);
46 al_flip_display();
47
48 bool quit = false;
49 while (!quit) {
50 ALLEGRO_EVENT ev;
51 al_wait_for_event(queue , &ev);
52 if (ev.type == ALLEGRO_EVENT_KEY_DOWN && ev.keyboard.keycode == ALLEGRO_KEY_ESCAPE) {quit = true;}
53 if (ev.type == ALLEGRO_EVENT_DISPLAY_CLOSE) {quit = true;}
54 }
55 return 0;
56}
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.
It was the same with the 