FPS camera in Allegro 5

FPS camera in Allegro 5

CrizerPL

Member #16,496

July 2016

So I'm trying to make a simple 3D game in Allegro5 and I'm stuck trying to make the camera class work.

Here's my loop:

#SelectExpand
  1al_clear_to_color(al_map_rgb(0,0,0));
  2
  3p = test.create_a5_perspective_transform();
  4c = test.create_a5_camera_transform();
  5
  6al_use_projection_transform(&p);
  7al_use_transform(&c);
  8al_draw_prim(&test_hmap[0], NULL, NULL, 0, test_hmap.size(), ALLEGRO_PRIM_TRIANGLE_LIST);
  9
 10test.handle_mouse();
 11al_flip_display();

and here are the 2 functions:

#SelectExpand
  1ALLEGRO_TRANSFORM LPG_CAMERA::create_a5_perspective_transform()
  2{
  3    double pt_width = tan(h_fov/360.0*3.14159265358979)*lpg_default_near;
  4    double pt_height= pt_width / double((double)al_get_display_width(lpg_a5_display)/(double)al_get_display_height(lpg_a5_display));
  5    al_identity_transform(&th_output);
  6    al_perspective_transform(&th_output,
  7                             -pt_width, pt_width, lpg_default_near,
  8                             -pt_height, pt_height, lpg_render_distance);
  9    return th_output;
 10}
 11ALLEGRO_TRANSFORM LPG_CAMERA::create_a5_camera_transform()
 12{
 13    al_identity_transform(&th_output);
 14    al_rotate_transform_3d(&th_output, -1.0, 0.0, 0.0, deg_to_rad(y_rot)); //pitch
 15    al_rotate_transform_3d(&th_output, 0.0, -1.0, 0.0, deg_to_rad(x_rot)); //yaw
 16    al_translate_transform_3d(&th_output, -x, -y, -z);
 17    return th_output;
 18}

The camera seems tilted and the FOV very limited (I attached the program to give you an idea), so I'm clearly doing something wrong here. I can't really see what's exactly causing the problem, though.
Does anyone know what's wrong?

EDIT: I'm an idiot, I looked at the documentation and realized I was passing arguments to al_perspective_transform in the wrong order Also, al_rotate_transform_3d() calls needed to be swapped. The camera is working perfectly now. I can't reply or delete this thread AFAIK, so I'm leaving it here