Tux sliding on belly sprite should be orientated to fit the angle of the slope they're sliding down

[RustoMCSpit]

13 seconds into the SuperTux: Development Summary of 2023! we see Tux stay perfectly horizontal on a slope while sliding rather than diagonally.

[RustoMCSpit]

Dependent on (https://github.com/SuperTux/supertux/issues/1448)

[bruhmoent]

Dependent on (#1448)

The sprite isn't dependent on the hitbox.

[RustoMCSpit]

This would also requires smooth transitioning / blending between orientations which are impacted by velocity / acceleration. This could be done via interpolation, easing, dynamic effect (blender animation suite terminology) and by plugging in the variables.

[Brockengespenst]

If it is just about simply rotating the sprite, this can be achieved by placing

if (m_sliding)
{
  float sprite_angle = 0.0f;
  if (m_floor_normal.y != 0.0f)
  {
   sprite_angle = math::degrees(math::angle(m_floor_normal)) + 90.0f;
 }
 m_sprite->set_angle(sprite_angle);
}

Around line 1436 in player.cpp (probably also other places possible). The result would be the following:

https://github.com/SuperTux/supertux/assets/155102424/b2f54dd8-b942-451b-a425-c83312bdbf85

This would not rotate the hitbox, just the sprite of Tux. It also does not include a "smooth transition" right now, which is most likely a bit more complex to implement.

If the above behavior would be Ok as a first step, I could create a PR if you like.

[tobbi]

Fuck yeah, this is already more awesome than what we have in the game.

[Brockengespenst]

I created a PR that, additionally to the above mentioned changes, also uses Tux' velocity for sprite orientation in case you jump off an edge while sliding.

[Frostwithasideofsalt]

THIS IS PEAK

[RustoMCSpit]

Supertux-Sliding-Angle.mp4

hold om this gives me a genius idea. we can have level design based on this new mechanic where tux has to slide to generate momentum and then fly off an edge to get over a gap like in https://apps.apple.com/gb/app/racing-penguin-slide-and-fly/id443637419

[RustoMCSpit]

there should also be particle effects depending on the environment!