character controller example: added 2 slopes to test max/min slopes

[Vrixyz]

From a report on discord, the max_slope_climb_angle are not respected in the character controller example.

This pull requests only adds 2 slopes to test this behaviour more easily

Analysis

• Character controller example from rapier doesn't have this bug.

the added example should have the same parameters as rapier:

• slope we can climb: https://github.com/dimforge/rapier/blob/master/examples3d/character_controller3.rs#L93

• slope we cannot climb: https://github.com/dimforge/rapier/blob/b7347860f71179a4675ec785644abe1bb09e415a/examples3d/character_controller3.rs#L107

• character controller parameters: https://github.com/dimforge/rapier/blob/master/src_testbed/testbed.rs#L786

  • ⚠️ ; this is interesting, rapier assumes the controller speed is going down as much as its speed.

• I moved this analysis to rapier, with a first setup PR to help with debugging: Fix character max/min slope rapier#701

Test instructions

run cargo run --example character_controller3 : 2 slopes are present, 1 we should be able to climb, one we shouldn't be able to.

[Vrixyz]

Related: dimforge/rapier.js#274