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Implement wheel rotation and friction

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This commit is contained in:
sergeypdev 2025-03-16 14:53:13 +04:00
parent 2410ed9b4b
commit bf7b7e6ae3
4 changed files with 93 additions and 30 deletions
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5
game/game.odin
View File

@ -325,6 +325,7 @@ update_runtime_world :: proc(runtime_world: ^Runtime_World, dt: f32) {
radius := f32(0.6)
wheel_front_z := f32(3.05)
wheel_back_z := f32(-2.45)
wheel_mass := f32(12)
wheel_fl := physics.immediate_suspension_constraint(
&world.physics_scene,
@ -338,6 +339,7 @@ update_runtime_world :: proc(runtime_world: ^Runtime_World, dt: f32) {
natural_frequency = natural_frequency,
damping = damping,
body = runtime_world.car_handle,
mass = wheel_mass,
},
)
wheel_fr := physics.immediate_suspension_constraint(
@ -352,6 +354,7 @@ update_runtime_world :: proc(runtime_world: ^Runtime_World, dt: f32) {
natural_frequency = natural_frequency,
damping = damping,
body = runtime_world.car_handle,
mass = wheel_mass,
},
)
wheel_rl := physics.immediate_suspension_constraint(
@ -366,6 +369,7 @@ update_runtime_world :: proc(runtime_world: ^Runtime_World, dt: f32) {
natural_frequency = natural_frequency,
damping = damping,
body = runtime_world.car_handle,
mass = wheel_mass,
},
)
wheel_rr := physics.immediate_suspension_constraint(
@ -380,6 +384,7 @@ update_runtime_world :: proc(runtime_world: ^Runtime_World, dt: f32) {
natural_frequency = natural_frequency,
damping = damping,
body = runtime_world.car_handle,
mass = wheel_mass,
},
)

20
game/physics/debug.odin
View File

@ -70,19 +70,31 @@ draw_debug_scene :: proc(scene: ^Scene) {
wheel := &sim_state.suspension_constraints_slice[i]
if wheel.alive {
body := get_body(sim_state, wheel.body)
t := wheel.hit_t > 0 ? wheel.hit_t : wheel.rest
pos := body.x
rot := body.q
pos += lg.quaternion_mul_vector3(rot, wheel.rel_pos)
dir := lg.quaternion_mul_vector3(rot, wheel.rel_dir)
rl.DrawLine3D(pos, pos + dir * t, rl.ORANGE)
rel_wheel_pos := wheel_get_rel_wheel_pos(body, wheel)
wheel_pos := body_local_to_world(body, rel_wheel_pos)
right := wheel_get_right_vec(body, wheel)
rotation_dir := body_local_to_world_vec(
body,
lg.matrix3_rotate(wheel.q, Vec3{-1, 0, 0}) * Vec3{0, 1, 0},
)
rl.DrawLine3D(
wheel_pos - right * 0.1,
wheel_pos - right * 0.1 + rotation_dir * wheel.radius,
rl.ORANGE,
)
rl.DrawLine3D(
wheel_pos + right * 0.1,
wheel_pos + right * 0.1 + rotation_dir * wheel.radius,
rl.ORANGE,
)
rl.DrawCylinderWiresEx(
wheel_pos - right * 0.1,
wheel_pos + right * 0.1,

53
game/physics/scene.odin
View File

@ -120,38 +120,49 @@ Collision_Shape :: union {
}
Suspension_Constraint :: struct {
alive: bool,
alive: bool,
// Pos relative to the body
rel_pos: Vec3,
rel_pos: Vec3,
// Dir relative to the body
rel_dir: Vec3,
rel_dir: Vec3,
// Handle of the rigid body
body: Body_Handle,
body: Body_Handle,
// Wheel radius
radius: f32,
radius: f32,
// Wheel mass
mass: f32,
// Rest distance
rest: f32,
rest: f32,
// Frequency of the spring, affects stiffness
natural_frequency: f32,
natural_frequency: f32,
// How much to damp velocity of the spring
damping: f32,
// Accumulated impulse
spring_impulse: f32,
lateral_impulse: f32,
damping: f32,
// Runtime state
hit: bool,
hit_point: Vec3,
// Accumulated impulse
spring_impulse: f32,
lateral_impulse: f32,
longitudinal_impulse: f32,
// Inverse inertia along wheel rotation axis
inv_inertia: f32,
// Rotation
q: f32,
// Angular velocity
w: f32,
hit: bool,
hit_point: Vec3,
// rel_hit_point = rel_pos + rel_dir * hit_t
hit_t: f32,
turn_angle: f32,
drive_impulse: f32,
brake_impulse: f32,
applied_impulse: Vec3,
hit_t: f32,
turn_angle: f32,
drive_impulse: f32,
brake_impulse: f32,
applied_impulse: Vec3,
// Free list
next_plus_one: i32,
next_plus_one: i32,
}
// Index plus one, so handle 0 maps to invalid body
@ -248,6 +259,7 @@ Suspension_Constraint_Config :: struct {
natural_frequency: f32,
damping: f32,
radius: f32,
mass: f32,
}
calculate_body_params_from_config :: proc(
@ -318,6 +330,7 @@ update_suspension_constraint_from_config :: proc(
constraint.natural_frequency = config.natural_frequency
constraint.damping = config.damping
constraint.radius = config.radius
constraint.inv_inertia = 1.0 / (0.5 * config.mass * config.radius * config.radius)
}

45
game/physics/simulation.odin
View File

@ -363,10 +363,10 @@ pgs_solve_contacts :: proc(
random_order[i] = i32(i)
}
for i in 0 ..< len(random_order) - 1 {
j := rand.int_max(len(random_order))
slice.swap(random_order, i, j)
}
// for i in 0 ..< len(random_order) - 1 {
// j := rand.int_max(len(random_order))
// slice.swap(random_order, i, j)
// }
}
for i in 0 ..< len(sim_state.contact_container.contacts) {
@ -488,6 +488,11 @@ pgs_solve_suspension :: proc(sim_state: ^Sim_State, config: Solver_Config, dt: f
{wheel_world_pos, pos2},
collision.plane_from_point_normal({}, collision.Vec3{0, 1, 0}),
)
forward := body_local_to_world_vec(body, Vec3{0, 0, 1})
contact_patch_linear_vel :=
body_velocity_at_point(body, v.hit_point) + (v.radius * v.w * forward)
w := get_body_angular_inverse_mass(body, dir)
inv_w := 1.0 / w
if v.hit {
@ -510,10 +515,30 @@ pgs_solve_suspension :: proc(sim_state: ^Sim_State, config: Solver_Config, dt: f
apply_velocity_correction(body, incremental_impulse * dir, wheel_world_pos)
}
right := wheel_get_right_vec(body, v)
// Longitudinal friction
if true {
vel_long := lg.dot(contact_patch_linear_vel, forward)
friction := f32(1)
friction_clamp := abs(v.spring_impulse) * friction
incremental_impulse := -v.inv_inertia * vel_long
new_total_impulse := clamp(
v.longitudinal_impulse + incremental_impulse,
-friction_clamp,
friction_clamp,
)
applied_impulse := new_total_impulse - v.longitudinal_impulse
v.longitudinal_impulse = new_total_impulse
v.w += v.inv_inertia * applied_impulse
}
// Drive forces
if true {
total_impulse := v.drive_impulse - v.brake_impulse
forward := body_local_to_world_vec(body, Vec3{0, 0, 1})
apply_velocity_correction(
body,
@ -525,7 +550,6 @@ pgs_solve_suspension :: proc(sim_state: ^Sim_State, config: Solver_Config, dt: f
// Lateral friction
if true {
vel_contact := body_velocity_at_point(body, wheel_world_pos)
right := wheel_get_right_vec(body, v)
lateral_vel := lg.dot(right, vel_contact)
@ -546,6 +570,7 @@ pgs_solve_suspension :: proc(sim_state: ^Sim_State, config: Solver_Config, dt: f
} else {
v.lateral_impulse = 0
v.spring_impulse = 0
v.longitudinal_impulse = 0
}
}
}
@ -601,6 +626,8 @@ pgs_substep :: proc(sim_state: ^Sim_State, config: Solver_Config, dt: f32, inv_d
p,
)
apply_velocity_correction(body, s.lateral_impulse * right, p)
s.w += s.inv_inertia * s.longitudinal_impulse
}
}
}
@ -631,6 +658,12 @@ pgs_substep :: proc(sim_state: ^Sim_State, config: Solver_Config, dt: f32, inv_d
}
}
for i in 0 ..< len(sim_state.suspension_constraints_slice) {
s := &sim_state.suspension_constraints_slice[i]
s.q = math.mod_f32(s.q + 0.5 * s.w * dt, math.PI * 2)
}
apply_bias = false
pgs_solve_contacts(sim_state, config, dt, inv_dt, apply_bias)
// pgs_solve_suspension(sim_state, config, dt, inv_dt, apply_bias)