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warm starting testing

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This commit is contained in:
jacob 2024-10-02 16:13:38 -05:00
parent 2758bdc394
commit 3c275dfc9a
2 changed files with 57 additions and 34 deletions
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2
src/config.h
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@ -31,7 +31,7 @@
#define GAME_FPS 50.0
#define GAME_TIMESCALE 1.0
#define GAME_PHYSICS_SUBSTEPS 16
#define GAME_PHYSICS_SUBSTEPS 4
/* How many ticks back in time should the user blend between?
* <Delay ms> = <USER_INTERP_OFFSET_TICK_RATIO> * <Game tick rate>

89
src/game.c
View File

@ -390,8 +390,6 @@ INTERNAL void create_contact_manifolds(void)
}
manifold->manifold_normal = res.normal;
/* Delete old contacts that are no longer present */
for (u32 i = 0; i < manifold->num_contacts; ++i) {
struct contact *old = &manifold->contacts[i];
@ -427,8 +425,10 @@ INTERNAL void create_contact_manifolds(void)
}
if (contact) {
/* Update existing */
#if 0
contact->normal_impulse = 0;
contact->tangent_impulse = 0;
#endif
} else {
/* Insert new */
contact = &manifold->contacts[manifold->num_contacts++];
@ -460,7 +460,7 @@ INTERNAL void create_contact_manifolds(void)
INTERNAL void warm_start_contacts(f32 dt)
INTERNAL void warm_start_contacts(void)
{
struct entity_store *store = G.tick.entity_store;
@ -469,32 +469,51 @@ INTERNAL void warm_start_contacts(f32 dt)
if (!entity_is_valid_and_active(manifold)) continue;
if (!entity_has_prop(manifold, ENTITY_PROP_MANIFOLD)) continue;
u32 num_contacts = manifold->num_contacts;
struct entity *e0 = entity_from_handle(store, manifold->manifold_e0);
struct entity *e1 = entity_from_handle(store, manifold->manifold_e1);
if (entity_is_valid_and_active(e0) && entity_is_valid_and_active(e1)) {
struct v2 normal = manifold->manifold_normal;
if (num_contacts > 0 && entity_is_valid_and_active(e0) && entity_is_valid_and_active(e1)) {
struct xform e0_xf = entity_get_xform(e0);
struct xform e1_xf = entity_get_xform(e1);
struct v2 v0 = e0->linear_velocity;
struct v2 v1 = e1->linear_velocity;
f32 w0 = e0->angular_velocity;
f32 w1 = e1->angular_velocity;
f32 scale0 = math_fabs(xform_get_determinant(e0_xf));
f32 scale1 = math_fabs(xform_get_determinant(e1_xf));
f32 m0 = e0->mass_unscaled * scale0;
f32 m1 = e1->mass_unscaled * scale1;
f32 i0 = e0->inertia_unscaled * scale0;
f32 i1 = e1->inertia_unscaled * scale1;
f32 inv_m0 = 1.f / m0;
f32 inv_m1 = 1.f / m1;
f32 inv_i0 = 1.f / i0;
f32 inv_i1 = 1.f / i1;
/* Warm start */
struct v2 normal = manifold->manifold_normal;
struct v2 tangent = v2_perp(normal);
for (u32 i = 0; i < manifold->num_contacts; ++i) {
struct contact *contact = &manifold->contacts[i];
struct v2 p0 = xform_mul_v2(e0_xf, contact->point_local_e0);
struct v2 p1 = xform_mul_v2(e1_xf, contact->point_local_e1);
f32 separation = v2_dot(v2_sub(p1, p0), normal) + contact->starting_separation;
struct v2 vcp0 = v2_sub(p0, e0_xf.og);
struct v2 vcp1 = v2_sub(p1, e1_xf.og);
(UNUSED)p0;
(UNUSED)p1;
(UNUSED)separation;
(UNUSED)dt;
contact->normal_impulse = 0;
}
struct v2 impulse = v2_add(v2_mul(normal, contact->normal_impulse), v2_mul(tangent, contact->tangent_impulse));
v0 = v2_sub(v0, v2_mul(impulse, inv_m0));
v1 = v2_add(v1, v2_mul(impulse, inv_m1));
w0 -= v2_wedge(vcp0, impulse) * inv_i0;
w1 += v2_wedge(vcp1, impulse) * inv_i1;
}
e0->linear_velocity = v0;
e0->angular_velocity = w0;
e1->linear_velocity = v1;
e1->angular_velocity = w1;
}
}
}
@ -515,8 +534,13 @@ INTERNAL void solve_collisions(f32 dt, b32 apply_bias)
struct v2 v0 = e0->linear_velocity;
struct v2 v1 = e1->linear_velocity;
struct v2 v0_start = v0;
struct v2 v1_start = v1;
f32 w0 = e0->angular_velocity;
f32 w1 = e1->angular_velocity;
f32 w0_start = w0;
f32 w1_start = w1;
u32 num_contacts = manifold->num_contacts;
f32 inv_num_contacts = 1.f / num_contacts;
@ -542,20 +566,19 @@ INTERNAL void solve_collisions(f32 dt, b32 apply_bias)
struct contact *contact = &manifold->contacts[contact_index];
struct v2 p0 = xform_mul_v2(e0_xf, contact->point_local_e0);
struct v2 p1 = xform_mul_v2(e1_xf, contact->point_local_e1);
struct v2 vcp0 = v2_sub(p0, e0_xf.og);
struct v2 vcp1 = v2_sub(p1, e1_xf.og);
f32 bias = 0;
if (apply_bias) {
const f32 bias_factor = 0.2f;
const f32 bias_slop = 0.005f;
const f32 bias_factor = 0.1f;
const f32 bias_slop = 0.02f;
f32 penetration = v2_dot(v2_sub(p0, p1), normal) - contact->starting_separation;
bias = (bias_factor / dt) * max_f32(penetration - bias_slop, 0);
}
struct v2 vcp0 = v2_sub(p0, e0_xf.og);
struct v2 vcp1 = v2_sub(p1, e1_xf.og);
struct v2 vel0 = v2_add(v0, v2_perp_mul(vcp0, w0));
struct v2 vel1 = v2_add(v1, v2_perp_mul(vcp1, w1));
struct v2 vel0 = v2_add(v0_start, v2_perp_mul(vcp0, w0_start));
struct v2 vel1 = v2_add(v1_start, v2_perp_mul(vcp1, w1_start));
struct v2 vrel = v2_sub(vel0, vel1);
f32 vcp0_wedge = v2_wedge(vcp0, normal);
@ -566,7 +589,7 @@ INTERNAL void solve_collisions(f32 dt, b32 apply_bias)
/* (to be applied along n) */
f32 vn = v2_dot(vrel, normal);
f32 j = (vn + bias) * k;
j *= inv_num_contacts;
//j *= inv_num_contacts;
f32 old_impulse = contact->normal_impulse;
f32 new_impulse = max_f32(contact->normal_impulse + j, 0);
@ -580,19 +603,17 @@ INTERNAL void solve_collisions(f32 dt, b32 apply_bias)
w1 += v2_wedge(vcp1, impulse) * inv_i1;
}
#if 1
/* Tangent impulse */
struct v2 tangent = v2_perp(normal);
for (u32 contact_index = 0; contact_index < num_contacts; ++contact_index) {
struct contact *contact = &manifold->contacts[contact_index];
struct v2 p0 = xform_mul_v2(e0_xf, contact->point_local_e0);
struct v2 p1 = xform_mul_v2(e1_xf, contact->point_local_e1);
struct v2 vcp0 = v2_sub(p0, e0_xf.og);
struct v2 vcp1 = v2_sub(p1, e1_xf.og);
struct v2 vel0 = v2_add(v0, v2_perp_mul(vcp0, w0));
struct v2 vel1 = v2_add(v1, v2_perp_mul(vcp1, w1));
struct v2 vel0 = v2_add(v0_start, v2_perp_mul(vcp0, w0_start));
struct v2 vel1 = v2_add(v1_start, v2_perp_mul(vcp1, w1_start));
struct v2 vrel = v2_sub(vel0, vel1);
f32 vcp0_wedge = v2_wedge(vcp0, tangent);
@ -600,12 +621,14 @@ INTERNAL void solve_collisions(f32 dt, b32 apply_bias)
f32 k = (inv_m0 + inv_m1) + (inv_i0 * vcp0_wedge * vcp0_wedge) + (inv_i1 * vcp1_wedge * vcp1_wedge);
k = k > 0.0f ? 1.0f / k : 0.0f;
/* (to be applied along n) */
/* (to be applied along t) */
f32 vt = v2_dot(vrel, tangent);
float j = vt * k;
//j *= inv_num_contacts;
f32 j = vt * k;
j *= inv_num_contacts;
f32 friction = F32_INFINITY;
f32 friction = 0.6f;
//f32 friction = 1.0f;
//f32 friction = 999999.f;
f32 max_friction = friction * contact->normal_impulse;
f32 old_impulse = contact->tangent_impulse;
f32 new_impulse = clamp_f32(old_impulse + j, -max_friction, max_friction);
@ -618,7 +641,6 @@ INTERNAL void solve_collisions(f32 dt, b32 apply_bias)
w0 -= v2_wedge(vcp0, impulse) * inv_i0;
w1 += v2_wedge(vcp1, impulse) * inv_i1;
}
#endif
e0->linear_velocity = v0;
e0->angular_velocity = w0;
@ -1322,16 +1344,17 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
{
create_contact_manifolds();
warm_start_contacts();
(UNUSED)create_contact_manifolds;
(UNUSED)solve_collisions;
(UNUSED)integrate_positions;
(UNUSED)warm_start_contacts;
f32 substep_dt = dt / GAME_PHYSICS_SUBSTEPS;
for (u32 i = 0; i < GAME_PHYSICS_SUBSTEPS; ++i) {
#if 1
//warm_start_contacts(dt);
solve_collisions(substep_dt, true);
integrate_positions(substep_dt);
solve_collisions(substep_dt, false); /* Relaxation */