1135 lines
48 KiB
C
1135 lines
48 KiB
C
#include "phys.h"
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#include "entity.h"
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GLOBAL struct {
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/* Constants */
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struct math_spring_result contact_softness;
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struct math_spring_result mouse_joint_linear_softness;
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struct math_spring_result mouse_joint_angular_softness;
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f32 mouse_joint_max_force;
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} G = ZI, DEBUG_ALIAS(G, G_phys);
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/* ========================== *
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* Startup
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* ========================== */
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struct phys_startup_receipt phys_startup(void)
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{
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/* Initialize constants */
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const f32 substep_dt = (1.f / ((f32)GAME_FPS * (f32)GAME_PHYSICS_SUBSTEPS));
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const f32 contact_frequency = (1.f / substep_dt) / 8.f;
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const f32 contact_damping_ratio = 10;
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G.contact_softness = math_spring(contact_frequency, contact_damping_ratio, substep_dt);
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const f32 mouse_joint_linear_frequency = 5.0;
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const f32 mouse_joint_linear_damping_ratio = 0.7;
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const f32 mouse_joint_angular_frequency = 0.5f;
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const f32 mouse_joint_angular_damping_ratio = 0.1f;
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G.mouse_joint_max_force = 1000;
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G.mouse_joint_linear_softness = math_spring(mouse_joint_linear_frequency, mouse_joint_linear_damping_ratio, substep_dt);
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G.mouse_joint_angular_softness = math_spring(mouse_joint_angular_frequency, mouse_joint_angular_damping_ratio, substep_dt);
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return (struct phys_startup_receipt) { 0 };
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}
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/* ========================== *
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* Contact
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* ========================== */
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void phys_create_contacts(struct entity_store *store, struct entity_lookup *contact_lookup, struct entity_lookup *debug_lookup, u64 tick_id)
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{
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struct entity *root = entity_from_handle(store, store->root);
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for (u64 check0_index = 0; check0_index < store->reserved; ++check0_index) {
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struct entity *check0 = &store->entities[check0_index];
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if (!entity_is_valid_and_active(check0)) continue;
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if (!(entity_has_prop(check0, ENTITY_PROP_PHYSICAL_DYNAMIC) || entity_has_prop(check0, ENTITY_PROP_PHYSICAL_KINEMATIC))) continue;
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if (check0->local_collider.count <= 0) continue;
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struct xform check0_xf = entity_get_xform(check0);
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struct collider_shape check0_collider = check0->local_collider;
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for (u64 check1_index = 0; check1_index < store->reserved; ++check1_index) {
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struct entity *check1 = &store->entities[check1_index];
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if (check1 == check0) continue;
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if (!entity_is_valid_and_active(check1)) continue;
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if (!(entity_has_prop(check1, ENTITY_PROP_PHYSICAL_DYNAMIC) || entity_has_prop(check1, ENTITY_PROP_PHYSICAL_KINEMATIC))) continue;
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if (check1->local_collider.count <= 0) continue;
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/* Deterministic entity order based on index */
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struct entity *e0;
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struct entity *e1;
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struct xform e0_xf;
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struct xform e1_xf;
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struct collider_shape e0_collider;
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struct collider_shape e1_collider;
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if (check0_index < check1_index) {
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e0 = check0;
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e1 = check1;
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e0_xf = check0_xf;
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e1_xf = entity_get_xform(check1);
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e0_collider = check0_collider;
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e1_collider = check1->local_collider;
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} else {
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e0 = check1;
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e1 = check0;
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e0_xf = entity_get_xform(check1);
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e1_xf = check0_xf;
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e0_collider = check1->local_collider;
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e1_collider = check0_collider;
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}
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struct entity_lookup_key key = entity_lookup_key_from_two_handles(e0->handle, e1->handle);
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struct entity_lookup_entry *entry = entity_lookup_get(contact_lookup, key);
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struct entity *constraint_ent = entity_nil();
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if (entry) {
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constraint_ent = entity_from_handle(store, entry->entity);
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if (entity_is_valid_and_active(constraint_ent)) {
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if (constraint_ent->contact_constraint_data.last_iteration >= tick_id) {
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/* Already processed constraint this iteration */
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continue;
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} else {
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++constraint_ent->contact_constraint_data.last_iteration;
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}
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} else {
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/* Constraint ent no longer valid, delete entry */
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entity_lookup_remove(contact_lookup, entry);
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entry = NULL;
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}
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}
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/* Calculate collision */
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struct collider_collision_points_result collider_res = collider_collision_points(&e0_collider, &e1_collider, e0_xf, e1_xf);
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/* Parts of algorithm are hard-coded to support 2 contact points */
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CT_ASSERT(ARRAY_COUNT(constraint_ent->contact_constraint_data.points) == 2);
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CT_ASSERT(ARRAY_COUNT(collider_res.points) == 2);
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struct phys_contact_constraint *constraint = NULL;
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if (collider_res.num_points > 0) {
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if (!entity_is_valid_and_active(constraint_ent)) {
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/* Create hit event */
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{
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struct entity *event = entity_alloc(root);
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entity_enable_prop(event, ENTITY_PROP_HIT_EVENT);
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event->hit_event.e0 = e0->handle;
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event->hit_event.e1 = e1->handle;
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event->hit_event.normal = collider_res.normal;
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entity_enable_prop(event, ENTITY_PROP_RELEASE_BEFORE_PUBLISH);
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entity_enable_prop(event, ENTITY_PROP_ACTIVE);
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/* Calculate point */
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struct v2 point = collider_res.points[0].point;
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if (collider_res.num_points > 1) {
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point = v2_add(point, v2_mul(v2_sub(collider_res.points[1].point, point), 0.5f));
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}
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event->hit_event.point = point;
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/* Calculate relative velocity */
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struct v2 vrel;
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{
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struct v2 v0 = e0->linear_velocity;
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struct v2 v1 = e1->linear_velocity;
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f32 w0 = e0->angular_velocity;
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f32 w1 = e1->angular_velocity;
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struct v2 vcp0 = v2_sub(point, e0_xf.og);
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struct v2 vcp1 = v2_sub(point, e1_xf.og);
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struct v2 vel0 = v2_add(v0, v2_perp_mul(vcp0, w0));
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struct v2 vel1 = v2_add(v1, v2_perp_mul(vcp1, w1));
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vrel = v2_sub(vel0, vel1);
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}
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event->hit_event.vrel = vrel;
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}
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/* Create constraint */
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{
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constraint_ent = entity_alloc(root);
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constraint_ent->contact_constraint_data.e1 = e1->handle;
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constraint_ent->contact_constraint_data.e0 = e0->handle;
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constraint_ent->contact_constraint_data.skip_solve = entity_has_prop(e0, ENTITY_PROP_SENSOR) || entity_has_prop(e1, ENTITY_PROP_SENSOR)
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|| !(entity_has_prop(e0, ENTITY_PROP_PHYSICAL_DYNAMIC) || entity_has_prop(e1, ENTITY_PROP_PHYSICAL_DYNAMIC));
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entity_enable_prop(constraint_ent, ENTITY_PROP_ACTIVE);
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/* TODO: Should we recalculate normal as more contact points are added? */
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entity_enable_prop(constraint_ent, ENTITY_PROP_CONTACT_CONSTRAINT);
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entity_activate(constraint_ent, tick_id);
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ASSERT(!entry); /* Existing entry should never be present here */
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entity_lookup_set(contact_lookup, key, constraint_ent->handle);
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}
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}
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constraint = &constraint_ent->contact_constraint_data;
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constraint->normal = collider_res.normal;
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constraint->friction = math_sqrt(e0->friction * e1->friction);
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/* Delete old contacts that are no longer present */
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for (u32 i = 0; i < constraint->num_points; ++i) {
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struct phys_contact_point *old = &constraint->points[i];
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u32 id = old->id;
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b32 found = false;
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for (u32 j = 0; j < collider_res.num_points; ++j) {
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if (collider_res.points[j].id == id) {
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found = true;
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break;
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}
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}
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if (!found) {
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/* Delete contact by replacing with last in array */
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*old = constraint->points[--constraint->num_points];
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--i;
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}
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}
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/* Update / insert returned contacts */
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for (u32 i = 0; i < collider_res.num_points; ++i) {
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struct collider_collision_point *res_point = &collider_res.points[i];
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struct v2 point = res_point->point;
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f32 sep = res_point->separation;
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u32 id = res_point->id;
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struct phys_contact_point *contact = NULL;
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/* Match */
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for (u32 j = 0; j < constraint->num_points; ++j) {
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struct phys_contact_point *t = &constraint->points[j];
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if (t->id == id) {
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contact = t;
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break;
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}
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}
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if (!contact) {
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/* Insert */
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contact = &constraint->points[constraint->num_points++];
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MEMZERO_STRUCT(contact);
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contact->id = id;
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constraint->softness = G.contact_softness;
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constraint->pushout_velocity = 3.0f;
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}
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/* Update points & separation */
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contact->point_local_e0 = xform_invert_mul_v2(e0_xf, point);
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contact->point_local_e1 = xform_invert_mul_v2(e1_xf, point);
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contact->starting_separation = sep;
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#if COLLIDER_DEBUG
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contact->dbg_pt = point;
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#endif
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}
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} else if (constraint_ent->valid) {
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constraint_ent->contact_constraint_data.num_points = 0;
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}
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/* TODO: Remove this (debugging) */
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#if COLLIDER_DEBUG
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{
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struct entity *dbg_ent = entity_nil();
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struct entity_lookup_entry *dbg_entry = entity_lookup_get(debug_lookup, key);
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if (dbg_entry) {
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dbg_ent = entity_from_handle(store, dbg_entry->entity);
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}
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if (!dbg_ent->valid) {
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/* FIXME: Entity never released */
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dbg_ent = entity_alloc(root);
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entity_enable_prop(dbg_ent, ENTITY_PROP_COLLISION_DEBUG);
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entity_lookup_set(debug_lookup, key, dbg_ent->handle);
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}
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struct phys_collision_debug *dbg = &dbg_ent->collision_debug_data;
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if (dbg->res.num_points == 0) {
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if (collider_res.num_points > 0) {
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++e0->colliding;
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++e1->colliding;
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}
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} else {
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if (collider_res.num_points == 0) {
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--e0->colliding;
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--e1->colliding;
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}
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}
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dbg->e0 = e0->handle;
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dbg->e1 = e1->handle;
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dbg->res = collider_res;
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if (constraint) {
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MEMCPY(dbg->points, constraint->points, sizeof(dbg->points));
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dbg->num_points = constraint->num_points;
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} else {
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dbg->num_points = 0;
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}
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dbg->xf0 = e0_xf;
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dbg->xf1 = e1_xf;
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/* Update closest points */
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{
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struct collider_closest_points_result closest_points_res = collider_closest_points(&e0_collider, &e1_collider, e0_xf, e1_xf);
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dbg->closest0 = closest_points_res.p0;
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dbg->closest1 = closest_points_res.p1;
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}
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}
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#endif
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}
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}
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}
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void phys_prepare_contacts(struct entity_store *store, struct entity_lookup *contact_lookup, struct entity_lookup *debug_lookup)
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{
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for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
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struct entity *constraint_ent = &store->entities[entity_index];
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if (!entity_is_valid_and_active(constraint_ent)) continue;
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if (!entity_has_prop(constraint_ent, ENTITY_PROP_CONTACT_CONSTRAINT)) continue;
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struct phys_contact_constraint *constraint = &constraint_ent->contact_constraint_data;
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u32 num_points = constraint->num_points;
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struct entity *e0 = entity_from_handle(store, constraint->e0);
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struct entity *e1 = entity_from_handle(store, constraint->e1);
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if (num_points > 0 && entity_is_valid_and_active(e0) && entity_is_valid_and_active(e1)) {
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struct v2 normal = constraint->normal;
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struct v2 tangent = v2_perp(normal);
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struct xform e0_xf = entity_get_xform(e0);
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struct xform e1_xf = entity_get_xform(e1);
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/* TODO: Cache this */
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/* Calculate masses */
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f32 inv_m0;
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f32 inv_m1;
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f32 inv_i0;
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f32 inv_i1;
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{
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f32 scale0 = math_fabs(xform_get_determinant(e0_xf));
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f32 scale1 = math_fabs(xform_get_determinant(e1_xf));
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inv_m0 = 1.f / (e0->mass_unscaled * scale0);
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inv_m1 = 1.f / (e1->mass_unscaled * scale1);
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inv_i0 = 1.f / (e0->inertia_unscaled * scale0);
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inv_i1 = 1.f / (e1->inertia_unscaled * scale1);
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}
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constraint->inv_m0 = inv_m0;
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constraint->inv_m1 = inv_m1;
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constraint->inv_i0 = inv_i0;
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constraint->inv_i1 = inv_i1;
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if (entity_has_prop(e0, ENTITY_PROP_PHYSICAL_KINEMATIC)) {
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constraint->inv_m0 = 0;
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constraint->inv_i0 = 0;
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}
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if (entity_has_prop(e1, ENTITY_PROP_PHYSICAL_KINEMATIC)) {
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constraint->inv_m1 = 0;
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constraint->inv_i1 = 0;
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}
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/* Update / insert returned contacts */
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for (u32 i = 0; i < num_points; ++i) {
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struct phys_contact_point *contact = &constraint->points[i];
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struct v2 vcp0 = v2_sub(xform_mul_v2(e0_xf, contact->point_local_e0), e0_xf.og);
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struct v2 vcp1 = v2_sub(xform_mul_v2(e1_xf, contact->point_local_e1), e1_xf.og);
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/* Normal mass */
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{
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f32 vcp0_wedge = v2_wedge(vcp0, normal);
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f32 vcp1_wedge = v2_wedge(vcp1, normal);
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f32 k = (inv_m0 + inv_m1) + (inv_i0 * vcp0_wedge * vcp0_wedge) + (inv_i1 * vcp1_wedge * vcp1_wedge);
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contact->inv_normal_mass = k > 0.0f ? 1.0f / k : 0.0f;
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}
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/* Tangent mass */
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{
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f32 vcp0_wedge = v2_wedge(vcp0, tangent);
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f32 vcp1_wedge = v2_wedge(vcp1, tangent);
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f32 k = (inv_m0 + inv_m1) + (inv_i0 * vcp0_wedge * vcp0_wedge) + (inv_i1 * vcp1_wedge * vcp1_wedge);
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contact->inv_tangent_mass = k > 0.0f ? 1.0f / k : 0.0f;
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}
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#if !GAME_PHYSICS_ENABLE_WARM_STARTING
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contact->normal_impulse = 0;
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contact->tangent_impulse = 0;
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#endif
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}
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} else {
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/* Mark constraint for removal */
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entity_disable_prop(constraint_ent, ENTITY_PROP_ACTIVE);
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entity_enable_prop(constraint_ent, ENTITY_PROP_RELEASE_BEFORE_PUBLISH);
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/* Remove from lookup */
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struct entity_lookup_key key = entity_lookup_key_from_two_handles(constraint->e0, constraint->e1);
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struct entity_lookup_entry *entry = entity_lookup_get(contact_lookup, key);
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if (entry) {
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entity_lookup_remove(contact_lookup, entry);
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} else {
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ASSERT(false); /* This should always exist */
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}
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}
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}
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#if COLLIDER_DEBUG
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for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
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struct entity *dbg_ent = &store->entities[entity_index];
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if (!entity_is_valid_and_active(dbg_ent)) continue;
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if (!entity_has_prop(dbg_ent, ENTITY_PROP_COLLISION_DEBUG)) continue;
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struct phys_collision_debug *dbg = &dbg_ent->collision_debug_data;
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struct entity *e0 = entity_from_handle(store, dbg->e0);
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struct entity *e1 = entity_from_handle(store, dbg->e1);
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if (!entity_is_valid_and_active(e0) || !entity_is_valid_and_active(e1)
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|| !(entity_has_prop(e0, ENTITY_PROP_PHYSICAL_DYNAMIC) || entity_has_prop(e0, ENTITY_PROP_PHYSICAL_KINEMATIC))
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|| !(entity_has_prop(e1, ENTITY_PROP_PHYSICAL_DYNAMIC) || entity_has_prop(e1, ENTITY_PROP_PHYSICAL_KINEMATIC))) {
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/* Mark dbg ent for removal */
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entity_disable_prop(dbg_ent, ENTITY_PROP_ACTIVE);
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entity_enable_prop(dbg_ent, ENTITY_PROP_RELEASE_BEFORE_PUBLISH);
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/* Remove from lookup */
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struct entity_lookup_key key = entity_lookup_key_from_two_handles(dbg->e0, dbg->e1);
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struct entity_lookup_entry *entry = entity_lookup_get(debug_lookup, key);
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if (e0->valid) {
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--e0->colliding;
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}
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if (e1->valid) {
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--e1->colliding;
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}
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if (entry) {
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entity_lookup_remove(debug_lookup, entry);
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} else {
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ASSERT(false); /* This should always exist */
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}
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}
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}
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#endif
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}
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void phys_warm_start_contacts(struct entity_store *store)
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{
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for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
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struct entity *constraint_ent = &store->entities[entity_index];
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if (!entity_is_valid_and_active(constraint_ent)) continue;
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if (!entity_has_prop(constraint_ent, ENTITY_PROP_CONTACT_CONSTRAINT)) continue;
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struct phys_contact_constraint *constraint = &constraint_ent->contact_constraint_data;
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u32 num_points = constraint->num_points;
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struct entity *e0 = entity_from_handle(store, constraint->e0);
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struct entity *e1 = entity_from_handle(store, constraint->e1);
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if (num_points > 0 && entity_is_valid_and_active(e0) && entity_is_valid_and_active(e1) && !constraint->skip_solve) {
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struct xform e0_xf = entity_get_xform(e0);
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struct xform e1_xf = entity_get_xform(e1);
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f32 inv_m0 = constraint->inv_m0;
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f32 inv_m1 = constraint->inv_m1;
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f32 inv_i0 = constraint->inv_i0;
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f32 inv_i1 = constraint->inv_i1;
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struct v2 v0 = e0->linear_velocity;
|
|
struct v2 v1 = e1->linear_velocity;
|
|
f32 w0 = e0->angular_velocity;
|
|
f32 w1 = e1->angular_velocity;
|
|
|
|
/* Warm start */
|
|
struct v2 normal = constraint->normal;
|
|
struct v2 tangent = v2_perp(normal);
|
|
f32 inv_num_points = 1.f / num_points;
|
|
for (u32 i = 0; i < num_points; ++i) {
|
|
struct phys_contact_point *point = &constraint->points[i];
|
|
struct v2 vcp0 = v2_sub(xform_mul_v2(e0_xf, point->point_local_e0), e0_xf.og);
|
|
struct v2 vcp1 = v2_sub(xform_mul_v2(e1_xf, point->point_local_e1), e1_xf.og);
|
|
|
|
struct v2 impulse = v2_add(v2_mul(normal, point->normal_impulse), v2_mul(tangent, point->tangent_impulse));
|
|
impulse = v2_mul(impulse, inv_num_points);
|
|
|
|
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;
|
|
}
|
|
}
|
|
}
|
|
|
|
void phys_solve_contacts(struct entity_store *store, f32 dt, b32 apply_bias)
|
|
{
|
|
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
|
|
struct entity *constraint_ent = &store->entities[entity_index];
|
|
if (!entity_is_valid_and_active(constraint_ent)) continue;
|
|
if (!entity_has_prop(constraint_ent, ENTITY_PROP_CONTACT_CONSTRAINT)) continue;
|
|
|
|
struct phys_contact_constraint *constraint = &constraint_ent->contact_constraint_data;
|
|
|
|
struct entity *e0 = entity_from_handle(store, constraint->e0);
|
|
struct entity *e1 = entity_from_handle(store, constraint->e1);
|
|
|
|
struct v2 v0 = e0->linear_velocity;
|
|
struct v2 v1 = e1->linear_velocity;
|
|
f32 w0 = e0->angular_velocity;
|
|
f32 w1 = e1->angular_velocity;
|
|
|
|
u32 num_points = constraint->num_points;
|
|
if (num_points > 0 && entity_is_valid_and_active(e0) && entity_is_valid_and_active(e1) && !constraint->skip_solve) {
|
|
struct xform e0_xf = entity_get_xform(e0);
|
|
struct xform e1_xf = entity_get_xform(e1);
|
|
|
|
f32 inv_m0 = constraint->inv_m0;
|
|
f32 inv_m1 = constraint->inv_m1;
|
|
f32 inv_i0 = constraint->inv_i0;
|
|
f32 inv_i1 = constraint->inv_i1;
|
|
|
|
/* Normal impulse */
|
|
struct v2 normal = constraint->normal;
|
|
for (u32 point_index = 0; point_index < num_points; ++point_index) {
|
|
struct phys_contact_point *point = &constraint->points[point_index];
|
|
struct v2 p0 = xform_mul_v2(e0_xf, point->point_local_e0);
|
|
struct v2 p1 = xform_mul_v2(e1_xf, point->point_local_e1);
|
|
struct v2 vcp0 = v2_sub(p0, e0_xf.og);
|
|
struct v2 vcp1 = v2_sub(p1, e1_xf.og);
|
|
|
|
f32 separation = v2_dot(v2_sub(p1, p0), normal) + point->starting_separation;
|
|
|
|
f32 velocity_bias = 0.0f;
|
|
f32 mass_scale = 1.0f;
|
|
f32 impulse_scale = 0.0f;
|
|
|
|
if (separation > 0.0f) {
|
|
/* Speculative */
|
|
velocity_bias = separation / dt;
|
|
} else if (apply_bias) {
|
|
/* Soft constraint */
|
|
struct math_spring_result softness = constraint->softness;
|
|
f32 pushout_velocity = constraint->pushout_velocity;
|
|
mass_scale = softness.mass_scale;
|
|
impulse_scale = softness.impulse_scale;
|
|
velocity_bias = max_f32(softness.bias_rate * separation, -pushout_velocity);
|
|
}
|
|
|
|
struct v2 vel0 = v2_add(v0, v2_perp_mul(vcp0, w0));
|
|
struct v2 vel1 = v2_add(v1, v2_perp_mul(vcp1, w1));
|
|
struct v2 vrel = v2_sub(vel0, vel1);
|
|
|
|
f32 k = point->inv_normal_mass;
|
|
|
|
/* (to be applied along n) */
|
|
f32 vn = v2_dot(vrel, normal);
|
|
f32 j = ((k * mass_scale) * (vn - velocity_bias)) - (point->normal_impulse * impulse_scale);
|
|
|
|
f32 old_impulse = point->normal_impulse;
|
|
f32 new_impulse = max_f32(old_impulse + j, 0);
|
|
f32 delta = new_impulse - old_impulse;
|
|
point->normal_impulse = new_impulse;
|
|
|
|
struct v2 impulse = v2_mul(normal, delta);
|
|
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;
|
|
}
|
|
|
|
/* Tangent impulse */
|
|
struct v2 tangent = v2_perp(normal);
|
|
for (u32 point_index = 0; point_index < num_points; ++point_index) {
|
|
struct phys_contact_point *point = &constraint->points[point_index];
|
|
struct v2 vcp0 = v2_sub(xform_mul_v2(e0_xf, point->point_local_e0), e0_xf.og);
|
|
struct v2 vcp1 = v2_sub(xform_mul_v2(e1_xf, point->point_local_e1), 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 vrel = v2_sub(vel0, vel1);
|
|
|
|
f32 k = point->inv_tangent_mass;
|
|
|
|
/* (to be applied along t) */
|
|
f32 vt = v2_dot(vrel, tangent);
|
|
f32 j = vt * k;
|
|
|
|
f32 max_friction = constraint->friction * point->normal_impulse;
|
|
f32 old_impulse = point->tangent_impulse;
|
|
f32 new_impulse = clamp_f32(old_impulse + j, -max_friction, max_friction);
|
|
f32 delta = new_impulse - old_impulse;
|
|
point->tangent_impulse = new_impulse;
|
|
|
|
struct v2 impulse = v2_mul(tangent, delta);
|
|
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;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* ========================== *
|
|
* Motor joint
|
|
* ========================== */
|
|
|
|
struct phys_motor_joint motor_joint_from_def(struct phys_motor_joint_def def)
|
|
{
|
|
struct phys_motor_joint res = ZI;
|
|
res.e0 = def.e0;
|
|
res.e1 = def.e1;
|
|
res.correction_rate = clamp_f32(def.correction_rate, 0, 1);
|
|
res.max_force = def.max_force;
|
|
res.max_torque = def.max_torque;
|
|
return res;
|
|
}
|
|
|
|
void phys_prepare_motor_joints(struct entity_store *store)
|
|
{
|
|
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
|
|
struct entity *joint_ent = &store->entities[entity_index];
|
|
if (!entity_is_valid_and_active(joint_ent)) continue;
|
|
if (!entity_has_prop(joint_ent, ENTITY_PROP_MOTOR_JOINT)) continue;
|
|
|
|
struct phys_motor_joint *joint = &joint_ent->motor_joint_data;
|
|
|
|
struct entity *e0 = entity_from_handle(store, joint->e0);
|
|
struct entity *e1 = entity_from_handle(store, joint->e1);
|
|
|
|
if (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);
|
|
|
|
/* TODO: Cache this */
|
|
/* Calculate masses */
|
|
f32 inv_m0;
|
|
f32 inv_m1;
|
|
f32 inv_i0;
|
|
f32 inv_i1;
|
|
{
|
|
f32 scale0 = math_fabs(xform_get_determinant(e0_xf));
|
|
f32 scale1 = math_fabs(xform_get_determinant(e1_xf));
|
|
inv_m0 = 1.f / (e0->mass_unscaled * scale0);
|
|
inv_m1 = 1.f / (e1->mass_unscaled * scale1);
|
|
inv_i0 = 1.f / (e0->inertia_unscaled * scale0);
|
|
inv_i1 = 1.f / (e1->inertia_unscaled * scale1);
|
|
}
|
|
joint->inv_m0 = inv_m0;
|
|
joint->inv_m1 = inv_m1;
|
|
joint->inv_i0 = inv_i0;
|
|
joint->inv_i1 = inv_i1;
|
|
|
|
joint->point_local_e0 = V2(0, 0);
|
|
joint->point_local_e1 = V2(0, 0);
|
|
|
|
struct v2 vcp0 = v2_sub(xform_mul_v2(e0_xf, joint->point_local_e0), e0_xf.og);
|
|
struct v2 vcp1 = v2_sub(xform_mul_v2(e1_xf, joint->point_local_e1), e1_xf.og);
|
|
|
|
struct xform linear_mass_xf;
|
|
linear_mass_xf.bx.x = inv_m0 + inv_m1 + vcp0.y * vcp0.y * inv_i0 + vcp1.y * vcp1.y * inv_i1;
|
|
linear_mass_xf.bx.y = -vcp0.y * vcp0.x * inv_i0 - vcp1.y * vcp1.x * inv_i1;
|
|
linear_mass_xf.by.x = linear_mass_xf.bx.y;
|
|
linear_mass_xf.by.y = inv_m0 + inv_m1 + vcp0.x * vcp0.x * inv_i0 + vcp1.x * vcp1.x * inv_i1;
|
|
joint->linear_mass_xf = xform_invert(linear_mass_xf);
|
|
|
|
joint->angular_mass = 1.f / (inv_i0 + inv_i1);
|
|
|
|
#if !GAME_PHYSICS_ENABLE_WARM_STARTING
|
|
joint->linear_impulse = V2(0, 0);
|
|
joint->angular_impulse = 0;
|
|
#endif
|
|
} else {
|
|
/* Mark joint for removal */
|
|
entity_disable_prop(joint_ent, ENTITY_PROP_ACTIVE);
|
|
entity_enable_prop(joint_ent, ENTITY_PROP_RELEASE_BEFORE_PUBLISH);
|
|
}
|
|
}
|
|
}
|
|
|
|
void phys_warm_start_motor_joints(struct entity_store *store)
|
|
{
|
|
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
|
|
struct entity *joint_ent = &store->entities[entity_index];
|
|
if (!entity_is_valid_and_active(joint_ent)) continue;
|
|
if (!entity_has_prop(joint_ent, ENTITY_PROP_MOTOR_JOINT)) continue;
|
|
|
|
struct phys_motor_joint *joint = &joint_ent->motor_joint_data;
|
|
|
|
struct entity *e0 = entity_from_handle(store, joint->e0);
|
|
struct entity *e1 = entity_from_handle(store, joint->e1);
|
|
|
|
struct xform e0_xf = entity_get_xform(e0);
|
|
struct xform e1_xf = entity_get_xform(e1);
|
|
|
|
f32 inv_m0 = joint->inv_m0;
|
|
f32 inv_m1 = joint->inv_m1;
|
|
f32 inv_i0 = joint->inv_i0;
|
|
f32 inv_i1 = joint->inv_i1;
|
|
|
|
struct v2 vcp0 = v2_sub(xform_mul_v2(e0_xf, joint->point_local_e0), e0_xf.og);
|
|
struct v2 vcp1 = v2_sub(xform_mul_v2(e1_xf, joint->point_local_e1), e1_xf.og);
|
|
|
|
e0->linear_velocity = v2_sub(e0->linear_velocity, v2_mul(joint->linear_impulse, inv_m0));
|
|
e1->linear_velocity = v2_add(e1->linear_velocity, v2_mul(joint->linear_impulse, inv_m1));
|
|
e0->angular_velocity -= (v2_wedge(vcp0, joint->linear_impulse) + joint->angular_impulse) * inv_i0;
|
|
e1->angular_velocity += (v2_wedge(vcp1, joint->linear_impulse) + joint->angular_impulse) * inv_i1;
|
|
}
|
|
}
|
|
|
|
void phys_solve_motor_joints(struct entity_store *store, f32 dt)
|
|
{
|
|
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
|
|
struct entity *joint_ent = &store->entities[entity_index];
|
|
if (!entity_is_valid_and_active(joint_ent)) continue;
|
|
if (!entity_has_prop(joint_ent, ENTITY_PROP_MOTOR_JOINT)) continue;
|
|
|
|
struct phys_motor_joint *joint = &joint_ent->motor_joint_data;
|
|
|
|
struct entity *e0 = entity_from_handle(store, joint->e0);
|
|
struct entity *e1 = entity_from_handle(store, joint->e1);
|
|
|
|
struct xform e0_xf = entity_get_xform(e0);
|
|
struct xform e1_xf = entity_get_xform(e1);
|
|
|
|
f32 inv_m0 = joint->inv_m0;
|
|
f32 inv_m1 = joint->inv_m1;
|
|
f32 inv_i0 = joint->inv_i0;
|
|
f32 inv_i1 = joint->inv_i1;
|
|
|
|
struct v2 v0 = e0->linear_velocity;
|
|
struct v2 v1 = e1->linear_velocity;
|
|
f32 w0 = e0->angular_velocity;
|
|
f32 w1 = e1->angular_velocity;
|
|
|
|
f32 correction_rate = joint->correction_rate / dt;
|
|
|
|
/* Angular constraint */
|
|
{
|
|
f32 max_impulse = joint->max_torque * dt;
|
|
|
|
f32 angular_separation = math_unwind_angle(xform_get_rotation(e1_xf) - xform_get_rotation(e0_xf));
|
|
f32 angular_bias = angular_separation * correction_rate;
|
|
|
|
f32 impulse = -joint->angular_mass * (w1 - w0 + angular_bias);
|
|
|
|
f32 old_impulse = joint->angular_impulse;
|
|
joint->angular_impulse = clamp_f32(joint->angular_impulse + impulse, -max_impulse, max_impulse);
|
|
impulse = joint->angular_impulse - old_impulse;
|
|
|
|
w0 -= impulse * inv_i0;
|
|
w1 += impulse * inv_i1;
|
|
}
|
|
|
|
/* Linear constraint */
|
|
{
|
|
struct v2 vcp0 = v2_sub(xform_mul_v2(e0_xf, joint->point_local_e0), e0_xf.og);
|
|
struct v2 vcp1 = v2_sub(xform_mul_v2(e1_xf, joint->point_local_e1), e1_xf.og);
|
|
|
|
f32 max_impulse = joint->max_force * dt;
|
|
|
|
struct v2 linear_separation = v2_sub(v2_add(e1_xf.og, vcp1), v2_add(e0_xf.og, vcp0));
|
|
struct v2 linear_bias = v2_mul(linear_separation, correction_rate);
|
|
|
|
struct v2 vrel = v2_sub(v2_add(v1, v2_perp_mul(vcp1, w1)), v2_add(v0, v2_perp_mul(vcp0, w0)));
|
|
struct v2 impulse = v2_neg(xform_basis_mul_v2(joint->linear_mass_xf, v2_add(vrel, linear_bias)));
|
|
|
|
struct v2 old_impulse = joint->linear_impulse;
|
|
joint->linear_impulse = v2_clamp_len(v2_add(joint->linear_impulse, impulse), max_impulse);
|
|
impulse = v2_sub(joint->linear_impulse, old_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;
|
|
}
|
|
}
|
|
|
|
/* ========================== *
|
|
* Mouse joint
|
|
* ========================== */
|
|
|
|
void phys_create_mouse_joints(struct entity_store *store, struct v2 cursor, b32 start_dragging, b32 stop_dragging)
|
|
{
|
|
struct entity *root = entity_from_handle(store, store->root);
|
|
|
|
struct entity *joint_ent = entity_find_first_match_one(store, ENTITY_PROP_MOUSE_JOINT);
|
|
struct entity *target_ent = entity_from_handle(store, joint_ent->mouse_joint_data.target);
|
|
|
|
if (start_dragging) {
|
|
struct xform mouse_xf = xform_from_pos(cursor);
|
|
struct collider_shape mouse_shape = ZI;
|
|
mouse_shape.points[0] = V2(0, 0);
|
|
mouse_shape.count = 1;
|
|
|
|
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
|
|
struct entity *ent = &store->entities[entity_index];
|
|
if (!entity_is_valid_and_active(ent)) continue;
|
|
if (!entity_has_prop(ent, ENTITY_PROP_PHYSICAL_DYNAMIC)) continue;
|
|
|
|
struct collider_shape ent_collider = ent->local_collider;
|
|
if (ent_collider.count > 0) {
|
|
struct xform ent_xf = entity_get_xform(ent);
|
|
/* TODO: Can just use boolean GJK */
|
|
struct collider_collision_points_result res = collider_collision_points(&ent_collider, &mouse_shape, ent_xf, mouse_xf);
|
|
if (res.num_points > 0) {
|
|
target_ent = ent;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
} else if (stop_dragging) {
|
|
target_ent = entity_nil();
|
|
}
|
|
|
|
if (entity_is_valid_and_active(target_ent)) {
|
|
if (!entity_is_valid_and_active(joint_ent)) {
|
|
joint_ent = entity_alloc(root);
|
|
joint_ent->mass_unscaled = F32_INFINITY;
|
|
joint_ent->inertia_unscaled = F32_INFINITY;
|
|
entity_enable_prop(joint_ent, ENTITY_PROP_MOUSE_JOINT);
|
|
entity_enable_prop(joint_ent, ENTITY_PROP_ACTIVE);
|
|
}
|
|
|
|
struct phys_mouse_joint *joint = &joint_ent->mouse_joint_data;
|
|
|
|
struct xform xf = entity_get_xform(target_ent);
|
|
f32 mass = target_ent->mass_unscaled * math_fabs(xform_get_determinant(xf));
|
|
|
|
if (!entity_handle_eq(joint->target, target_ent->handle)) {
|
|
joint->point_local_start = xform_invert_mul_v2(xf, cursor);
|
|
joint->target = target_ent->handle;
|
|
}
|
|
joint->point_local_end = xform_invert_mul_v2(xf, cursor);
|
|
|
|
joint->linear_softness = G.mouse_joint_linear_softness;
|
|
joint->angular_softness = G.mouse_joint_angular_softness;
|
|
joint->max_force = G.mouse_joint_max_force * mass;
|
|
} else {
|
|
if (entity_is_valid_and_active(joint_ent)) {
|
|
joint_ent->mouse_joint_data.target = entity_nil_handle();
|
|
}
|
|
}
|
|
}
|
|
|
|
void phys_prepare_mouse_joints(struct entity_store *store)
|
|
{
|
|
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
|
|
struct entity *joint_ent = &store->entities[entity_index];
|
|
if (!entity_is_valid_and_active(joint_ent)) continue;
|
|
if (!entity_has_prop(joint_ent, ENTITY_PROP_MOUSE_JOINT)) continue;
|
|
|
|
struct phys_mouse_joint *joint = &joint_ent->mouse_joint_data;
|
|
struct entity *ent = entity_from_handle(store, joint->target);
|
|
if (entity_is_valid_and_active(ent)) {
|
|
struct xform xf = entity_get_xform(ent);
|
|
|
|
/* TODO: Cache this */
|
|
/* Calculate masses */
|
|
f32 inv_m;
|
|
f32 inv_i;
|
|
{
|
|
f32 scale = math_fabs(xform_get_determinant(xf));
|
|
inv_m = 1.f / (ent->mass_unscaled * scale);
|
|
inv_i = 1.f / (ent->inertia_unscaled * scale);
|
|
}
|
|
joint->inv_m = inv_m;
|
|
joint->inv_i = inv_i;
|
|
|
|
struct v2 vcp = v2_sub(xform_mul_v2(xf, joint->point_local_start), xf.og);
|
|
|
|
struct xform linear_mass_xf;
|
|
linear_mass_xf.bx.x = inv_m + inv_i * vcp.y * vcp.y;
|
|
linear_mass_xf.bx.y = -inv_i * vcp.x * vcp.y;
|
|
linear_mass_xf.by.x = linear_mass_xf.bx.y;
|
|
linear_mass_xf.by.y = inv_m + inv_i * vcp.x * vcp.x;
|
|
joint->linear_mass_xf = xform_invert(linear_mass_xf);
|
|
|
|
#if !GAME_PHYSICS_ENABLE_WARM_STARTING
|
|
joint->linear_impulse = V2(0, 0);
|
|
joint->angular_impulse = 0;
|
|
#endif
|
|
} else {
|
|
/* Mark joint for removal */
|
|
entity_disable_prop(joint_ent, ENTITY_PROP_ACTIVE);
|
|
entity_enable_prop(joint_ent, ENTITY_PROP_RELEASE_BEFORE_PUBLISH);
|
|
}
|
|
}
|
|
}
|
|
|
|
void phys_warm_start_mouse_joints(struct entity_store *store)
|
|
{
|
|
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
|
|
struct entity *joint_ent = &store->entities[entity_index];
|
|
if (!entity_is_valid_and_active(joint_ent)) continue;
|
|
if (!entity_has_prop(joint_ent, ENTITY_PROP_MOUSE_JOINT)) continue;
|
|
|
|
struct phys_mouse_joint *joint = &joint_ent->mouse_joint_data;
|
|
struct entity *ent = entity_from_handle(store, joint->target);
|
|
if (entity_is_valid_and_active(ent)) {
|
|
f32 inv_m = joint->inv_m;
|
|
f32 inv_i = joint->inv_i;
|
|
struct xform xf = entity_get_xform(ent);
|
|
struct v2 vcp = v2_sub(xform_mul_v2(xf, joint->point_local_start), xf.og);
|
|
ent->linear_velocity = v2_add(ent->linear_velocity, v2_mul(joint->linear_impulse, inv_m));
|
|
ent->angular_velocity += (v2_wedge(vcp, joint->linear_impulse) + joint->angular_impulse) * inv_i;
|
|
}
|
|
}
|
|
}
|
|
|
|
void phys_solve_mouse_joints(struct entity_store *store, f32 dt)
|
|
{
|
|
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
|
|
struct entity *joint_ent = &store->entities[entity_index];
|
|
if (!entity_is_valid_and_active(joint_ent)) continue;
|
|
if (!entity_has_prop(joint_ent, ENTITY_PROP_MOUSE_JOINT)) continue;
|
|
|
|
struct phys_mouse_joint *joint = &joint_ent->mouse_joint_data;
|
|
struct entity *ent = entity_from_handle(store, joint->target);
|
|
if (entity_is_valid_and_active(ent)) {
|
|
struct v2 v = ent->linear_velocity;
|
|
f32 w = ent->angular_velocity;
|
|
|
|
f32 inv_m = joint->inv_m;
|
|
f32 inv_i = joint->inv_i;
|
|
|
|
/* Angular impulse */
|
|
{
|
|
struct math_spring_result softness = joint->angular_softness;
|
|
f32 mass_scale = softness.mass_scale;
|
|
f32 impulse_scale = softness.impulse_scale;
|
|
f32 impulse = mass_scale * (-w / inv_i) - impulse_scale * joint->angular_impulse;
|
|
joint->angular_impulse += impulse;
|
|
w += impulse * inv_i;
|
|
}
|
|
|
|
/* Linear impulse */
|
|
{
|
|
f32 max_impulse = joint->max_force / dt;
|
|
|
|
struct xform xf = entity_get_xform(ent);
|
|
|
|
struct v2 point_start = xform_mul_v2(xf, joint->point_local_start);
|
|
struct v2 point_end = xform_mul_v2(xf, joint->point_local_end);
|
|
|
|
struct v2 vcp = v2_sub(point_start, xf.og);
|
|
struct v2 separation = v2_sub(point_start, point_end);
|
|
|
|
struct math_spring_result softness = joint->linear_softness;
|
|
struct v2 bias = v2_mul(separation, softness.bias_rate);
|
|
f32 mass_scale = softness.mass_scale;
|
|
f32 impulse_scale = softness.impulse_scale;
|
|
|
|
#if 0
|
|
struct v2 vel = v2_add(v, v2_perp_mul(vcp, w));
|
|
struct v2 b = v2_mul(xform_basis_mul_v2(xform_invert(joint->linear_mass_xf), v2_add(vel, bias)), mass_scale);
|
|
|
|
struct v2 old_impulse = joint->linear_impulse;
|
|
struct v2 impulse = v2_sub(v2_mul(old_impulse, -impulse_scale), b);
|
|
joint->linear_impulse = v2_clamp_len(v2_add(joint->linear_impulse, impulse), max_impulse);
|
|
impulse = v2_sub(joint->linear_impulse, old_impulse);
|
|
#else
|
|
struct v2 vel = v2_add(v, v2_perp_mul(vcp, w));
|
|
struct v2 b = xform_basis_mul_v2(joint->linear_mass_xf, v2_add(vel, bias));
|
|
|
|
struct v2 impulse;
|
|
impulse.x = -mass_scale * b.x - impulse_scale * joint->linear_impulse.x;
|
|
impulse.y = -mass_scale * b.y - impulse_scale * joint->linear_impulse.y;
|
|
|
|
struct v2 old_impulse = joint->linear_impulse;
|
|
joint->linear_impulse.x += impulse.x;
|
|
joint->linear_impulse.y += impulse.y;
|
|
|
|
joint->linear_impulse = v2_clamp_len(joint->linear_impulse, max_impulse);
|
|
|
|
impulse.x = joint->linear_impulse.x - old_impulse.x;
|
|
impulse.y = joint->linear_impulse.y - old_impulse.y;
|
|
#endif
|
|
|
|
v = v2_add(v, v2_mul(impulse, inv_m));
|
|
w += v2_wedge(vcp, impulse) * inv_i;
|
|
}
|
|
|
|
ent->linear_velocity = v;
|
|
ent->angular_velocity = w;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* ========================== *
|
|
* Earliest time of impact
|
|
* ========================== */
|
|
|
|
f32 phys_determine_earliest_toi_for_bullets(struct entity_store *store, f32 step_dt, f32 tolerance, u32 max_iterations)
|
|
{
|
|
__prof;
|
|
f32 smallest_t = 1;
|
|
|
|
for (u64 e0_index = 0; e0_index < store->reserved; ++e0_index) {
|
|
struct entity *e0 = &store->entities[e0_index];
|
|
if (!entity_is_valid_and_active(e0)) continue;
|
|
if (!(entity_has_prop(e0, ENTITY_PROP_PHYSICAL_DYNAMIC) || entity_has_prop(e0, ENTITY_PROP_PHYSICAL_KINEMATIC))) continue;
|
|
if (e0->local_collider.count <= 0) continue;
|
|
|
|
b32 e0_is_bullet = entity_has_prop(e0, ENTITY_PROP_BULLET);
|
|
|
|
struct collider_shape e0_collider = e0->local_collider;
|
|
struct xform e0_xf_t0 = entity_get_xform(e0);
|
|
struct xform e0_xf_t1 = e0_xf_t0;
|
|
{
|
|
/* Calculate xform at t=1 */
|
|
struct v2 linear_velocity = v2_clamp_len(e0->linear_velocity, GAME_MAX_LINEAR_VELOCITY);
|
|
f32 angular_velocity = clamp_f32(e0->angular_velocity, -GAME_MAX_ANGULAR_VELOCITY, GAME_MAX_ANGULAR_VELOCITY);
|
|
struct v2 tick_linear_velocity = v2_mul(linear_velocity, step_dt);
|
|
f32 tick_angular_velocity = angular_velocity * step_dt;
|
|
e0_xf_t1.og = v2_add(e0_xf_t1.og, tick_linear_velocity);
|
|
e0_xf_t1 = xform_basis_rotated_world(e0_xf_t1, tick_angular_velocity);
|
|
}
|
|
|
|
/* Start e1 index at e0 index + 1 to prevent redundant checks */
|
|
for (u64 e1_index = e0_index + 1; e1_index < store->reserved; ++e1_index) {
|
|
struct entity *e1 = &store->entities[e1_index];
|
|
if (e1 == e0) continue;
|
|
if (!entity_is_valid_and_active(e1)) continue;
|
|
if (!(entity_has_prop(e1, ENTITY_PROP_PHYSICAL_DYNAMIC) || entity_has_prop(e1, ENTITY_PROP_PHYSICAL_KINEMATIC))) continue;
|
|
if (e1->local_collider.count <= 0) continue;
|
|
|
|
b32 e1_is_bullet = entity_has_prop(e1, ENTITY_PROP_BULLET);
|
|
|
|
/* Skip check if neither e0 or e1 are bullets */
|
|
if (!e0_is_bullet && !e1_is_bullet) continue;
|
|
|
|
struct collider_shape e1_collider = e1->local_collider;
|
|
struct xform e1_xf_t0 = entity_get_xform(e1);
|
|
struct xform e1_xf_t1 = e1_xf_t0;
|
|
{
|
|
/* Calculate xform at t=1 */
|
|
struct v2 linear_velocity = v2_clamp_len(e1->linear_velocity, GAME_MAX_LINEAR_VELOCITY);
|
|
f32 angular_velocity = clamp_f32(e1->angular_velocity, -GAME_MAX_ANGULAR_VELOCITY, GAME_MAX_ANGULAR_VELOCITY);
|
|
struct v2 tick_linear_velocity = v2_mul(linear_velocity, step_dt);
|
|
f32 tick_angular_velocity = angular_velocity * step_dt;
|
|
e1_xf_t1.og = v2_add(e1_xf_t1.og, tick_linear_velocity);
|
|
e1_xf_t1 = xform_basis_rotated_world(e1_xf_t1, tick_angular_velocity);
|
|
}
|
|
|
|
f32 t = collider_time_of_impact(&e0_collider, &e1_collider, e0_xf_t0, e1_xf_t0, e0_xf_t1, e1_xf_t1, tolerance, max_iterations);
|
|
if (t != 0 && t < smallest_t) {
|
|
smallest_t = t;
|
|
}
|
|
}
|
|
}
|
|
|
|
return smallest_t;
|
|
}
|
|
|
|
/* ========================== *
|
|
* Integration
|
|
* ========================== */
|
|
|
|
void phys_integrate_forces(struct entity_store *store, f32 dt)
|
|
{
|
|
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
|
|
struct entity *ent = &store->entities[entity_index];
|
|
if (!entity_is_valid_and_active(ent)) continue;
|
|
if (!entity_has_prop(ent, ENTITY_PROP_PHYSICAL_DYNAMIC) && !entity_has_prop(ent, ENTITY_PROP_PHYSICAL_KINEMATIC)) continue;
|
|
|
|
struct xform xf = entity_get_xform(ent);
|
|
f32 det_abs = math_fabs(xform_get_determinant(xf));
|
|
f32 mass = ent->mass_unscaled * det_abs;
|
|
f32 inertia = ent->inertia_unscaled * det_abs;
|
|
|
|
/* Determine force & torque acceleration */
|
|
struct v2 force_accel = v2_mul(v2_div(ent->force, mass), dt);
|
|
f32 torque_accel = (ent->torque / inertia) * dt;
|
|
|
|
/* Integrate & clamp */
|
|
ent->linear_velocity = v2_clamp_len(v2_add(ent->linear_velocity, force_accel), GAME_MAX_LINEAR_VELOCITY);
|
|
ent->angular_velocity = clamp_f32(ent->angular_velocity + torque_accel, -GAME_MAX_ANGULAR_VELOCITY, GAME_MAX_ANGULAR_VELOCITY);
|
|
|
|
/* Reset forces */
|
|
ent->force = V2(0, 0);
|
|
ent->torque = 0;
|
|
}
|
|
}
|
|
|
|
void phys_integrate_velocities(struct entity_store *store, f32 dt)
|
|
{
|
|
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
|
|
struct entity *ent = &store->entities[entity_index];
|
|
if (!entity_is_valid_and_active(ent)) continue;
|
|
if (!entity_has_prop(ent, ENTITY_PROP_PHYSICAL_DYNAMIC) && !entity_has_prop(ent, ENTITY_PROP_PHYSICAL_KINEMATIC)) continue;
|
|
|
|
/* Clamp velocities */
|
|
ent->linear_velocity = v2_clamp_len(ent->linear_velocity, GAME_MAX_LINEAR_VELOCITY);
|
|
ent->angular_velocity = clamp_f32(ent->angular_velocity, -GAME_MAX_ANGULAR_VELOCITY, GAME_MAX_ANGULAR_VELOCITY);
|
|
|
|
struct v2 tick_linear_velocity = v2_mul(ent->linear_velocity, dt);
|
|
f32 tick_angular_velocity = ent->angular_velocity * dt;
|
|
|
|
struct xform xf = entity_get_xform(ent);
|
|
xf.og = v2_add(xf.og, tick_linear_velocity);
|
|
xf = xform_basis_rotated_world(xf, tick_angular_velocity);
|
|
entity_set_xform(ent, xf);
|
|
}
|
|
}
|
|
|
|
/* ========================== *
|
|
* Step
|
|
* ========================== */
|
|
|
|
void phys_step(struct entity_store *store, f32 step_dt, struct entity_lookup *contact_lookup, struct entity_lookup *collision_debug_lookup, u64 tick_id, struct v2 dbg_cursor_pos, b32 dbg_start_dragging, b32 dbg_stop_dragging)
|
|
{
|
|
f32 remaining_dt = step_dt;
|
|
|
|
phys_integrate_forces(store, remaining_dt);
|
|
while (remaining_dt > 0) {
|
|
/* TOI */
|
|
{
|
|
#if GAME_PHYSICS_ENABLE_TOI
|
|
const f32 min_toi = 0.000001f;
|
|
const f32 tolerance = 0.00001f;
|
|
const u32 max_iterations = 16;
|
|
f32 earliest_toi = max_f32(phys_determine_earliest_toi_for_bullets(store, remaining_dt, tolerance, max_iterations), min_toi);
|
|
remaining_dt = remaining_dt * earliest_toi;
|
|
#else
|
|
(UNUSED)toi;
|
|
(UNUSED)determine_earliest_toi_for_bullets;
|
|
#endif
|
|
}
|
|
|
|
phys_create_contacts(store, contact_lookup, collision_debug_lookup, tick_id);
|
|
phys_create_mouse_joints(store, dbg_cursor_pos, dbg_start_dragging, dbg_stop_dragging);
|
|
|
|
phys_prepare_contacts(store, contact_lookup, collision_debug_lookup);
|
|
phys_prepare_motor_joints(store);
|
|
phys_prepare_mouse_joints(store);
|
|
|
|
f32 substep_dt = remaining_dt / GAME_PHYSICS_SUBSTEPS;
|
|
for (u32 i = 0; i < GAME_PHYSICS_SUBSTEPS; ++i) {
|
|
#if GAME_PHYSICS_ENABLE_WARM_STARTING
|
|
phys_warm_start_contacts(store);
|
|
phys_warm_start_motor_joints(store);
|
|
phys_warm_start_mouse_joints(store);
|
|
#endif
|
|
|
|
#if GAME_PHYSICS_ENABLE_COLLISION
|
|
phys_solve_contacts(store, substep_dt, true);
|
|
#endif
|
|
phys_solve_motor_joints(store, substep_dt);
|
|
phys_solve_mouse_joints(store, substep_dt);
|
|
|
|
phys_integrate_velocities(store, substep_dt);
|
|
|
|
#if GAME_PHYSICS_ENABLE_COLLISION && GAME_PHYSICS_ENABLE_RELAXATION
|
|
phys_solve_contacts(store, substep_dt, false); /* Relaxation */
|
|
#endif
|
|
}
|
|
remaining_dt -= remaining_dt;
|
|
}
|
|
}
|