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store & calculate friction

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This commit is contained in:
jacob 2024-10-29 18:35:35 -05:00
parent c966924760
commit 8eadda9931
3 changed files with 17 additions and 4 deletions
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2
src/entity.c
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@ -16,6 +16,7 @@ READONLY struct entity _g_entity_nil = {
.local_xform = XFORM_IDENT_NOCAST, .local_xform = XFORM_IDENT_NOCAST,
.cached_global_xform = XFORM_IDENT_NOCAST, .cached_global_xform = XFORM_IDENT_NOCAST,
.cached_global_xform_dirty = false, .cached_global_xform_dirty = false,
.friction = 0.5f,
.mass_unscaled = 1, .mass_unscaled = 1,
.inertia_unscaled = 1, .inertia_unscaled = 1,
.sprite_local_xform = XFORM_IDENT_NOCAST, .sprite_local_xform = XFORM_IDENT_NOCAST,
@ -27,6 +28,7 @@ GLOBAL READONLY struct entity g_entity_default = {
.local_xform = XFORM_IDENT_NOCAST, .local_xform = XFORM_IDENT_NOCAST,
.cached_global_xform = XFORM_IDENT_NOCAST, .cached_global_xform = XFORM_IDENT_NOCAST,
.cached_global_xform_dirty = true, .cached_global_xform_dirty = true,
.friction = 0.5f,
.mass_unscaled = 1, .mass_unscaled = 1,
.inertia_unscaled = 1, .inertia_unscaled = 1,
.sprite_local_xform = XFORM_IDENT_NOCAST, .sprite_local_xform = XFORM_IDENT_NOCAST,

7
src/entity.h
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@ -91,6 +91,8 @@ struct contact_constraint {
struct contact_point points[2]; struct contact_point points[2];
u32 num_points; u32 num_points;
f32 friction;
struct math_spring_result softness; struct math_spring_result softness;
f32 pushout_velocity; f32 pushout_velocity;
@ -275,8 +277,13 @@ struct entity {
/* ENTITY_PROP_PHYSICAL */ /* ENTITY_PROP_PHYSICAL */
//f32 density; /* Density in kg/m^2 */
f32 friction;
f32 mass_unscaled; /* Mass of entity in kg before any transformations */ f32 mass_unscaled; /* Mass of entity in kg before any transformations */
f32 inertia_unscaled; /* Inertia of entity in kg*m^2 before any transformations */ f32 inertia_unscaled; /* Inertia of entity in kg*m^2 before any transformations */
f32 linear_ground_friction; f32 linear_ground_friction;
f32 angular_ground_friction; f32 angular_ground_friction;

12
src/game.c
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@ -176,11 +176,13 @@ INTERNAL void spawn_test_entities(f32 offset)
e->angular_ground_friction = 100; e->angular_ground_friction = 100;
//e->control_force = 500;
e->control_force = 500; e->control_force = 500;
e->control_force_max_speed = 4; e->control_force_max_speed = 4;
e->control_torque = 5000; e->control_torque = 500;
entity_enable_prop(e, ENTITY_PROP_PHYSICAL); entity_enable_prop(e, ENTITY_PROP_PHYSICAL);
e->mass_unscaled = 10; e->mass_unscaled = 10;
e->inertia_unscaled = 10; e->inertia_unscaled = 10;
@ -189,7 +191,7 @@ INTERNAL void spawn_test_entities(f32 offset)
player_ent = e; player_ent = e;
#if 0 #if 1
{ {
struct entity *joint_ent = entity_alloc(root); struct entity *joint_ent = entity_alloc(root);
entity_enable_prop(joint_ent, ENTITY_PROP_PHYSICAL); entity_enable_prop(joint_ent, ENTITY_PROP_PHYSICAL);
@ -487,6 +489,8 @@ INTERNAL void create_contacts(void)
if (res.num_points > 0) { if (res.num_points > 0) {
struct contact_constraint *constraint = &constraint_ent->contact_constraint_data; struct contact_constraint *constraint = &constraint_ent->contact_constraint_data;
constraint->friction = math_sqrt(e0->friction * e1->friction);
/* Delete old contacts that are no longer present */ /* Delete old contacts that are no longer present */
for (u32 i = 0; i < constraint->num_points; ++i) { for (u32 i = 0; i < constraint->num_points; ++i) {
struct contact_point *old = &constraint->points[i]; struct contact_point *old = &constraint->points[i];
@ -769,10 +773,10 @@ INTERNAL void solve_contacts(f32 dt, b32 apply_bias)
f32 vt = v2_dot(vrel, tangent); f32 vt = v2_dot(vrel, tangent);
f32 j = vt * k; f32 j = vt * k;
f32 friction = 0.6f; //f32 friction = 0.6f;
//f32 friction = 1.0f; //f32 friction = 1.0f;
//f32 friction = F32_INFINITY; //f32 friction = F32_INFINITY;
f32 max_friction = friction * point->normal_impulse; f32 max_friction = constraint->friction * point->normal_impulse;
f32 old_impulse = point->tangent_impulse; f32 old_impulse = point->tangent_impulse;
f32 new_impulse = clamp_f32(old_impulse + j, -max_friction, max_friction); f32 new_impulse = clamp_f32(old_impulse + j, -max_friction, max_friction);
f32 delta = new_impulse - old_impulse; f32 delta = new_impulse - old_impulse;