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better impulse & force application

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This commit is contained in:
jacob 2024-08-19 19:20:55 -05:00
parent 0ed2a403dc
commit 10c9c833ba
4 changed files with 87 additions and 142 deletions
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5
src/entity.c
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@ -111,6 +111,7 @@ INTERNAL struct entity *entity_alloc_internal(struct entity_store *store)
struct entity *entity_alloc(struct entity *parent) struct entity *entity_alloc(struct entity *parent)
{ {
ASSERT(parent->valid);
struct entity_store *store = entity_get_store(parent); struct entity_store *store = entity_get_store(parent);
struct entity *e = entity_alloc_internal(store); struct entity *e = entity_alloc_internal(store);
entity_link_parent(e, parent); entity_link_parent(e, parent);
@ -137,7 +138,9 @@ INTERNAL void entity_release_internal(struct entity_store *store, struct entity
void entity_release(struct entity_store *store, struct entity *ent) void entity_release(struct entity_store *store, struct entity *ent)
{ {
entity_unlink_parent(ent); if (ent->parent.gen) {
entity_unlink_parent(ent);
}
entity_release_internal(store, ent); entity_release_internal(store, ent);
} }

13
src/entity.h
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@ -90,32 +90,23 @@ struct entity {
/* ====================================================================== */ /* ====================================================================== */
/* Control */ /* Control */
f32 control_move_force; /* How much force is applied to achieve desired control movement */
struct { struct {
struct v2 move; struct v2 move;
struct v2 focus; struct v2 focus;
} control; } control;
/* ====================================================================== */
/* Player control */
/* ENTITY_PROP_PLAYER_CONTROLLED */
f32 player_max_speed;
f32 player_acceleration;
/* ====================================================================== */ /* ====================================================================== */
/* Physics */ /* Physics */
/* ENTITY_PROP_PHYSICAL */ /* ENTITY_PROP_PHYSICAL */
f32 density; f32 density;
f32 ground_friction;
/* Xform of the entity from the previous frame (used to calculate velocity) */ /* Xform of the entity from the previous frame (used to calculate velocity) */
struct xform verlet_xform; struct xform verlet_xform;
/* Calculated */
struct v2 final_velocity;
struct v2 final_acceleration;
/* ====================================================================== */ /* ====================================================================== */
/* Impulse */ /* Impulse */

196
src/game.c
View File

@ -124,9 +124,10 @@ INTERNAL void spawn_test_entities(void)
e->sprite_span_name = STR("idle.two_handed"); e->sprite_span_name = STR("idle.two_handed");
entity_enable_prop(e, ENTITY_PROP_PLAYER_CONTROLLED); entity_enable_prop(e, ENTITY_PROP_PLAYER_CONTROLLED);
e->player_max_speed = 4.f; e->control_move_force = 50;
e->player_acceleration = 20;
e->control.focus = V2(0, -1); e->control.focus = V2(0, -1);
e->ground_friction = 12;
e->density = 1.0;
player_ent = e; player_ent = e;
@ -477,7 +478,6 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
entity_enable_prop(eq, ENTITY_PROP_TRIGGERED_THIS_TICK); entity_enable_prop(eq, ENTITY_PROP_TRIGGERED_THIS_TICK);
} }
} }
} }
/* ========================== * /* ========================== *
@ -528,120 +528,101 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
if (!(ent->valid && entity_has_prop(ent, ENTITY_PROP_ACTIVE))) continue; if (!(ent->valid && entity_has_prop(ent, ENTITY_PROP_ACTIVE))) continue;
struct v2 move = ent->control.move; struct v2 move = ent->control.move;
if (!v2_eq(move, V2(0, 0))) { if (entity_has_prop(ent, ENTITY_PROP_PLAYER_CONTROLLED)) {
struct xform xf = entity_get_xform(ent);
struct v2 tick_velocity = v2_sub(xf.og, ent->verlet_xform.og);
/* Player movement */
if (entity_has_prop(ent, ENTITY_PROP_PLAYER_CONTROLLED)) {
f32 max_speed = ent->player_max_speed;
f32 acceleration_rate = ent->player_acceleration;
acceleration_rate = clamp_f32(acceleration_rate, 0, GAME_FPS); /* Can't integrate acceleration rate higher than FPS */
struct v2 target_velocity = v2_mul(ent->control.move, max_speed);
struct v2 target_acceleration = v2_sub(target_velocity, v2_div(tick_velocity, dt));
struct v2 acceleration = v2_mul(target_acceleration, acceleration_rate);
/* Create force */
struct entity *f = entity_alloc(ent);
entity_enable_prop(f, ENTITY_PROP_FORCE);
f->force = acceleration;
activate_now(f);
}
}
}
/* ========================== *
* Create constant forces
* ========================== */
/* TODO: Just do this in simulation processing */
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
struct entity *ent = &store->entities[entity_index];
if (!(ent->valid && entity_has_prop(ent, ENTITY_PROP_ACTIVE))) continue;
if (!entity_has_prop(ent, ENTITY_PROP_PHYSICAL)) continue;
struct xform xf = entity_get_xform(ent);
struct v2 velocity = v2_div(v2_sub(xf.og, ent->verlet_xform.og), dt);
/* Ground friction */
{
struct entity *f = entity_alloc(ent); struct entity *f = entity_alloc(ent);
f32 force_len = -v2_len(velocity) * 8;
entity_enable_prop(f, ENTITY_PROP_FORCE); entity_enable_prop(f, ENTITY_PROP_FORCE);
f->force = v2_mul(v2_norm(velocity), force_len); f->force = v2_mul(move, ent->control_move_force);
activate_now(f); activate_now(f);
} }
} }
/* ========================== * /* ========================== *
* Apply impulses to verlet xform * Create ground friction force
* ========================== */ * ========================== */
/* TODO: Do this globally rather than creating entities for constant forces */
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) { for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
struct entity *ent = &store->entities[entity_index]; struct entity *ent = &store->entities[entity_index];
if (!(ent->valid && entity_has_prop(ent, ENTITY_PROP_ACTIVE))) continue; if (!(ent->valid && entity_has_prop(ent, ENTITY_PROP_ACTIVE))) continue;
if (!entity_has_prop(ent, ENTITY_PROP_PHYSICAL)) continue;
if (ent->ground_friction != 0) {
struct xform verlet_xform = ent->verlet_xform;
struct xform xf = entity_get_xform(ent);
struct v2 velocity = v2_div(v2_sub(xf.og, verlet_xform.og), dt);
/* FIXME: Why does marking all ents with ENTITY_PROP_RELEASE here raise exception */ /* Ground friction */
if (!v2_eq(velocity, V2(0, 0))) {
if (entity_has_prop(ent, ENTITY_PROP_IMPULSE)) { /* FIXME: Incorrect behavior at low FPS & low entity density */
struct entity *parent = entity_from_handle(store, ent->parent); const f32 clamp_epsilon = 0.025;
if (entity_has_prop(parent, ENTITY_PROP_ACTIVE)) { f32 velocity_len = v2_len(velocity);
struct v2 tick_velocity = v2_mul(ent->impulse, dt); if (velocity_len >= clamp_epsilon) {
parent->verlet_xform.og = v2_sub(parent->verlet_xform.og, tick_velocity); f32 force_len = -velocity_len * ent->ground_friction;
entity_enable_prop(ent, ENTITY_PROP_RELEASE); struct entity *force = entity_alloc(ent);
entity_enable_prop(force, ENTITY_PROP_FORCE);
force->force = v2_mul(v2_norm(velocity), force_len);
activate_now(force);
} else {
/* If velocity is below clamp_epsilon, stop entity movement. */
struct entity *impulse = entity_alloc(ent);
entity_enable_prop(impulse, ENTITY_PROP_IMPULSE);
impulse->impulse = v2_neg(velocity);
activate_now(impulse);
}
} }
} }
} }
/* ========================== * /* ========================== *
* Apply forces to verlet xform * Simulate physics
* ========================== */
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
struct entity *ent = &store->entities[entity_index];
if (!(ent->valid && entity_has_prop(ent, ENTITY_PROP_ACTIVE))) continue;
f32 density = ent->density;
f32 mass = density; /* TODO: Real mass calculation */
if (entity_has_prop(ent, ENTITY_PROP_FORCE)) {
struct entity *parent = entity_from_handle(store, ent->parent);
if (entity_has_prop(parent, ENTITY_PROP_ACTIVE)) {
struct v2 acceleration = v2_div(ent->force, mass);
struct v2 tick_acceleration = v2_mul(acceleration, dt * dt);
parent->verlet_xform.og = v2_sub(parent->verlet_xform.og, tick_acceleration);
entity_enable_prop(ent, ENTITY_PROP_RELEASE);
}
}
}
/* ========================== *
* Simulate entity physics
* ========================== */ * ========================== */
/* TODO: Run physics on top-level entities, and then calculate child xforms as part of physics step (rather than caching at each xform_get). */ /* TODO: Run physics on top-level entities, and then calculate child xforms as part of physics step (rather than caching at each xform_get). */
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) { for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
struct entity *ent = &store->entities[entity_index]; struct entity *ent = &store->entities[entity_index];
if (!(ent->valid && entity_has_prop(ent, ENTITY_PROP_ACTIVE))) continue; if (!(ent->valid && entity_has_prop(ent, ENTITY_PROP_ACTIVE))) continue;
if (!entity_has_prop(ent, ENTITY_PROP_PHYSICAL)) continue; if (entity_has_prop(ent, ENTITY_PROP_PHYSICAL)) {
f32 density = ent->density;
f32 mass = density; /* TODO: Real mass calculation */
struct v2 acceleration = V2(0, 0);
struct xform xf = entity_get_xform(ent); /* Apply impulses */
for (struct entity *child = entity_from_handle(store, ent->first); child->valid; child = entity_from_handle(store, child->next)) {
if (entity_has_prop(child, ENTITY_PROP_IMPULSE)) {
acceleration = v2_add(acceleration, child->impulse);
entity_enable_prop(child, ENTITY_PROP_RELEASE);
}
}
/* Calculate velocity from old position */ /* Apply forces */
struct v2 tick_velocity = V2(0, 0); for (struct entity *child = entity_from_handle(store, ent->first); child->valid; child = entity_from_handle(store, child->next)) {
{ if (entity_has_prop(child, ENTITY_PROP_FORCE)) {
tick_velocity = v2_sub(xf.og, ent->verlet_xform.og); struct v2 force_acceleration = v2_mul(v2_div(child->force, mass), dt);
acceleration = v2_add(acceleration, force_acceleration);
entity_enable_prop(child, ENTITY_PROP_RELEASE);
}
}
/* Verlet integration */
struct xform xf = entity_get_xform(ent);
struct v2 tick_velocity = v2_sub(xf.og, ent->verlet_xform.og);
ent->verlet_xform = xf; ent->verlet_xform = xf;
xf.og = v2_add(xf.og, v2_add(tick_velocity, v2_mul(acceleration, dt)));
entity_set_xform(ent, xf);
} }
}
/* ========================== *
* Player aim
* ========================== */
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
struct entity *ent = &store->entities[entity_index];
if (!(ent->valid && entity_has_prop(ent, ENTITY_PROP_ACTIVE))) continue;
/* Player angle */
if (entity_has_prop(ent, ENTITY_PROP_PLAYER_CONTROLLED)) { if (entity_has_prop(ent, ENTITY_PROP_PLAYER_CONTROLLED)) {
struct xform xf = entity_get_xform(ent);
/* Solve for final angle using law of sines */ /* Solve for final angle using law of sines */
f32 final_xf_angle; f32 final_xf_angle;
{ {
@ -693,52 +674,22 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
xf = xform_with_rotation(xf, final_xf_angle); xf = xform_with_rotation(xf, final_xf_angle);
} }
} }
entity_set_xform(ent, xf);
} }
/* Apply velocity */
xf.og = v2_add(xf.og, tick_velocity);
ent->final_velocity = v2_div(tick_velocity, dt);
ent->final_acceleration = v2_div(v2_sub(v2_sub(xf.og, ent->verlet_xform.og), tick_velocity), dt);
entity_set_xform(ent, xf);
} }
/* ========================== * /* ========================== *
* Initialize bullet kinematics from sources * Initialize bullet kinematics from sources
* ========================== */ * ========================== */
#if 0
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
struct entity *ent = &store->entities[entity_index];
if (!(ent->valid && entity_has_prop(ent, ENTITY_PROP_ACTIVE))) continue;
/* FIXME: Apply src entity velocity to bullet velocity */
/* TODO: Use impulse */
if (entity_has_prop(ent, ENTITY_PROP_BULLET) && !entity_has_prop(ent, ENTITY_PROP_PHYSICAL)) {
struct entity *src = entity_from_handle(store, ent->bullet_src);
struct xform src_xf = entity_get_xform(src);
struct v2 pos = xform_mul_v2(src_xf, ent->bullet_src_pos);
struct v2 vec = xform_basis_mul_v2(src_xf, ent->bullet_src_dir);
vec = v2_mul(v2_norm(vec), ent->bullet_impulse);
struct xform xf = XFORM_TRS(.t = pos, .r = v2_angle(vec) + PI / 2);
entity_set_xform(ent, xf);
ent->verlet_xform = XFORM_POS(v2_sub(pos, v2_mul(vec, dt)));
entity_enable_prop(ent, ENTITY_PROP_PHYSICAL);
}
}
#else
for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) { for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
struct entity *ent = &store->entities[entity_index]; struct entity *ent = &store->entities[entity_index];
if (!(ent->valid && entity_has_prop(ent, ENTITY_PROP_ACTIVE))) continue; if (!(ent->valid && entity_has_prop(ent, ENTITY_PROP_ACTIVE))) continue;
/* FIXME: Apply src entity velocity to bullet velocity */ /* FIXME: Apply src entity velocity to bullet velocity */
if (entity_has_prop(ent, ENTITY_PROP_BULLET) && !entity_has_prop(ent, ENTITY_PROP_PHYSICAL)) { if (entity_has_prop(ent, ENTITY_PROP_BULLET) && ent->activation_tick == G.tick.tick_id) {
struct entity *src = entity_from_handle(store, ent->bullet_src); struct entity *src = entity_from_handle(store, ent->bullet_src);
struct xform src_xf = entity_get_xform(src); struct xform src_xf = entity_get_xform(src);
@ -749,7 +700,6 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
struct xform xf = XFORM_TRS(.t = pos, .r = v2_angle(velocity) + PI / 2); struct xform xf = XFORM_TRS(.t = pos, .r = v2_angle(velocity) + PI / 2);
entity_set_xform(ent, xf); entity_set_xform(ent, xf);
ent->verlet_xform = xf; ent->verlet_xform = xf;
entity_enable_prop(ent, ENTITY_PROP_PHYSICAL); entity_enable_prop(ent, ENTITY_PROP_PHYSICAL);
/* Create impulse */ /* Create impulse */
@ -758,7 +708,6 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
entity_enable_prop(impulse, ENTITY_PROP_IMPULSE); entity_enable_prop(impulse, ENTITY_PROP_IMPULSE);
} }
} }
#endif
/* ========================== * /* ========================== *
* Update camera position * Update camera position
@ -857,7 +806,10 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
} }
for (u64 i = 0; i < ents_to_release_count; ++i) { for (u64 i = 0; i < ents_to_release_count; ++i) {
entity_release(store, ents_to_release[i]); struct entity *ent = ents_to_release[i];
if (ent->valid) {
entity_release(store, ent);
}
} }
arena_temp_end(temp); arena_temp_end(temp);

15
src/user.c
View File

@ -381,16 +381,14 @@ INTERNAL void debug_draw_movement(struct entity *ent)
f32 arrow_len = 15.f; f32 arrow_len = 15.f;
u32 color_vel = RGBA_32_F(1, 0.5, 0, 1); u32 color_vel = RGBA_32_F(1, 0.5, 0, 1);
u32 color_acc = RGBA_32_F(1, 1, 0.5, 1);
struct xform xf = entity_get_xform(ent); struct xform xf = entity_get_xform(ent);
struct v2 velocity = v2_div(v2_sub(xf.og, ent->verlet_xform.og), G.world.dt);
struct v2 pos = xform_mul_v2(G.world_view, xf.og); struct v2 pos = xform_mul_v2(G.world_view, xf.og);
struct v2 vel_ray = xform_basis_mul_v2(G.world_view, ent->final_velocity); struct v2 vel_ray = xform_basis_mul_v2(G.world_view, velocity);
struct v2 acc_ray = xform_basis_mul_v2(G.world_view, ent->final_acceleration);
draw_solid_arrow_ray(G.viewport_canvas, pos, vel_ray, thickness, arrow_len, color_vel); draw_solid_arrow_ray(G.viewport_canvas, pos, vel_ray, thickness, arrow_len, color_vel);
draw_solid_arrow_ray(G.viewport_canvas, pos, acc_ray, thickness, arrow_len, color_acc);
} }
INTERNAL void user_update(void) INTERNAL void user_update(void)
@ -443,6 +441,7 @@ INTERNAL void user_update(void)
/* Blend world globals */ /* Blend world globals */
G.world.time = math_lerp64(t0->time, t1->time, (f64)tick_blend); G.world.time = math_lerp64(t0->time, t1->time, (f64)tick_blend);
G.world.dt = math_lerp64(t0->dt, t1->dt, (f64)tick_blend);
/* Blend entities */ /* Blend entities */
u64 num_entities = min_u64(t0->entity_store->reserved, t1->entity_store->reserved); u64 num_entities = min_u64(t0->entity_store->reserved, t1->entity_store->reserved);
@ -466,10 +465,8 @@ INTERNAL void user_update(void)
e->cached_global_xform = xform_lerp(e0->cached_global_xform, e1->cached_global_xform, tick_blend); e->cached_global_xform = xform_lerp(e0->cached_global_xform, e1->cached_global_xform, tick_blend);
e->verlet_xform = xform_lerp(e0->verlet_xform, e1->verlet_xform, tick_blend); e->verlet_xform = xform_lerp(e0->verlet_xform, e1->verlet_xform, tick_blend);
e->final_acceleration = v2_lerp(e0->final_acceleration, e1->final_acceleration, tick_blend);
e->final_velocity = v2_lerp(e0->final_velocity, e1->final_velocity, tick_blend);
e->player_acceleration = math_lerp(e0->player_acceleration, e1->player_acceleration, tick_blend); e->control_move_force = math_lerp(e0->control_move_force, e1->control_move_force, tick_blend);
e->control.move = v2_lerp(e0->control.move, e1->control.move, tick_blend); e->control.move = v2_lerp(e0->control.move, e1->control.move, tick_blend);
e->control.focus = v2_lerp(e0->control.focus, e1->control.focus, tick_blend); e->control.focus = v2_lerp(e0->control.focus, e1->control.focus, tick_blend);
@ -896,7 +893,9 @@ INTERNAL void user_update(void)
} }
#endif #endif
debug_draw_movement(ent); if (entity_has_prop(ent, ENTITY_PROP_PHYSICAL)) {
debug_draw_movement(ent);
}
if (!skip_debug_draw_transform) { if (!skip_debug_draw_transform) {
debug_draw_xform(xf); debug_draw_xform(xf);