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use midpoint of clipped gjk contact faces

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jacob 2024-09-13 11:29:41 -05:00
parent 14958a8449
commit 1d7f9be8b4
5 changed files with 68 additions and 71 deletions
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26
src/entity.h
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@ -60,6 +60,9 @@ struct entity_store {
struct entity { struct entity {
/* ====================================================================== */ /* ====================================================================== */
/* Metadata */ /* Metadata */
@ -98,9 +101,7 @@ struct entity {
struct v2 pendir; struct v2 pendir;
b32 solved; b32 solved;
struct v2 point0; struct v2 point;
struct v2 point1;
b32 has_2nd_point;
b32 test_torque_applied; b32 test_torque_applied;
b32 test_collided; b32 test_collided;
@ -112,6 +113,25 @@ struct entity {
#if 0
/* ====================================================================== */
/* Contact */
struct entity *contact_e0;
struct entity *contact_e1;
struct gjk_contact_pair contact_pairs[4];
u32 num_contact_pairs;
#endif
/* ====================================================================== */ /* ====================================================================== */

26
src/game.c
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@ -910,11 +910,8 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
} }
b32 colliding = false; b32 colliding = false;
struct v2 pair0p0 = V2(0, 0); struct v2 p0 = V2(0, 0);
struct v2 pair0p1 = V2(0, 0); struct v2 p1 = V2(0, 0);
struct v2 pair1p0 = V2(0, 0);
struct v2 pair1p1 = V2(0, 0);
b32 has_2nd_pair = false;
struct entity *colliding_with = entity_nil(); struct entity *colliding_with = entity_nil();
struct gjk_simplex simplex = { 0 }; struct gjk_simplex simplex = { 0 };
struct gjk_prototype prototype = { 0 }; struct gjk_prototype prototype = { 0 };
@ -944,11 +941,8 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
struct gjk_contact_points_result res = gjk_contact_points(e0_poly, e1_poly); struct gjk_contact_points_result res = gjk_contact_points(e0_poly, e1_poly);
colliding = res.colliding; colliding = res.colliding;
pair0p0 = res.pair0p0; p0 = res.p0;
pair0p1 = res.pair0p1; p1 = res.p1;
pair1p0 = res.pair1p0;
pair1p1 = res.pair1p1;
has_2nd_pair = res.has_2nd_pair;
colliding_with = e1; colliding_with = e1;
simplex = res.simplex; simplex = res.simplex;
prototype = res.prototype; prototype = res.prototype;
@ -957,9 +951,7 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
e0->colliding = colliding; e0->colliding = colliding;
e0->colliding_with = colliding_with->handle; e0->colliding_with = colliding_with->handle;
e0->point0 = pair0p0; e0->point = p0;
e0->point1 = pair1p0;
e0->has_2nd_point = has_2nd_pair;
e0->simplex = simplex; e0->simplex = simplex;
e0->prototype = prototype; e0->prototype = prototype;
e0->pendir = velocity; e0->pendir = velocity;
@ -968,13 +960,11 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
if (colliding_with->valid) { if (colliding_with->valid) {
colliding_with->colliding = colliding; colliding_with->colliding = colliding;
colliding_with->colliding_with = e0->handle; colliding_with->colliding_with = e0->handle;
colliding_with->point0 = pair0p1; colliding_with->point = p1;
colliding_with->point1 = pair1p1;
colliding_with->has_2nd_point = has_2nd_pair;
} }
{ {
#if 0 #if 1
if (colliding) { if (colliding) {
struct entity *e1 = colliding_with; struct entity *e1 = colliding_with;
struct xform e1_xf = entity_get_xform(e1); struct xform e1_xf = entity_get_xform(e1);
@ -999,7 +989,7 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
#if 1 #if 1
f32 bias_factor = 0.2; f32 bias_factor = 0.2;
f32 bias_slop = 0.005; f32 bias_slop = 0.001;
f32 bias = (bias_factor / dt) * max((v2_len(pen) - bias_slop), 0); f32 bias = (bias_factor / dt) * max((v2_len(pen) - bias_slop), 0);
#else #else

76
src/gjk.c
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@ -146,6 +146,9 @@ struct v2_array cloud(struct arena *arena, struct v2_array poly0, struct v2_arra
/* TODO: Update this function to only calculate contact pairs if colliding. Will allow for shortcut-style GJK.
* `colliding` & `has_2nd_pair` become "num_pairs", where 0 = no collision. */
struct gjk_contact_points_result gjk_contact_points(struct v2_array shape0, struct v2_array shape1) struct gjk_contact_points_result gjk_contact_points(struct v2_array shape0, struct v2_array shape1)
{ {
struct temp_arena scratch = scratch_begin_no_conflict(); struct temp_arena scratch = scratch_begin_no_conflict();
@ -158,11 +161,8 @@ struct gjk_contact_points_result gjk_contact_points(struct v2_array shape0, stru
struct gjk_menkowski_point *proto = NULL; struct gjk_menkowski_point *proto = NULL;
u32 proto_count = 0; u32 proto_count = 0;
struct v2 pair0p0 = { 0 }; struct v2 p0 = { 0 };
struct v2 pair0p1 = { 0 }; struct v2 p1 = { 0 };
struct v2 pair1p0 = { 0 };
struct v2 pair1p1 = { 0 };
b32 has_2nd_pair = false;
#if GJK_DEBUG #if GJK_DEBUG
u32 dbg_step = 0; u32 dbg_step = 0;
@ -370,36 +370,14 @@ struct gjk_contact_points_result gjk_contact_points(struct v2_array shape0, stru
/* Resolve points */ /* Resolve points */
if (s.len == 1) { if (s.len == 1) {
pair0p0 = s.a.p0; p0 = s.a.p0;
pair0p1 = s.a.p1; p1 = s.a.p1;
} else if (s.len == 2) { } else {
ASSERT(s.len == 2);
/* TODO: Epsilon */ b32 p0_is_on_edge = !v2_eq(s.a.p0, s.b.p0);
if (v2_eq(s.a.p0, s.b.p0) || v2_eq(s.a.p1, s.b.p1)) { b32 p1_is_on_edge = !v2_eq(s.a.p1, s.b.p1);
/* FIXME: Winding order dependent? */ if (p0_is_on_edge && p1_is_on_edge) {
ASSERT(s.len == 2); /* Closest features are both faces, use midpoint of clipped faces to represent contact points */
f32 ratio;
{
/* Determine ratio between edge a & b that projected origin lies */
struct v2 vab = v2_sub(s.b.p, s.a.p);
struct v2 vao = v2_neg(s.a.p);
ratio = clamp_f32(v2_dot(vab, vao) / v2_dot(vab, vab), 0, 1);
}
/* Shape 0 */
pair0p0 = v2_sub(s.b.p0, s.a.p0);
pair0p0 = v2_mul(pair0p0, ratio);
pair0p0 = v2_add(pair0p0, s.a.p0);
/* Shape 1 */
pair0p1 = v2_sub(s.b.p1, s.a.p1);
pair0p1 = v2_mul(pair0p1, ratio);
pair0p1 = v2_add(pair0p1, s.a.p1);
} else {
/* Face -> face, need 2nd pair */
has_2nd_pair = true;
/* TODO: Rename abcd variables */
struct v2 a = s.a.p0; struct v2 a = s.a.p0;
struct v2 b = s.b.p0; struct v2 b = s.b.p0;
struct v2 c = s.a.p1; struct v2 c = s.a.p1;
@ -416,10 +394,23 @@ struct gjk_contact_points_result gjk_contact_points(struct v2_array shape0, stru
f32 inv_vab_len_sq = 1.f / v2_len_sq(vab); f32 inv_vab_len_sq = 1.f / v2_len_sq(vab);
f32 inv_vcd_len_sq = 1.f / v2_len_sq(vcd); f32 inv_vcd_len_sq = 1.f / v2_len_sq(vcd);
pair0p0 = v2_add(a, v2_mul(vab, clamp_f32(v2_dot(vab, vac) * inv_vab_len_sq, 0, 1))); f32 ab_clip_c = clamp_f32(v2_dot(vab, vac) * inv_vab_len_sq, 0, 1);
pair1p0 = v2_add(a, v2_mul(vab, clamp_f32(v2_dot(vab, vad) * inv_vab_len_sq, 0, 1))); f32 ab_clip_d = clamp_f32(v2_dot(vab, vad) * inv_vab_len_sq, 0, 1);
pair0p1 = v2_add(c, v2_mul(vcd, clamp_f32(v2_dot(vcd, vca) * inv_vcd_len_sq, 0, 1))); f32 cd_clip_a = clamp_f32(v2_dot(vcd, vca) * inv_vcd_len_sq, 0, 1);
pair1p1 = v2_add(c, v2_mul(vcd, clamp_f32(v2_dot(vcd, vcb) * inv_vcd_len_sq, 0, 1))); f32 cd_clip_b = clamp_f32(v2_dot(vcd, vcb) * inv_vcd_len_sq, 0, 1);
p0 = v2_add(a, v2_mul(vab, (ab_clip_c + ab_clip_d) * 0.5f));
p1 = v2_add(c, v2_mul(vcd, (cd_clip_a + cd_clip_b) * 0.5f));
} else {
/* Determine ratio between edge a & b that projected origin lies */
f32 ratio;
{
struct v2 vab = v2_sub(s.b.p, s.a.p);
struct v2 vao = v2_neg(s.a.p);
ratio = clamp_f32(v2_dot(vab, vao) / v2_dot(vab, vab), 0, 1);
}
p0 = v2_add(s.a.p0, v2_mul(v2_sub(s.b.p0, s.a.p0), ratio));
p1 = v2_add(s.a.p1, v2_mul(v2_sub(s.b.p1, s.a.p1), ratio));
} }
} }
@ -443,11 +434,8 @@ abort:
res.prototype.len = s.len; res.prototype.len = s.len;
} }
res.colliding = colliding; res.colliding = colliding;
res.pair0p0 = pair0p0; res.p0 = p0;
res.pair0p1 = pair0p1; res.p1 = p1;
res.pair1p0 = pair1p0;
res.pair1p1 = pair1p1;
res.has_2nd_pair = has_2nd_pair;
res.simplex = s; res.simplex = s;
scratch_end(scratch); scratch_end(scratch);
return res; return res;

7
src/gjk.h
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@ -24,11 +24,8 @@ b32 gjk_boolean(struct v2_array shape0, struct v2_array shape1);
struct gjk_prototype { struct v2 points[64]; u32 len; }; struct gjk_prototype { struct v2 points[64]; u32 len; };
struct gjk_contact_points_result { struct gjk_contact_points_result {
b32 colliding; b32 colliding;
struct v2 p0;
struct v2 p1;
struct v2 pair0p0, pair0p1;
struct v2 pair1p0, pair1p1;
b32 has_2nd_pair;
/* For debugging */ /* For debugging */
b32 solved; b32 solved;

4
src/user.c
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@ -1118,14 +1118,16 @@ INTERNAL void user_update(void)
f32 radius = 5; f32 radius = 5;
{ {
u32 color = entity_has_prop(ent, ENTITY_PROP_PLAYER_CONTROLLED) ? RGBA_32_F(1, 0, 0, 0.75) : RGBA_32_F(0, 1, 1, 0.75); u32 color = entity_has_prop(ent, ENTITY_PROP_PLAYER_CONTROLLED) ? RGBA_32_F(1, 0, 0, 0.75) : RGBA_32_F(0, 1, 1, 0.75);
struct v2 point = xform_mul_v2(G.world_view, ent->point0); struct v2 point = xform_mul_v2(G.world_view, ent->point);
draw_solid_circle(G.viewport_canvas, point, radius, color, 10); draw_solid_circle(G.viewport_canvas, point, radius, color, 10);
} }
#if 0
if (ent->has_2nd_point) { if (ent->has_2nd_point) {
u32 color = entity_has_prop(ent, ENTITY_PROP_PLAYER_CONTROLLED) ? RGBA_32_F(1, 1, 0, 0.75) : RGBA_32_F(1, 0, 1, 0.75); u32 color = entity_has_prop(ent, ENTITY_PROP_PLAYER_CONTROLLED) ? RGBA_32_F(1, 1, 0, 0.75) : RGBA_32_F(1, 0, 1, 0.75);
struct v2 point = xform_mul_v2(G.world_view, ent->point1); struct v2 point = xform_mul_v2(G.world_view, ent->point1);
draw_solid_circle(G.viewport_canvas, point, radius, color, 10); draw_solid_circle(G.viewport_canvas, point, radius, color, 10);
} }
#endif
} }
} }