gjk closest point working for non-colliding entities

src/entity.h

@@ -95,8 +95,7 @@ struct entity {
     b32 colliding;
     struct entity_handle colliding_with;
     struct gjk_extended_simplex simplex;
-    struct v2 pen;
+    struct v2 point;
-    struct v2 spot;
 
 
 

src/game.c

@@ -775,10 +775,10 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
         }
 
         b32 colliding = false;
-        struct gjk_extended_simplex simplex = { 0 };
+        struct v2 point0 = V2(0, 0);
-        struct v2 pen = V2(0, 0);
+        struct v2 point1 = V2(0, 0);
-        struct v2 spot = V2(0, 0);
+        struct entity *colliding_with = entity_nil();
-        struct entity_handle colliding_with = { 0 };
+        struct gjk_extended_simplex final_simplex = { 0 };
         for (u64 e1_index = 0; e1_index < store->reserved; ++e1_index) {
             struct entity *e1 = &store->entities[e1_index];
             if (e1 == e0) continue;
@@ -801,11 +801,13 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
 
             struct gjk_extended_result res = gjk_extended(e0_poly, e1_poly, G.gjk_steps);
             colliding = res.colliding;
-            colliding_with = e1->handle;
+            point0 = res.p0;
-            simplex = res.final_simplex;
+            point1 = res.p1;
-            pen = res.colliding_pen;
+            colliding_with = e1;
+            final_simplex = res.final_simplex;
 
             if (colliding) {
+
                 //pen = epa_colliding_pen(e0_poly, e1_poly, simplex);
 #if 0
             /* Pen movement test */
@@ -816,16 +818,20 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
                     //e1->verlet_xform.og = v2_add(e1->verlet_xform.og, pen);
                 }
 #endif
-            } else {
-                spot = e0->spot;
             }
         }
 
         e0->colliding = colliding;
-        e0->colliding_with = colliding_with;
+        e0->colliding_with = colliding_with->handle;
-        e0->simplex = simplex;
+        e0->point = point0;
-        e0->pen = pen;
+        e0->simplex = final_simplex;
-        e0->spot = spot;
+
+        if (colliding_with->valid) {
+            colliding_with->colliding = colliding;
+            colliding_with->colliding_with = e0->handle;
+            colliding_with->point = point1;
+        }
+
     }
 #endif
 

src/user.c

@@ -988,13 +988,14 @@ INTERNAL void user_update(void)
                 }
             }
 
-            /* Draw player collision */
+            /* Draw collision */
-            if (entity_has_prop(ent, ENTITY_PROP_PLAYER_CONTROLLED)) {
+            if (ent->is_top) {
                 b32 colliding = ent->colliding;
                 struct entity *e1 = entity_from_handle(store, ent->colliding_with);
+                (UNUSED)colliding;
 
                 /* Draw menkowski */
-                {
+                if (entity_has_prop(ent, ENTITY_PROP_PLAYER_CONTROLLED)) {
                     struct quad ent_quad;
                     struct v2_array ent_poly;
                     struct quad e1_quad;
@@ -1032,6 +1033,14 @@ INTERNAL void user_update(void)
                     //draw_solid_poly(G.viewport_canvas, m, color);
                 }
 
+                /* Draw point */
+                {
+                    u32 color = COLOR_RED;
+                    f32 thickness = 4;
+                    struct v2 point = xform_mul_v2(G.world_view, ent->point);
+                    draw_solid_circle(G.viewport_canvas, point, thickness, color, 10);
+                }
+
                 /* Draw simplex */
                 {
                     f32 thickness = 2;
@@ -1062,6 +1071,7 @@ INTERNAL void user_update(void)
                     }
                 }
 
+#if 0
                 /* Draw pen */
                 if (colliding) {
                     f32 thickness = 2;
@@ -1072,6 +1082,7 @@ INTERNAL void user_update(void)
 
                     draw_solid_arrow_ray(G.viewport_canvas, start, ray, thickness, thickness * 4, color);
                 }
+#endif
             }
 
             /* Draw hierarchy */

src/util.c

@@ -358,7 +358,8 @@ struct gjk_extended_result gjk_extended(struct v2_array poly0, struct v2_array p
 {
     struct temp_arena scratch = scratch_begin_no_conflict();
     b32 colliding = false;
-    struct v2 pen = V2(0, 0);
+    struct v2 shape0_p = V2(0, 0);
+    struct v2 shape1_p = V2(0, 0);
     u32 step = 0;
 
     /* Simplex */
@@ -461,7 +462,7 @@ struct gjk_extended_result gjk_extended(struct v2_array poly0, struct v2_array p
         }
         u32 proto_count = 3;
 
-        pen = V2(0, 0);
+        struct v2 pen = V2(0, 0);
         f32 pen_len = F32_INFINITY;
         while (true) {
             pen = V2(0, 0);
@@ -521,12 +522,35 @@ struct gjk_extended_result gjk_extended(struct v2_array poly0, struct v2_array p
             proto[pen_pe_index] = m.p;
         }
         pen = v2_mul(v2_norm(pen), pen_len);
+    } else {
+        if (s.len == 1) {
+            shape0_p = s.a.p0;
+            shape1_p = s.a.p1;
+        } else if (s.len == 2) {
+            /* 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);
+            f32 ratio = clamp_f32(v2_dot(vab, vao) / v2_dot(vab, vab), 0, 1);
+            /* Determine point on shape 0 */
+            {
+                shape0_p = v2_sub(s.b.p0, s.a.p0);
+                shape0_p = v2_mul(shape0_p, ratio);
+                shape0_p = v2_add(shape0_p, s.a.p0);
+            }
+            /* Determine point on shape 1 */
+            {
+                shape1_p = v2_sub(s.b.p1, s.a.p1);
+                shape1_p = v2_mul(shape1_p, ratio);
+                shape1_p = v2_add(shape1_p, s.a.p1);
+            }
+        }
     }
 
     abort:
     struct gjk_extended_result res = { 0 };
     res.colliding = colliding;
-    res.colliding_pen = pen;
+    res.p0 = shape0_p;
+    res.p1 = shape1_p;
     res.final_simplex = s;
     scratch_end(scratch);
     return res;

src/util.h

@@ -199,7 +199,10 @@ struct gjk_extended_simplex {
 
 struct gjk_extended_result {
     b32 colliding;
-    struct v2 colliding_pen;
+    struct v2 p0;  /* Closest / deepest point on first shape's edge */
+    struct v2 p1;  /* Closest / deepest point on second shape's edge */
+
+    /* For debugging */
     struct gjk_extended_simplex final_simplex;
 };