Initial landing gear (no detach)

Flight.vcxproj

@@ -177,12 +177,13 @@
       <PreprocessorDefinitions>NDEBUG;RELEASE;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <ConformanceMode>true</ConformanceMode>
       <AdditionalIncludeDirectories>$(ProjectDir)\thirdparty\enet\include;$(ProjectDir)\thirdparty\Chipmunk2D\include\chipmunk;$(ProjectDir)\thirdparty;$(ProjectDir)\thirdparty\Chipmunk2D\include;$(ProjectDir)\thirdparty\minilzo;$(ProjectDir)\thirdparty\opus\include</AdditionalIncludeDirectories>
+      <OmitFramePointers>false</OmitFramePointers>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <GenerateDebugInformation>DebugFull</GenerateDebugInformation>
       <AdditionalDependencies>$(CoreLibraryDependencies);%(AdditionalDependencies);Ws2_32.lib;winmm.lib;$(ProjectDir)\thirdparty\opus\win32\VS2015\x64\Release\opus.lib</AdditionalDependencies>
     </Link>
   </ItemDefinitionGroup>

Flight.vcxproj.user

@@ -4,7 +4,7 @@
     <ShowAllFiles>false</ShowAllFiles>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
-    <LocalDebuggerCommandArguments>--host</LocalDebuggerCommandArguments>
+    <LocalDebuggerCommandArguments>host=true</LocalDebuggerCommandArguments>
     <DebuggerFlavor>WindowsLocalDebugger</DebuggerFlavor>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug No Host|x64'">

buildsettings.h

@@ -26,7 +26,7 @@
 #define DEBUG_TOOLS
 #define CHIPMUNK_INTEGRITY_CHECK
 // #define FAT_THRUSTERS
-#define NO_GRAVITY
+//#define NO_GRAVITY
 // #define NO_SUNS
 
 #else

gamestate.c

@@ -407,6 +407,13 @@ LauncherTarget missile_launcher_target(GameState *gs, Entity *launcher)
   return (LauncherTarget){.target_found = target_found, .facing_angle = to_face};
 }
 
+void destroy_constraints(cpBody *body, cpConstraint *constraint, void *data)
+{
+  ((Entity*)cpConstraintGetUserData(constraint))->landed_constraint = NULL;
+  cpSpaceRemoveConstraint(cpBodyGetSpace(body), constraint);
+  cpConstraintFree(constraint);
+}
+
 void destroy_child_shape(cpBody *body, cpShape *shape, void *data)
 {
   GameState *gs = (GameState *)data;
@@ -447,14 +454,22 @@ void entity_memory_free(GameState *gs, Entity *e)
     cpShapeFree(e->shape);
     e->shape = NULL;
   }
+  if (e->landed_constraint != NULL)
+  {
+    cpSpaceRemoveConstraint(gs->space, e->landed_constraint);
+    cpConstraintFree(e->landed_constraint);
+    e->landed_constraint = NULL;
+  }
   if (e->body != NULL)
   {
+    // need to do this here because body which constraint is attached to can be destroyed
+		// NOT TRUE: can't do this here because the handle to the constraint cannot be set to NULL. Constraints are freed by the entities that own them
+    cpBodyEachConstraint(e->body, destroy_constraints, NULL); 
     cpBodyEachShape(e->body, destroy_child_shape, (void *)gs);
     cpSpaceRemoveBody(gs->space, e->body);
     cpBodyFree(e->body);
     e->body = NULL;
   }
-
   Entity *front_of_free_list = get_entity(gs, gs->free_list);
   if (front_of_free_list != NULL)
     flight_assert(!front_of_free_list->exists);
@@ -518,6 +533,12 @@ void create_body(GameState *gs, Entity *e)
   cpBodySetUserData(e->body, (void *)e);
 }
 
+// must always call this after creating a constraint
+void on_create_constraint(Entity *e, cpConstraint* c)
+{
+  cpConstraintSetUserData(c, (cpDataPointer)e);
+}
+
 cpVect player_vel(GameState *gs, Entity *player)
 {
   flight_assert(player->is_player);
@@ -666,7 +687,7 @@ void box_add_to_boxes(GameState *gs, Entity *grid, Entity *box_to_add)
 // box must be passed as a parameter as the box added to chipmunk uses this pointer in its
 // user data. pos is in local coordinates. Adds the box to the grid's chain of boxes
 // Must pass in a type so it knows what filter to give the collision shape
-void box_create(GameState *gs, Entity *new_box, Entity *grid, cpVect pos, enum BoxType type)
+void create_box(GameState *gs, Entity *new_box, Entity *grid, cpVect pos, enum BoxType type)
 {
   new_box->is_box = true;
   flight_assert(gs->space != NULL);
@@ -951,7 +972,7 @@ static void grid_correct_for_holes(GameState *gs, struct Entity *grid)
       cpShapeSetUserData(cur->shape, NULL);
       cur->shape = NULL;
 
-      box_create(gs, cur, new_grid, new_shape_position, cur->box_type); // destroys next/prev fields on cur
+      create_box(gs, cur, new_grid, new_shape_position, cur->box_type); // destroys next/prev fields on cur
       cur = next;
     }
 
@@ -1604,6 +1625,41 @@ SerMaybeFailure ser_entity(SerState *ser, GameState *gs, Entity *e)
     case BoxMissileLauncher:
       SER_MAYBE_RETURN(ser_f(ser, &e->missile_construction_charge));
       break;
+    case BoxLandingGear:
+    {
+      bool is_null = e->landed_constraint == NULL;
+      SER_VAR(&is_null);
+      if (!is_null)
+      {
+        EntityID from = {0};
+        EntityID to = {0};
+        cpVect pin = {0};
+        if (ser->serializing)
+        {
+          from = get_id(gs, cp_body_entity(cpConstraintGetBodyA(e->landed_constraint)));
+          to = get_id(gs, cp_body_entity(cpConstraintGetBodyB(e->landed_constraint)));
+          pin = cpPivotJointGetAnchorA(e->landed_constraint);
+        }
+        SER_MAYBE_RETURN(ser_entityid(ser, &from));
+        SER_MAYBE_RETURN(ser_entityid(ser, &to));
+        SER_MAYBE_RETURN(ser_V2(ser, &pin));
+        if (!ser->serializing)
+        {
+          Entity *from_entity = get_entity(gs, from);
+          Entity *to_entity = get_entity(gs, to);
+          if (from_entity == NULL || to_entity == NULL)
+          {
+          }
+          else
+          {
+            e->landed_constraint = cpPivotJointNew(from_entity->body, to_entity->body, pin);
+            cpSpaceAddConstraint(gs->space, e->landed_constraint);
+            on_create_constraint(e, e->landed_constraint);
+          }
+        }
+      }
+      break;
+    }
     default:
       break;
     }
@@ -2306,7 +2362,7 @@ void create_bomb_station(GameState *gs, cpVect pos, enum BoxType platonic_type)
 #define BOX_AT_TYPE(grid, pos, type)      \
   {                                       \
     Entity *box = new_entity(gs);         \
-    box_create(gs, box, grid, pos, type); \
+    create_box(gs, box, grid, pos, type); \
     box->compass_rotation = rot;          \
     box->indestructible = indestructible; \
   }
@@ -2317,7 +2373,7 @@ void create_bomb_station(GameState *gs, cpVect pos, enum BoxType platonic_type)
   grid_create(gs, grid);
   entity_set_pos(grid, pos);
   Entity *platonic_box = new_entity(gs);
-  box_create(gs, platonic_box, grid, (cpVect){0}, platonic_type);
+  create_box(gs, platonic_box, grid, (cpVect){0}, platonic_type);
   platonic_box->is_platonic = true;
   BOX_AT_TYPE(grid, ((cpVect){BOX_SIZE, 0}), BoxExplosive);
   BOX_AT_TYPE(grid, ((cpVect){BOX_SIZE * 2, 0}), BoxHullpiece);
@@ -2355,7 +2411,7 @@ void create_hard_shell_station(GameState *gs, cpVect pos, enum BoxType platonic_
   grid_create(gs, grid);
   entity_set_pos(grid, pos);
   Entity *platonic_box = new_entity(gs);
-  box_create(gs, platonic_box, grid, (cpVect){0}, platonic_type);
+  create_box(gs, platonic_box, grid, (cpVect){0}, platonic_type);
   platonic_box->is_platonic = true;
   BOX_AT_TYPE(grid, ((cpVect){BOX_SIZE * 2, 0}), BoxHullpiece);
   BOX_AT_TYPE(grid, ((cpVect){BOX_SIZE * 3, 0}), BoxHullpiece);
@@ -2432,7 +2488,7 @@ void create_initial_world(GameState *gs)
   create_hard_shell_station(gs, (cpVect){-5.0, 5.0}, BoxCloaking);
 #endif
 
-#if 1 // scanner box
+#if 0 // scanner box
   bool indestructible = false;
   enum CompassRotation rot = Right;
   {
@@ -2456,6 +2512,29 @@ void create_initial_world(GameState *gs)
 
 #endif
 
+#if 1 // landing gear box
+  bool indestructible = false;
+  cpVect from = cpv(4.0 * BOX_SIZE, 0.0);
+  enum CompassRotation rot = Right;
+  {
+    Entity *grid = new_entity(gs);
+    grid_create(gs, grid);
+    entity_set_pos(grid, from);
+    BOX_AT_TYPE(grid, ((cpVect){0.0, 0.0}), BoxLandingGear);
+    // BOX_AT(grid, ((cpVect){0.0, -BOX_SIZE}));
+    // BOX_AT_TYPE(grid, ((cpVect){BOX_SIZE, 0.0}), BoxMerge);
+    entity_ensure_in_orbit(gs, grid);
+    cpBodySetVelocity(grid->body, cpv(0.1, 0.0));
+  }
+  {
+    Entity *grid = new_entity(gs);
+    grid_create(gs, grid);
+    entity_set_pos(grid, cpvadd(from, cpv(2.0 * BOX_SIZE, 0.0)));
+    BOX_AT_TYPE(grid, ((cpVect){0.0, 0.0}), BoxHullpiece);
+    entity_ensure_in_orbit(gs, grid);
+  }
+#endif
+
 #if 0  // merge box
   bool indestructible = false;
   double theta = deg2rad(65.0);
@@ -2793,7 +2872,7 @@ void process(struct GameState *gs, double dt)
 #if 1 // building
         if (player->input.dobuild)
         {
-          player->input.dobuild = false; // handle the input. if didn't do this, after destruction of hovered box, would try to build on it again the next frame
+          player->input.dobuild = false; // handle the input. if didn't do this, after destruction of hovered box, would try to build on it again the next frame. @Robust handle the input in one place
 
           cpPointQueryInfo info = {0};
           cpVect world_build = world_hand_pos;
@@ -2830,7 +2909,7 @@ void process(struct GameState *gs, double dt)
                 created_box_position = grid_world_to_local(target_grid, world_build);
               }
               Entity *new_box = new_entity(gs);
-              box_create(gs, new_box, target_grid, created_box_position, player->input.build_type);
+              create_box(gs, new_box, target_grid, created_box_position, player->input.build_type);
               new_box->owning_squad = player->squad;
               grid_correct_for_holes(gs, target_grid); // no holey ship for you!
               new_box->compass_rotation = player->input.build_rotation;
@@ -3097,7 +3176,7 @@ void process(struct GameState *gs, double dt)
                         enum CompassRotation new_rotation = facing_vector_to_compass(from_grid, other_grid, box_facing_vector(cur));
                         cur->compass_rotation = new_rotation;
                         cpVect new_cur_pos = grid_snapped_box_pos(from_grid, cpvadd(snap_movement_vect, world));
-                        box_create(gs, cur, from_grid, grid_world_to_local(from_grid, new_cur_pos), cur->box_type); // destroys next/prev fields on cur
+                        create_box(gs, cur, from_grid, grid_world_to_local(from_grid, new_cur_pos), cur->box_type); // destroys next/prev fields on cur
                         flight_assert(box_grid(cur) == box_grid(from_merge));
                         cur = next;
                       }
@@ -3413,6 +3492,27 @@ void process(struct GameState *gs, double dt)
                 cur_box->scanner_head_rotate += cur_box->scanner_head_rotate_speed * dt;
                 cur_box->scanner_head_rotate = fmod(cur_box->scanner_head_rotate, 2.0 * PI);
               }
+              if (cur_box->box_type == BoxLandingGear)
+              {
+                if (cur_box->landed_constraint == NULL)
+                {
+                  cpVect along = box_facing_vector(cur_box);
+                  cpVect from = cpvadd(entity_pos(cur_box), cpvmult(along, BOX_SIZE / 2.0 + 0.03));
+                  cpVect to = cpvadd(from, cpvmult(along, LANDING_GEAR_MAX_DIST));
+
+                  cpSegmentQueryInfo query_result = {0};
+                  cpShape *found = cpSpaceSegmentQueryFirst(gs->space, from, to, 0.0, FILTER_DEFAULT, &query_result);
+                  if (found != NULL && cpShapeGetBody(found) != box_grid(cur_box)->body)
+                  {
+                    cpVect anchor = cpvadd(entity_pos(cur_box), cpvmult(along, BOX_SIZE / 2.0));
+                    cpBody *a = box_grid(cur_box)->body;
+                    cpBody *b = cpShapeGetBody(found);
+                    cur_box->landed_constraint = cpPivotJointNew(a, b, anchor);
+                    cpSpaceAddConstraint(gs->space, cur_box->landed_constraint);
+                    on_create_constraint(cur_box, cur_box->landed_constraint);
+                  }
+                }
+              }
             }
           }
         }

main.c

@@ -139,6 +139,7 @@ static sg_image image_noenergy;
 static sg_image image_orb;
 static sg_image image_orb_frozen;
 static sg_image image_radardot;
+static sg_image image_landing_gear;
 static sg_image image_pip;
 
 static sg_image fire_rendertarget;
@@ -232,6 +233,10 @@ static struct BoxInfo
         .type = BoxMerge,
         .image_path = "loaded/merge.png",
     },
+    {
+        .type = BoxLandingGear,
+        .image_path = "loaded/landing_gear.png",
+    },
 };
 // suppress compiler warning about ^^ above used in floating point context
 #define ARRLENF(arr) ((float)sizeof(arr) / sizeof(*arr))
@@ -852,6 +857,7 @@ static void init(void)
     image_orb = load_image("loaded/orb.png");
     image_orb_frozen = load_image("loaded/orb_frozen.png");
     image_radardot = load_image("loaded/radardot.png");
+    image_landing_gear = load_image("loaded/landing_gear.png");
     image_pip = load_image("loaded/pip.png");
   }
 

server.c

@@ -99,7 +99,7 @@ void server(void *info_raw)
 #define BOX_AT_TYPE(grid, pos, type) \
   {                                  \
     Entity *box = new_entity(&gs);   \
-    box_create(&gs, box, grid, pos); \
+    create_box(&gs, box, grid, pos); \
     box->box_type = type;            \
   }
 #define BOX_AT(grid, pos) BOX_AT_TYPE(grid, pos, BoxHullpiece)

types.h

@@ -58,6 +58,8 @@
 #define THRUSTER_ENERGY_USED_PER_SECOND 0.005
 #define THRUSTER_DAMAGE_PER_SEC 2.0
 
+#define LANDING_GEAR_MAX_DIST (BOX_SIZE * 0.25)
+
 #define GYROSCOPE_ENERGY_USED_PER_SECOND 0.005f
 #define GYROSCOPE_TORQUE 1.5f
 #define GYROSCOPE_PROPORTIONAL_INERTIAL_RESPONSE 0.7 // between 0-1. How strongly responds to rotation, to stop the rotation
@@ -189,6 +191,7 @@ enum BoxType
   BoxCloaking,
   BoxMissileLauncher,
   BoxMerge,
+  BoxLandingGear,
   BoxLast,
 };
 
@@ -277,7 +280,7 @@ typedef struct Entity
 
   double damage;  // used by box, player, and orb
   cpBody *body;   // used by grid, player, and box
-  cpShape *shape; // must be a box so shape_size can be set appropriately, and serialized
+  cpShape *shape; // see notes on serializing the shape
 
   // players and boxes can be cloaked
   // If this is within 2 timesteps of the current game time, the entity is invisible.
@@ -374,6 +377,9 @@ typedef struct Entity
   double scanner_head_rotate_speed; // not serialized, cosmetic
   double scanner_head_rotate;
 
+  // landing gear only
+  cpConstraint *landed_constraint; // when null is landed
+
   PlatonicDetection detected_platonics[SCANNER_MAX_PLATONICS]; // intensity of 0.0 means undetected
 
   struct ScannerPoint
@@ -562,7 +568,7 @@ LauncherTarget missile_launcher_target(GameState *gs, Entity *launcher);
 
 // grid
 void grid_create(struct GameState *gs, Entity *e);
-void box_create(struct GameState *gs, Entity *new_box, Entity *grid, cpVect pos, enum BoxType type);
+void create_box(struct GameState *gs, Entity *new_box, Entity *grid, cpVect pos, enum BoxType type);
 Entity *box_grid(Entity *box);
 cpVect grid_com(Entity *grid);
 cpVect grid_vel(Entity *grid);