src/game/level/rigid_bodies.c

   1 #include <stdlib.h>
   2 #include <stdbool.h>
   3
   4 #include "game/camera.h"
   5 #include "game/level/platforms.h"
   6 #include "system/lt.h"
   7 #include "system/nth_alloc.h"
   8 #include "system/stacktrace.h"
   9
  10 #include "./rigid_bodies.h"
  11
  12 struct RigidBodies
  13 {
  14     Lt *lt;
  15     size_t capacity;
  16     size_t count;
  17
  18     Vec *positions;
  19     Vec *velocities;
  20     Vec *movements;
  21     Vec *sizes;
  22     Color *colors;
  23     bool *grounded;
  24     Vec *forces;
  25 };
  26
  27 static const Vec opposing_rect_side_forces[RECT_SIDE_N] = {
  28     { .x = 1.0f,  .y =  0.0f  },  /* RECT_SIDE_LEFT = 0, */
  29     { .x = -1.0f, .y =  0.0f  },  /* RECT_SIDE_RIGHT, */
  30     { .x = 0.0f,  .y =  1.0f, },  /* RECT_SIDE_TOP, */
  31     { .x = 0.0f,  .y = -1.0f, }   /* RECT_SIDE_BOTTOM, */
  32 };
  33
  34 static Vec opposing_force_by_sides(int sides[RECT_SIDE_N])
  35 {
  36     Vec opposing_force = {
  37         .x = 0.0f,
  38         .y = 0.0f
  39     };
  40
  41     for (Rect_side side = 0; side < RECT_SIDE_N; ++side) {
  42         if (sides[side]) {
  43             vec_add(
  44                 &opposing_force,
  45                 opposing_rect_side_forces[side]);
  46         }
  47     }
  48
  49     return opposing_force;
  50 }
  51
  52 RigidBodies *create_rigid_bodies(size_t capacity)
  53 {
  54     Lt *lt = create_lt();
  55     if (lt == NULL) {
  56         return NULL;
  57     }
  58
  59     RigidBodies *rigid_bodies = PUSH_LT(lt, nth_calloc(1, sizeof(RigidBodies)), free);
  60     if (rigid_bodies == NULL) {
  61         RETURN_LT(lt, NULL);
  62     }
  63     rigid_bodies->lt = lt;
  64
  65     rigid_bodies->capacity = capacity;
  66     rigid_bodies->count = 0;
  67
  68     rigid_bodies->positions = PUSH_LT(lt, nth_calloc(capacity, sizeof(Vec)), free);
  69     if (rigid_bodies->positions == NULL) {
  70         RETURN_LT(lt, NULL);
  71     }
  72
  73     rigid_bodies->velocities = PUSH_LT(lt, nth_calloc(capacity, sizeof(Vec)), free);
  74     if (rigid_bodies->velocities == NULL) {
  75         RETURN_LT(lt, NULL);
  76     }
  77
  78     rigid_bodies->movements = PUSH_LT(lt, nth_calloc(capacity, sizeof(Vec)), free);
  79     if (rigid_bodies->movements == NULL) {
  80         RETURN_LT(lt, NULL);
  81     }
  82
  83     rigid_bodies->sizes = PUSH_LT(lt, nth_calloc(capacity, sizeof(Vec)), free);
  84     if (rigid_bodies->sizes == NULL) {
  85         RETURN_LT(lt, NULL);
  86     }
  87
  88     rigid_bodies->colors = PUSH_LT(lt, nth_calloc(capacity, sizeof(Color)), free);
  89     if (rigid_bodies->colors == NULL) {
  90         RETURN_LT(lt, NULL);
  91     }
  92
  93     rigid_bodies->grounded = PUSH_LT(lt, nth_calloc(capacity, sizeof(bool)), free);
  94     if (rigid_bodies->grounded == NULL) {
  95         RETURN_LT(lt, NULL);
  96     }
  97
  98     rigid_bodies->forces = PUSH_LT(lt, nth_calloc(capacity, sizeof(Vec)), free);
  99     if (rigid_bodies->forces == NULL) {
 100         RETURN_LT(lt, NULL);
 101     }
 102
 103     return rigid_bodies;
 104 }
 105
 106 void destroy_rigid_bodies(RigidBodies *rigid_bodies)
 107 {
 108     trace_assert(rigid_bodies);
 109     RETURN_LT0(rigid_bodies->lt);
 110 }
 111
 112 int rigid_bodies_collide_with_itself(RigidBodies *rigid_bodies)
 113 {
 114     trace_assert(rigid_bodies);
 115
 116     /* TODO(#647): rigid_bodies_collide_with_itself is not implemented */
 117
 118     return 0;
 119 }
 120
 121 int rigid_bodies_collide_with_platforms(
 122     RigidBodies *rigid_bodies,
 123     const Platforms *platforms)
 124 {
 125     trace_assert(rigid_bodies);
 126     trace_assert(platforms);
 127
 128     int sides[RECT_SIDE_N] = { 0, 0, 0, 0 };
 129
 130     for (size_t i = 0; i < rigid_bodies->count; ++i) {
 131         memset(sides, 0, sizeof(int) * RECT_SIDE_N);
 132
 133         platforms_touches_rect_sides(platforms, rigid_bodies_hitbox(rigid_bodies, i), sides);
 134
 135         if (sides[RECT_SIDE_BOTTOM]) {
 136             rigid_bodies->grounded[i] = true;
 137         }
 138
 139         Vec opforce_direction = opposing_force_by_sides(sides);
 140
 141         /* It's an opposing force that we apply to platforms. But
 142          * since platforms are impenetrable, it's not needed
 143          * here. Plus we are trying to apply that force to the rigid
 144          * body itself, because I'm dumb. */
 145         /*
 146         rigid_bodies_apply_force(
 147             rigid_bodies, i,
 148             vec_scala_mult(
 149                 vec_neg(vec_norm(opforce_direction)),
 150                 vec_length(
 151                     vec_sum(rigid_bodies->velocities[i],
 152                             rigid_bodies->movements[i])) * 8.0f));
 153         */
 154
 155         if (fabs(opforce_direction.x) > 1e-6 && (opforce_direction.x < 0.0f) != ((rigid_bodies->velocities[i].x + rigid_bodies->movements[i].x) < 0.0f)) {
 156             rigid_bodies->velocities[i].x = 0.0f;
 157             rigid_bodies->movements[i].x = 0.0f;
 158         }
 159
 160         if (fabs(opforce_direction.y) > 1e-6 && (opforce_direction.y < 0.0f) != ((rigid_bodies->velocities[i].y + rigid_bodies->movements[i].y) < 0.0f)) {
 161             rigid_bodies->velocities[i].y = 0.0f;
 162             rigid_bodies->movements[i].y = 0.0f;
 163
 164             if (vec_length(rigid_bodies->velocities[i]) > 1e-6) {
 165                 rigid_bodies_apply_force(
 166                     rigid_bodies, i,
 167                     vec_scala_mult(
 168                         vec_neg(rigid_bodies->velocities[i]),
 169                         16.0f));
 170             }
 171         }
 172
 173         for (int j = 0; j < 1000 && vec_length(opforce_direction) > 1e-6; ++j) {
 174             rigid_bodies->positions[i] = vec_sum(
 175                 rigid_bodies->positions[i],
 176                 vec_scala_mult(
 177                     opforce_direction,
 178                     1e-2f));
 179
 180             memset(sides, 0, sizeof(int) * RECT_SIDE_N);
 181             platforms_touches_rect_sides(platforms, rigid_bodies_hitbox(rigid_bodies, i), sides);
 182             opforce_direction = opposing_force_by_sides(sides);
 183         }
 184     }
 185
 186     return 0;
 187 }
 188
 189 int rigid_bodies_update(RigidBodies *rigid_bodies,
 190                         float delta_time)
 191 {
 192     trace_assert(rigid_bodies);
 193
 194     memset(rigid_bodies->grounded, 0,
 195            sizeof(bool) * rigid_bodies->count);
 196
 197     for (size_t i = 0; i < rigid_bodies->count; ++i) {
 198         rigid_bodies->velocities[i] = vec_sum(
 199             rigid_bodies->velocities[i],
 200             vec_scala_mult(
 201                 rigid_bodies->forces[i],
 202                 delta_time));
 203     }
 204
 205     for (size_t i = 0; i < rigid_bodies->count; ++i) {
 206         rigid_bodies->positions[i] = vec_sum(
 207             rigid_bodies->positions[i],
 208             vec_scala_mult(
 209                 vec_sum(
 210                     rigid_bodies->velocities[i],
 211                     rigid_bodies->movements[i]),
 212                 delta_time));
 213     }
 214
 215     memset(rigid_bodies->forces, 0,
 216            sizeof(Vec) * rigid_bodies->count);
 217
 218     return 0;
 219 }
 220
 221 int rigid_bodies_render(RigidBodies *rigid_bodies,
 222                         Camera *camera)
 223 {
 224     trace_assert(rigid_bodies);
 225     trace_assert(camera);
 226
 227     for (size_t i = 0; i < rigid_bodies->count; ++i) {
 228         if (camera_fill_rect(
 229                 camera,
 230                 rect_from_vecs(
 231                     rigid_bodies->positions[i],
 232                     rigid_bodies->sizes[i]),
 233                 rigid_bodies->colors[i]) < 0) {
 234             return -1;
 235         }
 236     }
 237
 238     return 0;
 239 }
 240
 241 RigidBodyId rigid_bodies_add(RigidBodies *rigid_bodies,
 242                              Rect rect,
 243                              Color color)
 244 {
 245     trace_assert(rigid_bodies);
 246     trace_assert(rigid_bodies->count < rigid_bodies->capacity);
 247
 248     RigidBodyId id = rigid_bodies->count++;
 249     rigid_bodies->positions[id] = vec(rect.x, rect.y);
 250     rigid_bodies->sizes[id] = vec(rect.w, rect.h);
 251     rigid_bodies->colors[id] = color;
 252
 253     return id;
 254 }
 255
 256 Rect rigid_bodies_hitbox(const RigidBodies *rigid_bodies,
 257                          RigidBodyId id)
 258 {
 259     trace_assert(rigid_bodies);
 260     trace_assert(id < rigid_bodies->count);
 261
 262     return rect_from_vecs(rigid_bodies->positions[id],
 263                           rigid_bodies->sizes[id]);
 264 }
 265
 266 void rigid_bodies_move(RigidBodies *rigid_bodies,
 267                        RigidBodyId id,
 268                        Vec movement)
 269 {
 270     trace_assert(rigid_bodies);
 271     trace_assert(id < rigid_bodies->count);
 272
 273     rigid_bodies->movements[id] = movement;
 274 }
 275
 276 int rigid_bodies_touches_ground(const RigidBodies *rigid_bodies,
 277                                 RigidBodyId id)
 278 {
 279     trace_assert(rigid_bodies);
 280     trace_assert(id < rigid_bodies->count);
 281
 282     return rigid_bodies->grounded[id];
 283 }
 284
 285 void rigid_bodies_apply_omniforce(RigidBodies *rigid_bodies,
 286                                   Vec force)
 287 {
 288     for (size_t i = 0; i < rigid_bodies->count; ++i) {
 289         rigid_bodies_apply_force(rigid_bodies, i, force);
 290     }
 291 }
 292
 293 void rigid_bodies_apply_force(RigidBodies * rigid_bodies,
 294                               RigidBodyId id,
 295                               Vec force)
 296 {
 297     trace_assert(rigid_bodies);
 298     trace_assert(id < rigid_bodies->count);
 299
 300     rigid_bodies->forces[id] = vec_sum(rigid_bodies->forces[id], force);
 301 }
 302
 303 void rigid_bodies_transform_velocity(RigidBodies *rigid_bodies,
 304                                      RigidBodyId id,
 305                                      mat3x3 trans_mat)
 306 {
 307     trace_assert(rigid_bodies);
 308     trace_assert(id < rigid_bodies->count);
 309
 310     rigid_bodies->velocities[id] = point_mat3x3_product(
 311         rigid_bodies->velocities[id],
 312         trans_mat);
 313 }
 314
 315 void rigid_bodies_teleport_to(RigidBodies *rigid_bodies,
 316                               RigidBodyId id,
 317                               Vec position)
 318 {
 319     trace_assert(rigid_bodies);
 320     trace_assert(id < rigid_bodies->count);
 321
 322     rigid_bodies->positions[id] = position;
 323 }
 324
 325 void rigid_bodies_damper(RigidBodies *rigid_bodies,
 326                          RigidBodyId id,
 327                          Vec v)
 328 {
 329     trace_assert(rigid_bodies);
 330     trace_assert(id < rigid_bodies->count);
 331
 332     rigid_bodies_apply_force(
 333         rigid_bodies, id,
 334         vec(
 335             rigid_bodies->velocities[id].x * v.x,
 336             rigid_bodies->velocities[id].y * v.y));
 337 }