Some Updates

1 files changed, 78 insertions, 0 deletions

diff --git a/src/physics.c b/src/physics.c
new file mode 100644
index 0000000..33065a9
--- /dev/null
+++ b/src/physics.c
@@ -0,0 +1,78 @@
+#include <stdbool.h>
+#include "game.h"
+#include "entity.h"
+#include "physics.h"
+
+extern struct game game;
+
+static inline bool can_collide(const struct entity* entity) {
+  return (entity->flags & ENTITY_ACTIVE) && (entity->flags & ENTITY_COLLISION_ACTIVE);
+}
+
+static inline bool aabb(const struct entity* a, const struct entity* b) {
+  Rectangle acol = get_entity_collider_world(a);
+  Rectangle bcol = get_entity_collider_world(b);
+
+  bool collision_x = (acol.x <= bcol.x && acol.x + acol.width > bcol.x) ||
+    (bcol.x <= acol.x && bcol.x + bcol.width > acol.x);
+  bool collision_y = (acol.y <= bcol.y && acol.y + acol.height > bcol.y) ||
+    (bcol.y <= acol.y && bcol.y + bcol.height > acol.y);
+  
+  return collision_x && collision_y;
+}
+
+void move_and_collide
+(
+ struct entity* entity,
+ float delta_time
+ ) {
+  entity->position.x += entity->velocity.x * delta_time;
+
+  if (can_collide(entity)) {
+    for (int i = 0; i < MAX_ENTITY_COUNT; i++) {
+      struct entity* other = &game.entities[i];
+      if (same_entity(entity, other) || !can_collide(other) || !aabb(entity, other))
+        continue;
+
+      Rectangle acol = get_entity_collider_world(entity);
+      Rectangle bcol = get_entity_collider_world(other);
+
+      if (entity->velocity.x > 0) {
+        entity->position.x = bcol.x - acol.width - entity->collider.x;
+
+        entity_handle_collision(entity, other, Direction_Right);
+        entity_handle_collision(other, entity, Direction_Left);
+      } else {
+        entity->position.x = bcol.x + bcol.width - entity->collider.x;
+
+        entity_handle_collision(entity, other, Direction_Left);
+        entity_handle_collision(other, entity, Direction_Right);
+      }
+    }
+  }
+
+  entity->position.y += entity->velocity.y * delta_time;
+
+  if (can_collide(entity)) {
+    for (int i = 0; i < MAX_ENTITY_COUNT; i++) {
+      struct entity* other = &game.entities[i];
+      if (same_entity(other, entity) || !can_collide(other) || !aabb(entity, other))
+        continue;
+
+      Rectangle acol = get_entity_collider_world(entity);
+      Rectangle bcol = get_entity_collider_world(other);
+
+      if (entity->velocity.y > 0) {
+        entity->position.y = bcol.y - acol.height - entity->collider.y;
+
+        entity_handle_collision(entity, other, Direction_Down);
+        entity_handle_collision(other, entity, Direction_Up);
+      } else {
+        entity->position.y = bcol.y + bcol.height - entity->collider.y;
+
+        entity_handle_collision(entity, other, Direction_Up);
+        entity_handle_collision(other, entity, Direction_Down);
+      }
+    }
+  }
+}