From 47264c3da3c9d186b167c976dbcd4e08e219e756 Mon Sep 17 00:00:00 2001
From: Sara <sara@saragerretsen.nl>
Date: Sun, 8 Oct 2023 23:10:37 +0200
Subject: [PATCH] added tilemap collision

---
 src/physics_world.c | 94 +++++++++++++++++++++++++++++++++++++++++++--
 src/physics_world.h |  4 ++
 2 files changed, 94 insertions(+), 4 deletions(-)

diff --git a/src/physics_world.c b/src/physics_world.c
index 0000963..66a6d4f 100644
--- a/src/physics_world.c
+++ b/src/physics_world.c
@@ -1,23 +1,37 @@
 #include "physics_world.h"
 #include "debug.h"
 #include "collision.h"
+#include "tilemap.h"
 
 static PhysicsEntity* _world_bodies = NULL;
 static size_t _world_bodies_cap = 0;
 static size_t _world_bodies_len = 0;
 
+static Tilemap** _world_maps = NULL;
+static size_t _world_maps_cap = 0;
+static size_t _world_maps_len = 0;
+
 void physics_world_init() {
     _world_bodies = malloc(8 * sizeof(PhysicsEntity));
-    _world_bodies_cap = 0;
+    _world_bodies_cap = 8;
+    _world_bodies_len = 0;
+
+    _world_maps = malloc(4 * (sizeof(Tilemap*)));
+    _world_maps_cap = 4;
+    _world_maps_len = 0;
 }
 
 void physics_world_clean() {
     free(_world_bodies);
     _world_bodies_cap = 0;
-    _world_bodies_cap = 0;
+    _world_bodies_len = 0;
+
+    free(_world_maps);
+    _world_maps_cap = 0;
+    _world_maps_len = 0;
 }
 
-void _physics_world_resize(size_t minimum) {
+void _internal_physics_world_resize_entities(size_t minimum) {
     if(minimum < _world_bodies_cap) {
         return;
     }
@@ -35,7 +49,7 @@ void _physics_world_resize(size_t minimum) {
 }
 
 void physics_world_add_entity(PhysicsEntity entity) {
-    _physics_world_resize(_world_bodies_len + 1);
+    _internal_physics_world_resize_entities(_world_bodies_len + 1);
 
     _world_bodies[_world_bodies_len] = entity;
     ++_world_bodies_len;
@@ -59,6 +73,50 @@ void physics_world_remove_entity(PhysicsEntity entity) {
     ASSERT_RETURN(0,, "Physics entity with data at %p is not registered in physics world", entity.data);
 }
 
+static
+void _internal_physics_world_resize_maps(size_t minimum) {
+    if(minimum < _world_maps_cap) {
+        return;
+    }
+
+    size_t amount = _world_maps_cap;
+    while(amount < minimum) {
+        amount *= 2;
+    }
+
+    Tilemap** new = realloc(_world_maps, amount * sizeof(Tilemap*));
+    ASSERT_RETURN(new != NULL,, "Could not grow physics tilemaps array");
+
+    _world_maps = new;
+    _world_maps_cap = amount;
+}
+
+void physics_world_add_map(Tilemap* map) {
+    _internal_physics_world_resize_maps(_world_maps_len + 1);
+
+    _world_maps[_world_maps_len] = map;
+    ++_world_maps_len;
+}
+
+static
+void _internal_physics_world_remove_map(Tilemap** at) {
+    Tilemap** from = at + 1;
+    memmove(at, from, (at - _world_maps + _world_bodies_len) * sizeof(Tilemap*));
+    --_world_bodies_len;
+}
+
+void physics_world_remove_map(Tilemap* map) {
+    Tilemap** end = _world_maps + _world_maps_len;
+    for(Tilemap** itr = _world_maps; itr < end; ++itr) {
+        if(*itr == map) {
+            _internal_physics_world_remove_map(itr);
+            return;
+        }
+    }
+
+    ASSERT_RETURN(0,, "Physics tilemap with data at %p is not registered in physics world and cannot be removed.", map);
+}
+
 static
 void _internal_physics_narrow_collision() {
     PhysicsEntity* end = _world_bodies + _world_bodies_len;
@@ -75,6 +133,33 @@ void _internal_physics_narrow_collision() {
     }
 }
 
+static
+void _internal_tilemap_entity_collision_check(Tilemap* map, PhysicsEntity entity) {
+    Collision collision_a;
+    Collision collision_b;
+    PhysicsEntity tileentity; 
+
+    size_t len = tilemap_get_tile_count(map);
+    for(size_t i = 0; i < len; ++i) {
+        tileentity = TileInstance_as_PhysicsEntity(tilemap_get_tile(map, i));
+
+        if(collision_check(entity, tileentity, &collision_a, &collision_b)) {
+            entity.tc->on_collision(entity.data, collision_a);
+        }
+    }
+}
+
+static
+void _internal_physics_tilemap_collision() {
+    PhysicsEntity* bodies_end = _world_bodies + _world_bodies_len;
+    Tilemap** maps_end = _world_maps + _world_maps_len;
+    for(PhysicsEntity* entity = _world_bodies; entity < bodies_end; ++entity) {
+        for(Tilemap** map = _world_maps; map < maps_end; ++map)  {
+            _internal_tilemap_entity_collision_check(*map, *entity);
+        }
+    }
+}
+
 static
 void _internal_physics_move() {
     PhysicsEntity* end = _world_bodies + _world_bodies_len;
@@ -89,5 +174,6 @@ void _internal_physics_move() {
 void physics_world_tick() {
     // _internal_physics_broad_collision();
     _internal_physics_narrow_collision();
+    _internal_physics_tilemap_collision();
     _internal_physics_move();
 }
diff --git a/src/physics_world.h b/src/physics_world.h
index 088b251..5aacb7e 100644
--- a/src/physics_world.h
+++ b/src/physics_world.h
@@ -2,6 +2,7 @@
 #define _fencer_physics_world_h
 
 #include "physics_entity.h"
+#include "tilemap.h"
 
 extern void physics_world_init();
 extern void physics_world_clean();
@@ -9,6 +10,9 @@ extern void physics_world_clean();
 extern void physics_world_add_entity(PhysicsEntity entity);
 extern void physics_world_remove_entity(PhysicsEntity entity);
 
+extern void physics_world_add_map(Tilemap* map);
+extern void physics_world_remove_map(Tilemap* map);
+
 extern void physics_world_tick();
 
 #endif // !_fencer_physics_world_h