1 files changed, 105 insertions, 0 deletions
diff --git a/src/collision.c b/src/collision.c
new file mode 100644
index 0000000..d21e321
--- /dev/null
+++ b/src/collision.c
@@ -0,0 +1,105 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   collision.c                                        :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dkaiser <dkaiser@student.42heilbronn.de    +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2024/05/14 11:48:59 by dkaiser           #+#    #+#             */
+/*   Updated: 2024/05/15 12:06:55 by dkaiser          ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "so_long.h"
+
+static int	check_wall_collision_with_cell(t_vector a_pos, t_ivector a_size,
+										   t_tilemap *map, t_ivector tile);
+
+/*
+ * Checks if a and b are colliding and returns the direction relative to a.
+ * Example: The top left edge of a and the bottom right of b overlap.
+ * In this case, check_collision() will return (UP | LEFT).
+ */
+int	check_collision(t_vector a_pos, t_ivector a_size, t_vector b_pos,
+		t_ivector b_size)
+{
+	int	result;
+
+	result = 0;
+	if (a_pos.x < b_size.x + b_pos.x && a_pos.x + a_size.x > b_pos.x
+		&& a_pos.y < b_size.y + b_pos.y && a_pos.y + a_size.y > b_pos.y)
+	{
+		if (a_pos.x < b_pos.x)
+			result |= RIGHT;
+		if (a_pos.x > b_pos.x)
+			result |= LEFT;
+		if (a_pos.y < b_pos.y)
+			result |= DOWN;
+		if (a_pos.y > b_pos.y)
+			result |= UP;
+	}
+	return (result);
+}
+
+int	check_wall_collision(t_vector a_pos, t_ivector a_size, t_tilemap *map)
+{
+	int			result;
+	t_ivector	a_tile;
+	t_ivector	check_tile;
+	int			x;
+	int			y;
+
+    result = 0;
+	a_tile = screen_to_grid_pos(a_pos, map->tile_size);
+	x = -1;
+	while (x <= 1)
+	{
+		y = -1;
+		while (y <= 1)
+		{
+            check_tile.x = a_tile.x + x;
+            check_tile.y = a_tile.y + y;
+			result |= check_wall_collision_with_cell(a_pos, a_size, map,
+					check_tile);
+			y++;
+		}
+		x++;
+	}
+	return (result);
+}
+
+static int	check_wall_collision_with_cell(t_vector a_pos, t_ivector a_size,
+		t_tilemap *map, t_ivector tile)
+{
+	t_vector	wall_pos;
+	t_ivector	wall_size;
+
+	if (get_tile(map, tile.x, tile.y) == WALL)
+	{
+		wall_pos = grid_to_screen_pos(tile, map->tile_size);
+		wall_size.x = map->tile_size.x;
+		wall_size.y = map->tile_size.y;
+		return (check_collision(a_pos, a_size, wall_pos, wall_size));
+	}
+	return (0);
+}
+
+void move_and_slide(t_player *player, t_tilemap *map)
+{
+	t_vector move_pos;
+
+	move_pos.x = player->position.x + player->velocity.x;
+	move_pos.y = player->position.y;
+
+	if ((check_wall_collision(move_pos, player->size, map) & (RIGHT | LEFT)) == 0)
+		player->position.x = move_pos.x;
+	else
+		player->velocity.x = 0;
+
+	move_pos.x = player->position.x;
+	move_pos.y = player->position.y + player->velocity.y;
+	if ((check_wall_collision(move_pos, player->size, map) & (UP | DOWN)) == 0)
+		player->position.y = move_pos.y;
+	else
+		player->velocity.y = 0;
+}