diff --git a/README.md b/README.md
index 59dfb25..5fd0b58 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 # todo
 
+- resolve wall height
 - resolve view buble
-- add slide against wall
 - resolve vertical ray
 - add textures
 
diff --git a/headers/cube3d_struct.h b/headers/cube3d_struct.h
index 012c6d6..8f81dad 100644
--- a/headers/cube3d_struct.h
+++ b/headers/cube3d_struct.h
@@ -32,6 +32,7 @@ typedef struct		s_vec
 
 typedef struct		s_rcast
 {
+	int				tmp;
 	t_vec			screen_dist;
 	t_vec			screen_size;
 	t_vec			ray;
@@ -56,6 +57,7 @@ typedef struct		s_rcast
 	int				ray_step_y;
 	int				is_x;
 	int				ray_nb;
+	int				ray_len;
 	double			ratio;
 }					t_rcast;
 
diff --git a/srcs/draw/ray_intersect.c b/srcs/draw/ray_intersect.c
index 163160e..c491c88 100644
--- a/srcs/draw/ray_intersect.c
+++ b/srcs/draw/ray_intersect.c
@@ -22,37 +22,67 @@ static void	init_raycast(t_rcast *rcast, t_vec *ray)
 	// ray steps in both axis
 	rcast->ray_step_x = ft_abs(rcast->cell * rcast->slope_y);
 	rcast->ray_step_y = ft_abs(rcast->cell * rcast->slope_x);
+	
+	// tmp
+		if (rcast->tmp)
+			printf(" [slope_x:%i, slope_y:%i]", rcast->slope_x, rcast->slope_y);
+	//tmp
+
 }
 
 static void	init_first_step(t_rcast *rcast, t_vec *ray)
 {
-	rcast->first_next_x = ray->start.x % rcast->cell;
-	if (rcast->first_next_x && rcast->ray_sign_x < 0)
-		rcast->first_next_x = rcast->cell - rcast->first_next_x;
-	if (!rcast->first_next_x && rcast->ray_sign_x < 0)
-		rcast->first_next_x = rcast->cell;
-	rcast->first_next_y = ray->start.y % rcast->cell;
-	if (rcast->first_next_y && rcast->ray_sign_y < 0)
-		rcast->first_next_y = rcast->cell - rcast->first_next_y;
-	if (!rcast->first_next_y && rcast->ray_sign_y < 0)
-		rcast->first_next_y = rcast->cell;
+	rcast->first_next_x = 0;
+	if (rcast->slope_x)
+		rcast->first_next_x = ray->start.x % rcast->cell;
+	if (rcast->ray_sign_x < 0)
+		rcast->first_next_x -= rcast->cell;
+	rcast->first_next_y = 0;
+	if (rcast->slope_y)
+		rcast->first_next_y = ray->start.y % rcast->cell;
+	if (rcast->ray_sign_y < 0)
+		rcast->first_next_y -= rcast->cell;
 	rcast->next_x = ft_abs(rcast->first_next_x * rcast->slope_y);
 	rcast->next_y = ft_abs(rcast->first_next_y * rcast->slope_x);
+
+	// tmp
+		if (rcast->tmp)
+			printf(" [next_x:%i, next_y:%i]", rcast->next_x, rcast->next_y);
+	//tmp
+
 }
 
 static void	next_cell(t_rcast *rcast)
 {
-	if (rcast->next_x > rcast->next_y)
+
+	// tmp
+		if (rcast->tmp)
+			printf("\n [next_x(%i) > next_y(%i) ?]", rcast->next_x, rcast->next_y);
+	//tmp
+
+	if (rcast->slope_x == 0 || rcast->next_x > rcast->next_y)
 	{
 		rcast->cell_y += rcast->next_cell_y;
 		rcast->next_y += rcast->ray_step_y;
 		rcast->is_x = 0;
+
+	// tmp
+		if (rcast->tmp)
+			printf(" [yes] (increase y by %i)", rcast->ray_step_y);
+	//tmp
+
 	}
 	else
 	{
 		rcast->cell_x += rcast->next_cell_x;
 		rcast->next_x += rcast->ray_step_x;
 		rcast->is_x = 1;
+
+	// tmp
+		if (rcast->tmp)
+			printf(" [no] (increase x by %i)", rcast->ray_step_x);
+	//tmp
+
 	}
 }
 
@@ -64,8 +94,25 @@ void	ray_intersect(t_game *game, t_rcast *rcast, t_vec *ray)
 	ray->end.x += rcast->ray_nb;
 	ray->end.y = rcast->ray.end.y + game->plr.pos.y;
 	rotate(&(game->plr), &(ray->end));
+
+	// tmp
+		rcast->tmp = 0;
+		if (ray->end.x - ray->start.x == 0)
+			rcast->tmp = 1;
+		if (ray->end.y - ray->start.y == 0)
+			rcast->tmp = 1;
+		if (rcast->tmp)
+			printf("[ray nb : %3i]", rcast->ray_nb);
+	//tmp end
+
 	init_raycast(rcast, ray);
 	init_first_step(rcast, ray);
 	while (!is_wall(game, rcast->cell_x, rcast->cell_y))
 		next_cell(rcast);
+
+	// tmp
+		if (rcast->tmp)
+			printf("\n");
+	//tmp end
+
 }
diff --git a/srcs/draw/raycast.c b/srcs/draw/raycast.c
index c0d0ea1..0b6b39b 100644
--- a/srcs/draw/raycast.c
+++ b/srcs/draw/raycast.c
@@ -30,10 +30,14 @@
 	}
 // tmp end
 
-static void	calcul_wall(t_rcast *rcast)
+static void	wall_length(t_rcast *rcast)
 {
 	int	length;
-	int	height;
+
+	// tmp, to draw the map
+		if (rcast->tmp)
+			printf("length:");
+	// tmp end
 
 	rcast->wall.start.x = rcast->ray_nb;
 	rcast->wall.end.x = rcast->ray_nb;
@@ -41,16 +45,38 @@ static void	calcul_wall(t_rcast *rcast)
 	{
 		length = (rcast->next_x - rcast->ray_step_x) / ft_abs(rcast->slope_y);
 		length = (double)length * (double)rcast->screen_dist.end.y / (double)rcast->slope_x;
-//		length = (rcast->next_x - rcast->ray_step_x) / ft_abs(rcast->slope_y);
+
+		// tmp, to draw the map
+			if (rcast->tmp)
+				printf("(is_x == 1, slope_y != 0)");
+		// tmp end
+
 	}
 	if (rcast->is_x == 0 && rcast->slope_x != 0)
 	{
 		length = (rcast->next_y - rcast->ray_step_y) / ft_abs(rcast->slope_x);
 		length = (double)length * (double)rcast->screen_dist.end.y / (double)rcast->slope_y;
-//		length = (rcast->next_y - rcast->ray_step_y) / ft_abs(rcast->slope_x);
+
+		// tmp, to draw the map
+			if (rcast->tmp)
+				printf("(is_x == 0, slope_x != 0)");
+		// tmp end
+
 	}
-	length = ft_abs(length);
-	height = rcast->wall_height - length;
+	rcast->ray_len = ft_abs(length);
+
+	// tmp, to draw the map
+		if (rcast->tmp)
+			printf(" %i", rcast->ray_len);
+	// tmp end
+
+}
+
+static void	wall_height(t_rcast *rcast)
+{
+	int	height;
+
+	height = rcast->wall_height - rcast->ray_len;
 	if (height < 0)
 		height = 0;
 	if (height > rcast->screen_height)
@@ -98,8 +124,16 @@ void	raycast(t_game *game, t_rcast *rcast)
 			draw_line(&game->map_img, &ray, 0x00FF00FF);
 		// tmp end
 
-		calcul_wall(rcast);
+
+		wall_length(rcast);
+		wall_height(rcast);
 		draw_column(game, rcast);
 		(rcast->ray_nb)++;
+
+		// tmp, to draw the map
+			if (rcast->tmp)
+				printf("\n");
+		// tmp end
+
 	}
 }