From 8c70d6a70f50c740d59f32c4cc8ba9058386a8b3 Mon Sep 17 00:00:00 2001
From: Camden Dixie O'Brien <cdo@wip.sh>
Date: Sun, 3 Nov 2024 22:40:06 +0000
Subject: [PATCH] Draw walls seperately to maze and generate backwards

---
 main.c | 52 ++++++++++++++++++++++++++++++----------------------
 1 file changed, 30 insertions(+), 22 deletions(-)

diff --git a/main.c b/main.c
index 3fc1f73..3560954 100644
--- a/main.c
+++ b/main.c
@@ -43,11 +43,8 @@ static const vec2_t steps[] = {
 	[DOWN] = { .x = 0, .y = 2 },
 };
 
-static void draw_maze(Display *dpy, Window w, GC gc, const maze_t *m)
+static void draw_walls(Display *dpy, Window w, GC gc)
 {
-	XClearWindow(dpy, w);
-
-	// Draw walls
 	XFillRectangle(
 	    dpy, w, gc, PX(MARGIN), PX(MARGIN), PX(GRID_SIZE + 2),
 	    PX(WALL_THICKNESS));
@@ -55,19 +52,27 @@ static void draw_maze(Display *dpy, Window w, GC gc, const maze_t *m)
 	    dpy, w, gc, PX(MARGIN), PX(MARGIN + WALL_THICKNESS + GRID_SIZE),
 	    PX(GRID_SIZE + 2), PX(WALL_THICKNESS));
 	XFillRectangle(
-	    dpy, w, gc, PX(MARGIN), PX(MARGIN + WALL_THICKNESS + 1),
-	    PX(WALL_THICKNESS), PX(GRID_SIZE - 1));
+	    dpy, w, gc, PX(MARGIN), PX(MARGIN + WALL_THICKNESS),
+	    PX(WALL_THICKNESS), PX(GRID_SIZE));
 	XFillRectangle(
 	    dpy, w, gc, PX(MARGIN + WALL_THICKNESS + GRID_SIZE),
-	    PX(MARGIN + WALL_THICKNESS), PX(WALL_THICKNESS), PX(GRID_SIZE));
+	    PX(MARGIN + WALL_THICKNESS), PX(WALL_THICKNESS), PX(GRID_SIZE - 1));
+
+	XFlush(dpy);
+}
+
+static void draw_maze(Display *dpy, Window w, GC gc, const maze_t *m)
+{
+	const int margin_px = PX(MARGIN + WALL_THICKNESS);
+	XClearArea(
+	    dpy, w, margin_px, margin_px, PX(GRID_SIZE), PX(GRID_SIZE), false);
 
-	// Draw cells
 	for (int x = 0; x < GRID_SIZE; ++x) {
 		for (int y = 0; y < GRID_SIZE; ++y) {
 			if (m->cells[x][y])
 				continue;
-			const int left = PX(MARGIN + WALL_THICKNESS + x);
-			const int top = PX(MARGIN + WALL_THICKNESS + y);
+			const int left = margin_px + PX(x);
+			const int top = margin_px + PX(y);
 			XFillRectangle(dpy, w, gc, left, top, PX(1), PX(1));
 		}
 	}
@@ -76,14 +81,14 @@ static void draw_maze(Display *dpy, Window w, GC gc, const maze_t *m)
 }
 
 static void
-generate_maze(Display *dpy, Window w, GC gc, maze_t *m, int x, int y)
+generate_maze(Display *dpy, Window w, GC gc, maze_t *m, vec2_t p, vec2_t g)
 {
-	m->cells[x][y] = true;
+	m->cells[p.x][p.y] = true;
 
 	draw_maze(dpy, w, gc, m);
 	nanosleep(&pause, NULL);
 
-	if (GOAL == x && GOAL == y)
+	if (p.x == g.x && p.y == g.y)
 		return;
 
 	dir_t visit[] = { LEFT, RIGHT, UP, DOWN };
@@ -94,18 +99,19 @@ generate_maze(Display *dpy, Window w, GC gc, maze_t *m, int x, int y)
 		visit[i] = tmp;
 	}
 
+	vec2_t n;
 	for (int i = 0; i < 4; ++i) {
-		const int xp = x + steps[visit[i]].x;
-		const int yp = y + steps[visit[i]].y;
+		n.x = p.x + steps[visit[i]].x;
+		n.y = p.y + steps[visit[i]].y;
 
-		const bool x_in_bounds = xp >= 0 && xp < GRID_SIZE;
-		const bool y_in_bounds = yp >= 0 && yp < GRID_SIZE;
-		if (x_in_bounds && y_in_bounds && !m->cells[xp][yp]) {
-			const int xi = (x + xp) / 2;
-			const int yi = (y + yp) / 2;
+		const bool x_in_bounds = n.x >= 0 && n.x < GRID_SIZE;
+		const bool y_in_bounds = n.y >= 0 && n.y < GRID_SIZE;
+		if (x_in_bounds && y_in_bounds && !m->cells[n.x][n.y]) {
+			const int xi = (p.x + n.x) / 2;
+			const int yi = (p.y + n.y) / 2;
 			m->cells[xi][yi] = true;
 
-			generate_maze(dpy, w, gc, m, xp, yp);
+			generate_maze(dpy, w, gc, m, n, g);
 		}
 	}
 }
@@ -142,7 +148,9 @@ int main(void)
 	// Generate and draw maze
 	maze_t m;
 	memset(&m, 0, sizeof(maze_t));
-	generate_maze(dpy, w, gc, &m, 0, 0);
+	draw_walls(dpy, w, gc);
+	const vec2_t start = { GOAL, GOAL }, end = { 0, 0 };
+	generate_maze(dpy, w, gc, &m, start, end);
 
 	// Wait for window exit
 	bool is_del = false;