From 60c6a5df8d68d33d560b58c6004e70164691ed79 Mon Sep 17 00:00:00 2001
From: Louis Pearson <opensource@louispearson.work>
Date: Thu, 4 Aug 2022 03:17:23 -0600
Subject: [PATCH] Auto-tile circuits

---
 src/extract.zig | 79 +++++++++++++++++++++++++++++++++++++++++++++++--
 src/rewrite.zig | 72 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 148 insertions(+), 3 deletions(-)

diff --git a/src/extract.zig b/src/extract.zig
index cdfc819..57b87d7 100644
--- a/src/extract.zig
+++ b/src/extract.zig
@@ -14,6 +14,10 @@ pub const Options = struct {
     alloc: std.mem.Allocator,
     level: world.Level,
     tileset: world.AutoTileset,
+    conduit: world.AutoTileset,
+    plug: world.AutoTileset,
+    switch_on: world.AutoTileset,
+    switch_off: world.AutoTileset,
 };
 
 fn is_solid(tile: u7) bool {
@@ -55,9 +59,10 @@ pub fn extractLevel(opt: Options) !void {
     var autotiles = try alloc.alloc(?AutoTile, size);
     defer alloc.free(autotiles);
 
+    // Auto generate walls
     {
         var i: usize = 0;
-        while (i < level.tiles.len) : (i += 1) {
+        while (i < size) : (i += 1) {
             const x = @mod(i, width);
             const y = @divTrunc(i, width);
             const stride = width;
@@ -111,10 +116,78 @@ pub fn extractLevel(opt: Options) !void {
             const li = autotile.to_u4();
             const tile = tileset.lookup[li];
             map.tiles[i] = tile;
-        } else {
+        }
+    }
+
+    // Auto generate circuit
+    // Re-use autotiles to save memory
+    {
+        var i: usize = 0;
+        while (i < size) : (i += 1) {
             const x = @mod(i, width);
             const y = @divTrunc(i, width);
-            w4.trace("{}, {}: {}", .{ x, y, map.tiles[i] });
+            const stride = width;
+
+            if (circuit_map[i] == .None) {
+                autotiles[i] = null;
+                continue;
+            }
+
+            const out_of_bounds = switch (circuit_map[i]) {
+                .Join, .Source => true,
+                else => false,
+            };
+            var north = false;
+            var south = false;
+            var west = false;
+            var east = false;
+
+            // Check horizontal neighbors
+            if (x == 0) {
+                west = out_of_bounds;
+                east = circuit_map[i + 1] != .None;
+            } else if (x == width - 1) {
+                west = circuit_map[i - 1] != .None;
+                east = out_of_bounds;
+            } else {
+                west = circuit_map[i - 1] != .None;
+                east = circuit_map[i + 1] != .None;
+            }
+
+            // Check vertical neighbours
+            if (y == 0) {
+                north = out_of_bounds;
+                south = circuit_map[i + stride] != .None;
+            } else if (y == height - 1) {
+                north = circuit_map[i - stride] != .None;
+                south = out_of_bounds;
+            } else {
+                north = circuit_map[i - stride] != .None;
+                south = circuit_map[i + stride] != .None;
+            }
+
+            autotiles[i] = AutoTile{
+                .North = north,
+                .South = south,
+                .West = west,
+                .East = east,
+            };
+        }
+    }
+
+    for (autotiles) |autotile_opt, i| {
+        if (autotile_opt) |autotile| {
+            const li = autotile.to_u4();
+            const tile = switch (circuit_map[i]) {
+                .Conduit, .Source, .Join => opt.conduit.lookup[li],
+                .Switch_On => opt.switch_on.lookup[li],
+                .Switch_Off => opt.switch_off.lookup[li],
+                .Plug => opt.plug.lookup[li],
+                .And => 60,
+                .Xor => 62,
+                else => 0,
+            };
+            circuit.map[i] = tile;
         }
     }
 }
diff --git a/src/rewrite.zig b/src/rewrite.zig
index fc60eb2..01a0163 100644
--- a/src/rewrite.zig
+++ b/src/rewrite.zig
@@ -62,6 +62,78 @@ pub fn start() !void {
             22, // South-East-West
             0, // South-East-West-North
         }},
+        .conduit = world.AutoTileset{ .lookup = .{
+            42, // Island
+            58, // North
+            59, // West
+            41, // West-North
+            57, // East
+            40, // East-North
+            26, // East-West
+            73, // East-West-North
+            56, // South
+            27, // South-North
+            25, // South-West
+            74, // South-West-North
+            24, // South-East
+            75, // South-East-North
+            72, // South-East-West
+            43, // South-East-West-North
+        } },
+        .plug = world.AutoTileset{ .lookup = .{
+            02, // Island
+            45, // North
+            46, // West
+            02, // West-North
+            47, // East
+            02, // East-North
+            02, // East-West
+            02, // East-West-North
+            44, // South
+            02, // South-North
+            02, // South-West
+            02, // South-West-North
+            02, // South-East
+            02, // South-East-North
+            02, // South-East-West
+            02, // South-East-West-North
+        } },
+        .switch_off = world.AutoTileset{ .lookup = .{
+            02, // Island
+            02, // North
+            02, // West
+            02, // West-North
+            02, // East
+            02, // East-North
+            02, // East-West
+            02, // East-West-North
+            02, // South
+            32, // South-North
+            02, // South-West
+            29, // South-West-North
+            02, // South-East
+            31, // South-East-North
+            02, // South-East-West
+            02, // South-East-West-North
+        } },
+        .switch_on = world.AutoTileset{ .lookup = .{
+            02, // Island
+            02, // North
+            02, // West
+            02, // West-North
+            02, // East
+            02, // East-North
+            02, // East-West
+            02, // East-West-North
+            02, // South
+            48, // South-North
+            02, // South-West
+            28, // South-West-North
+            02, // South-East
+            02, // South-East-North
+            30, // South-East-West
+            02, // South-East-West-North
+        } },
     });
 }