Add and allow for more optional slots (#1612)

This checks slots based on texture connectivity. It really is just a
gimmick at this point, but it has potential to be more than that with
the right modifier restrictions.
![Screenshot at 2025-06-07
10-03-05](https://github.com/user-attachments/assets/e2aa96d4-8add-47cf-abc4-97f383c5fe41)
![Screenshot at 2025-06-07
09-59-46](https://github.com/user-attachments/assets/6aa00d24-8a97-4200-8c77-86b9751d2e2d)
![Screenshot at 2025-06-07
09-54-42](https://github.com/user-attachments/assets/247a2fdd-29ce-4467-85ff-3183f0ec36f1)

The big questions I have for you are:
- Is it obvious why some tools don't work while others do or is this too
confusing?
- @careeoki can you improve the texture to look better for these crooked
tools? Many slots do just seem to produce a thin line of diagonally
connected pixels, and this really doesn't look good and the algorithm
doesn't accept those as valid connections.

fixes #1589

assets/cubyz/tools/axe.zig.zon

@@ -9,9 +9,9 @@
 	},
 	.optional = .{
 		1, 1, 0, 0, 0,
-		1, 0, 1, 0, 0,
-		0, 0, 0, 1, 0,
-		0, 0, 1, 0, 0,
+		1, 1, 1, 0, 0,
+		0, 1, 1, 1, 0,
+		0, 0, 1, 1, 0,
 		0, 0, 0, 0, 0,
 	},
 	.parameters = .{

assets/cubyz/tools/pickaxe.zig.zon

@@ -8,10 +8,10 @@
 		1, 1, 1, 1, 0,
 	},
 	.optional = .{
-		1, 1, 0, 0, 0,
-		1, 0, 1, 0, 0,
-		0, 1, 0, 0, 0,
-		0, 0, 0, 0, 0,
+		1, 1, 1, 1, 0,
+		1, 1, 1, 0, 0,
+		1, 1, 1, 0, 0,
+		0, 0, 0, 1, 0,
 		0, 0, 0, 0, 0,
 	},
 	.parameters = .{

assets/cubyz/tools/shover.zig.zon

@@ -9,8 +9,8 @@
 	},
 	.optional = .{
 		1, 0, 1, 0, 0,
-		0, 0, 0, 1, 0,
-		1, 0, 0, 1, 0,
+		0, 1, 1, 1, 0,
+		1, 1, 1, 1, 0,
 		0, 1, 1, 0, 0,
 		0, 0, 0, 0, 0,
 	},

assets/cubyz/tools/sickle.zig.zon

@@ -9,9 +9,9 @@
 	},
 	.optional = .{
 		0, 1, 1, 1, 0,
-		1, 0, 0, 0, 1,
-		0, 0, 0, 0, 1,
-		0, 0, 0, 0, 0,
+		1, 1, 1, 1, 1,
+		0, 0, 0, 1, 1,
+		0, 0, 0, 1, 0,
 		0, 0, 0, 0, 0,
 	},
 	.parameters = .{

src/gui/windows/workbench.zig

@@ -112,7 +112,7 @@ pub fn render() void {
 	const offsetY = 4*ItemSlot.sizeWithBorder;
 	const fontSize = 16;
 
-	main.graphics.draw.print("#ffffff{} durability", .{@as(usize, @intFromFloat(currentResult.tool.maxDurability))}, offsetX, offsetY, fontSize, .left);
+	main.graphics.draw.print("{s}{} durability", .{if(currentResult.tool.maxDurability != 0) "#ffffff" else "#ff0000", @as(usize, @intFromFloat(currentResult.tool.maxDurability))}, offsetX, offsetY, fontSize, .left);
 	main.graphics.draw.print("#ffffff{d:.1} swings/s", .{1.0/currentResult.tool.swingTime}, offsetX, offsetY + fontSize, fontSize, .left);
 	main.graphics.draw.print("#ffffff{d:.1} damage", .{currentResult.tool.damage}, offsetX, offsetY + 2*fontSize, fontSize, .left);
 }

src/items.zig

@@ -435,6 +435,47 @@ const ToolPhysics = struct { // MARK: ToolPhysics
 		tool.maxDurability = @round(tool.maxDurability);
 		if(tool.maxDurability < 1) tool.maxDurability = 1;
 		tool.durability = std.math.lossyCast(u32, tool.maxDurability);
+
+		if(!checkConnectivity(tool)) {
+			tool.maxDurability = 0;
+			tool.durability = 1;
+		}
+	}
+
+	fn checkConnectivity(tool: *Tool) bool {
+		var gridCellsReached: [16][16]bool = @splat(@splat(false));
+		var floodfillQueue = main.utils.CircularBufferQueue(Vec2i).init(main.stackAllocator, 16);
+		defer floodfillQueue.deinit();
+		outer: for(tool.materialGrid, 0..) |row, x| {
+			for(row, 0..) |entry, y| {
+				if(entry != null) {
+					floodfillQueue.enqueue(.{@intCast(x), @intCast(y)});
+					gridCellsReached[x][y] = true;
+					break :outer;
+				}
+			}
+		}
+		while(floodfillQueue.dequeue()) |pos| {
+			for([4]Vec2i{.{-1, 0}, .{1, 0}, .{0, -1}, .{0, 1}}) |delta| {
+				const newPos = pos + delta;
+				if(newPos[0] < 0 or newPos[0] >= gridCellsReached.len) continue;
+				if(newPos[1] < 0 or newPos[1] >= gridCellsReached.len) continue;
+				const x: usize = @intCast(newPos[0]);
+				const y: usize = @intCast(newPos[1]);
+				if(gridCellsReached[x][y]) continue;
+				if(tool.materialGrid[x][y] == null) continue;
+				gridCellsReached[x][y] = true;
+				floodfillQueue.enqueue(newPos);
+			}
+		}
+		for(tool.materialGrid, 0..) |row, x| {
+			for(row, 0..) |entry, y| {
+				if(entry != null and !gridCellsReached[x][y]) {
+					return false;
+				}
+			}
+		}
+		return true;
 	}
 };