Deletion implemented

src/errors.zig

@@ -1,3 +1,6 @@
+/// Contains collection of errors connected with an entity (road, node, car, etc.)
 pub const Entity = error {
     AlreadyReferenced,
+    NotFound,
+    HasReferences,
 };

src/infrastructure/node.zig

@@ -6,10 +6,14 @@ const e = @import("../errors.zig");
 const Road = @import("road.zig").Road;
 
 pub const Node = struct {
+    /// Possibly unnecessary, but for now it's good as a secondary mean of identification
     id: usize,
+    /// Node's position on the simulation 'field'
     pos: rl.Vector2,
+    /// Contains references of all the roads this node is connected to
     roads: std.ArrayList(*Road),
 
+    /// Simple constructor
     pub fn init(new_id: usize, new_pos: rl.Vector2) Node {
         return .{
             .id = new_id,
@@ -18,20 +22,31 @@ pub const Node = struct {
         };
     }
 
-    pub fn deinit(self: *Node, allocator: std.mem.Allocator) void {
+    /// This function frees the list that holds road references that are connected to this node
+    ///
+    /// Next it invalidates itself (the pointer), making it invalid
+    pub fn deinit(self: *Node, allocator: std.mem.Allocator) !void {
+        if (self.roads.items.len != 0) return e.Entity.AlreadyReferenced;
+
         self.roads.deinit(allocator);
+        allocator.destroy(self);
     }
 
+    /// Simple function which draws the node
     pub fn draw(self: *const Node, direct_colour: ?rl.Color) void {
         const colour = if (direct_colour) |clr| clr else c.NODE_COLOUR;
 
         rl.drawCircleV(self.pos, c.NODE_RADIUS, colour);
     }
 
+    /// Identifies whether the pos (location) is within the snapping radius of the node
     pub fn posWithinRadius(self: *const Node, pos: rl.Vector2) bool {
         return rl.checkCollisionPointCircle(pos, self.pos, c.NODE_SNAP_RADIUS);
     }
 
+    /// Tries to reference the passed road to self
+    ///
+    /// Returns an error if the passed road cannot be appended to the list or if said road is already in the list
     pub fn referenceRoad(self: *Node, allocator: std.mem.Allocator, road_to_add: *Road) !void {
         // Note the road_to_add pointer must be one from the roads list as otherwise the pointer is dangling one
         for (self.roads.items) |road| {
@@ -40,6 +55,22 @@ pub const Node = struct {
 
         try self.roads.append(allocator, road_to_add);
     }
+
+    /// Attempts to unreference the passed road from self (node)
+    ///
+    /// Returns whether the node still has node references (true) or not (false)
+    ///
+    /// Returns an error if the road is not referenced to self in the first place
+    pub fn unreferenceRoad(self: *Node, road_to_remove: *const Road) !void {
+        for (0..self.roads.items.len) |i| {
+            if (self.roads.items[i] != road_to_remove) continue;
+
+            _ = self.roads.swapRemove(i);
+            return;
+        }
+
+        return e.Entity.NotFound;
+    }
 };
 
 // TODO tests

src/infrastructure/node_manager.zig

@@ -2,6 +2,7 @@ const std = @import("std");
 const Vector2 = @import("raylib").Vector2;
 
 const c = @import("../constants.zig");
+const e = @import("../errors.zig");
 const Node = @import("node.zig").Node;
 const Road = @import("road.zig").Road;
 
@@ -18,10 +19,9 @@ pub const NodeManager = struct {
         };
     }
 
-    pub fn deinit(self: *NodeManager, allocator: std.mem.Allocator) void {
+    pub fn deinit(self: *NodeManager, allocator: std.mem.Allocator) !void {
         for (self.nodes.items) |node| {
-            node.deinit(allocator);
+            try node.deinit(allocator);
-            allocator.destroy(node);
         }
         self.nodes.deinit(allocator);
     }
@@ -36,7 +36,7 @@ pub const NodeManager = struct {
             var cur_node = Node.init(0, pos);
             // Temporary road that is to be drawn as one in the making
             const road: Road = .init(0, node, &cur_node);
-            road.draw();
+            road.draw(false);
 
             node.*.draw(c.NODE_TEMP_COLOUR);
             cur_node.draw(c.NODE_CURSOR_COLOUR);
@@ -64,15 +64,28 @@ pub const NodeManager = struct {
         return id;
     }
 
-    pub fn clear(self: *NodeManager, allocator: std.mem.Allocator) void {
+    pub fn clear(self: *NodeManager, allocator: std.mem.Allocator) !void {
         self.temp_node = null;
         for (self.nodes.items) |node| {
-            node.deinit(allocator);
+            try node.deinit(allocator);
-            allocator.destroy(node);
         }
         self.nodes.clearRetainingCapacity();
         self.next_id = 0;
     }
+
+    pub fn deleteNode(self: *NodeManager, allocator: std.mem.Allocator, node_to_delete: *Node) !void {
+        if (node_to_delete.roads.items.len != 0) return e.Entity.HasReferences;
+
+        for (0..self.nodes.items.len) |i| {
+            if (self.nodes.items[i] != node_to_delete) continue;
+
+            try node_to_delete.deinit(allocator);
+            _ = self.nodes.swapRemove(i);
+            return;
+        }
+
+        return e.Entity.NotFound;
+    }
 };
 
 const expect = std.testing.expect;
@@ -102,3 +115,4 @@ test "id tracking" {
 
 // TODO tests
 // force resize pointer test
+// deleting nodes

src/infrastructure/road.zig

@@ -11,6 +11,7 @@ pub const Road = struct {
     /// Calculated road length
     length: f32,
 
+    /// Constructor, which sets nodes for the road and calculates its length
     pub fn init(new_id: usize, start: *Node, end: *Node) Road {
         var road: Road = .{
             .id = new_id,
@@ -22,6 +23,11 @@ pub const Road = struct {
         return road;
     }
 
+    /// This makes the road ptr DEAD
+    pub fn deinit(self: *Road, allocator: std.mem.Allocator) void {
+        allocator.destroy(self);
+    }
+
     /// Calculates length of the road by taking its two nodes
     fn calculate_length(self: *const Road) f32 {
         const start = self.nodes[0];
@@ -34,8 +40,26 @@ pub const Road = struct {
         return @sqrt(square_diff);
     }
 
-    pub fn draw(self: *const Road) void {
+    /// Simple function which draws the node
-        rl.drawLineEx(self.nodes[0].*.pos, self.nodes[1].*.pos, c.ROAD_SIZE, c.ROAD_COLOUR);
+    ///
+    /// In the future as we improve and make roads more complex with multiple lanes and such
+    /// it will gradually become more complex
+    pub fn draw(self: *const Road, highlighted: bool) void {
+        const colour = if (highlighted) c.ROAD_HIGHLIGHTED_COLOUR else c.ROAD_COLOUR;
+        rl.drawLineEx(self.nodes[0].*.pos, self.nodes[1].*.pos, c.ROAD_SIZE, colour);
+    }
+
+    /// Important: after this function executes, this road is no longer reachable from its bounding nodes
+    ///
+    /// The function unreferences self (road) from its bounding nodes
+    pub fn unreferenceNodes(self: *const Road) !void {
+        try self.nodes[0].unreferenceRoad(self);
+        try self.nodes[1].unreferenceRoad(self);
+    }
+
+    /// Checks whether pos coordinate is on the referenced road
+    pub fn isHighlighted(self: *const Road, pos: rl.Vector2) bool {
+        return rl.checkCollisionPointLine(pos, self.nodes[0].*.pos, self.nodes[1].*.pos, c.ROAD_SIZE);
     }
 };
 

src/infrastructure/road_manager.zig

@@ -1,28 +1,33 @@
 const std = @import("std");
+
+const e = @import("../errors.zig");
 const Road = @import("road.zig").Road;
 const Node = @import("node.zig").Node;
 
 pub const RoadManager = struct {
     next_id: usize,
     roads: std.ArrayList(*Road),
+    highlighted_road: ?*Road,
 
     pub fn init() RoadManager {
         return .{
             .next_id = 0,
             .roads = .empty,
+            .highlighted_road = null,
         };
     }
 
     pub fn deinit(self: *RoadManager, allocator: std.mem.Allocator) void {
         for (self.roads.items) |road| {
-            allocator.destroy(road);
+            road.deinit(allocator);
         }
         self.roads.deinit(allocator);
     }
 
-    pub fn draw(self: *const RoadManager) void {
+    pub fn draw(self: *const RoadManager, delete_mode: bool) void {
         for (self.roads.items) |road| {
-            road.draw();
+            const is_highlighted = delete_mode and self.highlighted_road != null and self.highlighted_road.? == road;
+            road.draw(is_highlighted);
         }
     }
 
@@ -46,11 +51,40 @@ pub const RoadManager = struct {
 
     pub fn clear(self: *RoadManager, allocator: std.mem.Allocator) void {
         for (self.roads.items) |road| {
-            allocator.destroy(road);
+            road.deinit(allocator);
         }
         self.roads.clearRetainingCapacity();
         self.next_id = 0;
     }
+
+    pub fn deleteRoad(self: *RoadManager, allocator: std.mem.Allocator, road_to_delete: *Road) !void {
+        // unreference the road from its bounding functions
+        road_to_delete.unreferenceNodes() catch |err| {
+            std.debug.panic("Failed to unreference the road from its nodes: {}\n", .{err});
+        };
+
+        for (0..self.roads.items.len) |i| {
+            if (self.roads.items[i] != road_to_delete) continue;
+
+            road_to_delete.deinit(allocator);
+            _ = self.roads.swapRemove(i);
+            return;
+        }
+
+        return e.Entity.NotFound;
+    }
+
+    /// Sets the pointer to the road that is intersection with pos coordinate
+    pub fn update_highlighted_road(self: *RoadManager, pos: Vector2) void {
+        for (self.roads.items) |road| {
+            if (!road.isHighlighted(pos)) continue;
+
+            self.highlighted_road = road;
+            return;
+        }
+
+        self.highlighted_road = null;
+    }
 };
 
 const Vector2 = @import("raylib").Vector2;
@@ -91,4 +125,5 @@ test "id tracking" {
 
 // TODO tests
 // force resize pointer test
+// add, remove road
 // destroy road and then verify the nodes do not have a pointer to it

src/main.zig

@@ -19,7 +19,9 @@ pub fn main(init: std.process.Init) !void {
     rl.setTargetFPS(rl.getMonitorRefreshRate(monitor));
 
     var sim: Simulator = .init(allocator);
-    defer sim.deinit();
+    defer sim.deinit() catch |err| {
+        std.debug.panic("Failed to deinitialise the sim: {}\n", .{err});
+    };
 
     while (!rl.windowShouldClose()) {
         rl.beginDrawing();
@@ -27,6 +29,7 @@ pub fn main(init: std.process.Init) !void {
 
         const pos = rl.getMousePosition();
         sim.handleInput(pos);
+        sim.update(pos);
 
         sim.draw(pos);
     }

src/simulator.zig

@@ -11,6 +11,7 @@ pub const Simulator = struct {
     road_man: RoadManager,
     // vars
     auto_continue: bool,
+    delete_mode: bool,
 
     pub fn init(new_allocator: std.mem.Allocator) Simulator {
         return .{
@@ -18,21 +19,26 @@ pub const Simulator = struct {
             .node_man = .init(),
             .road_man = .init(),
             .auto_continue = false,
+            .delete_mode = false,
         };
     }
 
-    pub fn deinit(self: *Simulator) void {
+    pub fn deinit(self: *Simulator) !void {
         self.road_man.deinit(self.allocator);
-        self.node_man.deinit(self.allocator);
+        try self.node_man.deinit(self.allocator);
     }
 
     pub fn draw(self: *const Simulator, pos: rl.Vector2) void {
         rl.clearBackground(c.BACKGROUND_COLOR);
 
-        self.road_man.draw();
+        self.road_man.draw(self.delete_mode);
         self.node_man.draw(pos);
     }
 
+    pub fn update(self: *Simulator, pos: rl.Vector2) void {
+        self.road_man.update_highlighted_road(pos);
+    }
+
     pub fn handleInput(self: *Simulator, pos: rl.Vector2) void {
         self.handleKeyboardInput();
         self.handleMouseInput(pos);
@@ -40,8 +46,11 @@ pub const Simulator = struct {
 
     fn handleKeyboardInput(self: *Simulator) void {
         self.auto_continue = rl.isKeyDown(.left_control);
+        self.delete_mode = rl.isKeyDown(.left_shift);
 
-        if (rl.isKeyReleased(.c)) self.clear();
+        if (rl.isKeyReleased(.c)) self.clear() catch |err| {
+            std.debug.panic("Failed to clear the entities: {}\n", .{err});
+        };
     }
 
     fn handleMouseInput(self: *Simulator, pos: rl.Vector2) void {
@@ -49,6 +58,16 @@ pub const Simulator = struct {
     }
 
     fn leftClickEvent(self: *Simulator, pos: rl.Vector2) void {
+        if (self.delete_mode) {
+            self.delete_road() catch |err| {
+                std.debug.panic("Failed to delete the road: {}\n", .{err});
+            };
+            return;
+        }
+        self.new_road(pos);
+    }
+
+    fn new_road(self: *Simulator, pos: rl.Vector2) void {
         const cur_node = self.node_man.getSelectedNode(self.allocator, pos) catch |err| {
             std.debug.panic("Failed to append the newly created node at pos ({d}, {d}) to node list: {}\n", .{
                 pos.x, pos.y, err
@@ -68,8 +87,27 @@ pub const Simulator = struct {
         self.node_man.temp_node = cur_node;
     }
 
-    fn clear(self: *Simulator) void {
+    fn delete_road(self: *Simulator) !void {
+        if (self.road_man.highlighted_road == null) return;
+        const h_road = self.road_man.highlighted_road.?;
+
+        const start_node = h_road.*.nodes[0];
+        const end_node = h_road.*.nodes[1];
+
+        self.road_man.deleteRoad(self.allocator, h_road) catch |err| {
+            std.debug.panic("Road deletion failed: {}\n", .{err});
+        };
+        self.road_man.highlighted_road = null;
+
+        if (start_node.roads.items.len == 0)
+            try self.node_man.deleteNode(self.allocator, start_node);
+
+        if (end_node.roads.items.len == 0)
+            try self.node_man.deleteNode(self.allocator, end_node);
+    }
+
+    fn clear(self: *Simulator) !void {
         self.road_man.clear(self.allocator);
-        self.node_man.clear(self.allocator);
+        try self.node_man.clear(self.allocator);
     }
 };

src/test.zig

@@ -1,3 +1,4 @@
+// Main test file that imports all files that have testing blocks in them
 test {
     _ = @import("infrastructure/road.zig");
     _ = @import("infrastructure/node_manager.zig");