Basic drawing

src/constants.zig

@@ -1,12 +1,25 @@
 const clr = @import("raylib").Color;
 
+/// Screen Width
 pub const WIDTH = 2560;
+/// Screen Height
 pub const HEIGHT = 1440;
 
+/// Base node radius
 pub const NODE_RADIUS = 20;
+
+/// The radius around node center where no new node gets created but rather it snaps onto existing one
+pub const NODE_SNAP_RADIUS = 3 * NODE_RADIUS;
+/// Regular (finished) node colour
 pub const NODE_COLOUR = clr.brown;
+/// Temporary node colour - currently being pulled from
 pub const NODE_TEMP_COLOUR = clr.orange;
+/// The colour of the node being at the cursor
 pub const NODE_CURSOR_COLOUR = clr.blue;
 
+/// Road (line) size
 pub const ROAD_SIZE = 20;
+/// Regular road colour
 pub const ROAD_COLOUR = clr.black;
+/// Colour of the road that is highlighted
+pub const ROAD_HIGHLIGHTED_COLOUR = clr.green;

src/infrastructure/node.zig

@@ -1,21 +1,43 @@
+const std = @import("std");
 const rl = @import("raylib");
 
 const c = @import("../constants.zig");
+const Road = @import("road.zig").Road;
 
 pub const Node = struct {
     id: usize,
     pos: rl.Vector2,
+    roads: std.ArrayList(*Road),
 
     pub fn init(new_id: usize, new_pos: rl.Vector2) Node {
         return .{
             .id = new_id,
             .pos = new_pos,
+            .roads = .empty,
         };
     }
 
+    pub fn deinit(self: *Node, allocator: std.mem.Allocator) void {
+        self.roads.deinit(allocator);
+    }
+
     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);
     }
+
+    pub fn posWithinRadius(self: *const Node, pos: rl.Vector2) bool {
+        return rl.checkCollisionPointCircle(pos, self.pos, c.NODE_SNAP_RADIUS);
+    }
+
+
+    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| {
+            if (road.*.id == road_to_add.*.id) return error.RoadAlreadyReferenced;
+        }
+
+        try self.roads.append(allocator, road_to_add);
+    }
 };

src/infrastructure/node_manager.zig

@@ -6,28 +6,33 @@ const Node = @import("node.zig").Node;
 const Road = @import("road.zig").Road;
 
 pub const NodeManager = struct {
+    next_id: usize,
     nodes: std.ArrayList(Node),
     temp_node: ?*Node,
 
     pub fn init() NodeManager {
         return .{
+            .next_id = 0,
             .nodes = .empty,
             .temp_node = null,
         };
     }
 
     pub fn deinit(self: *NodeManager, allocator: std.mem.Allocator) void {
+        for (self.nodes.items) |*node| {
+            node.deinit(allocator);
+        }
         self.nodes.deinit(allocator);
     }
 
     pub fn draw(self: *const NodeManager, pos: Vector2) void {
         for (self.nodes.items) |node| {
-            node.draw();
+            node.draw(null);
         }
 
         if (self.temp_node) |node| {
             // Temporary node that points at the cursor
-            const cur_node = Node.init(0, pos);
+            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();
@@ -36,4 +41,32 @@ pub const NodeManager = struct {
             cur_node.draw(c.NODE_CURSOR_COLOUR);
         }
     }
+
+    pub fn getSelectedNode(self: *NodeManager, allocator: std.mem.Allocator, pos: Vector2) !*Node {
+        for (self.nodes.items) |*node| {
+            if (node.posWithinRadius(pos)) return node;
+        }
+
+        // No node is within that position, so we must create a new one
+        const node: Node = .init(self.getNextID(), pos);
+        try self.nodes.append(allocator, node);
+
+        return &self.nodes.items[self.nodes.items.len - 1];
+    }
+
+    fn getNextID(self: *NodeManager) usize {
+        const id = self.next_id;
+        self.next_id += 1;
+
+        return id;
+    }
+
+    pub fn clear(self: *NodeManager, allocator: std.mem.Allocator) void {
+        self.temp_node = null;
+        for (self.nodes.items) |*node| {
+            node.deinit(allocator);
+        }
+        self.nodes.clearRetainingCapacity();
+        self.next_id = 0;
+    }
 };

src/infrastructure/road_manager.zig

@@ -1,11 +1,14 @@
 const std = @import("std");
 const Road = @import("road.zig").Road;
+const Node = @import("node.zig").Node;
 
 pub const RoadManager = struct {
+    next_id: usize,
     roads: std.ArrayList(Road),
 
     pub fn init() RoadManager {
         return .{
+            .next_id = 0,
             .roads = .empty,
         };
     }
@@ -19,4 +22,25 @@ pub const RoadManager = struct {
             road.draw();
         }
     }
+
+    pub fn addRoad(self: *RoadManager, allocator: std.mem.Allocator, start: *Node, end: *Node) !void {
+        const road: Road = .init(self.getNextID(), start, end);
+        try self.roads.append(allocator, road);
+
+        const ref = &self.roads.items[self.roads.items.len - 1];
+        try ref.*.nodes[0].referenceRoad(allocator, ref);
+        try ref.*.nodes[1].referenceRoad(allocator, ref);
+    }
+
+    fn getNextID(self: *RoadManager) usize {
+        const id = self.next_id;
+        self.next_id += 1;
+
+        return id;
+    }
+
+    pub fn clear(self: *RoadManager) void {
+        self.roads.clearRetainingCapacity();
+        self.next_id = 0;
+    }
 };

src/main.zig

@@ -10,6 +10,7 @@ pub fn main(init: std.process.Init) !void {
     defer rl.closeWindow();
 
     var sim: Simulator = .init(allocator);
+    defer sim.deinit();
 
     while (!rl.windowShouldClose()) {
         rl.beginDrawing();

src/simulator.zig

@@ -30,14 +30,39 @@ pub const Simulator = struct {
     }
 
     pub fn handleInput(self: *Simulator, pos: rl.Vector2) void {
+        self.handleKeyboardInput();
         self.handleMouseInput(pos);
     }
 
+    fn handleKeyboardInput(self: *Simulator) void {
+        if (rl.isKeyReleased(.c)) self.clear();
+    }
+
     fn handleMouseInput(self: *Simulator, pos: rl.Vector2) void {
         if (rl.isMouseButtonReleased(.left)) self.leftClickEvent(pos);
     }
 
     fn leftClickEvent(self: *Simulator, pos: rl.Vector2) void {
-        // TODO
+        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
+            });
+        };
+
+        if (self.node_man.temp_node) |temp| {
+            self.road_man.addRoad(self.allocator, temp, cur_node) catch |err| {
+                std.debug.panic("Failed to add a new road or assigning its nodes: {}\n", .{err});
+            };
+
+            self.node_man.temp_node = null;
+            return;
+        }
+
+        self.node_man.temp_node = cur_node;
+    }
+
+    fn clear(self: *Simulator) void {
+        self.road_man.clear();
+        self.node_man.clear(self.allocator);
     }
 };