zig-civ / src / world.zig

const std = @import("std");
const hex = @import("hex.zig");
const tst = std.testing;

// Generate hexagon-shaped map with given radius (N rings around center)
// Uses axial coords: |q|<=N, |r|<=N, |q+r|<=N
pub fn generateHexWorld(comptime N: i32, outer_radius: f32, allocator: std.mem.Allocator) !std.ArrayListUnmanaged(hex.Cell) {
    var cells = std.ArrayListUnmanaged(hex.Cell){};

    var q: i32 = -N;
    while (q <= N) : (q += 1) {
        const r1 = @max(-N, -q - N);
        const r2 = @min(N, -q + N);
        var r: i32 = r1;
        while (r <= r2) : (r += 1) {
            try cells.append(allocator, hex.new_hex(outer_radius, hex.Axial.init(q, r)));
        }
    }

    return cells;
}

// Template-based generation using axial coords
// Template indexed by [r][q] where r,q range from -N to +N
// Template size is (2*N+1) x (2*N+1), center is at [N][N]
pub fn generateFromTemplate(comptime N: i32, template: *const [2 * N + 1][2 * N + 1]u1, outer_radius: f32, allocator: std.mem.Allocator) !std.ArrayListUnmanaged(hex.Cell) {
    var cells = std.ArrayListUnmanaged(hex.Cell){};

    var q: i32 = -N;
    while (q <= N) : (q += 1) {
        var r: i32 = -N;
        while (r <= N) : (r += 1) {
            const ti_r: usize = @intCast(r + N);
            const ti_q: usize = @intCast(q + N);
            if (template[ti_r][ti_q] == 1) {
                try cells.append(allocator, hex.new_hex(outer_radius, hex.Axial.init(q, r)));
            }
        }
    }

    return cells;
}

// Old template-based generation (offset coords)
pub fn generateWorld(comptime H: usize, comptime W: usize, template: *const [H][W]u1, outer_radius: f32) [H][W]?hex.Cell {
    var grid: [H][W]?hex.Cell = undefined;

    for (0..H) |row| {
        for (0..W) |col| {
            if (template[row][col] == 1) {
                const offset = hex.Offset{ .col = @intCast(col), .row = @intCast(row) };
                grid[row][col] = hex.new_hex(outer_radius, offset.toAxial());
            } else {
                grid[row][col] = null;
            }
        }
    }

    return grid;
}

test "generateWorld creates grid from template" {
    const template = [3][3]u1{
        .{ 1, 1, 0 },
        .{ 1, 0, 1 },
        .{ 0, 1, 1 },
    };
    const grid = generateWorld(3, 3, &template, 50.0);
    try tst.expect(grid[0][0] != null);
    try tst.expect(grid[0][2] == null);
    try tst.expect(grid[1][1] == null);
}