help.zig

const std = @import("std");
const print = std.debug.print;

pub const Vec3 = packed struct {
    x: u32,
    y: u32,
    z: u32,

    pub fn new(x: u32, y: u32, z: u32) Vec3 {
        return Vec3{
            .x = x,
            .y = y,
            .z = z,
        };
    }
};

pub const Vertex = struct {
    position: Vec3, color: [4]u16
};

pub const MeshData = struct {
    indices: []const u16, vertices: []const Vertex
};

pub fn render() MeshData {
    return MeshData{
        .vertices = &[_]Vertex{
            Vertex{ .position = Vec3.new(100, 100, 0), .color = [4]u16{ 1.0, 1.0, 1.0, 1.0 } },
            Vertex{ .position = Vec3.new(400, 100, 0), .color = [4]u16{ 1.0, 1.0, 1.0, 1.0 } },
            Vertex{ .position = Vec3.new(400, 100, 0), .color = [4]u16{ 1.0, 1.0, 1.0, 1.0 } },
            Vertex{ .position = Vec3.new(100, 100, 0), .color = [4]u16{ 1.0, 1.0, 1.0, 1.0 } },
        },
        .indices = &[_]u16{ 0, 1, 2, 2, 3, 0 },
    };
}


pub fn main() !void {
   var gpa = std.heap.GeneralPurposeAllocator(.{}){};
   const allocator = &gpa.allocator;

   var data_working = MeshData{
        .vertices = &[_]Vertex{
            Vertex{ .position = Vec3.new(100, 100, 0), .color = [4]u16{ 1.0, 1.0, 1.0, 1.0 } },
            Vertex{ .position = Vec3.new(400, 100, 0), .color = [4]u16{ 1.0, 1.0, 1.0, 1.0 } },
            Vertex{ .position = Vec3.new(400, 100, 0), .color = [4]u16{ 1.0, 1.0, 1.0, 1.0 } },
            Vertex{ .position = Vec3.new(100, 100, 0), .color = [4]u16{ 1.0, 1.0, 1.0, 1.0 } },
        },
        .indices = &[_]u16{ 0, 1, 2, 2, 3, 0 },
    };

    var data_broken = render();
    var save = std.ArrayList(Vertex).init(allocator);

    for (result.vertices) |vert| {
        print("vert {} \n", .{vert.position.x});
        try save.append(vert);
    }
    
    // When using data_working prints
    //     vert 100 
    //     vert 400 
    //     vert 400 
    //     vert 100 

    // When using data_broken prints
    //     vert 100 
    //     vert 400 
    //     vert 405411416 
    //     vert 32533 

    defer {
        save.deinit();
        _ = gpa.deinit();
    }
}