GameDev | Christopher Peret

import torch import torch.nn as nn def train(model, loader, epochs=10): opt = torch.optim.AdamW( model.parameters(), lr=3e-4) loss_fn = nn.CrossEntropyLoss() model.train() for epoch in range(epochs): for x, y in loader: x, y = x.cuda(), y.cuda() opt.zero_grad() loss = loss_fn(model(x), y) loss.backward() opt.step() print(f"epoch {epoch} done") class ConvNet(nn.Module): def __init__(self, n_classes=10): super().__init__() self.net = nn.Sequential( nn.Conv2d(3, 32, 3, 1, 1), nn.ReLU(), nn.Conv2d(32, 64, 3, 1, 1), nn.ReLU(), nn.MaxPool2d(2), nn.Dropout(0.25), nn.Flatten(), nn.Linear(64 * 16 * 16, 128), nn.ReLU(), nn.Linear(128, n_classes), ) def forward(self, x): return self.net(x) from torchvision import transforms tfm = transforms.Compose([ transforms.RandomResizedCrop(64), transforms.RandomHorizontalFlip(), transforms.ToTensor(), transforms.Normalize(mean, std), ]) train_ds = ImageFolder("train", tfm) loader = DataLoader( train_ds, batch_size=64, shuffle=True, num_workers=4, ) @torch.no_grad() def evaluate(model, loader): model.eval() correct = total = 0 for x, y in loader: x, y = x.cuda(), y.cuda() pred = model(x).argmax(dim=1) correct += (pred == y).sum() total += y.size(0) acc = correct / total print(f"val acc: {acc:.3%}") return acc model.eval() x = torch.randn(1, 3, 64, 64).cuda() traced = torch.jit.trace(model, x) traced.save("model.pt") # ONNX export for deployment torch.onnx.export( model, x, "model.onnx", input_names=["input"], output_names=["logits"], opset_version=17, ) print("exported model.pt")

import torch import torch.nn as nn def attention(q, k, v, mask=None): d_k = q.size(-1) scores = q @ k.transpose(-2, -1) scores = scores / d_k ** 0.5 if mask is not None: scores = scores.masked_fill( mask == 0, -1e9) w = torch.softmax(scores, dim=-1) return w @ v, w class MultiHeadAttention(nn.Module): def __init__(self, dim, heads=8): super().__init__() self.heads = heads self.qkv = nn.Linear(dim, 3 * dim) self.proj = nn.Linear(dim, dim) def forward(self, x): B, N, D = x.shape h = self.heads qkv = self.qkv(x).reshape( B, N, 3, h, D // h) q, k, v = qkv.unbind(2) out, _ = attention(q, k, v) out = out.reshape(B, N, D) return self.proj(out)

#include <Eigen/Dense> #include <array> #include <cmath> using Vec7 = std::array<double, 7>; using Eigen::Matrix4d; // KUKA iiwa DH parameters constexpr double A[7] = { -M_PI_2, M_PI_2, M_PI_2, -M_PI_2, -M_PI_2, M_PI_2, 0}; constexpr double D[7] = { 0.34, 0.0, 0.40, 0.0, 0.40, 0.0, 0.126}; // One DH link transform Matrix4d link(double a, double d, double q) { double ct = cos(q), st = sin(q); double ca = cos(a), sa = sin(a); Matrix4d T; T << ct, -st*ca, st*sa, 0, st, ct*ca, -ct*sa, 0, 0, sa, ca, d, 0, 0, 0, 1; return T; } // 7-DOF forward kinematics Matrix4d fk(const Vec7& q) { Matrix4d T = Matrix4d::Identity(); for (int i = 0; i < 7; ++i) T *= link(A[i], D[i], q[i]); return T; } using Eigen::Vector3d; using Mat67 = Eigen::Matrix<double, 6, 7>; // Geometric Jacobian at q Mat67 jacobian(const Vec7& q) { Mat67 J; Matrix4d T = Matrix4d::Identity(); Vector3d pe = fk(q).block<3,1>(0,3); for (int i = 0; i < 7; ++i) { Vector3d z = T.block<3,1>(0,2); Vector3d p = T.block<3,1>(0,3); J.block<3,1>(0,i)=z.cross(pe-p); J.block<3,1>(3,i)=z; T *= link(A[i], D[i], q[i]); } return J; } using Eigen::Matrix3d; // Damped least-squares IK step Vec7 ik_step(const Vec7& q, const Vector3d& goal) { auto J = jacobian(q).topRows<3>(); Vector3d e = goal - fk(q).block<3,1>(0,3); double k = 0.05; auto Jt = J.transpose(); Vector3d dx = (J*Jt + k*k*Matrix3d::Identity()) .ldlt().solve(e); Vec7 dq; for (int i = 0; i < 7; ++i) dq[i] = (Jt*dx)(i); return dq; }

use std::collections::BinaryHeap; use std::collections::HashMap; use std::cmp::Ordering; #[derive(Copy, Clone, Eq, PartialEq)] struct Node { cost: u32, pos: (i32, i32), } // min-heap: reverse the ordering impl Ord for Node { fn cmp(&self, other: &Self) -> Ordering { other.cost.cmp(&self.cost) } } impl PartialOrd for Node { fn partial_cmp(&self, other: &Self) -> Option<Ordering> { Some(self.cmp(other)) } } fn heur(a: (i32, i32), b: (i32, i32)) -> u32 { let dx = (a.0 - b.0).abs(); let dy = (a.1 - b.1).abs(); (dx + dy) as u32 } // A* shortest path over a grid fn astar( start: (i32, i32), goal: (i32, i32), adj: impl Fn((i32, i32)) -> Vec<(i32, i32)>, ) -> Option<u32> { let mut open = BinaryHeap::new(); let mut best = HashMap::new(); open.push(Node { cost: 0, pos: start }); best.insert(start, 0u32); while let Some(cur) = open.pop() { if cur.pos == goal { return Some(cur.cost); } for nb in adj(cur.pos) { let g = best[&cur.pos] + 1; let seen = best.get(&nb) .copied() .unwrap_or(u32::MAX); if g < seen { best.insert(nb, g); let f = g + heur(nb, goal); open.push(Node { cost: f, pos: nb, }); } } } None }

gamedev

Real-time multiplayer, from the wire up

I build multiplayer games and the engine underneath them: authoritative servers, binary protocols, and physics that cannot desync. The browser is the distribution platform. No installs, no launchers.

the studio

Top Quark Studios

Games with charge. Wizard's War and everything after it ships under the TQ banner.

visit studio ↗

2026 · in development · OpenAI Buildweek

C++WebSocketBinary Protocol

Wizard's War

A web-based game holding 100 simultaneous players in one shared world. A C++ authoritative server owns everything that matters: movement, projectiles, collision, combat, transformations, interactions, and a shared boss encounter. The wire protocol is binary over WebSocket, on revision 22, with live bandwidth, queue, backpressure, and ingress metrics on a /stats endpoint.

One hundred players is the constraint every design decision answers to.

read the build notes →

The engine underneath

The core bet: one C simulation core, compiled twice from the same source. Native for the authoritative server, WASM for in-browser client prediction. The physics is cross-platform deterministic, so the two builds are bit-identical and prediction cannot drift from the server. Verified, not assumed: 600 simulation steps across 251 bodies on two seeds, every step hashed on both builds, every hash equal.

30 Hz
server tick · snapshots every 2nd tick: 8 B
full input command on the wire: 500
bot connections in the load swarm: 166 KB
gzipped WASM simulation module: 1.6×
WASM cost vs native, same source: 100%
step hashes matched, native vs WASM

Inputs drive the clock: the server consumes exactly one queued input command per tick and acknowledges its sequence number, so client prediction and server simulation advance 1:1 and network jitter is absorbed by the input queue instead of desyncing the world. Load testing uses headless bot swarms that import the real client packages. No mocks.

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