BloonsTD

• A remake of Ninja Kiwi's BTD5 + BTD6 games.
• Written in C++ with the SDL2 library for graphic rendering and SDL2_mixer for music + sound effects.

Preview

Web version

Play now using the power of WebAssembly! https://idomoz.github.io/BloonsTD/

Project layout

BloonsTD-master/
├── assets/                  # game assets (shared)
├── src/                     # game sources (shared)
├── ios/                     # Info.plist for the iOS .app bundle
├── third_party/             # vendored SDL2 sources for the iOS build (not committed; cloned at build time)
├── CMakeLists.txt           # dispatcher — picks the right config below
├── build-windows.cmake      # Windows / MinGW toolchain & deps
├── build-macos.cmake        # macOS / Homebrew toolchain & deps
├── build-ios.cmake          # iOS — links vendored SDL2 statically into the .app
├── build-emscripten.cmake   # Web — uses emsdk's bundled SDL2 ports (no clones)
└── scripts/

All four targets compile from the same src/. The top-level CMakeLists.txt detects the host platform / configured toolchain and include()s the matching build-*.cmake.

How to play (pre-built release)

• Go to the releases page and download the zip file for windows/mac.
• Exctract it and run the .bat file (windows) or .app file (mac).

Continuous integration

A GitHub Actions workflow at .github/workflows/build.yml builds all four targets on every push to master and on every PR:

Job	Runner	Output artifact
macos	macos-latest (Apple Silicon)	BloonsTD-macos-arm64.zip — BloonsTD.app bundled via dylibbundler, ad-hoc signed, zipped with ditto to preserve permissions and signatures
windows	windows-latest + MSYS2/MinGW64	BloonsTD-windows-x64.zip — exe + recursively-resolved MinGW DLLs + assets
ios	macos-latest	BloonsTD-ios-simulator.zip — unsigned .app for iOS Simulator (arm64). The job clones SDL2/SDL2_image/SDL2_ttf/SDL2_mixer fresh into third_party/ per run; nothing SDL-related is stored in the repo.
web	ubuntu-latest + emsdk	BloonsTD-web artifact (HTML/JS/WASM/data). Uses Emscripten's built-in SDL2 ports — no clones.
pages	ubuntu-latest	Deploys the web build to GitHub Pages so the game is playable in any modern browser, including iPad Safari, with no install / signing dance. Master pushes only.

Artifacts are uploaded to the workflow run page; download from the Actions tab on GitHub. The Pages URL is shown on the workflow run page after the pages job finishes (typically https://<owner>.github.io/<repo>/).

Automatic releases

On every push to master (not on PRs or forks), a third release job runs after both build jobs succeed. It downloads the two zips and publishes them as a GitHub Release tagged build-<run_number> (marked prerelease: true, make_latest: true). The release body includes:

• the source commit SHA,
• macOS launch instructions (double-click BloonsTD.app; first-run may need xattr -dr com.apple.quarantine BloonsTD.app since the bundle is ad-hoc signed, not notarized),
• Windows launch instructions (double-click BloonsTD.bat at the top of the unzipped tree, or run bin\BloonsTD.exe directly).

The workflow declares permissions: contents: write so the release job can publish via softprops/action-gh-release@v2. Releases are visible on the repo's Releases page.

How to compile with MinGW for Windows

This project depends on:

• SDL2-2.0.9
• SDL2_image-2.0.5
• SDL2_ttf-2.0.15
• SDL2_mixer-2.x (MP3 support)

Steps (CLion + CMake):

1. Download the SDL2 development libraries and copy the lib and include directories into the project root.
2. Do the same for the rest of the SDL2_x libraries.
3. Open the project in CLion and build with the built-in CMake configuration. The dispatcher picks up build-windows.cmake automatically when WIN32 is set.
4. Copy the SDL2_x DLLs next to BloonsTD.exe so it can run.

How to compile on macOS

Install dependencies via Homebrew (Apple Silicon /opt/homebrew and Intel /usr/local are both auto-detected):

brew install cmake sdl2 sdl2_image sdl2_ttf sdl2_mixer

SDL2_gfx and Boost are no longer required — circle primitives are inlined in RenderSystem.cpp and std::filesystem replaced boost::filesystem. Both were dropped to keep iOS portable.

Build & run:

cmake -S . -B build
cmake --build build -j8
cd build && ./BloonsTD

The game uses ../assets/... paths relative to the working directory at runtime, so launching from inside build/ resolves correctly to the project-root assets/ folder — no symlinks or copies needed.

Standalone .app bundle for macOS

The CI workflow (.github/workflows/build.yml) packages the macOS build as a proper BloonsTD.app so it can be double-clicked from Finder or dragged to Applications. To produce one locally:

brew install dylibbundler          # one-time
cmake --build build -j8

APP=dist/BloonsTD.app
mkdir -p "$APP/Contents/MacOS" "$APP/Contents/lib" "$APP/Contents/assets"
cp build/BloonsTD "$APP/Contents/MacOS/BloonsTD-bin"
cp -R assets/.    "$APP/Contents/assets/"
cat > "$APP/Contents/MacOS/BloonsTD" <<'EOF'
#!/bin/bash
cd "$(dirname "$0")"
exec ./BloonsTD-bin "$@"
EOF
chmod +x "$APP/Contents/MacOS/BloonsTD"
dylibbundler -od -b -x "$APP/Contents/MacOS/BloonsTD-bin" \
             -d "$APP/Contents/lib" -p '@executable_path/../lib/'
# (also write Contents/Info.plist — see workflow for the exact contents)
codesign --force --deep --sign - "$APP"

macOS Gatekeeper notes

The bundle is ad-hoc signed (no Apple Developer ID, no notarization). On a freshly-downloaded copy macOS will refuse to load the bundled dylibs with errors like:

dyld[…]: Library not loaded: @executable_path/../lib/libSDL2-2.0.0.dylib
  Reason: code signature in 'libSDL2-2.0.0.dylib' not valid for use in process:
          library load disallowed by system policy

Two ways to allow it:

1. Right-click → Open the .app in Finder. Approve the "unidentified developer" prompt once; the whole bundle is then trusted.
2. Strip the quarantine xattr from the command line (works on either the .app or the older directory layout):

   xattr -dr com.apple.quarantine BloonsTD.app
   # or, for the directory layout:
   xattr -dr com.apple.quarantine BloonsTD/

How to build for iOS / iPad

The iOS build vendors SDL2 + extensions as static libraries linked into a single .app bundle. App Store rules forbid loose dylibs the app didn't sign itself, and CMake's iOS support cleanly drives an Xcode project with these libraries and the game sources.

One-time setup — clone the SDL2 sources

mkdir -p third_party && cd third_party
git clone --depth 1 --branch release-2.30.10 https://github.com/libsdl-org/SDL.git
git clone --depth 1 --branch release-2.8.4    https://github.com/libsdl-org/SDL_image.git
git clone --depth 1 --branch release-2.22.0   https://github.com/libsdl-org/SDL_ttf.git
git clone --depth 1 --branch release-2.8.0    https://github.com/libsdl-org/SDL_mixer.git
cd ..

The four trees are gitignored locally; CI doesn't need them.

Configure & build for the iOS Simulator (Apple Silicon Mac → arm64-sim)

cmake -G Xcode -B build-ios \
    -DCMAKE_SYSTEM_NAME=iOS \
    -DCMAKE_OSX_SYSROOT=iphonesimulator \
    -DCMAKE_OSX_ARCHITECTURES=arm64 \
    -DCMAKE_OSX_DEPLOYMENT_TARGET=13.0
cmake --build build-ios --config Debug -- -sdk iphonesimulator

This produces build-ios/Debug-iphonesimulator/BloonsTD.app containing the binary, all static SDL2 libs linked in, and the entire assets/ tree under Resources/assets/.

Run in the Simulator

# pick a destination — list with `xcrun simctl list devices available`
DEVICE="iPad Pro (12.9-inch) (6th generation)"
xcrun simctl boot "$DEVICE" 2>/dev/null
open -a Simulator
xcrun simctl install booted build-ios/Debug-iphonesimulator/BloonsTD.app
xcrun simctl launch --console booted com.idmozes.BloonsTD

How to build for the Web (WebAssembly)

The Web target produces a single static site (HTML/JS/WASM/data) you can host anywhere. CI publishes it to GitHub Pages automatically; locally:

brew install emscripten                   # one-time, ~1GB

emcmake cmake -S . -B build-web -DCMAKE_BUILD_TYPE=Release
cmake --build build-web -j

# Serve over HTTP — opening the .html file directly via file:// fails because
# Emscripten fetches the .wasm/.data over XHR.
(cd build-web && python3 -m http.server 8000)
# then open http://localhost:8000/BloonsTD.html

No SDL2 clones needed — emsdk ships SDL2 + SDL2_image + SDL2_ttf + SDL2_mixer as ports, enabled via -sUSE_SDL=2 -sUSE_SDL_IMAGE=2 … in build-emscripten.cmake. The assets/ tree is packed into the .data file at virtual path /assets/ via --preload-file; Assets.h reads from there under __EMSCRIPTEN__.

The bundle is ~54 MB total (mostly PNG and MP3 assets), downloaded once and cached by the browser.

iOS-specific source notes

File	Why
src/Assets.h	Thin helper. On iOS assetPath() prepends SDL_GetBasePath() (the bundle's Resources/); on desktop it prepends ../assets/ (relative to build/). Lets the same source compile against both layouts.
src/systems/RenderSystem.cpp	Range circles drawn via inlined midpoint/scanline routines instead of SDL2_gfx so the iOS build doesn't need an extra library.
src/Game.cpp	boost::filesystem → std::filesystem (C++17). iOS toolchain's libc++ ships <filesystem>; Boost would be a heavyweight extra dependency.