Fix Linux build issues by integrating system-level dependencies

[killerdevildog]

• Add pkg-config detection for Bullet Physics (libbullet-dev)
• Add pkg-config detection for Lua 5.3 (liblua5.3-dev)
• Generate lua/lua.hpp compatibility header for deprecated API calls
• Add missing system libraries: GLEW, OpenAL, Vorbis to linking
• Resolve CMake resource management conflicts between samples
• Remove duplicate logo file references causing build failures

This fixes build issues on Linux where the system looks for local lua instead of system-level lua installation, and ensures proper integration with system-installed Bullet Physics and Lua libraries.

[killerdevildog]

@reven86 @rcmaniac25 @Benjamin-Dobell @timleader

When you have a moment, I'd appreciate your review on this PR.

I've implemented a feature that automatically builds dependencies from https://github.com/gameplay3d/gameplay-deps.git during the build process, with a fallback to system-installed dependencies if needed. This should streamline the setup and make the project more accessible for contributors.

I was inspired to tackle this as part of my interest in open-source contributions, aiming to improve the build experience on my own system—and hopefully others' as well. Looking forward to your feedback!

[killerdevildog]

GamePlay Engine - Dependency Management System

Overview

This CMake system provides flexible dependency management for the GamePlay engine with three modes:

1. SOURCE - Build dependencies from source (downloads gameplay-deps Git repository)
2. SYSTEM - Use system-installed libraries
3. AUTO - Automatic fallback: SOURCE → SYSTEM (default)

Usage

Quick Start (Default - AUTO mode)

mkdir build && cd build
cmake ..
cmake --build . --parallel 4

Specific Modes

# Build from source only
cmake -DDEPENDENCY_MODE=SOURCE ..

# Use system libraries only
cmake -DDEPENDENCY_MODE=SYSTEM ..

# Automatic mode (default)
cmake -DDEPENDENCY_MODE=AUTO ..

Dependency Management Modes

AUTO Mode (Recommended)

• Default behavior - no flags needed
• Automatically tries to build from source first
• Falls back to system libraries if source build fails
• Best for most users and CI systems

SOURCE Mode

• Forces building all dependencies from source
• Downloads gameplay-deps repository via Git
• Builds libjson, tinyxml2, lua, openal, glew, zlib, png, ogg, vorbis, bullet physics
• Uses C++11 standard and disables FluidSynth for compatibility
• Best for: Development, ensuring consistent dependency versions

SYSTEM Mode

• Uses system-installed libraries only
• Requires system packages: gtk+-2.0, bullet, lua5.3, etc.
• Best for: Linux distributions, package managers, minimal builds

Dependencies Built from Source

When using SOURCE or AUTO mode, the following libraries are built:

• libjson 7.6.1 - JSON parsing
• tinyxml2 2.1.0 - XML parsing
• lua 5.2.3 - Scripting engine
• OpenAL 1.16.0 - Audio (FluidSynth disabled for compatibility)
• GLEW 1.10.0 - OpenGL extensions
• zlib 1.2.8 - Compression
• libpng 1.6.15 - PNG image support
• ogg/vorbis 1.3.x - Audio codecs
• Bullet Physics 2.82 - Physics engine
• base64 1.0.0 - Base64 encoding

System Requirements

For SOURCE mode:

• CMake 3.11+
• Git
• C++ compiler with C++11 support
• OpenGL development libraries
• GTK+ 2.0 development libraries

For SYSTEM mode:

• Same as above plus system packages:
  • libgtk2.0-dev
  • libbullet-dev
  • liblua5.3-dev
  • libopenal-dev
  • libglew-dev
  • libpng-dev
  • libogg-dev
  • libvorbis-dev
  • zlib1g-dev

Build Output

Successful build produces:

• libgameplay.a - Main GamePlay engine library
• sample-browser - Interactive samples browser
• sample-character - Character animation demo
• sample-racer - Racing game demo
• sample-spaceship - Spaceship game demo

Troubleshooting

Source Build Issues

• Check internet connection (needs to download gameplay-deps)
• Ensure C++11 compatible compiler
• Check CMake version (3.11+ required)

System Library Issues

• Install missing development packages
• Check pkg-config can find libraries: pkg-config --list-all

FluidSynth Errors

• Automatically disabled in this build system
• If still encountering issues, ensure ALSOFT_MIDI_FLUIDSYNTH=OFF

Implementation Details

The system uses modular CMake files:

• cmake/BuildDependenciesFromSource.cmake - Source building logic
• Main CMakeLists.txt - Mode selection and orchestration

External dependencies are built in external-deps/ directory and libraries are output to external-deps/out/external-deps/lib/linux/x86_64/.