# How the Makefile Works
This document attempts to explain how the project's build-system works, as well as general concepts in Makefile. It was created with the intention to help newcomers to C/C++ and Make understand how everything in the project is done, so that they can even dive in and make changes of their own if necessary.

### Contents
- [Macro Definitions](#macro-definitions)
  - [Custom Functions](#custom-functions)
  - [Global Macros](#global-macros)
  - [Platform-Specific Macros](#platform-specific-macros)
- [Targets](#targets)
  - [setup](#setup)
  - [all](#all)
  - [.PHONY](#phony)

## Macro Definitions
#### This section is still being written

### Custom Functions

Some text

```Makefile
rwildcard = $(wildcard $1$2) $(foreach d,$(wildcard $1*),$(call rwildcard,$d/,$2))
platformpth = $(subst /,$(PATHSEP),$1)
```

### Global Macros

Some text

```Makefile
buildDir := bin
executable := app
target := $(buildDir)/$(executable)
sources := $(call rwildcard,src/,*.cpp)
objects := $(patsubst src/%, $(buildDir)/%, $(patsubst %.cpp, %.o, $(sources)))
depends := $(patsubst %.o, %.d, $(objects))
compileFlags := -std=c++17 -I include
linkFlags = -L lib/$(platform) -l raylib
```

### Platform-Specific Macros

Some text

```Makefile
ifeq ($(OS), Windows_NT)
	# Set Windows macros
	platform := Windows
	CXX ?= g++
	linkFlags += -Wl,--allow-multiple-definition -pthread -lopengl32 -lgdi32 -lwinmm -mwindows
	libGenDir := src
	THEN := &&
	PATHSEP := \$(BLANK)
	MKDIR := -mkdir
	RM := -del /q
	COPY = -robocopy "$(call platformpth,$1)" "$(call platformpth,$2)" $3
else
	# Check for MacOS/Linux
	UNAMEOS := $(shell uname)
	ifeq ($(UNAMEOS), Linux)
		# Set Linux macros
		platform := Linux
		CXX ?= g++
		linkFlags += -l GL -l m -l pthread -l dl -l rt -l X11
	endif
	ifeq ($(UNAMEOS), Darwin)
		# Set macOS macros
		platform := macOS
		CXX ?= clang++
		linkFlags += -framework CoreVideo -framework IOKit -framework Cocoa -framework GLUT -framework OpenGL
		libGenDir := src
	endif

	# Set UNIX macros
	THEN := ;
	PATHSEP := /
	MKDIR := mkdir -p
	RM := rm -rf
	COPY = cp $1$(PATHSEP)$3 $2
endif
```

## Targets
This section describes most of the Makefile's functionality target-by-target, where we explain how they each execute step-by-step.

### setup
The first target we get you to call before building the project is `setup`, which essentially pulls in all raylib and raylib-cpp dependencies, and then formats the project file structure.

As you can see below, the target simply depends on two sub-targets, `include` and `lib`:
```Makefile
setup: include lib
```

However, looking at `include`, we can see that it depends on `submodules`, so we'll look at that first.
```Makefile
include: submodules
	...
```

`submodules` is a very simple target that will update the git submodules in the project recursively, pulling in the current raylib-cpp repository under the `/vendor` directory and then raylib itself under its own `/vendor` directory. The reason for this, is to make sure that the pulled versions of raylib and the bindings match in version. You can [read more about git submodules here](https://git-scm.com/book/en/v2/Git-Tools-Submodules).
```Makefile
submodules:
	git submodule update --init --recursive
```

Having satisfied `submodules` and now returning to `include`, we can being to run its body (as can be seen below).

It begins by creating the `/include` directory (converting the directory path for Windows if necessary with the custom `platformpth` function) if it doesn't already exist. 

Next, the target proceeds to call another custom function, `COPY` (a platform agnostic copy command), manually copying `raylib.h` and `raymath.h` from raylib's source code, and all files ending with `.hpp` from raylib-cpp's source code, into the newly created `/include` directory.
```Makefile
include: submodules
	$(MKDIR) $(call platformpth, ./include)
	$(call COPY,vendor/raylib-cpp/vendor/raylib/src,./include,raylib.h)
	$(call COPY,vendor/raylib-cpp/vendor/raylib/src,./include,raymath.h)
	$(call COPY,vendor/raylib-cpp/include,./include,*.hpp)
```

Finally, we move on to `lib`, which also depends on `submodules`, however because submodules has already run, it will not run again.

Next, we create the `/lib` directory (and a subdirectory for your current platform) if it doesn't already exist using the same method as above.

Moving on to the body of the target, we move into raylib's `/src` directory and immediately run Make on raylib. Once complete, this results in the creation of a static library file named `libraylib.a` (*which will appear in slightly different directories based on the platform you build it in for whatever reason...*).

To complete the target, it then copies that library file into the relevant directory for your platform under `/lib`.
```Makefile
lib: submodules
	cd vendor/raylib-cpp/vendor/raylib/src $(THEN) "$(MAKE)" PLATFORM=PLATFORM_DESKTOP
	$(MKDIR) $(call platformpth, lib/$(platform))
	$(call COPY,vendor/raylib-cpp/vendor/raylib/$(libGenDir),lib/$(platform),libraylib.a)
```

Once all of these targets have been fulfilled, `setup` ends and your project should now contain a copy of the relevant static library for your platform in `/lib`, and all the necessary header files under `/include`.

### all
#### This section is still being written

### .PHONY
#### This section is still being written

```Makefile
.PHONY: all setup submodules execute clean
```