From 5b996b345952a582cd151d395774d896fff9a663 Mon Sep 17 00:00:00 2001
From: Clownacy <Clownacy@users.noreply.github.com>
Date: Fri, 3 Apr 2020 01:34:47 +0100
Subject: [PATCH] Give glad a CMake file

Today I learned that CMake will error if the project shares a
dependency with a nested CMake file (which could be from an
entirely-separate project that you have no control over).

I'm starting to really hate CMake.
---
 CMakeLists.txt                     |  3 ++-
 DoConfig/CMakeLists.txt            | 13 ++++++++++---
 external/glad/CMakeLists.txt       | 11 +++++++++++
 external/glad/include/glad/glad.h  |  2 +-
 external/glad/src/glad.c           |  2 +-
 src/Backends/Rendering/OpenGL3.cpp |  2 +-
 6 files changed, 26 insertions(+), 7 deletions(-)
 create mode 100644 external/glad/CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 609f8636..6e79bed7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -526,7 +526,8 @@ else()
 endif()
 
 if(BACKEND_RENDERER MATCHES "OpenGL3")
-	target_sources(CSE2 PRIVATE "external/glad/src/glad.c" "external/glad/include/glad/glad.h" "external/glad/include/KHR/khrplatform.h")
+	add_subdirectory("external/glad" EXCLUDE_FROM_ALL)
+	target_link_libraries(CSE2 PRIVATE glad)
 
 	find_package(OpenGL REQUIRED)
 	target_link_libraries(CSE2 PRIVATE OpenGL::GL ${CMAKE_DL_LIBS})
diff --git a/DoConfig/CMakeLists.txt b/DoConfig/CMakeLists.txt
index 6df9ec78..3edd211f 100644
--- a/DoConfig/CMakeLists.txt
+++ b/DoConfig/CMakeLists.txt
@@ -9,9 +9,6 @@ project(DoConfig LANGUAGES C CXX)
 
 add_executable(DoConfig WIN32
 	"icon.rc"
-	"../external/glad/include/glad/glad.h"
-	"../external/glad/include/KHR/khrplatform.h"
-	"../external/glad/src/glad.c"
 	"DoConfig.cpp"
 	"imgui/imconfig.h"
 	"imgui/imgui.cpp"
@@ -71,6 +68,16 @@ endif()
 # Dependencies #
 ################
 
+# glad
+
+if(NOT TARGET glad)
+	add_subdirectory("../external/glad" "glad" EXCLUDE_FROM_ALL)
+endif()
+
+target_link_libraries(DoConfig PRIVATE glad)
+
+# GLFW3
+
 if(NOT FORCE_LOCAL_LIBS)
 	find_package(PkgConfig QUIET)
 endif()
diff --git a/external/glad/CMakeLists.txt b/external/glad/CMakeLists.txt
new file mode 100644
index 00000000..2b6298c1
--- /dev/null
+++ b/external/glad/CMakeLists.txt
@@ -0,0 +1,11 @@
+cmake_minimum_required(VERSION 3.12)
+
+project(glad LANGUAGES C)
+
+add_library(glad
+	"include/glad/glad.h"
+	"include/KHR/khrplatform.h"
+	"src/glad.c"
+)
+
+target_include_directories(glad PUBLIC "include")
diff --git a/external/glad/include/glad/glad.h b/external/glad/include/glad/glad.h
index 1b59b588..39d8722e 100644
--- a/external/glad/include/glad/glad.h
+++ b/external/glad/include/glad/glad.h
@@ -86,7 +86,7 @@ GLAPI int gladLoadGL(void);
 
 GLAPI int gladLoadGLLoader(GLADloadproc);
 
-#include "../KHR/khrplatform.h"
+#include <KHR/khrplatform.h>
 typedef unsigned int GLenum;
 typedef unsigned char GLboolean;
 typedef unsigned int GLbitfield;
diff --git a/external/glad/src/glad.c b/external/glad/src/glad.c
index dfeaf6fc..6e1f11d9 100644
--- a/external/glad/src/glad.c
+++ b/external/glad/src/glad.c
@@ -22,7 +22,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include "../include/glad/glad.h"
+#include <glad/glad.h>
 
 static void* get_proc(const char *namez);
 
diff --git a/src/Backends/Rendering/OpenGL3.cpp b/src/Backends/Rendering/OpenGL3.cpp
index 65b1cd87..abd19e1f 100644
--- a/src/Backends/Rendering/OpenGL3.cpp
+++ b/src/Backends/Rendering/OpenGL3.cpp
@@ -10,7 +10,7 @@
 #ifdef USE_OPENGLES2
 #include <GLES2/gl2.h>
 #else
-#include "../../../external/glad/include/glad/glad.h"
+#include <glad/glad.h>
 #endif
 
 #define SPRITEBATCH_IMPLEMENTATION