From 1ee93ff0f0ea481874cfadfd857ff5de0ec38f98 Mon Sep 17 00:00:00 2001
From: mmcwilliams <hi@mmcwilliams.com>
Date: Sat, 30 Mar 2024 22:01:02 -0400
Subject: [PATCH] Got it compiling on macOS

---
 CMakeLists.txt | 13 ++++++++++---
 main.cpp       | 12 +++++++++---
 triangle.cpp   | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 71 insertions(+), 6 deletions(-)
 create mode 100644 triangle.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a8f8c41..f72781c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,6 +5,9 @@ project(OpengGL_Example)
 set(CMAKE_CXX_STANDARD 17)     
 set(CMAKE_VERBOSE_MAKEFILE ON)
 
+find_package(OpenGL REQUIRED)
+find_package(GLUT REQUIRED)
+
 set( NAME_SRC
     main.cpp    
 )
@@ -12,6 +15,10 @@ set( NAME_SRC
 set(EXECUTABLE_OUTPUT_PATH ${CMAKE_BINARY_DIR}/bin)
 add_executable( opengl_example ${NAME_SRC} ${NAME_HEADERS} )
 
-# Set executable dependency libraries
-# Equivalent to pass flags -lGL, -lGLU and -lglut 
-target_link_libraries(opengl_example GL GLU glut)
\ No newline at end of file
+if (APPLE)
+    # Equivalent to pass flags -framework OpenGL 
+    target_link_libraries(opengl_example OpenGL::GL GLUT::GLUT)
+else()
+    # Equivalent to pass flags -lGL, -lGLU and -lglut 
+    target_link_libraries(opengl_example GL GLU glut )
+endif()
\ No newline at end of file
diff --git a/main.cpp b/main.cpp
index d32fe61..563d54a 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,7 +1,13 @@
 // http://www.codebind.com/linux-tutorials/install-opengl-ubuntu-linux/
-#include <GL/glew.h>
-#include <GL/glut.h>
- 
+#ifdef __APPLE__
+    #include <OpenGL/gl.h>
+    #include <OpenGL/gl3.h>
+    #include <GLUT/glut.h>
+#else
+    #include <GL/glew.h>
+    #include <GL/glut.h>
+#endif
+
 void displayMe(void)
 {
     glClear(GL_COLOR_BUFFER_BIT);
diff --git a/triangle.cpp b/triangle.cpp
new file mode 100644
index 0000000..57d097f
--- /dev/null
+++ b/triangle.cpp
@@ -0,0 +1,52 @@
+// A simple introductory program; its main window contains a static picture
+// of a triangle, whose three vertices are red, green and blue.  The program
+// illustrates viewing with default viewing parameters only.
+
+#ifdef __APPLE_CC__
+#include <GLUT/glut.h>
+#else
+#include <GL/glut.h>
+#endif
+
+// Clears the current window and draws a triangle.
+void display() {
+
+  // Set every pixel in the frame buffer to the current clear color.
+  glClear(GL_COLOR_BUFFER_BIT);
+
+  // Drawing is done by specifying a sequence of vertices.  The way these
+  // vertices are connected (or not connected) depends on the argument to
+  // glBegin.  GL_POLYGON constructs a filled polygon.
+  glBegin(GL_POLYGON);
+    glColor3f(1, 0, 0); glVertex3f(-0.6, -0.75, 0.5);
+    glColor3f(0, 1, 0); glVertex3f(0.6, -0.75, 0);
+    glColor3f(0, 0, 1); glVertex3f(0, 0.75, 0);
+  glEnd();
+
+  // Flush drawing command buffer to make drawing happen as soon as possible.
+  glFlush();
+}
+
+// Initializes GLUT, the display mode, and main window; registers callbacks;
+// enters the main event loop.
+int main(int argc, char** argv) {
+
+  // Use a single buffered window in RGB mode (as opposed to a double-buffered
+  // window or color-index mode).
+  glutInit(&argc, argv);
+  glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
+
+  // Position window at (80,80)-(480,380) and give it a title.
+  glutInitWindowPosition(80, 80);
+  glutInitWindowSize(400, 300);
+  glutCreateWindow("A Simple Triangle");
+
+  // Tell GLUT that whenever the main window needs to be repainted that it
+  // should call the function display().
+  glutDisplayFunc(display);
+
+  // Tell GLUT to start reading and processing events.  This function
+  // never returns; the program only exits when the user closes the main
+  // window or kills the process.
+  glutMainLoop();
+}
\ No newline at end of file