/// Inlcudes

 #include <iostream>

 #include "MicroGlut.h"

 #include "GL_utilities.h"
 
 
 /// Defines
 #define ARRAY_COUNT(ARRAY) (sizeof(ARRAY)/sizeof(*(ARRAY)))

 
 /// Globals
 GLuint  vertexArray;

 GLfloat positions[][3] =

 {

     {-0.5f, -0.5f, 0.0f},
     {-0.5f, +0.5f, 0.0f},
     {+0.5f, -0.5f, 0.0f},

 };
 
 

 /// Debug message callback
 void APIENTRY debugMessageCallback(
     GLenum          /* source    */,
     GLenum          /* type      */,
     GLuint          /* id        */,
     GLenum          /* severity  */,
     GLsizei         /* length    */,
     GLchar  const *    message,
     void    const * /* userParam */
 )
 {
     std::cerr << message << std::endl;
 }
 
 

 /// Init

 void init(void)
 {

     // Debug message callback.
     // Requires OpenGL 4.3 or the GL_KHR_debug extension (which is not hardware
     // dependent and supported almost everywhere *except* MacOS).
     glEnable(GL_DEBUG_OUTPUT);
     glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS);
     glDebugMessageCallback(debugMessageCallback, nullptr);
 

     // GL inits.
     glClearColor(0.2, 0.2, 0.5, 0.0);
     glDisable(GL_DEPTH_TEST);
 
     // Load and compile shader.
     GLuint program = loadShaders("tsbk07.vert", "tsbk07.frag");
 
     // Allocate and activate Vertex Array Object (VAO), used for uploading
     // the geometry.
     glGenVertexArrays(1, &vertexArray);
     glBindVertexArray(vertexArray);
 
     // Allocate and activate Vertex Buffer Objects (VBO), for vertex data.
     GLint  positionLocation = glGetAttribLocation(program, "inPosition");
     GLuint positionBuffer;
     glGenBuffers(1, &positionBuffer);
     glBindBuffer(GL_ARRAY_BUFFER, positionBuffer);
     glBufferData(GL_ARRAY_BUFFER, sizeof(positions), positions, GL_STATIC_DRAW);
     glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
     glEnableVertexAttribArray(positionLocation);

 }
 
 

 /// Display

 void display(void)
 {

     // Clear the screen.
     glClear(GL_COLOR_BUFFER_BIT);

     // Select VAO.
     glBindVertexArray(vertexArray);

     // Draw.

     glDrawArrays(GL_TRIANGLES, 0, ARRAY_COUNT(positions));

     // Show on the screen.
     glutSwapBuffers();

 }
 

 
 /// Main
 int main(int argc, char * argv[])

 {

     glutInit(&argc, argv);
     glutInitContextVersion(3, 2);
     glutInitWindowSize(600, 600);
     glutCreateWindow("TSBK07");

     glutDisplayFunc(display);

     dumpInfo();
     init();
     glutMainLoop();

 }