Hello all,

I'm very new on OpenGL and at this beginning I've found it very complex. I would think C++ is the most complex language but it's better.

Anyway, the code below is for rendering my first triangle. Please take a look:

#include <glad/glad.h> 
#include <GLFW/glfw3.h>
#include <C:\Users\Abbasi\Desktop\std_lib_facilities_4.h>
using namespace std;


//*********************************

int main()
{
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

	GLFWwindow* window = glfwCreateWindow(800, 600, "The First Triangle", NULL, NULL);

	if (window == NULL)
	{
		cout << "Failed to create GLFW window" << endl;
		glfwTerminate();
		return -1;
	}

	glfwMakeContextCurrent(window);


	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) 
	{
		cout << "Failed to initialize GLAD" << endl;
		return -1;
	}

	glViewport(0, 0, 700, 500);

	float vertices[] = {
	   -0.5f, -0.5f, 0.5f,
		0.5f, -0.5f, 0.5f,
		0.0f,  0.5f, 0.0f
	};

  unsigned int VBO;  // Creating a vertex buffer object
  glGenBuffers(1, &VBO);
  glBindBuffer(GL_ARRAY_BUFFER, VBO);
  glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    // Creating the Vertex Shader
  const char* vertexShaderSource = "#version 330 core\nlayout (location = 0)"
		"in vec3 aPos;\n\nvoid main()\n{\ngl_Position ="
		"vec4(aPos.x, aPos.y, aPos.z, 1.0);\n}\n\0";
  
  unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
  glShaderSource(vertexShader, 1, &vertexShaderSource, nullptr);
  glCompileShader(vertexShader);

   //check the vertex shader compilation error(s)
  int success;
  char infoLog[512];
  glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
  if (!success)
  {
	  glGetShaderInfoLog(vertexShader, 512, nullptr, infoLog);
	  cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << endl;
  }

   // Creating the Fragment Shader
  const char* fragmentShaderSource = "#version 330 core\n"
	  "out vec4 FragColor;\n\nvoid main()\n{\n"
	  "FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n}\n\0";

  unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
  glShaderSource(fragmentShader, 1, &fragmentShaderSource, nullptr);
  glCompileShader(fragmentShader);

  //check the fragment shader compilation error(s)
  glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
  if (!success)
  {
	  glGetShaderInfoLog(fragmentShader, 512, nullptr, infoLog);
	  cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << endl;
  }

    // Linking both shaders into a shader program for rendering
  unsigned int shaderProgram = glCreateProgram();
  glAttachShader(shaderProgram, vertexShader);
  glAttachShader(shaderProgram, fragmentShader);
  glLinkProgram(shaderProgram);

  //check the shader program linking error(s)
  glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
  if (!success)
  {
	  glGetProgramInfoLog(shaderProgram, 512, nullptr, infoLog);
	  cout << "ERROR::PROGRAM::SHADER::LINKING_FAILED\n" << infoLog << endl;
  }

  glUseProgram(shaderProgram);

    // We no longer need the prior shaders after the linking
  glDeleteShader(vertexShader);
  glDeleteShader(fragmentShader);

  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
  glEnableVertexAttribArray(0);
  
  unsigned int VAO;
  glGenVertexArrays(1, &VAO);
  glBindVertexArray(VAO);
  glDrawArrays(GL_TRIANGLES, 0, 3);

  system("pause");
	return 0;
}

the output is the following image. My questions are:

1- why doesn't the code render the triangle which is meant in the code please?

2- Apart from that part, is the code standard? That is is the code the one a teacher would write for a student to be well written and good code?

You need to call glfwSwapBuffers(window) at the end of your function to present the rendered result to the screen.

Thanks, but what function did you mean please? There are many functions in the code.

On 11/7/2017 at 12:26 AM, test opty said:

No other answers!?

Try right before system("pause")

It only made the background window black instead of white!!