sfml-opemgl.cpp

// Link statically with GLEW
//#define GLEW_STATIC

// Headers
#include <GL/glew.h>
#include <SFML/Window.hpp>

// Shader sources
const GLchar* vertexSource = R"glsl(
    #version 150 core
    in vec2 position;
    void main()
    {
        gl_Position = vec4(position, 0.0, 1.0);
    }
)glsl";
const GLchar* fragmentSource = R"glsl(
    #version 150 core
    out vec4 outColor;
    void main()
    {
        outColor = vec4(1.0, 1.0, 1.0, 1.0);
    }
)glsl";

int main()
{
	sf::ContextSettings settings;
	settings.depthBits = 24;
	settings.stencilBits = 8;

	sf::Window window(sf::VideoMode(800, 600, 32), "OpenGL", sf::Style::Titlebar | sf::Style::Close, settings);

	// Initialize GLEW
	glewExperimental = GL_TRUE;
	glewInit();

	// Create Vertex Array Object
	GLuint vao;
	glGenVertexArrays(1, &vao);
	glBindVertexArray(vao);

	// Create a Vertex Buffer Object and copy the vertex data to it
	GLuint vbo;
	glGenBuffers(1, &vbo);

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

	glBindBuffer(GL_ARRAY_BUFFER, vbo);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

	// Create and compile the vertex shader
	GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
	glShaderSource(vertexShader, 1, &vertexSource, NULL);
	glCompileShader(vertexShader);

	// Create and compile the fragment shader
	GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
	glShaderSource(fragmentShader, 1, &fragmentSource, NULL);
	glCompileShader(fragmentShader);

	// Link the vertex and fragment shader into a shader program
	GLuint shaderProgram = glCreateProgram();
	glAttachShader(shaderProgram, vertexShader);
	glAttachShader(shaderProgram, fragmentShader);
	glBindFragDataLocation(shaderProgram, 0, "outColor");
	glLinkProgram(shaderProgram);
	glUseProgram(shaderProgram);

	// Specify the layout of the vertex data
	GLint posAttrib = glGetAttribLocation(shaderProgram, "position");
	glEnableVertexAttribArray(posAttrib);
	glVertexAttribPointer(posAttrib, 2, GL_FLOAT, GL_FALSE, 0, 0);

	bool running = true;
	while (running)
	{
		sf::Event windowEvent;
		while (window.pollEvent(windowEvent))
		{
			switch (windowEvent.type)
			{
			case sf::Event::Closed:
				running = false;
				break;
			}
		}

		// Clear the screen to black
		glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT);

		// Draw a triangle from the 3 vertices
		glDrawArrays(GL_TRIANGLES, 0, 3);

		// Swap buffers
		window.display();
	}

	glDeleteProgram(shaderProgram);
	glDeleteShader(fragmentShader);
	glDeleteShader(vertexShader);

	glDeleteBuffers(1, &vbo);

	glDeleteVertexArrays(1, &vao);

	window.close();

	return 0;
}