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+# Getting started {#quick_guide}
+
+[TOC]
+
+This guide takes you through writing a small application using GLFW 3.  The
+application will create a window and OpenGL context, render a rotating triangle
+and exit when the user closes the window or presses _Escape_.  This guide will
+introduce a few of the most commonly used functions, but there are many more.
+
+This guide assumes no experience with earlier versions of GLFW.  If you
+have used GLFW 2 in the past, read @ref moving_guide, as some functions
+behave differently in GLFW 3.
+
+
+## Step by step {#quick_steps}
+
+### Including the GLFW header {#quick_include}
+
+In the source files of your application where you use GLFW, you need to include
+its header file.
+
+```c
+#include <GLFW/glfw3.h>
+```
+
+This header provides all the constants, types and function prototypes of the
+GLFW API.
+
+By default it also includes the OpenGL header from your development environment.
+On some platforms this header only supports older versions of OpenGL.  The most
+extreme case is Windows, where it typically only supports OpenGL 1.2.
+
+Most programs will instead use an
+[extension loader library](@ref context_glext_auto) and include its header.
+This example uses files generated by [glad](https://gen.glad.sh/).  The GLFW
+header can detect most such headers if they are included first and will then not
+include the one from your development environment.
+
+```c
+#include <glad/gl.h>
+#include <GLFW/glfw3.h>
+```
+
+To make sure there will be no header conflicts, you can define @ref
+GLFW_INCLUDE_NONE before the GLFW header to explicitly disable inclusion of the
+development environment header.  This also allows the two headers to be included
+in any order.
+
+```c
+#define GLFW_INCLUDE_NONE
+#include <GLFW/glfw3.h>
+#include <glad/gl.h>
+```
+
+
+### Initializing and terminating GLFW {#quick_init_term}
+
+Before you can use most GLFW functions, the library must be initialized.  On
+successful initialization, `GLFW_TRUE` is returned.  If an error occurred,
+`GLFW_FALSE` is returned.
+
+```c
+if (!glfwInit())
+{
+    // Initialization failed
+}
+```
+
+Note that `GLFW_TRUE` and `GLFW_FALSE` are and will always be one and zero.
+
+When you are done using GLFW, typically just before the application exits, you
+need to terminate GLFW.
+
+```c
+glfwTerminate();
+```
+
+This destroys any remaining windows and releases any other resources allocated by
+GLFW.  After this call, you must initialize GLFW again before using any GLFW
+functions that require it.
+
+
+### Setting an error callback {#quick_capture_error}
+
+Most events are reported through callbacks, whether it's a key being pressed,
+a GLFW window being moved, or an error occurring.  Callbacks are C functions (or
+C++ static methods) that are called by GLFW with arguments describing the event.
+
+In case a GLFW function fails, an error is reported to the GLFW error callback.
+You can receive these reports with an error callback.  This function must have
+the signature below but may do anything permitted in other callbacks.
+
+```c
+void error_callback(int error, const char* description)
+{
+    fprintf(stderr, "Error: %s\n", description);
+}
+```
+
+Callback functions must be set, so GLFW knows to call them.  The function to set
+the error callback is one of the few GLFW functions that may be called before
+initialization, which lets you be notified of errors both during and after
+initialization.
+
+```c
+glfwSetErrorCallback(error_callback);
+```
+
+
+### Creating a window and context {#quick_create_window}
+
+The window and its OpenGL context are created with a single call to @ref
+glfwCreateWindow, which returns a handle to the created combined window and
+context object
+
+```c
+GLFWwindow* window = glfwCreateWindow(640, 480, "My Title", NULL, NULL);
+if (!window)
+{
+    // Window or OpenGL context creation failed
+}
+```
+
+This creates a 640 by 480 windowed mode window with an OpenGL context.  If
+window or OpenGL context creation fails, `NULL` will be returned.  You should
+always check the return value.  While window creation rarely fails, context
+creation depends on properly installed drivers and may fail even on machines
+with the necessary hardware.
+
+By default, the OpenGL context GLFW creates may have any version.  You can
+require a minimum OpenGL version by setting the `GLFW_CONTEXT_VERSION_MAJOR` and
+`GLFW_CONTEXT_VERSION_MINOR` hints _before_ creation.  If the required minimum
+version is not supported on the machine, context (and window) creation fails.
+
+You can select the OpenGL profile by setting the `GLFW_OPENGL_PROFILE` hint.
+This program uses the core profile as that is the only profile macOS supports
+for OpenGL 3.x and 4.x.
+
+```c
+glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+GLFWwindow* window = glfwCreateWindow(640, 480, "My Title", NULL, NULL);
+if (!window)
+{
+    // Window or context creation failed
+}
+```
+
+When a window and context is no longer needed, destroy it.
+
+```c
+glfwDestroyWindow(window);
+```
+
+Once this function is called, no more events will be delivered for that window
+and its handle becomes invalid.
+
+
+### Making the OpenGL context current {#quick_context_current}
+
+Before you can use the OpenGL API, you must have a current OpenGL context.
+
+```c
+glfwMakeContextCurrent(window);
+```
+
+The context will remain current until you make another context current or until
+the window owning the current context is destroyed.
+
+If you are using an [extension loader library](@ref context_glext_auto) to
+access modern OpenGL then this is when to initialize it, as the loader needs
+a current context to load from.  This example uses
+[glad](https://github.com/Dav1dde/glad), but the same rule applies to all such
+libraries.
+
+```c
+gladLoadGL(glfwGetProcAddress);
+```
+
+
+### Checking the window close flag {#quick_window_close}
+
+Each window has a flag indicating whether the window should be closed.
+
+When the user attempts to close the window, either by pressing the close widget
+in the title bar or using a key combination like Alt+F4, this flag is set to 1.
+Note that __the window isn't actually closed__, so you are expected to monitor
+this flag and either destroy the window or give some kind of feedback to the
+user.
+
+```c
+while (!glfwWindowShouldClose(window))
+{
+    // Keep running
+}
+```
+
+You can be notified when the user is attempting to close the window by setting
+a close callback with @ref glfwSetWindowCloseCallback.  The callback will be
+called immediately after the close flag has been set.
+
+You can also set it yourself with @ref glfwSetWindowShouldClose.  This can be
+useful if you want to interpret other kinds of input as closing the window, like
+for example pressing the _Escape_ key.
+
+
+### Receiving input events {#quick_key_input}
+
+Each window has a large number of callbacks that can be set to receive all the
+various kinds of events.  To receive key press and release events, create a key
+callback function.
+
+```c
+static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
+{
+    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
+        glfwSetWindowShouldClose(window, GLFW_TRUE);
+}
+```
+
+The key callback, like other window related callbacks, are set per-window.
+
+```c
+glfwSetKeyCallback(window, key_callback);
+```
+
+In order for event callbacks to be called when events occur, you need to process
+events as described below.
+
+
+### Rendering with OpenGL {#quick_render}
+
+Once you have a current OpenGL context, you can use OpenGL normally.  In this
+tutorial, a multicolored rotating triangle will be rendered.  The framebuffer
+size needs to be retrieved for `glViewport`.
+
+```c
+int width, height;
+glfwGetFramebufferSize(window, &width, &height);
+glViewport(0, 0, width, height);
+```
+
+You can also set a framebuffer size callback using @ref
+glfwSetFramebufferSizeCallback and be notified when the size changes.
+
+The details of how to render with OpenGL is outside the scope of this tutorial,
+but there are many excellent resources for learning modern OpenGL.  Here are
+a few of them:
+
+ - [Anton's OpenGL 4 Tutorials](https://antongerdelan.net/opengl/)
+ - [Learn OpenGL](https://learnopengl.com/)
+ - [Open.GL](https://open.gl/)
+
+These all happen to use GLFW, but OpenGL itself works the same whatever API you
+use to create the window and context.
+
+
+### Reading the timer {#quick_timer}
+
+To create smooth animation, a time source is needed.  GLFW provides a timer that
+returns the number of seconds since initialization.  The time source used is the
+most accurate on each platform and generally has micro- or nanosecond
+resolution.
+
+```c
+double time = glfwGetTime();
+```
+
+
+### Swapping buffers {#quick_swap_buffers}
+
+GLFW windows by default use double buffering.  That means that each window has
+two rendering buffers; a front buffer and a back buffer.  The front buffer is
+the one being displayed and the back buffer the one you render to.
+
+When the entire frame has been rendered, the buffers need to be swapped with one
+another, so the back buffer becomes the front buffer and vice versa.
+
+```c
+glfwSwapBuffers(window);
+```
+
+The swap interval indicates how many frames to wait until swapping the buffers,
+commonly known as _vsync_.  By default, the swap interval is zero, meaning
+buffer swapping will occur immediately.  On fast machines, many of those frames
+will never be seen, as the screen is still only updated typically 60-75 times
+per second, so this wastes a lot of CPU and GPU cycles.
+
+Also, because the buffers will be swapped in the middle the screen update,
+leading to [screen tearing](https://en.wikipedia.org/wiki/Screen_tearing).
+
+For these reasons, applications will typically want to set the swap interval to
+one.  It can be set to higher values, but this is usually not recommended,
+because of the input latency it leads to.
+
+```c
+glfwSwapInterval(1);
+```
+
+This function acts on the current context and will fail unless a context is
+current.
+
+
+### Processing events {#quick_process_events}
+
+GLFW needs to communicate regularly with the window system both in order to
+receive events and to show that the application hasn't locked up.  Event
+processing must be done regularly while you have visible windows and is normally
+done each frame after buffer swapping.
+
+There are two methods for processing pending events; polling and waiting.  This
+example will use event polling, which processes only those events that have
+already been received and then returns immediately.
+
+```c
+glfwPollEvents();
+```
+
+This is the best choice when rendering continually, like most games do.  If
+instead you only need to update your rendering once you have received new input,
+@ref glfwWaitEvents is a better choice.  It waits until at least one event has
+been received, putting the thread to sleep in the meantime, and then processes
+all received events.  This saves a great deal of CPU cycles and is useful for,
+for example, many kinds of editing tools.
+
+
+## Putting it together {#quick_example}
+
+Now that you know how to initialize GLFW, create a window and poll for
+keyboard input, it's possible to create a small program.
+
+This program creates a 640 by 480 windowed mode window and starts a loop that
+clears the screen, renders a triangle and processes events until the user either
+presses _Escape_ or closes the window.
+
+@snippet triangle-opengl.c code
+
+The program above can be found in the [source package][download] as
+`examples/triangle-opengl.c` and is compiled along with all other examples when
+you build GLFW.  If you built GLFW from the source package then you already have
+this as `triangle-opengl.exe` on Windows, `triangle-opengl` on Linux or
+`triangle-opengl.app` on macOS.
+
+[download]: https://www.glfw.org/download.html
+
+This tutorial used only a few of the many functions GLFW provides.  There are
+guides for each of the areas covered by GLFW.  Each guide will introduce all the
+functions for that category.
+
+ - @ref intro_guide
+ - @ref window_guide
+ - @ref context_guide
+ - @ref monitor_guide
+ - @ref input_guide
+
+You can access reference documentation for any GLFW function by clicking it and
+the reference for each function links to related functions and guide sections.
+
+The tutorial ends here.  Once you have written a program that uses GLFW, you
+will need to compile and link it.  How to do that depends on the development
+environment you are using and is best explained by the documentation for that
+environment.  To learn about the details that are specific to GLFW, see
+@ref build_guide.
+