This guide introduces the window related functions of GLFW. For details on a specific function in this category, see the Window reference. There are also guides for the other areas of GLFW.
The GLFWwindow object encapsulates both a window and a context. They are created with glfwCreateWindow and destroyed with glfwDestroyWindow, or glfwTerminate, if any remain. As the window and context are inseparably linked, the object pointer is used as both a context and window handle.
To see the event stream provided to the various window related callbacks, run the events test program.
A window and its OpenGL or OpenGL ES context are created with glfwCreateWindow, which returns a handle to the created window object. For example, this creates a 640 by 480 windowed mode window:
If window creation fails, NULL will be returned, so it is necessary to check the return value.
The window handle is passed to all window related functions and is provided to along with all input events, so event handlers can tell which window received the event.
To create a full screen window, you need to specify which monitor the window should use. In most cases, the user's primary monitor is a good choice. For more information about retrieving monitors, see Retrieving monitors.
Full screen windows cover the entire display area of a monitor, have no border or decorations.
Windowed mode windows can be made full screen by setting a monitor with glfwSetWindowMonitor, and full screen ones can be made windowed by unsetting it with the same function.
Each field of the GLFWvidmode structure corresponds to a function parameter or window hint and combine to form the desired video mode for that window. The supported video mode most closely matching the desired video mode will be set for the chosen monitor as long as the window has input focus. For more information about retrieving video modes, see Video modes.
| Video mode field | Corresponds to |
|---|---|
| GLFWvidmode.width | width parameter |
| GLFWvidmode.height | height parameter |
| GLFWvidmode.redBits | GLFW_RED_BITS hint |
| GLFWvidmode.greenBits | GLFW_GREEN_BITS hint |
| GLFWvidmode.blueBits | GLFW_BLUE_BITS hint |
| GLFWvidmode.refreshRate | GLFW_REFRESH_RATE hint |
Once you have a full screen window, you can change its resolution, refresh rate and monitor with glfwSetWindowMonitor. If you just need change its resolution you can also call glfwSetWindowSize. In all cases, the new video mode will be selected the same way as the video mode chosen by glfwCreateWindow. If the window has an OpenGL or OpenGL ES context, it will be unaffected.
By default, the original video mode of the monitor will be restored and the window iconified if it loses input focus, to allow the user to switch back to the desktop. This behavior can be disabled with the GLFW_AUTO_ICONIFY window hint, for example if you wish to simultaneously cover multiple windows with full screen windows.
If the closest match for the desired video mode is the current one, the video mode will not be changed, making window creation faster and application switching much smoother. This is sometimes called windowed full screen or borderless full screen window and counts as a full screen window. To create such a window, simply request the current video mode.
This also works for windowed mode windows that are made full screen.
Note that glfwGetVideoMode returns the current video mode of a monitor, so if you already have a full screen window on that monitor that you want to make windowed full screen, you need to have saved the desktop resolution before.
When a window is no longer needed, destroy it with glfwDestroyWindow.
Window destruction always succeeds. Before the actual destruction, all callbacks are removed so no further events will be delivered for the window. All windows remaining when glfwTerminate is called are destroyed as well.
When a full screen window is destroyed, the original video mode of its monitor is restored, but the gamma ramp is left untouched.
There are a number of hints that can be set before the creation of a window and context. Some affect the window itself, others affect the framebuffer or context. These hints are set to their default values each time the library is initialized with glfwInit, can be set individually with glfwWindowHint and reset all at once to their defaults with glfwDefaultWindowHints.
Note that hints need to be set before the creation of the window and context you wish to have the specified attributes.
Some window hints are hard constraints. These must match the available capabilities exactly for window and context creation to succeed. Hints that are not hard constraints are matched as closely as possible, but the resulting context and framebuffer may differ from what these hints requested.
The following hints are always hard constraints:
GLFW_STEREOGLFW_DOUBLEBUFFERGLFW_CLIENT_APIGLFW_CONTEXT_CREATION_APIThe following additional hints are hard constraints when requesting an OpenGL context, but are ignored when requesting an OpenGL ES context:
GLFW_OPENGL_FORWARD_COMPATGLFW_OPENGL_PROFILEGLFW_RESIZABLE specifies whether the windowed mode window will be resizable by the user. The window will still be resizable using the glfwSetWindowSize function. This hint is ignored for full screen windows.
GLFW_VISIBLE specifies whether the windowed mode window will be initially visible. This hint is ignored for full screen windows.
GLFW_DECORATED specifies whether the windowed mode window will have window decorations such as a border, a close widget, etc. An undecorated window may still allow the user to generate close events on some platforms. This hint is ignored for full screen windows.
GLFW_FOCUSED specifies whether the windowed mode window will be given input focus when created. This hint is ignored for full screen and initially hidden windows.
GLFW_AUTO_ICONIFY specifies whether the full screen window will automatically iconify and restore the previous video mode on input focus loss. This hint is ignored for windowed mode windows.
GLFW_FLOATING specifies whether the windowed mode window will be floating above other regular windows, also called topmost or always-on-top. This is intended primarily for debugging purposes and cannot be used to implement proper full screen windows. This hint is ignored for full screen windows.
GLFW_MAXIMIZED specifies whether the windowed mode window will be maximized when created. This hint is ignored for full screen windows.
GLFW_RED_BITS, GLFW_GREEN_BITS, GLFW_BLUE_BITS, GLFW_ALPHA_BITS, GLFW_DEPTH_BITS and GLFW_STENCIL_BITS specify the desired bit depths of the various components of the default framebuffer. GLFW_DONT_CARE means the application has no preference.
GLFW_ACCUM_RED_BITS, GLFW_ACCUM_GREEN_BITS, GLFW_ACCUM_BLUE_BITS and GLFW_ACCUM_ALPHA_BITS specify the desired bit depths of the various components of the accumulation buffer. GLFW_DONT_CARE means the application has no preference.
GLFW_AUX_BUFFERS specifies the desired number of auxiliary buffers. GLFW_DONT_CARE means the application has no preference.
GLFW_STEREO specifies whether to use stereoscopic rendering. This is a hard constraint.
GLFW_SAMPLES specifies the desired number of samples to use for multisampling. Zero disables multisampling. GLFW_DONT_CARE means the application has no preference.
GLFW_SRGB_CAPABLE specifies whether the framebuffer should be sRGB capable. If supported, a created OpenGL context will support the GL_FRAMEBUFFER_SRGB enable, also called GL_FRAMEBUFFER_SRGB_EXT) for controlling sRGB rendering and a created OpenGL ES context will always have sRGB rendering enabled.
GLFW_DOUBLEBUFFER specifies whether the framebuffer should be double buffered. You nearly always want to use double buffering. This is a hard constraint.
GLFW_REFRESH_RATE specifies the desired refresh rate for full screen windows. If set to GLFW_DONT_CARE, the highest available refresh rate will be used. This hint is ignored for windowed mode windows.
GLFW_CLIENT_API specifies which client API to create the context for. Possible values are GLFW_OPENGL_API, GLFW_OPENGL_ES_API and GLFW_NO_API. This is a hard constraint.
GLFW_CONTEXT_CREATION_API specifies which context creation API to use to create the context. Possible values are GLFW_NATIVE_CONTEXT_API and GLFW_EGL_CONTEXT_API. This is a hard constraint. If no client API is requested, this hint is ignored.
GLFW_CONTEXT_VERSION_MAJOR and GLFW_CONTEXT_VERSION_MINOR specify the client API version that the created context must be compatible with. The exact behavior of these hints depend on the requested client API.
GLFW_CONTEXT_VERSION_MAJOR and GLFW_CONTEXT_VERSION_MINOR are not hard constraints, but creation will fail if the OpenGL version of the created context is less than the one requested. It is therefore perfectly safe to use the default of version 1.0 for legacy code and you will still get backwards-compatible contexts of version 3.0 and above when available.GLFW_CONTEXT_VERSION_MAJOR and GLFW_CONTEXT_VERSION_MINOR are not hard constraints, but creation will fail if the OpenGL ES version of the created context is less than the one requested. Additionally, OpenGL ES 1.x cannot be returned if 2.0 or later was requested, and vice versa. This is because OpenGL ES 3.x is backward compatible with 2.0, but OpenGL ES 2.0 is not backward compatible with 1.x.GLFW_OPENGL_FORWARD_COMPAT specifies whether the OpenGL context should be forward-compatible, i.e. one where all functionality deprecated in the requested version of OpenGL is removed. This must only be used if the requested OpenGL version is 3.0 or above. If OpenGL ES is requested, this hint is ignored.
GLFW_OPENGL_DEBUG_CONTEXT specifies whether to create a debug OpenGL context, which may have additional error and performance issue reporting functionality. If OpenGL ES is requested, this hint is ignored.
GLFW_OPENGL_PROFILE specifies which OpenGL profile to create the context for. Possible values are one of GLFW_OPENGL_CORE_PROFILE or GLFW_OPENGL_COMPAT_PROFILE, or GLFW_OPENGL_ANY_PROFILE to not request a specific profile. If requesting an OpenGL version below 3.2, GLFW_OPENGL_ANY_PROFILE must be used. If OpenGL ES is requested, this hint is ignored.
GLFW_CONTEXT_ROBUSTNESS specifies the robustness strategy to be used by the context. This can be one of GLFW_NO_RESET_NOTIFICATION or GLFW_LOSE_CONTEXT_ON_RESET, or GLFW_NO_ROBUSTNESS to not request a robustness strategy.
GLFW_CONTEXT_RELEASE_BEHAVIOR specifies the release behavior to be used by the context. Possible values are one of GLFW_ANY_RELEASE_BEHAVIOR, GLFW_RELEASE_BEHAVIOR_FLUSH or GLFW_RELEASE_BEHAVIOR_NONE. If the behavior is GLFW_ANY_RELEASE_BEHAVIOR, the default behavior of the context creation API will be used. If the behavior is GLFW_RELEASE_BEHAVIOR_FLUSH, the pipeline will be flushed whenever the context is released from being the current one. If the behavior is GLFW_RELEASE_BEHAVIOR_NONE, the pipeline will not be flushed on release.
GLFW_CONTEXT_NO_ERROR specifies whether errors should be generated by the context. If enabled, situations that would have generated errors instead cause undefined behavior.
GL_KHR_no_error contexts may fail on early drivers where this flag is supported without those extensions being listed.| Window hint | Default value | Supported values |
|---|---|---|
GLFW_RESIZABLE | GLFW_TRUE | GLFW_TRUE or GLFW_FALSE |
GLFW_VISIBLE | GLFW_TRUE | GLFW_TRUE or GLFW_FALSE |
GLFW_DECORATED | GLFW_TRUE | GLFW_TRUE or GLFW_FALSE |
GLFW_FOCUSED | GLFW_TRUE | GLFW_TRUE or GLFW_FALSE |
GLFW_AUTO_ICONIFY | GLFW_TRUE | GLFW_TRUE or GLFW_FALSE |
GLFW_FLOATING | GLFW_FALSE | GLFW_TRUE or GLFW_FALSE |
GLFW_MAXIMIZED | GLFW_FALSE | GLFW_TRUE or GLFW_FALSE |
GLFW_RED_BITS | 8 | 0 to INT_MAX or GLFW_DONT_CARE |
GLFW_GREEN_BITS | 8 | 0 to INT_MAX or GLFW_DONT_CARE |
GLFW_BLUE_BITS | 8 | 0 to INT_MAX or GLFW_DONT_CARE |
GLFW_ALPHA_BITS | 8 | 0 to INT_MAX or GLFW_DONT_CARE |
GLFW_DEPTH_BITS | 24 | 0 to INT_MAX or GLFW_DONT_CARE |
GLFW_STENCIL_BITS | 8 | 0 to INT_MAX or GLFW_DONT_CARE |
GLFW_ACCUM_RED_BITS | 0 | 0 to INT_MAX or GLFW_DONT_CARE |
GLFW_ACCUM_GREEN_BITS | 0 | 0 to INT_MAX or GLFW_DONT_CARE |
GLFW_ACCUM_BLUE_BITS | 0 | 0 to INT_MAX or GLFW_DONT_CARE |
GLFW_ACCUM_ALPHA_BITS | 0 | 0 to INT_MAX or GLFW_DONT_CARE |
GLFW_AUX_BUFFERS | 0 | 0 to INT_MAX or GLFW_DONT_CARE |
GLFW_SAMPLES | 0 | 0 to INT_MAX or GLFW_DONT_CARE |
GLFW_REFRESH_RATE | GLFW_DONT_CARE | 0 to INT_MAX or GLFW_DONT_CARE |
GLFW_STEREO | GLFW_FALSE | GLFW_TRUE or GLFW_FALSE |
GLFW_SRGB_CAPABLE | GLFW_FALSE | GLFW_TRUE or GLFW_FALSE |
GLFW_DOUBLEBUFFER | GLFW_TRUE | GLFW_TRUE or GLFW_FALSE |
GLFW_CLIENT_API | GLFW_OPENGL_API | GLFW_OPENGL_API, GLFW_OPENGL_ES_API or GLFW_NO_API |
GLFW_CONTEXT_CREATION_API | GLFW_NATIVE_CONTEXT_API | GLFW_NATIVE_CONTEXT_API or GLFW_EGL_CONTEXT_API |
GLFW_CONTEXT_VERSION_MAJOR | 1 | Any valid major version number of the chosen client API |
GLFW_CONTEXT_VERSION_MINOR | 0 | Any valid minor version number of the chosen client API |
GLFW_CONTEXT_ROBUSTNESS | GLFW_NO_ROBUSTNESS | GLFW_NO_ROBUSTNESS, GLFW_NO_RESET_NOTIFICATION or GLFW_LOSE_CONTEXT_ON_RESET |
GLFW_CONTEXT_RELEASE_BEHAVIOR | GLFW_ANY_RELEASE_BEHAVIOR | GLFW_ANY_RELEASE_BEHAVIOR, GLFW_RELEASE_BEHAVIOR_FLUSH or GLFW_RELEASE_BEHAVIOR_NONE |
GLFW_OPENGL_FORWARD_COMPAT | GLFW_FALSE | GLFW_TRUE or GLFW_FALSE |
GLFW_OPENGL_DEBUG_CONTEXT | GLFW_FALSE | GLFW_TRUE or GLFW_FALSE |
GLFW_OPENGL_PROFILE | GLFW_OPENGL_ANY_PROFILE | GLFW_OPENGL_ANY_PROFILE, GLFW_OPENGL_COMPAT_PROFILE or GLFW_OPENGL_CORE_PROFILE |
See Event processing.
Each window has a user pointer that can be set with glfwSetWindowUserPointer and fetched with glfwGetWindowUserPointer. This can be used for any purpose you need and will not be modified by GLFW throughout the life-time of the window.
The initial value of the pointer is NULL.
When the user attempts to close the window, for example by clicking the close widget or using a key chord like Alt+F4, the close flag of the window is set. The window is however not actually destroyed and, unless you watch for this state change, nothing further happens.
The current state of the close flag is returned by glfwWindowShouldClose and can be set or cleared directly with glfwSetWindowShouldClose. A common pattern is to use the close flag as a main loop condition.
If you wish to be notified when the user attempts to close a window, set a close callback.
The callback function is called directly after the close flag has been set. It can be used for example to filter close requests and clear the close flag again unless certain conditions are met.
The size of a window can be changed with glfwSetWindowSize. For windowed mode windows, this sets the size, in screen coordinates of the client area or content area of the window. The window system may impose limits on window size.
For full screen windows, the specified size becomes the new resolution of the window's desired video mode. The video mode most closely matching the new desired video mode is set immediately. The window is resized to fit the resolution of the set video mode.
If you wish to be notified when a window is resized, whether by the user or the system, set a size callback.
The callback function receives the new size, in screen coordinates, of the client area of the window when it is resized.
There is also glfwGetWindowSize for directly retrieving the current size of a window.
glViewport or other pixel-based OpenGL calls. The window size is in screen coordinates, not pixels. Use the framebuffer size, which is in pixels, for pixel-based calls.The above functions work with the size of the client area, but decorated windows typically have title bars and window frames around this rectangle. You can retrieve the extents of these with glfwGetWindowFrameSize.
The returned values are the distances, in screen coordinates, from the edges of the client area to the corresponding edges of the full window. As they are distances and not coordinates, they are always zero or positive.
While the size of a window is measured in screen coordinates, OpenGL works with pixels. The size you pass into glViewport, for example, should be in pixels. On some machines screen coordinates and pixels are the same, but on others they will not be. There is a second set of functions to retrieve the size, in pixels, of the framebuffer of a window.
If you wish to be notified when the framebuffer of a window is resized, whether by the user or the system, set a size callback.
The callback function receives the new size of the framebuffer when it is resized, which can for example be used to update the OpenGL viewport.
There is also glfwGetFramebufferSize for directly retrieving the current size of the framebuffer of a window.
The size of a framebuffer may change independently of the size of a window, for example if the window is dragged between a regular monitor and a high-DPI one.
The minimum and maximum size of the client area of a windowed mode window can be enforced with glfwSetWindowSizeLimits. The user may resize the window to any size and aspect ratio within the specified limits, unless the aspect ratio is also set.
To specify only a minimum size or only a maximum one, set the other pair to GLFW_DONT_CARE.
To disable size limits for a window, set them all to GLFW_DONT_CARE.
The aspect ratio of the client area of a windowed mode window can be enforced with glfwSetWindowAspectRatio. The user may resize the window freely unless size limits are also set, but the size will be constrained to maintain the aspect ratio.
The aspect ratio is specified as a numerator and denominator, corresponding to the width and height, respectively. If you want a window to maintain its current aspect ratio, simply use its current size as the ratio.
To disable the aspect ratio limit for a window, set both terms to GLFW_DONT_CARE.
You can have both size limits and aspect ratio set for a window, but the results are undefined if they conflict.
The position of a windowed-mode window can be changed with glfwSetWindowPos. This moves the window so that the upper-left corner of its client area has the specified screen coordinates. The window system may put limitations on window placement.
If you wish to be notified when a window is moved, whether by the user, system or your own code, set a position callback.
The callback function receives the new position of the upper-left corner of the client area when the window is moved.
There is also glfwGetWindowPos for directly retrieving the current position of the client area of the window.
All GLFW windows have a title, although undecorated or full screen windows may not display it or only display it in a task bar or similar interface. You can set a UTF-8 encoded window title with glfwSetWindowTitle.
The specified string is copied before the function returns, so there is no need to keep it around.
As long as your source file is encoded as UTF-8, you can use any Unicode characters directly in the source.
If you are using C++11 or C11, you can use a UTF-8 string literal.
Decorated windows have icons on some platforms. You can set this icon by specifying a list of candidate images with glfwSetWindowIcon.
To revert to the default window icon, pass in an empty image array.
Full screen windows are associated with a specific monitor. You can get the handle for this monitor with glfwGetWindowMonitor.
This monitor handle is one of those returned by glfwGetMonitors.
For windowed mode windows, this function returns NULL. This is how to tell full screen windows from windowed mode windows.
You can move windows between monitors or between full screen and windowed mode with glfwSetWindowMonitor. When making a window full screen on the same or on a different monitor, specify the desired monitor, resolution and refresh rate. The position arguments are ignored.
When making the window windowed, specify the desired position and size. The refresh rate argument is ignored.
This restores any previous window settings such as whether it is decorated, floating, resizable, has size or aspect ratio limits, etc.. To restore a window that was originally windowed to its original size and position, save these before making it full screen and then pass them in as above.
Windows can be iconified (i.e. minimized) with glfwIconifyWindow.
When a full screen window is iconified, the original video mode of its monitor is restored until the user or application restores the window.
Iconified windows can be restored with glfwRestoreWindow.
When a full screen window is restored, the desired video mode is restored to its monitor as well.
If you wish to be notified when a window is iconified or restored, whether by the user, system or your own code, set a iconify callback.
The callback function receives changes in the iconification state of the window.
You can also get the current iconification state with glfwGetWindowAttrib.
Windowed mode windows can be hidden with glfwHideWindow.
This makes the window completely invisible to the user, including removing it from the task bar, dock or window list. Full screen windows cannot be hidden and calling glfwHideWindow on a full screen window does nothing.
Hidden windows can be shown with glfwShowWindow.
Windowed mode windows can be created initially hidden with the GLFW_VISIBLE window hint. Windows created hidden are completely invisible to the user until shown. This can be useful if you need to set up your window further before showing it, for example moving it to a specific location.
You can also get the current visibility state with glfwGetWindowAttrib.
Windows can be given input focus and brought to the front with glfwFocusWindow.
If you wish to be notified when a window gains or loses input focus, whether by the user, system or your own code, set a focus callback.
The callback function receives changes in the input focus state of the window.
You can also get the current input focus state with glfwGetWindowAttrib.
If you wish to be notified when the contents of a window is damaged and needs to be refreshed, set a window refresh callback.
The callback function is called when the contents of the window needs to be refreshed.
Windows have a number of attributes that can be returned using glfwGetWindowAttrib. Some reflect state that may change during the lifetime of the window, while others reflect the corresponding hints and are fixed at the time of creation. Some are related to the actual window and others to its context.
GLFW_FOCUSED indicates whether the specified window has input focus. Initial input focus is controlled by the window hint with the same name.
GLFW_ICONIFIED indicates whether the specified window is iconified, whether by the user or with glfwIconifyWindow.
GLFW_MAXIMIZED indicates whether the specified window is maximized, whether by the user or with glfwMaximizeWindow.
GLFW_VISIBLE indicates whether the specified window is visible. Window visibility can be controlled with glfwShowWindow and glfwHideWindow and initial visibility is controlled by the window hint with the same name.
GLFW_RESIZABLE indicates whether the specified window is resizable by the user. This is set on creation with the window hint with the same name.
GLFW_DECORATED indicates whether the specified window has decorations such as a border, a close widget, etc. This is set on creation with the window hint with the same name.
GLFW_FLOATING indicates whether the specified window is floating, also called topmost or always-on-top. This is controlled by the window hint with the same name.
GLFW_CLIENT_API indicates the client API provided by the window's context; either GLFW_OPENGL_API, GLFW_OPENGL_ES_API or GLFW_NO_API.
GLFW_CONTEXT_CREATION_API indicates the context creation API used to create the window's context; either GLFW_NATIVE_CONTEXT_API or GLFW_EGL_CONTEXT_API.
GLFW_CONTEXT_VERSION_MAJOR, GLFW_CONTEXT_VERSION_MINOR and GLFW_CONTEXT_REVISION indicate the client API version of the window's context.
GLFW_OPENGL_FORWARD_COMPAT is GLFW_TRUE if the window's context is an OpenGL forward-compatible one, or GLFW_FALSE otherwise.
GLFW_OPENGL_DEBUG_CONTEXT is GLFW_TRUE if the window's context is an OpenGL debug context, or GLFW_FALSE otherwise.
GLFW_OPENGL_PROFILE indicates the OpenGL profile used by the context. This is GLFW_OPENGL_CORE_PROFILE or GLFW_OPENGL_COMPAT_PROFILE if the context uses a known profile, or GLFW_OPENGL_ANY_PROFILE if the OpenGL profile is unknown or the context is an OpenGL ES context. Note that the returned profile may not match the profile bits of the context flags, as GLFW will try other means of detecting the profile when no bits are set.
GLFW_CONTEXT_ROBUSTNESS indicates the robustness strategy used by the context. This is GLFW_LOSE_CONTEXT_ON_RESET or GLFW_NO_RESET_NOTIFICATION if the window's context supports robustness, or GLFW_NO_ROBUSTNESS otherwise.
GLFW does not expose attributes of the default framebuffer (i.e. the framebuffer attached to the window) as these can be queried directly with either OpenGL, OpenGL ES or Vulkan.
If you are using version 3.0 or later of OpenGL or OpenGL ES, the glGetFramebufferAttachmentParameteriv function can be used to retrieve the number of bits for the red, green, blue, alpha, depth and stencil buffer channels. Otherwise, the glGetIntegerv function can be used.
The number of MSAA samples are always retrieved with glGetIntegerv. For contexts supporting framebuffer objects, the number of samples of the currently bound framebuffer is returned.
| Attribute | glGetIntegerv | glGetFramebufferAttachmentParameteriv |
|---|---|---|
| Red bits | GL_RED_BITS | GL_FRAMEBUFFER_ATTACHMENT_RED_SIZE |
| Green bits | GL_GREEN_BITS | GL_FRAMEBUFFER_ATTACHMENT_GREEN_SIZE |
| Blue bits | GL_BLUE_BITS | GL_FRAMEBUFFER_ATTACHMENT_BLUE_SIZE |
| Alpha bits | GL_ALPHA_BITS | GL_FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE |
| Depth bits | GL_DEPTH_BITS | GL_FRAMEBUFFER_ATTACHMENT_DEPTH_SIZE |
| Stencil bits | GL_STENCIL_BITS | GL_FRAMEBUFFER_ATTACHMENT_STENCIL_SIZE |
| MSAA samples | GL_SAMPLES | Not provided by this function |
When calling glGetFramebufferAttachmentParameteriv, the red, green, blue and alpha sizes are queried from the GL_BACK_LEFT, while the depth and stencil sizes are queried from the GL_DEPTH and GL_STENCIL attachments, respectively.
GLFW windows are by default double buffered. That means that you have 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, it is time to swap the back and the front buffers in order to display what has been rendered and begin rendering a new frame. This is done with glfwSwapBuffers.
Sometimes it can be useful to select when the buffer swap will occur. With the function glfwSwapInterval it is possible to select the minimum number of monitor refreshes the driver wait should from the time glfwSwapBuffers was called before swapping the buffers:
If the interval is zero, the swap will take place immediately when glfwSwapBuffers is called without waiting for a refresh. Otherwise at least interval retraces will pass between each buffer swap. Using a swap interval of zero can be useful for benchmarking purposes, when it is not desirable to measure the time it takes to wait for the vertical retrace. However, a swap interval of one lets you avoid tearing.
Note that this may not work on all machines, as some drivers have user-controlled settings that override any swap interval the application requests.
Last update on Thu Aug 18 2016 for GLFW 3.2.1