glfw/docs/moving.dox

/*!

@page moving Moving from GLFW 2 to 3

@tableofcontents

This is a guide for people moving from GLFW 2 to 3.  It describes API *changes*,
but does *not* include entirely new features unless they are required when
moving an existing code base onto the new API.  One example of this is the new
multi-monitor support, which you are now required to use to create fullscreen
windows.

@section moving_names Library and header names

The GLFW 3 header is named @ref glfw3.h, to avoid collisions with the GLFW 2
`glfw.h` header, in case they are both installed.  Similarly, the GLFW 3 library
is named `glfw3,` except when it's installed as a shared library on Unix-like
systems, where it uses the [soname](https://en.wikipedia.org/wiki/soname)
`libglfw.so.3`.

@section moving_threads Removal of threading functions

The threading functions have been removed.  However, GLFW 3 has better support
for use from multiple threads than GLFW 2 had.  Contexts can be made current on
and used from secondary threads, and the documentation explicitly states which
functions may and may not be used from secondary threads.

@section moving_image Removal of image and texture loading

The image and texture loading support has been removed.

@section moving_window_handles Window handles

Because GLFW 3 supports multiple windows, window handle parameters have been
added to all window-related functions and callbacks.  Window handles are of the
`GLFWwindow*` type, i.e. a pointer to an opaque struct.

@section moving_monitor Multi-monitor support

GLFW 3 provides support for multiple monitors, adding the `GLFWmonitor*` handle
type and a set of related functions.  To request a fullscreen mode window, you
need to specify which monitor you wish the window to use.  There is @ref
glfwGetPrimaryMonitor that provides something similar to the earlier behaviour.

@section moving_window_close Window closing

Window closing is now just an event like any other.  GLFW 3 windows won't
disappear from underfoot even when no close callback is set; instead the
window's close flag is set.  You can query this flag using @ref
glfwWindowShouldClose, or capture close events by setting a close callback.  The
return value of the close callback then becomes the new value of the close flag.

@section moving_context Explicit context management

Each GLFW 3 window has its own OpenGL context and only you, the user, can know
which context should be current on which thread at any given time.  Therefore,
GLFW 3 makes no assumptions about when you want a certain context current,
leaving that decision to you.

This means that you need to call @ref glfwMakeContextCurrent after creating
a window but before calling any OpenGL functions.

@section moving_keys Physical key input

GLFW 3 uses the physical key locations named after the symbols they generate
using the US keyboard layout, instead of layout-dependent characters like in
GLFW 2.  This means that (for example) `GLFW_KEY_BACKSLASH` is always a single
key and is the same key in the same place regardless of what keyboard layouts
the users of your program has.

GLFW 3 has key tokens for all keys, so instead of trying to remember whether to
check for `'a'` or `'A'`, you now check for `GLFW_KEY_A`.

The key input facility was never meant for text input, although using it that
way worked slightly better in GLFW 2.  If you were using it to input text, you
should be using the character callback instead, on both GLFW 2 and 3.  This will
give you the characters being input, as opposed to the keys being pressed.

@section moving_video_modes Video mode enumeration

Video mode enumeration is now per-monitor.  The `glfwGetDesktopMode` function
has been replaced by @ref glfwGetVideoMode, which returns the current mode of
a monitor.  The @ref glfwGetVideoMode function now returns all available modes
for a monitor instead of requiring you to guess how large an array you need.

@section moving_glu GLU header inclusion

Unlike GLFW 2, GLFW 3 doesn't include the GLU header by default, but you can
make it do so by defining `GLFW_INCLUDE_GLU` before including the GLFW
3 header.

@section moving_cursor Cursor positioning

GLFW 3 only allows you to position the cursor within a window (using @ref
glfwSetCursorPos) when that window is active.  Unless the window is active, the
function fails silently.

@section moving_renamed Symbol name changes

@subsection moving_renamed_functions Renamed functions

| GLFW 2                      | GLFW 3                        | Notes |
| --------------------------- | ----------------------------- | ----- |
| `glfwOpenWindow`            | @ref glfwCreateWindow         | All channel bit depths are now hints<br />Accepts initial window title, optional monitor to go fullscreen on and optional context to share objects with |
| `glfwCloseWindow`           | @ref glfwDestroyWindow        |       |
| `glfwOpenWindowHint`        | @ref glfwWindowHint           | Now accepts all `GLFW_*_BITS` tokens |
| `glfwEnable`                | @ref glfwSetInputMode         |       |
| `glfwDisable`               | @ref glfwSetInputMode         |       |
| `glfwGetMousePos`           | @ref glfwGetCursorPos         |       |
| `glfwSetMousePos`           | @ref glfwSetCursorPos         |       |
| `glfwSetMousePosCallback`   | @ref glfwSetCursorPosCallback |       |
| `glfwSetMouseWheelCallback` | @ref glfwSetScrollCallback    | Accepts two-dimensional scroll offsets as doubles |
| `glfwGetJoystickPos`        | @ref glfwGetJoystickAxes      |       |
| `glfwGetGLVersion`          | @ref glfwGetWindowParam       | Use `GLFW_OPENGL_VERSION_MAJOR`, `GLFW_OPENGL_VERSION_MINOR` and `GLFW_OPENGL_REVISION` |
| `glfwGetDesktopMode`        | @ref glfwGetVideoMode         | Returns the current mode of a monitor |

@subsection moving_renamed_tokens Renamed tokens

| GLFW 2                      | GLFW 3                       | Notes |
| --------------------------- | ---------------------------- | ----- |
| `GLFW_OPENGL_VERSION_MAJOR` | `GLFW_CONTEXT_VERSION_MAJOR` | Renamed as it applies to OpenGL ES as well |
| `GLFW_OPENGL_VERSION_MINOR` | `GLFW_CONTEXT_VERSION_MINOR` | Renamed as it applies to OpenGL ES as well |
| `GLFW_FSAA_SAMPLES`         | `GLFW_SAMPLES`               | Renamed to match the OpenGL API |
| `GLFW_ACTIVE`               | `GLFW_FOCUSED`               | Renamed to match the window focus callback |
| `GLFW_WINDOW_NO_RESIZE`     | `GLFW_RESIZABLE`             | The default has been inverted |
| `GLFW_MOUSE_CURSOR`         | `GLFW_CURSOR_MODE`           | Used with @ref glfwSetInputMode |
| `GLFW_KEY_ESC`              | `GLFW_KEY_ESCAPE`            |       |
| `GLFW_KEY_DEL`              | `GLFW_KEY_DELETE`            |       |
| `GLFW_KEY_PAGEUP`           | `GLFW_KEY_PAGE_UP`           |       |
| `GLFW_KEY_PAGEDOWN`         | `GLFW_KEY_PAGE_DOWN`         |       |
| `GLFW_KEY_KP_NUM_LOCK`      | `GLFW_KEY_NUM_LOCK`          |       |
| `GLFW_KEY_LCTRL`            | `GLFW_KEY_LEFT_CONTROL`      |       |
| `GLFW_KEY_LSHIFT`           | `GLFW_KEY_LEFT_SHIFT`        |       |
| `GLFW_KEY_LALT`             | `GLFW_KEY_LEFT_ALT`          |       |
| `GLFW_KEY_LSUPER`           | `GLFW_KEY_LEFT_SUPER`        |       |
| `GLFW_KEY_RCTRL`            | `GLFW_KEY_RIGHT_CONTROL`     |       |
| `GLFW_KEY_RSHIFT`           | `GLFW_KEY_RIGHT_SHIFT`       |       |
| `GLFW_KEY_RALT`             | `GLFW_KEY_RIGHT_ALT`         |       |
| `GLFW_KEY_RSUPER`           | `GLFW_KEY_RIGHT_SUPER`       |       |

*/