Creating a Window

You can create a Window with the new method:

window = CrystGLFW::Window.new
window # => CrystGLFW::Window

Using new to create a Window will cause an actual GUI window to be created on the machine - this window contains the OpenGL or OpenGL ES context that can be used for drawing.

new accepts the following arguments, all of which are optional:

• width, the starting width of the window, in screen coordinates.
• height, the starting height of the window, in screen coordinates.
• title, the title of the window, commonly displayed at the top of its frame.
• monitor, the Monitor to use for full screen mode.
• sharing_window, the Window with which the new window should share resources.
• hints, a Hash of desired constraints that will be placed on the created window.

Let's examine each of these arguments in detail.

width and height

The starting width and height of a window can be configured using the width and height arguments, respectively:

# create a window with initial dimensions of 1024x576.
window = CrystGLFW::Window.new(width: 1024, height: 576)

# create a window with initial dimensions of 800x800
window = CrystGLFW::Window.new(width: 800, height: 800)

Both arguments have a default values:

• width defaults to 640
• height defaults to 480

Each of these calls to new creates a 640x480 window:

window = Window.new(width: 640, height: 480)

window = Window.new(width: 640)

window = Window.new(height: 480)

window = Window.new

Remember: these dimensions are screen coordinates, not pixels.

title

You can set the window's starting title by using the title argument:

# create a window titled "test window"
window = Window.new(title: "test window")

# create a window titled "Winston the Window"
window = Window.new(title: "Winston the Window")

The default value of title is an empty String. This won't throw an error, but it's also not a great window title. Give your window some love - let it have a title!

monitor

If you'd like for the new window to immediately begin running in full screen mode, you can use the monitor argument to indicate which monitor should be used:

primary_monitor = Monitor.primary
window = Window.new(monitor: primary_monitor)

By default, windows run in windowed mode rather than full screen. Providing a Monitor to the monitor argument tells CrystGLFW that you'd like to run in full screen mode. Because of this, if width and height are given alongside monitor, then width and height will be ignored:

primary_monitor = Monitor.primary

# still creates a full screen window on the primary monitor.
window = Window.new(width: 1024, height: 576, monitor: primary_monitor)

sharing_window

If the new window needs to share its context objects with another window's context, you can use the sharing_window argument:

winston = Window.new
wilfred = Window.new(sharing_window: winston)

hints

There are a number of constraints that can be placed on the created window that are set with a Hash of "hints." Window creation hints are robust and complex, so they have their own article.

Windows can only be created from within a run block definition.