CrystGLFW::MouseButton

A CrystGLFW::MouseButton (or MouseButton, for the purposes of this guide) represents an individual mouse button on the mouse. Internally, MouseButton is implemented as a Crystal Enum.

Mouse button member names are derived from the names of the constants that represent them in the GLFW specification. The list of GLFW mouse buttons can be found here. Take the name of the constant, remove the "GLFWMOUSE_BUTTON" prefix and replace it with "MouseButton::", and convert the rest to UpperCamelCase to get the name. For example:

GLFW_MOUSE_BUTTON_LEFT is represented in CrystGLFW as MouseButton::Left. GLFW_MOUSE_BUTTON_RIGHT is MouseButton::Right. GLFW_MOUSE_BUTTON_MIDDLE is MouseButton::Middle.

And so on and so forth. A drawback of this approach is that mouse button names that begin with a number must have that number spelled out:

GLFW_MOUSE_BUTTON_1 is represented in CrystGLFW as MouseButton::One.

Checking Mouse Buttons

Because MouseButton is an Enum, question methods are available for each possible value of a given MouseButton:

window.on_mouse_button do |event|
  mouse_button = event.mouse_button
  if mouse_button.one?
    puts "mouse button 1"
  elsif mouse_button.two?
    puts "mouse button 2"
  elsif mouse_button.left?
    puts "left mouse button"
  else
    puts "other mouse button"
  end
end