====== Main screen functions ======
===== mglOpen: Opens the screen =====

**usage:** mglOpen(whichScreen, <screenWidth>, <screenHeight>, <frameRate>, <bitDepth>)\\ **purpose:** Opens an openGL window

^ argument ^ value ^
| whichScreen | 0=Window, 1=primary screen, 2=secondary screen, etc |
| <screenWidth> | [width] in pixels |
| <screenHeight> | [height] in pixels |
| <frameRate> | [frameRate] in hertz |
| <bitDepth> | [bitDepth] this is usually 32 bits |

Open last monitor in list with current window settings

  mglOpen

Open with resolution 800x600 60Hz 32bit fullscreen

  mglOpen(1,800,600,60,32);

Open in a window

  mglOpen(0);

\\  Note that mglOpen hides the mouse cursor as a default. If you want to show the mouse cursor, you should call mglDisplayCursor after opening the screen.

===== mglFlush: Flips front and back buffer =====

**purpose:** swap front and back buffer (waits for one frame tick)\\ **usage:** mglFlush \\ **N.B.** mglFlush has to be called after each operation that involves drawing or erasing from the currently open window

===== mglClose: Closes the screen =====

**purpose:** close OpenGL screen\\ **usage:** mglClose
====== Other screen functions ======
===== mglResolution: Get and set display resolution =====
**availability**: [[mgl:beta|mgl 2.0]]\\
**usage**: mglResolution(<whichScreen>, <screenWidth>, <screenHeight>, <frameRate>, <bitDepth>)\\
**purpose**: Gets or sets the resolution of a display
**usage**: To get the resolution of the default display:
 
  mglResolution
 
To get the resolution of display 1:
 
  mglResolution(1)
 
To set the resolution of display 2 to 1440x900:
 
  mglResolution(2,1440,900)

===== mglSwitchDisplay: Switch between multiple monitors =====

**usage:** mglSwitchDisplay(<displayID>)\\ **purpose:** If you are using multiple monitors to display stimuli (like for a dichoptic presentation), you can open up multiple displays using this function.

^ argument ^ value ^
| <displayID> | which display to switch to |

You can use this to open up two separate screens and control them independently. For example, say you have two monitors 1 and 2. You open the first in the usual way:

  mglOpen(1)

Then you switch monitors so that you can open up the other one

  mglSwitchDisplay
  mglOpen(2)

Now if you want draw to the first display, you can do

  mglSwitchDisplay(1)
  mglClearScreen(0.5);
  mglFlush;

Similarly, to draw to the second display

  mglSwitchDisplay(2);
  mglClearScreen(1);
  mglFlush;

You can check the status of all open displays with:

  mglSwitchDisplay(-2);

If you want to close all displays at once, you can do:

  mglSwitchDisplay(-1);

===== mglMoveWindow: Moves windows created by mglOpen(0) =====

**usage:** mglMoveWindow(leftPos,topPos)\\ **purpose:** Moves a window created by mglOpen(0)

^ argument ^ value ^
| leftPos | Left position of where the window will be moved to |
| topPos | Top position of where the window will be moved to |

  mglOpen(0);
  mglMoveWindow(100,100);

\\

===== mglDescribeDisplays: Get information about your monitor and computer system =====

**usage:** [displayInfo computerInfo] = mglDescribeDisplays()\\ **purpose:** Gets information about your displays (as an array of structs with values for each monitor). As well as a single struct with info about your computer.
===== mglFrameGrab: Frame grab to a matlab matrix =====

**usage:** mglFrameGrab(<frameRect>)\\ **purpose:** Does a frame grab of the current mgl screen and returns it as a matrix of dimensions widthxheightx3

^ argument ^ value ^
| frameRect | Optional argument that is a 1x4 array specifying a rectangular part of the frame to grab in the format [x y width height] |

  mglOpen();
  mglScreenCoordinates;
  mglClearScreen([0 0 0]);
  mglPoints2(mglGetParam('screenWidth')*rand(5000,1),mglGetParam('screenHeight')*rand(5000,1));
  mglPolygon([0 0 mglGetParam('screenWidth') mglGetParam('screenWidth')],[mglGetParam('screenHeight')/3 mglGetParam('screenHeight')*2/3 mglGetParam('screenHeight')*2/3 mglGetParam('screenHeight')/3],0);
  mglTextSet('Helvetica',32,[1 1 1]);
  mglTextDraw('Frame Grab',[mglGetParam('screenWidth')/2 mglGetParam('screenHeight')/2]);
  frame = mglFrameGrab;
  imagesc(mean(frame,3)');colormap('gray')
  mglFlush