New extension: gluttonGetOption

In GLUT, there is a handy-dandy function for setting various global options:

void glutSetOption( GLenum eWhat , int value );

This is great, but what if you want to change things temporarily and you don't know what the original settings are? This could happen, for example, if you're writing a library function that sits between GLUT and the rest of your application.

What you need is a reading analogue to glutSetOption, something like a glutGetOption. Unfortunately, there is no glutGetOption.

Fortunately, there is a gluttonGetOption in the extended GLUT-like library I'm working on, glutton.

To make this function, I first added the declaration in freeglut_ext.h (glutton is based upon the marvelous freeglut library):

int FGAPIENTRY gluttonGetOption( GLenum eWhat );

Then, in freeglut_state.c, I copied the glutSetOption implementation and reversed the data flow:

int FGAPIENTRY gluttonGetOption( GLenum eWhat )
  {
  FREEGLUT_EXIT_IF_NOT_INITIALISED ( "gluttonGetOption" );
  
    switch( eWhat )
    {
    case GLUT_INIT_WINDOW_X:
        return fgState.Position.X;
        break;

    case GLUT_INIT_WINDOW_Y:
        return fgState.Position.Y;
        break;

    case GLUT_INIT_WINDOW_WIDTH:
        return fgState.Size.X;
        break;

    case GLUT_INIT_WINDOW_HEIGHT:
        return fgState.Size.Y;
        break;

    case GLUT_INIT_DISPLAY_MODE:
        return (int)fgState.DisplayMode;
        break;

    case GLUT_ACTION_ON_WINDOW_CLOSE:
        return fgState.ActionOnWindowClose;
        break;

    case GLUT_RENDERING_CONTEXT:
        return fgState.UseCurrentContext;
        break;

    case GLUT_DIRECT_RENDERING:
        return fgState.DirectContext;
        break;

    case GLUT_WINDOW_CURSOR:
        return fgStructure.CurrentWindow->State.Cursor;
        break;

    case GLUT_AUX:
      return fgState.AuxiliaryBufferNumber;
      break;

    case GLUT_MULTISAMPLE:
      return fgState.SampleNumber;
      break;

    default:
      fgWarning( "glutGetOption(): missing enum handle %d", eWhat );
      return 0xDeadBeef;
      break;
    }
  }

It doesn't get much easier than that.