Merge pull request #39 from rcmaniac25/feature/negative_window_coordinates

Support for negative window position coordinates

freeglut/freeglut/include/GL/freeglut_ext.h

@@ -90,6 +90,8 @@
 
 #define  GLUT_STROKE_FONT_DRAW_JOIN_DOTS    0x0206  /* Draw dots between line segments of stroke fonts? */
 
+#define  GLUT_ALLOW_NEGATIVE_WINDOW_POSITION 0x0207 /* GLUT doesn't allow negative window positions by default */
+
 /*
  * New tokens for glutInitDisplayMode.
  * Only one GLUT_AUXn bit may be used at a time.

freeglut/freeglut/src/fg_init.c

@@ -88,6 +88,7 @@ SFG_State fgState = { { -1, -1, GL_FALSE },  /* Position */
                       4,                      /* SampleNumber */
                       GL_FALSE,               /* SkipStaleMotion */
                       GL_FALSE,               /* StrokeFontDrawJoinDots */
+                      GL_FALSE,               /* AllowNegativeWindowPosition */
                       1,                      /* OpenGL context MajorVersion */
                       0,                      /* OpenGL context MinorVersion */
                       0,                      /* OpenGL ContextFlags */
@@ -370,10 +371,10 @@ void FGAPIENTRY glutInit( int* pargc, char** argv )
         if( (mask & (WidthValue|HeightValue)) == (WidthValue|HeightValue) )
             fgState.Size.Use = GL_TRUE;
 
-        if( mask & XNegative )
+        if( ( mask & XNegative ) && !fgState.AllowNegativeWindowPosition )
             fgState.Position.X += fgDisplay.ScreenWidth - fgState.Size.X;
 
-        if( mask & YNegative )
+        if( ( mask & YNegative ) && !fgState.AllowNegativeWindowPosition )
             fgState.Position.Y += fgDisplay.ScreenHeight - fgState.Size.Y;
 
         if( (mask & (XValue|YValue)) == (XValue|YValue) )
@@ -397,7 +398,7 @@ void FGAPIENTRY glutInitWindowPosition( int x, int y )
     fgState.Position.X = x;
     fgState.Position.Y = y;
 
-    if( ( x >= 0 ) && ( y >= 0 ) )
+    if( ( ( x >= 0 ) && ( y >= 0 ) ) || fgState.AllowNegativeWindowPosition )
         fgState.Position.Use = GL_TRUE;
     else
         fgState.Position.Use = GL_FALSE;

freeglut/freeglut/src/fg_internal.h

@@ -354,6 +354,7 @@ struct tagSFG_State
     GLboolean        SkipStaleMotion;      /* skip stale motion events */
 
     GLboolean        StrokeFontDrawJoinDots;/* Draw dots between line segments of stroke fonts? */
+    GLboolean        AllowNegativeWindowPosition; /* GLUT, by default, doesn't allow negative window positions. Enable it? */
 
     int              MajorVersion;         /* Major OpenGL context version  */
     int              MinorVersion;         /* Minor OpenGL context version  */

freeglut/freeglut/src/fg_state.c

@@ -122,6 +122,10 @@ void FGAPIENTRY glutSetOption( GLenum eWhat, int value )
       fgState.StrokeFontDrawJoinDots = !!value;
       break;
 
+    case GLUT_ALLOW_NEGATIVE_WINDOW_POSITION:
+      fgState.AllowNegativeWindowPosition = !!value;
+      break;
+
     default:
         fgWarning( "glutSetOption(): missing enum handle %d", eWhat );
         break;
@@ -225,6 +229,9 @@ int FGAPIENTRY glutGet( GLenum eWhat )
     case GLUT_STROKE_FONT_DRAW_JOIN_DOTS:
         return fgState.StrokeFontDrawJoinDots;
 
+    case GLUT_ALLOW_NEGATIVE_WINDOW_POSITION:
+        return fgState.AllowNegativeWindowPosition;
+
     default:
         return fgPlatformGlutGet ( eWhat );
         break;

freeglut/freeglut/src/fg_structure.c

@@ -75,6 +75,11 @@ SFG_Window* fgCreateWindow( SFG_Window* parent, const char* title,
     /* Have the window object created */
     SFG_Window *window = (SFG_Window *)calloc( 1, sizeof(SFG_Window) );
 
+    if( !window )
+    {
+        fgError( "Out of memory. Could not create window." );
+    }
+
 	fgPlatformCreateWindow ( window );
 
     fghClearCallBacks( window );

freeglut/freeglut/src/fg_window.c

@@ -177,12 +177,12 @@ int FGAPIENTRY glutCreateWindow( const char* title )
      * XXX application has not already done so.  The "freeglut" community
      * XXX decided not to go this route (freeglut-developer e-mail from
      * XXX Steve Baker, 12/16/04, 4:22 PM CST, "Re: [Freeglut-developer]
-     * XXX Desired 'freeglut' behaviour when there is no current window"
+     * XXX Desired 'freeglut' behaviour when there is no current window")
      */
     FREEGLUT_EXIT_IF_NOT_INITIALISED ( "glutCreateWindow" );
 
-    return fgCreateWindow( NULL, title, fgState.Position.Use,
+    return fgCreateWindow( NULL, title, 
-                           fgState.Position.X, fgState.Position.Y,
+                           fgState.Position.Use, fgState.Position.X, fgState.Position.Y,
                            fgState.Size.Use, fgState.Size.X, fgState.Size.Y,
                            GL_FALSE, GL_FALSE )->ID;
 }
@@ -199,10 +199,24 @@ int FGAPIENTRY glutCreateSubWindow( int parentID, int x, int y, int w, int h )
     FREEGLUT_EXIT_IF_NOT_INITIALISED ( "glutCreateSubWindow" );
     parent = fgWindowByID( parentID );
     freeglut_return_val_if_fail( parent != NULL, 0 );
-    if ( x < 0 )
+
+    if ( fgState.AllowNegativeWindowPosition )
+    {
+        /* XXX This results in different widths/heights than if AllowNegativeWindowPosition
+         * XXX was false. The "freeglut" community defined this logic.
+         * XXX (freeglut-developer e-mail from Diederick C. Niehorster, 11/15/2015, 4:06 PM EST.
+         * XXX "Re: [Freeglut-developer] glutInitWindowPosition with negative coordinate(s)")
+         */
+
+        if ( w < 0 ) w = parent->State.Width + w ;
+        if ( h < 0 ) h = parent->State.Height + h ;
+    }
+    else
+    {
+        if ( ( x < 0 ) )
         {
             x = parent->State.Width + x ;
-        if ( w >= 0 ) x -= w ;
+            if ( w > 0 ) x -= w ;
         }
 
         if ( w < 0 ) w = parent->State.Width - x + w ;
@@ -212,10 +226,10 @@ int FGAPIENTRY glutCreateSubWindow( int parentID, int x, int y, int w, int h )
             w = -w ;
         }
 
-    if ( y < 0 )
+        if ( ( y < 0 ) )
         {
             y = parent->State.Height + y ;
-        if ( h >= 0 ) y -= h ;
+            if ( h > 0 ) y -= h ;
         }
 
         if ( h < 0 ) h = parent->State.Height - y + h ;
@@ -224,8 +238,12 @@ int FGAPIENTRY glutCreateSubWindow( int parentID, int x, int y, int w, int h )
             y += h ;
             h = -h ;
         }
+    }
 
-    window = fgCreateWindow( parent, "", GL_TRUE, x, y, GL_TRUE, w, h, GL_FALSE, GL_FALSE );
+    window = fgCreateWindow( parent, "", 
+                             GL_TRUE, x, y, 
+                             GL_TRUE, w, h, 
+                             GL_FALSE, GL_FALSE );
     ret = window->ID;
 
     return ret;

freeglut/freeglut/src/mswin/fg_spaceball_mswin.c

@@ -64,6 +64,7 @@ void fgPlatformInitializeSpaceball(void)
 	}
 	hwnd = fgStructure.CurrentWindow->Window.Handle;
 
+	{
 		BOOL ok;
 		UINT cbSize = sizeof(__fgSpaceball);
 		__fgSpaceball.hwndTarget = hwnd;
@@ -74,6 +75,7 @@ void fgPlatformInitializeSpaceball(void)
 			sball_initialized = 0;
 		}
 	}
+}
 
 void fgPlatformSpaceballClose(void)
 {
@@ -138,7 +140,7 @@ void fgSpaceballHandleWinEvent(HWND hwnd, WPARAM wParam, LPARAM lParam)
 	res = GetRawInputDeviceInfo(pRawInput->header.hDevice, RIDI_DEVICEINFO, &sRidDeviceInfo, &size);
 	if (res == -1)
 		return;
-
+	{
 		SFG_Window* window = fgWindowByHandle(hwnd);
 		if ((window == NULL))
 			return;
@@ -192,5 +194,6 @@ void fgSpaceballHandleWinEvent(HWND hwnd, WPARAM wParam, LPARAM lParam)
 			}
 		}
 	}
+}
 
 #endif

freeglut/web-src/docs/api.php

@@ -313,10 +313,14 @@ upper left hand corner of the outside of the window (the non-client
 area) is at (x,y) and the size of the drawable (client) area is (w,h).
 The coordinates taken by <tt>glutInitPosition</tt> and
 <tt>glutPositionWindow</tt>, as well as the coordinates provided by
-<i>FreeGLUT</i> when it calls the <tt>glutPositionFunc</tt> callback,
+<i>freeglut</i> when it calls the <tt>glutPositionFunc</tt> callback,
-specify the top-left of the non-client area of the window.</li>
+specify the top-left of the non-client area of the window. By default
+only positive-signed coordinates are supported. If GLUT_ALLOW_NEGATIVE_WINDOW_POSITION
+is enabled, then negative coordinates are supported. An exception
+for <tt>glutPositionWindow</tt> exists as it's always supported negative
+window coordinates.</li>
 <li>When you query the size and position of the window using
-<tt>glutGet</tt>, <i>FreeGLUT</i> will return the size of the drawable
+<tt>glutGet</tt>, <i>freeglut</i> will return the size of the drawable
 area--the (w,h) that you specified when you created the window--and the
 coordinates of the upper left hand corner of the drawable (client)
 area--which is <u>NOT</u> the (x,y) position of the window you specified
@@ -457,7 +461,14 @@ With <tt>glutGet</tt> information can be acquired about the current
 window's size, position and decorations. Note however that according to
 <a href="#Conventions">FreeGLUT's conventions</a>, the information
 returned about the window coordinates does not correspond to the
-coordinates used when setting window position.
+coordinates used when setting window position. In addition, GLUT only
+accepts positive window coordinates, and ignores all negative window
+coordinates. But if GLUT_ALLOW_NEGATIVE_WINDOW_POSITION is enabled,
+then negative window coordinates can be used. This is useful for
+multi-montitor setups where the second monitor may be in the negative
+desktop space of the primary monitor, as now the window can be placed
+on the additional monitors. Furthermore, this flag also determines how 
+negative coordinates and sizes are interpreted for subwindows.
 </p>
 
 <p>
@@ -479,6 +490,11 @@ the window will immediately snap out to this width, but the application can
 call <tt>glutReshapeWindow</tt> and make a window narrower again.
 </p>
 
+<p>
+If GLUT_ALLOW_NEGATIVE_WINDOW_POSITION is enabled, <tt>glutInitWindowPosition</tt>
+will accept negative window coordinates.
+</p>
+
 <h2>4.3 glutInitDisplayMode</h2>
 
 <h2>4.4 glutInitDisplayString</h2>
@@ -634,9 +650,9 @@ will exit.
 <p>
 If the application has two nested calls to <tt>glutMainLoop</tt> and calls
 <tt>glutLeaveMainLoop</tt>, the behaviour
-of <i>freeglut</i> is undefined.  It may leave only the inner nested
+of <i>FreeGLUT</i> is undefined.  It may leave only the inner nested
 loop or it may leave both loops.  If the reader has a strong preference
-for one behaviour over the other he should contact the <i>freeglut</i> Programming
+for one behaviour over the other he should contact the <i>FreeGLUT</i> Programming
 Consortium and ask for the code to be fixed.
 </p>
 
@@ -650,6 +666,44 @@ Consortium and ask for the code to be fixed.
 
 <h2>6.2 glutCreateSubwindow</h2>
 
+<p>
+The <tt>glutCreateSubwindow</tt> function creates a subwindow of an existing window.
+</p>
+
+<p><b>Usage</b></p>
+
+<p>
+<tt>int glutCreateSubwindow(int window, int x, int y, int width, int height);</tt>
+</p>
+
+<p><b>Description</b></p>
+
+<p>
+Creates a subwindow of <i>window</i> that is at location <i>x</i> and <i>y</i>
+relative to the window's upper-left corner, and is of the specified <i>width</i> and <i>height</i>. The newly created
+window ID is returned by <tt>glutCreateSubwindow</tt>. By default, the position coordinates will only allow windows within the bounds of the parent.
+Negative coordinates be treated as coordinates from the opposite edge for a given axis. In addition, the width of the window will be taken into account.
+For example, if the parent window is 100 pixels wide, and the <i>x</i> is 10, and <i>width</i> is 20, the subwindow will be located at <tt>x = 10</tt>.
+If <i>x</i> is -10, then the subwindow will be located at 70 <tt>(parent - abs(pos) - dim)</tt>. If the <i>width</i> or <i>height</i> are negative, then the dimension is taken as a
+subtraction of the parent dimension. For example, if the parent window is 100 pixels wide, and the <i>x</i> is 10, and <i>width</i> is 20, the 
+subwindow will have a size of 20. If <i>width</i> is -20, then the subwindow will have a width of 70 <tt>(parent - pos - abs(dim))</tt>.
+</p>
+
+<p>
+If GLUT_ALLOW_NEGATIVE_WINDOW_POSITION is enabled, the window behavior differs. Negative window coordinates are now accepted and may result in windows outside
+of the viewing area, depending on the platform of operation. Negative <i>width</i> and <i>height</i> are still used as a subtraction of the parent window dimension,
+but they do not take <i>x</i> or <i>y</i> into account. For example, if the parent window is 100 pixels wide, and the <i>x</i> is 10, and <i>width</i> is 20, the 
+subwindow will be located at <tt>x = 10</tt>. If <i>x</i> is -10, then the subwindow will be located at <tt>x = -10</tt>. If the parent window is 100 pixels wide, 
+and the <i>x</i> is 10, and <i>width</i> is 20, the subwindow will have a size of 20. If <i>width</i> is -20, then the subwindow will have a width of 80 <tt>(parent - abs(dim))</tt>.
+</p>
+
+<p><b>Changes From GLUT</b></p>
+
+<p>
+GLUT does not support negative <i>x</i> or <i>y</i>. Nor does it have GLUT_ALLOW_NEGATIVE_WINDOW_POSITION 
+which changes the the functionality of <tt>glutCreateSubwindow</tt>.
+</p>
+
 <h2>6.3 glutDestroyWindow</h2>
 
 <h2>6.4 glutSetWindow, glutGetWindow</h2>
@@ -1528,6 +1582,8 @@ href="#GeometricObject"><i>FreeGLUT</i>'s geometric object rendering
 functions</a> also visualize the object's normals or not.</li>
 <li>GLUT_STROKE_FONT_DRAW_JOIN_DOTS - Set whether join dots are drawn
 between line segments when drawing letters of stroke fonts or not.</li>
+<li>GLUT_ALLOW_NEGATIVE_WINDOW_POSITION - Set if negative positions can be
+used for window coordinates.</li>
 </ul>
 </p>
 
@@ -1606,6 +1662,7 @@ glutInitDisplayMode or glutSetOption(GLUT_INIT_DISPLAY_MODE, value)</li>
 <li>GLUT_VERSION - Return value will be X*10000+Y*100+Z where X is the
     major version, Y is the minor version and Z is the patch level.
     This query is only supported in <i>freeglut</i> (version 2.0.0 or later).</li>
+<li>GLUT_ALLOW_NEGATIVE_WINDOW_POSITION - 1 if negative window positions are enabled, 0 otherwise</li>
 </ul>
 
 <h2>13.3 glutDeviceGet</h2>