+: (bitmap-info) ( dim -- BITMAPINFO )
+ "BITMAPINFO" <c-object> [
+ BITMAPINFO-bmiHeader {
+ [ nip "BITMAPINFOHEADER" heap-size swap set-BITMAPINFOHEADER-biSize ]
+ [ [ first ] dip set-BITMAPINFOHEADER-biWidth ]
+ [ [ second ] dip set-BITMAPINFOHEADER-biHeight ]
+ [ nip 1 swap set-BITMAPINFOHEADER-biPlanes ]
+ [ nip 32 swap set-BITMAPINFOHEADER-biBitCount ]
+ [ nip BI_RGB swap set-BITMAPINFOHEADER-biCompression ]
+ [ [ first2 * 4 * ] dip swap set-BITMAPINFOHEADER-biSizeImage ]
+ [ nip 72 swap set-BITMAPINFOHEADER-biXPelsPerMeter ]
+ [ nip 72 swap set-BITMAPINFOHEADER-biYPelsPerMeter ]
+ [ nip 0 swap set-BITMAPINFOHEADER-biClrUsed ]
+ [ nip 0 swap set-BITMAPINFOHEADER-biClrImportant ]
+ } 2cleave
+ ] keep ;
+
+: make-offscreen-dc-and-bitmap ( dim -- hDC hBitmap bits )
+ f CreateCompatibleDC
+ swap (bitmap-info) DIB_RGB_COLORS f <void*>
+ [ f 0 CreateDIBSection ] keep *void*
+ [ 2dup SelectObject drop ] dip ;
+
+: setup-offscreen-gl ( dim -- hDC hRC hBitmap bits )
+ make-offscreen-dc-and-bitmap [
+ [ dup offscreen-pfd-dwFlags setup-pixel-format ]
+ [ get-rc ] bi
+ ] 2dip ;
+
+M: windows-ui-backend (open-offscreen-buffer) ( world -- )
+ dup dim>> setup-offscreen-gl <win-offscreen>
+ >>handle drop ;
+M: windows-ui-backend (close-offscreen-buffer) ( handle -- )
+ [ hDC>> DeleteObject drop ]
+ [ hBitmap>> DeleteObject drop ] bi ;
+
+M: win-offscreen offscreen-pixels ( handle -- alien )
+ bits>> ;
+