====== Function Calls ======


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The following Graphics folio calls control bitmaps, screens, and the display generator. They also write to bitmaps and frame buffers. See [[:documentation:development:opera:pf25:ppgfldr:ggsfldr:gprfldr:01gpr#xref37440|Graphics Folio Calls]] for complete descriptions of each call.

==== Screen Calls ====

  * ''%%AddScreenGroup() Adds a screen group to the display.%%''
  * ''%%CreateScreenGroup() %%''Creates a screen group and all its screens, bitmaps, buffers, and VDLs.
  * ''%%DisplayScreen() %%''Displays the bitmap(s) of the specified screen (or screens).
  * ''%%RemoveScreenGroup() %%''Removes a screen group from the display.

==== VDL Calls ====

  * ''%%SetVDL() %%''Sets a screen to display a specific VDL.
  * ''%%SubmitVDL() %%''Submits a VDL for approval by the 3DO system.
  * ''%%ModifyVDL() %%''Changes one or more attributes of a VDL.

==== Screen Color Calls ====

  * ''%%MakeCLUTColorEntry() %%''Packs a color index and red, green, and blue values into a single word.
  * ''%%MakeCLUTBlueEntry() %%''Packs a color index and blue values into a single word.
  * ''%%MakeCLUTGreenEntry() %%''Packs a color index and green values into a single word.
  * ''%%MakeCLUTRedEntry() %%''Packs a color index and red values into a single word.
  * ''%%SetScreenColor() %%''Sets a color in the 3DO system's color palette.
  * ''%%SetScreenColors() %%''Sets a number of colors in the 3DO system's color palette.
  * ''%%ResetScreenColors() %%''Resets a screen's colors to a linear color palette.

==== Drawing Calls ====

  * ''%%DrawTo() %%''Draws a line from the GrafCon's current position to a specified position.
  * ''%%FillRect() %%''Draws a filled rectangle.
  * ''%%GetPixelAddress() %%''Gets a pointer to the pixel at the specified GrafCon coordinates.
  * ''%%MakeRGB15() %%''Creates a 3DO RGB value out of separate red, green, and blue values.
  * ''%%MoveTo() %%''Moves the pen position of a GrafCon to a new location.
  * ''%%SetBGPen() %%''Sets the background pen of a GrafCon.
  * ''%%SetFGPen() %%''Sets the foreground pen of a GrafCon.
  * ''%%WritePixel() %%''Writes a pixel to a bitmap in a GrafCon's foreground color.

==== Text Calls ====

  * ''%%DrawChar() %%''Draws a text character to a display window.
  * ''%%DrawText16() %%''Draws a text character to a display window.
  * ''%%GetCurrentFont() %%''Gets the pointer to the 3DO system's default font.
  * ''%%ResetCurrentFont() %%''Resets the 3DO system's default font.
  * ''%%SetCurrentFontCCB() %%''Sets the font.

==== Clipping Calls ====

  * ''%%SetClipHeight() %%''Sets the clip height of a bitmap.
  * ''%%SetClipOrigin() %%''Sets the clip origin of a bitmap.
  * ''%%SetClipWidth() %%''Sets the clip width of a bitmap.

==== Bitmap Copying Calls ====

  * ''%%CloneVRAMPages() %%''Copies one page of VRAM to a contiguous range of VRAM pages.
  * ''%%CopyVRAMPages() %%''Copies a contiguous number of VRAM pages to a VRAM destination.
  * ''%%MakeRGB15Pair() %%''Creates a double 3DO RGB value out of separate red, green, and blue values.
  * ''%%SetVRAMPages() %%''Sets contiguous pages of VRAM to a specified value.

==== Display Timing Calls ====

  * ''%%WaitVBL() Waits the specified number of VBLs.%%''

==== Interpolation Calls ====

  * ''%%DisableHAVG() %%''Disables horizontal averaging.
  * ''%%DisableVAVG() %%''Disables vertical averaging.
  * ''%%EnableHAVG() %%''Enables horizontal averaging.
  * ''%%EnableVAVG() %%''Enables vertical averaging.

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