TABLE OF CONTENTS opal.library/ActiveScreen24 opal.library/AmigaPriority opal.library/AppendCopper24 opal.library/AutoSync24 opal.library/BitPlanetoOV opal.library/ClearDisplayBottom24 opal.library/ClearPFStencil24 opal.library/ClearPRStencil24 opal.library/ClearQuick24 opal.library/ClearScreen24 opal.library/CloseScreen24 opal.library/Config24 opal.library/CreateScreen24 opal.library/DisablePRStencil24 opal.library/DisplayFrame24 opal.library/DisplayThumbnail24 opal.library/DrawEllipse24 opal.library/DrawLine24 opal.library/DualDisplay24 opal.library/DualPlayField2 opal.library/EnablePRStencil24 opal.library/FadeIn24 opal.library/FadeOut24 opal.library/FreeScreen24 opal.library/FreezeFrame24 opal.library/ILBMtoOV opal.library/LatchDisplay24 opal.library/LoadImage24 opal.library/LowMemUpdate24 opal.library/LowMem2Update24 opal.library/LowMemRGB24 opal.library/OpenScreen24 opal.library/OVPriority opal.library/OVtoBitPlane opal.library/OVtoILBM opal.library/OVtoRGB opal.library/PaletteMap24 opal.library/ReadPFPixel24 opal.library/ReadPixel24 opal.library/ReadPRPixel24 opal.library/RectFill24 opal.library/Refresh24 opal.library/RegWait24 opal.library/RGBtoOV opal.library/SaveIFF24 opal.library/SaveJPEG24 opal.library/Scroll24 opal.library/SetControlBit24 opal.library/SetCoPro24 opal.library/SetDisplayBottom24 opal.library/SetHires24 opal.library/SetLoadAddress24 opal.library/SetLores24 opal.library/SetPFStencil24 opal.library/SetPRStencil24 opal.library/SetRGB24 opal.library/SetScreen24 opal.library/SetSprite24 opal.library/SingleDisplay24 opal.library/SinglePlayField24 opal.library/StopUpdate24 opal.library/UpdateAll24 opal.library/UpdateCoPro24 opal.library/UpdateDelay24 opal.library/UpdatePalette24 opal.library/UpdatePFStencil24 opal.library/UpdateRegs24() opal.library/WriteFrame24 opal.library/WritePFPixel24 opal.library/WritePixel24 opal.library/WritePRPixel24 opal.library/WriteThumbnail24 opalreq.library/OpalRequester opal.library/ActiveScreen24 NAME ActiveScreen24 -- Provides a pointer to the currently displayed OpalVision screen. SYNOPSIS OScrn = ActiveScreen24 (void); D0 struct OpalScreen *OScrn; FUNCTION This function provides a pointer to the currently displayed OpalVision screen. If there is no OpalVision display active then a null value is returned. This call is useful for writing background colour cycling or coprocessor effects programs to affect the currently open screen. INPUTS None RESULT OScrn -A pointer to the currently open OpalVision screen, or NULL. CONSIDERATIONS Caution must be exercised when dealing with screens owned by another task. Bitplane access should be avoided unless running cooperative tasks with mutually exclusive bitplane access. SEE ALSO OpenScreen24() opal.library/AmigaPriority NAME AmigaPriority -- Gives Amiga graphics priority over OpalVision display. SYNOPSIS void AmigaPriority (void); FUNCTION This function clears the OVPRI bit of all CoPro instructions which gives Amiga graphics priority over OpalVision graphics. If a dual display has not been set, only Amiga graphics will be visible. INPUTS None RESULT None CONSIDERATIONS If an Opal display bottom has been set, the coprocessor instructions will not be modified for that region of the display. SEE ALSO OVPriority() DualDisplay24() opal.library/AppendCopper24 NAME AppendCopper24 -- Attaches user copper lists to existing display copper lists. SYNOPSIS void AppendCopper24 (CopLists); A0 UWORD **CopLists[12]; FUNCTION Up to 12 different Amiga copper lists are used to update the OpalVision memory. This function allows user copper lists to be attached to the end of each of the lists to enable split screen 24bit displays and other copper effects. Each copper list must be terminated with $FFFFFFFE followed by 30 free bytes for linkage code. After attaching copper lists, the LastWait field in the OpalScreen structure must be initialised with the last vertical position wait in the attached copper lists. The VStart field in the OpalScreen structure contains the scan line of the first displayed line for the screen. To convert a display 'y' coordinate to a vertical copper wait instruction, use VWait = y + VStart. INPUTS CopLists - Pointer to an array of 12 copper list pointers to be joined to the current display copper lists. RESULT None CONSIDERATIONS All copper lists must reside in chip ram. SEE ALSO opal.library/AutoSync24 NAME AutoSync24 -- Enables auto horizontal synchronisation. SYNOPSIS void AutoSync24 (Sync); D0 BOOL Sync; FUNCTION Enables the OpalVision's auto synchronisation mode (see "Horizontal Synchronisation"). This mode will be automatically disabled when frame buffer updates are occurring, and re-enabled when they cease. INPUTS Sync = 0 = Disable auto syncing, 1 = Enable auto syncing. RESULT None CONSIDERATIONS SEE ALSO opal.library/BitPlanetoOV NAME BitPlanetoOV -- Converts standard bitplane data to OpalVision format. SYNOPSIS void BitPlanetoOV (OScrn, SrcPlanes, SrcWidth, Lines, TopLine, SrcDepth) A0 A1 D0 D1 D2 D3 struct OpalScreen *OScrn; UBYTE **SrcPlanes[]; long SrcWidth; long Lines; long TopLine; long SrcDepth; FUNCTION Converts bit plane data from the supplied bitplanes into OpalVision memory format and stores this in the OpalScreen supplied. The source data will be clipped if it is wider than the destination screen, or will be padded out if it is narrower. INPUTS OScrn = Destination OpalScreen. SrcPlanes = A pointer to an array of pointers to source Bitplanes. SrcWidth = Byte width of source planes (must be even). Lines = Number of lines to convert. TopLine = Starting line to place destination data. SrcDepth = The number of bitplanes in SrcPlanes. RESULT None CONSIDERATIONS All bitplanes must start on a word boundary, and SrcWidth must be even. SEE ALSO OVtoBitPlane() opal.library/ClearDisplayBottom24 NAME ClearDisplayBottom24 -- Clears the OpalVision display bottom setting. SYNOPSIS void ClearDisplayBottom24 (void) FUNCTION Remove the OpalVision display bottom previously set with a call to SetDisplayBottom24(). INPUTS None RESULT None CONSIDERATIONS SEE ALSO SetDisplayBottom24() opal.library/ClearPFStencil24 NAME ClearPFStencil24 -- Clears the PlayField Stencil of the specified screen. SYNOPSIS void ClearPFStencil24 (OScrn); A0 struct OpalScreen *OScrn; FUNCTION Clears the playfield stencil (least significant bit of green bank 0) of all of the pixels in the specified screen. INPUTS OScrn = OpalScreen structure. RESULT None CONSIDERATIONS This will only have a visible effect if Dual Playfield mode has been set up using DualPlayField24(). SEE ALSO SetPFStencil24() DualPlayField24() SinglePlayField24() opal.library/ClearPRStencil24 NAME ClearPRStencil24 -- Clears the Priority Stencil of the specified Screen. SYNOPSIS void ClearPRStencil24 (OScrn); A0 struct OpalScreen *OScrn; FUNCTION Clears the priority stencil (least significant bit of blue bank 0) of the all of the pixels in the specified screen. INPUTS OScrn = OpalScreen structure. RESULT None CONSIDERATIONS This will only have a visible effect if dual OpalVision/Amiga display mode has been set up using DualDisplay24(). SEE ALSO SetPRStencil24() DualDisplay24() SingleDisplay24() opal.library/ClearQuick24 NAME ClearQuick24 -- Clears OpalVision frame buffer memory. SYNOPSIS void ClearQuick24 (void) FUNCTION This function clears the frame buffer memory as quickly as possible by enabling a write to all banks of memory. This function will also zero all bitplanes in memory (see ClearScreen24()). This operation will take 1 frame to clear any resolution non-interlaced display, and 2 frames for an interlaced display.This function acts on the current display screen and cannot be used for virtual screens. This function is called by OpenScreen24. INPUTS None RESULT None CONSIDERATIONS SEE ALSO ClearScreen24() opal.library/ClearScreen24 NAME ClearScreen24 -- Clears all bitplanes in a screen. SYNOPSIS void ClearScreen24 (OScrn) A0 struct OpalScreen *OScrn; FUNCTION Clear all bitplanes contained in the OpalScreen structure which may be a virtual screen or the display screen. This function clears the bitplane memory without updating the frame buffer (unless frame buffer updates are enabled). INPUTS OScrn = Pointer to the Opal screen to be cleared. RESULT None CONSIDERATIONS SEE ALSO ClearQuick24() opal.library/CloseScreen24 NAME CloseScreen24 -- Stop current display and free resources. SYNOPSIS void CloseScreen24 (void); FUNCTION This function closes the current displayed screen if it was opened by the current task. A screen opened by another task can be closed if it was opened with the CLOSEABLE24 flag. Backdrop and other low priority programs should use the following procedure to open screen. OScrn = OpenScreen24 (CLOSEABLE24); . . . . if (OScrn!=NULL) { WaitPort (OScrn->UserPort); CloseScreen24(); Mesg = GetMsg (OScrn->UserPort); ReplyMsg (Mesg); } The task will be sent a message when another task is trying to open a screen or close down the one already open. Note that the screen MUST be closed before replying to the message. An alternative method to create a backdrop is to update the frame buffer, latch the 24 bit display using LatchDisplay24() and then call CloseScreen24(). The contents of the frame buffer will remain visible until another task calls OpenScreen24(). INPUTS None RESULT None CONSIDERATIONS SEE ALSO OpenScreen24() opal.library/Config24 NAME Config24 -- Returns the OpalVision hardware configuration. SYNOPSIS Config = Config24 (void); D0 long Config; FUNCTION Returns flags indicating the hardware configuration of the 24bit display card, future flags will give details on the existence of OpalVision modules such as the Video Roaster Chip and the frame grabber genlock module. Current return flags are: OVCF_OPALVISION - Display board is an OpalVision card. OVCF_COLORBURST - Display board is a ColorBurst. INPUTS RESULT CONSIDERATIONS SEE ALSO opal.library/CreateScreen24 NAME CreateScreen24 -- Creates an arbitrarily sized virtual OpalScreen. SYNOPSIS OScrn = CreateScreen24 (ScreenModes,Width,Height) D0 D1 D2 struct OpalScreen *OScrn; long Width; long Height; long ScreenModes; FUNCTION This function can create an arbitrarily sized OpalScreen in Fast Ram. The bitplanes for the screen are allocated and an OpalScreen structure initialised, this is the virtual screen equivalent of OpenScreen24(). Once this screen has been opened, all drawing, file and Memory conversion functions can be applied to this screen, however it cannot be directly displayed. This allows large super bitmap screens to be allocated in fast ram for manipulation, or to be partially copied to a primary OpalScreen in chip ram for display (to allow for scrolling). NOTE: Virtual screens are now displayable using the LowMemUpdate() function, virtual screens are therefore recommended when doing one off frame buffer updates (such as the Show24 command) as it significantly reduces the chip ram requirements INPUTS Width = Width in pixels of the screen to be opened. Height = Height in pixels of the screen to be opened. ScreenModes = ScreenModes are identical to those of OpenScreen24(). RESULT OScrn = Is a pointer to the new OpalScreen structure or NULL if there is insufficient memory to open the screen size specified. CONSIDERATIONS This function allocates memory with no MEMF_ bits set, the program FastMemFirst should be executed to force all planes to be loaded into fast ram, under AmigaDOS 1.3 or previous. SEE ALSO FreeScreen24() OpenScreeen24() opal.library/DisablePRStencil24 NAME DisablePRStencil24 -- Disables the use of the priority stencil in dual display mode. SYNOPSIS void DisablePRStencil24 (void); FUNCTION This function clears the PRISTENCIL bit of all CoPro instructions. INPUTS None RESULT None CONSIDERATIONS If an Amiga display bottom has been set using SetDisplayBottom24(), the CoPro instructions will not be modified for that part of the display. The priority stencil will only have an effect when a Dual Display is enabled by calling DualDisplay24(). SEE ALSO EnablePRStencil() DualDisplay24() SingleDisplay24() opal.library/DisplayFrame24 NAME DisplayFrame24 -- Sets the currently displayed frame within the frame buffer memory. SYNOPSIS void DisplayFrame24 (Frame); D0 long Frame; FUNCTION Depending on the resolution of the displayed OpalVision screen, a number of screens can be stored in the frame buffer memory. The number of frames available for the screens resolution are given in the MaxFrames field in the OpalScreen structure. DisplayFrame24() allows each individual frame to be displayed separately where Frame is in the range 0...MaxFrames. Using a combination of WriteFrame24 and DisplayFrame24, it is possible to store several images in frame buffer memory and to perform simple page flip animation. INPUTS Frame = Frame number to display (0...MaxFrames). RESULT None CONSIDERATIONS The display frame and the write frame, must reside in the same field area in the frame buffer memory. (See "Memory Segment Diagram"). Due to this DisplayFrame24() has the side effect of changing the write frame if the new display frame is in a different field. SEE ALSO WriteFrame24() opal.library/DisplayThumbnail24 NAME DisplayThumbnail24 -- Displays a file's thumbnail. SYNOPSIS ReturnCode = DisplayThumbnail24 (OScrn, FileName, x, y); D0 A0 A1 D0 D1 long ReturnCode; struct OpalScreen *OScrn; char *FileName; long x; long y; FUNCTION This function displays the imbedded thumbnail in the file described by FileName if it exists. The x coordinate is rounded down to the nearest multiple of four in low resolution mode and to the nearest multiple of 8 in high resolution mode. The y coordinate is rounded down to the nearest even line in interlaced mode. INPUTS OScrn = Pointer to an OpalScreen structure. FileName= The file name of the picture file with the thumbnail. x = The x coordinate of the screen position to display the thumbnail. y = The y coordinate of the screen position to display the thumbnail. RESULT ReturnCode = OL_ERR Codes described in Opallib.h. OL_ERR_NOTHUMBNAIL is returned if no thumbnail exists in the file. CONSIDERATIONS Thumbnails must always be displayed in low resolution non interlaced mode. For an example of displaying thumbnails in a high resolution and interlaced screen, see the example program "DisplayDir.c" SEE ALSO WriteThumbnail24() SaveIFF24() opal.library/DrawEllipse24 NAME DrawEllipse24 -- Draw an ellipse of given dimensions. SYNOPSIS void DrawEllipse24 (OScrn, cx, cy, a, b) A0 D0 D1 D2 D3 struct OpalScreen *OScrn; long cx; long cy; long a; long b; FUNCTION Draws an ellipse in the supplied screen. NOTE: set a=b for circles. INPUTS OScrn = Destination OpalScreen. cx = Centre x-Coordinate of ellipse. cy = Centre y-Coordinate of ellipse. a = horizontal radius of ellipse (must be >0). b = vertical radius of ellipse (must be >0). RESULT CONSIDERATIONS The ellipse will only be rendered in the region specified by the clip region in the screen structure. SEE ALSO opal.library/DrawLine24 NAME DrawLine24 -- Draws a line into an OpalScreen. SYNOPSIS void DrawLine24 (OScrn, x1, y1, x2, y2) A0 D0 D1 D2 D3 struct OpalScreen *OScrn; long x1; long y1; long x2; long y2; FUNCTION Draws a line in the specified screen structure which may be a virtual or display screen. In 24bit mode the colour of the line is specified by the Pen_R, Pen_G and Pen_B fields in the OpalScreen structure. In 15bit mode, Pen_R and Pen_G specify the colour of the line, while in 8bit only Pen_R is used. INPUTS OScrn = The OpalScreen structure in which to draw. x1, y1 = The starting co-ordinates of the line. x2, y2 = The ending co-ordinates of the line. RESULT CONSIDERATIONS The line will only be rendered in the region specified by the clip region in the screen structure. SEE ALSO opal.library/DualDisplay24 NAME DualDisplay24 -- Sets up an Amiga/OpalVision dual display. SYNOPSIS void DualDisplay24 (void); FUNCTION This function clears the DUALDISPLAY bit of all CoPro instructions, enabling a Dual Amiga/OpalVision display. The priority of the Amiga/OpalVision graphics can be set with OVPriority() and AmigaPriority(). INPUTS None RESULT None CONSIDERATIONS If an Amiga display bottom has been set, using the SetDisplayBottom24() the CoPro instructions will not be modified for that region of the display. SEE ALSO SingleDisplay24() AmigaPriority() OVPriority() opal.library/DualPlayField2 NAME DualPlayField24 -- Sets up an OpalVision 24bit dual playfield. SYNOPSIS void DualPlayField (void) FUNCTION This function sets the DUALPLAYFIELD bit of all CoPro instructions, allowing a dual 24 bit overlay mode. To determine which bank is displayed for each pixel, the playfield stencil needs to be set accordingly. INPUTS None RESULT None CONSIDERATIONS If an Amiga display bottom has been set using SetDisplayBottom24(), the coprocessor instructions will not be modified for that region of the display. SEE ALSO SinglePlayField24() opal.library/EnablePRStencil24 NAME EnablePRStencil24 -- Enables the use of the priority stencil in dual display mode. SYNOPSIS void EnablePRStencil24 (void); FUNCTION This function set the PRISTENCIL bit of all CoPro instructions. INPUTS None RESULT None CONSIDERATIONS If an Amiga display bottom has been set using SetDisplayBottom24(), the CoPro instructions will not be modified for that part of the display. The priority stencil will only have an effect when a Dual Display is enabled by calling DualDisplay24(). SEE ALSO DisablePRStencil() DualDisplay24() SingleDisplay24() opal.library/FadeIn24 NAME FadeIn24 -- Fades display in from black. SYNOPSIS void FadeIn24 (Time); D0 long Time; FUNCTION Fade the current display from black to true colour. The Time parameter specifies the amount of time in 1/100 seconds the fade should take and is independent of PAL or NTSC refresh rates. INPUTS Time = Time in 1/100 seconds to complete fade. RESULT None CONSIDERATIONS This function cannot be used in 15bit mode. SEE ALSO FadeOut24() opal.library/FadeOut24 NAME FadeOut24 -- Fade display to black. SYNOPSIS void FadeOut24 (Time) D0 long Time; FUNCTION Fade the current display from true colour to black. The Time parameter specifies the amount of time the fade should take and is independent of PAL or NTSC machines. INPUTS Time = Number of 1/100ths seconds in which to complete the fade. RESULT None CONSIDERATIONS This function cannot be used in 15bit mode. SEE ALSO FadeIn24() opal.library/FreeScreen24 NAME FreeScreen24 -- Frees a virtual OpalScreen. SYNOPSIS void FreeScreen24 (OScrn); A0 struct OpalScreen *OScrn; FUNCTION This function deallocates all memory associated with a virtual screen. This is the virtual screen equivalent of CloseScreen24. INPUTS OScrn = A pointer to the virtual screen to be freed RESULT None CONSIDERATIONS SEE ALSO CreateScreen24() CloseScreen24() opal.library/FreezeFrame24 NAME FreezeFrame24 -- Freezes the currently displayed screen. SYNOPSIS void FreezeFrame24 (Freeze); D0 BOOL Freeze FUNCTION This function freezes the current display. If freeze is TRUE, the display is held static. The display is returned to normal when the value for freeze is FALSE. Freeze freezes everything on the display including Amiga graphics. INPUTS Freeze = TRUE (1) = Freeze, FALSE (0) = Unfreeze RESULT None CONSIDERATIONS This functions is available only while a Scan Rate Converter is present. SEE ALSO opal.library/ILBMtoOV NAME ILBMtoOV -- Converts interleaved bitmap to OpalVision format. SYNOPSIS void ILBMtoOV (OScrn, ILBMData, SrcWidth, Lines, TopLine, SrcPlanes) A0 A1 D0 D1 D2 D3 struct OpalScreen *OScrn; UBYTE *ILBMData; long SrcWidth; long Lines; long TopLine; long SrcPlanes; FUNCTION Converts interleaved bitmap memory into OpalVision memory format and stores this in the OpalScreen supplied. The source data will be clipped if it is wider than the destination screen, or will be padded out if it is narrower. This function is provided to simplify the task of writing a custom IFF loader. INPUTS OScrn = Destination OpalScreen. ILBMData = interleaved planes of source data. SourceWidth = Width of source ILBM data. Lines = Number of lines to convert. TopLine = Starting line to place destination data. SrcPlanes =The number of planes contained in the ILBM data. RESULT None CONSIDERATIONS SEE ALSO OVtoILBM() opal.library/LatchDisplay24 NAME LatchDisplay24 -- Locks OpalVision display SYNOPSIS void LatchDisplay24 (Latch) BOOL Latch; FUNCTION LatchDisplay24 sets or clears the Latch bit in the control line register. If this bit is set, the OpalVision display will remain active regardless of whether there is a valid control line in the Amigas' output. If CloseScreen24() is called after the latch bit is set, all memory and resources will be freed but the display will still be active, even if the Amiga is reset. OpalHotKey uses this technique, images are loaded and updated into the buffer, latched and then the screen is closed. If any register information needs to be changed, such as changing display priority a display screen is opened using the CONTROLONLY24 flag which enables registers to be changed without effecting the contents of the frame buffer. INPUTS Latch = 0 = Free display, 1 = Latch display. RESULT None CONSIDERATIONS SEE ALSO opal.library/LoadImage24 NAME LoadImage24 / LoadIFF24 -- Loads an Image file. SYNOPSIS ReturnCode = LoadImage24 (OScrn,FileName,Flags) D0 A0 A1 D0 long ReturnCode; struct OpalScreen *OScrn; long Flags; char *FileName; FUNCTION Load an IFF or JPEG file. This is a general purpose image loading routine which will automatically detect and load IFF and JPEG files. As this is a general loader, the name of this function has been renamed to LoadImage24(), which is used as a synonym for the previous function name LoadIFF24() to maintain backward compatibility. The IFF portion of this loader will load IFF 24bit, Fast Format 24 bit, Palette mapped (up to 256 colours), Hold and Modify and Extra half brite files. All palette mapped files will be loaded in the 8 bit palette mapped mode unless the CONVERT24 flag is set, in which case they will be converted to a non palette mapped 24 bit display. There are several different forms in which LoadImage24 can load an image. The way in which it functions is dependant on the specified screen and the flags. If the screen pointer is NULL then LoadImage24 will open a screen itself, the screen it opens will be a display screen unless VIRTUALSCREEN24 is set in which case a virtual screen will be created. If the passed screen structure is not NULL and the image being loaded is the same resolution, then it will be loaded into that screen. If this is not the case then the screen will be closed and a new screen of the same resolution as the file will be opened. However if KEEPRES24 is set, the file will be loaded into the supplied screen regardless of its resolution. LoadImage24 returns one of two things. If the files was loaded successfully, a pointer to the screen into which it was loaded is returned. If an error occurred, then an error code will be returned. To determine which of these messages has been returned, the value can be compared to OL_ERR_MAXERR, if it is lower than this value then the result is an error code, if it is greater than this number then it is a screen pointer. If the image is not IFF or JPEG, OL_ERR_FORMATUNKOWN is returned. Flags: FORCE24 - Convert palette mapped files to 24 bit. KEEPRES24 - Keep the same screen resolution. CLOSEABLE24 - Opened screen will be closeable. LOADMASK24 - Load mask plane if present (IFF only). VIRTUALSCREEN24 - Load image into a virtual screen. The JPEG loader is a baseline loader as specified in the draft standard ISO/IEC Bis 10918-1 it supports only 8 bit quantization tables and Huffman entropy compression. It can load files with source colour space of Y Cb Cr, RGB and Grey scale. It does not support non interleaved files, progressive, hierarchical or lossless modes. INPUTS FileName = Filename of image to be display (including path). Flags = see above. RESULT ReturnCode = > OL_ERR_MAXERR Return code is a pointer to an Opal screen structure. ReturnCode = < OL_ERR_MAXERR, Return code indicates error. CONSIDERATIONS This function only loads an image, it does not update the frame buffer. To do this you must call Refresh24() or LowMemUpdate24(). SEE ALSO SaveIFF24() SaveJPEG24() Refresh24() LowMemUpdate24() opal.library/LowMemUpdate24 NAME LowMemUpdate24 -- Low chip ram usage OpalVision update. SYNOPSIS RetScrn = LowMemUpdate24 (OScrn, Frame); D0 A0 D0 struct OpalScreen *RetScrn; struct OpalScreen *OScrn; long Frame; FUNCTION Updates the frame buffer from a virtual screen. This function can update an entire image of any resolution while only using a small amount of chip ram. This routine uses an 8bit screen to update each memory segment separately, the CPU is used to copy the bitplane data from the virtual screen to chip ram. The 8bit plane display screen opened to perform the update is returned, and should be subsequently closed. The Frame input sets the first memory segment to be updated, this will normally be 0. This can be set to 6 for example to update a lores screen to bank1 instead of bank0. NOTE: OScrn must be a pointer to a virtual screen. INPUTS OScrn = The virtual OpalScreen to be displayed Frame = Memory segment to start update (0..11). RESULT RetScrn >= OL_ERR_MAXERR Return code is a pointer to an Opal screen structure. RetScrn < OL_ERR_MAXERR, Return code indicates error. CONSIDERATIONS SEE ALSO LowMem2Update24() opal.library/LowMem2Update24 NAME LowMem2Update24 -- Low chip ram usage OpalVision update. SYNOPSIS RetScrn = LowMem2Update24 (OScrn, Frame); D0 A0 D0 struct OpalScreen *RetScrn; struct OpalScreen *OScrn; long Frame; FUNCTION Updates the frame buffer from a virtual screen. This function can update an entire image of any resolution while only using a small amount of chip ram. This routine uses an 8bit screen to update each memory segment separately, the CPU is used to copy the bitplane data from the virtual screen to chip ram. The 8bit plane display screen opened to perform the update is returned, and should be subsequently closed. The Frame input sets the first memory segment to be updated, this will normally be 0. This can be set to 6 for example to update a lores screen to bank1 instead of bank0. This function is similar to LowMemUpdate24() although it only updates the frame buffer memory, it does not modify the display modes, CoPro bits or palette information. This is very useful for performing transitions between two images in lores, the first image can be written into bank1 and displayed using LowMemUpdate24(OScrn,6), the second image is then updated transparently into bank0 using LowMem2Update24(OScrn,0). The dual display stencil can then be used to perform the transition between bank1 and bank0. Note that bank0 is written to last , as only bank0 contains the dual display stencil. NOTE: OScrn must be a pointer to a virtual screen. INPUTS OScrn = The virtual OpalScreen to be displayed Frame = Memory segment to start update (0..11). RESULT RetScrn >= OL_ERR_MAXERR Return code is a pointer to an Opal screen structure. RetScrn < OL_ERR_MAXERR, Return code indicates error. CONSIDERATIONS SEE ALSO LowMemUpdate24() opal.library/LowMemRGB24 NAME LowMemRGB24 -- Low chip ram usage OpalVision update from an RGB array. SYNOPSIS RetScrn = LowMemRGB24 (ScreenModes, Frame, Width, Height, Modulo, RGBPlanes); D0 D0 D1 D2 D3 D4 A0 struct OpalScreen *RetScrn; long ScreenModes,Frame,Width,Height,Modulo; UBYTE *RGBPlanes[3] FUNCTION Updates the frame buffer from RGB byte planes. This function can update an entire image of any resolution while only using a small amount of chip ram. This routine uses an 8bit screen to update each memory segment separately, the RGB data is converted into bitplane format one segment at a time and transferred into the framebuffer. The 8bit plane display screen opened to perform the update is returned, and should be subsequently closed. The Modulo parameter allows interleaved RGB data to be updated as well, in this case RGBPlanes would be initialised 'Width' bytes apart, and modulo would be set to 2*Width. This function is useful for image processing programs such as ADPro and Imagemaster which store images in byte planes. INPUTS ScreenModes = See OpenScreen24, these flags enable the resolution and format of the displayed image to be set. Frame = The memory segment to start the update, (0..1) Width = Width of the RGB Array (in pixels). Height = Height of the RGB Array. Modulo = Modulo to be added after each line in the RGB Array. RGBPlanes = Pointers to the three byte planes required (R,G,B). RESULT RetScrn >= OL_ERR_MAXERR Return code is a pointer to an Opal screen structure. RetScrn < OL_ERR_MAXERR, Return code indicates error. CONSIDERATIONS SEE ALSO opal.library/OpenScreen24 NAME OpenScreen24 -- Allocates all resources and displays an OpalVision screen. SYNOPSIS OScrn = OpenScreen24 (ScreenModes) D0 D0 struct OpalScreen *OScrn; long ScreenModes; FUNCTION This function creates a display screen and allocates all the resources required to display the screen. The Frame buffer memory is cleared and updates are disabled to the frame buffer memory. The screen is positioned according to Amiga preferences, however if the vertical starting position defined in preferences is too high up, preferences will be modified to set the vertical starting position to the highest possible, the preferences will be restored when the screen is closed. The screen will be opened as single playfield, single display mode with OVPriority. If the CONTROLONLY24 flag is set, the screen will be opened without any bitplanes, this enables the copro or palette information of a 'latched on' to be modified without losing the contents of the frame buffer. ScreenModes: INTERLACE24 - Open an interlaced screen. HIRES24 - Open a Hires screen. OVERSCAN24 - Open an overscan screen. PLANES15 - 15 bit true colour display. PLANES8 - 8 bit true colour/palette mapped display. CLOSEABLE24 - Screen can be closed by another task. PALMAP24 - Open a palette mapped screen. CONTROLONLY24 - Open a bitplaneless screen. Screen Sizes: Hires Interlaced Overscan PAL NTSC No No No 320x256 320x200 Yes No No 640x256 640x200 No Yes No 320x512 320x400 Yes Yes No 640x512 640x400 The size of the screen opened will be as specified above unless there is not enough chip ram available, in which case the maximum amount of lines possible will be displayed. If there is insufficient chip memory, to hold half of the scan lines, then OpenScreen will be aborted and NULL returned. If the PLANES8 or PLANES15 flag is not set, a 24 bit screen will be opened. INPUTS ScreenModes = See above. RESULT OScrn = A pointer to an OpalScreen structure or NULL if unsuccessful. CONSIDERATIONS SEE ALSO CloseScreen24() LatchDisplay24() opal.library/OVPriority NAME OVPriority -- Give OpalVision graphics priority over Amiga graphics. SYNOPSIS void OVPriority (void); FUNCTION This function sets the OVPRI bit of all coprocessor instructions which gives OpalVision graphics priority over Amiga graphics. If a dual display has not been set, only OpalVision graphics will be visible. INPUTS None RESULT None CONSIDERATIONS If an Amiga display bottom has been set using SetDisplayBottom24(), the coprocessor instructions will not be modified for that region of the display. SEE ALSO AmigaPriority24() DualDisplay24() opal.library/OVtoBitPlane NAME OVtoBitPlane -- Convert OpalVision bit plane data to standard bitplanes. SYNOPSIS void OVtoBitPlane (OScrn, BitPlanes, DestWidth, Lines, TopLine) A0 A1 D0 D1 D2 struct OpalScreen *OScrn; UBYTE **BitPlanes[]; long DestWidth; long Lines; long TopLine; FUNCTION Converts OpalVision bitplane format to standard bitplane data. The destination data will be non- interleaved 24, 15 or 8 planes depending on the type of display OScrn is. Note that the 15bit display mode is actually stored internally as 16 bitplanes which in turn causes this function to return 16 planes instead of 15. DestWidth specifies the width of the destination bitplanes, if the width is less than the source planes, they will be clipped. If the destination width is larger, the remaining bytes on each scan line will be skipped. The OpalScreen can be any size, and reside in fast or chip ram. The array of bitplane pointers passed to this function must contain 8, 16 or 24 entries depending on the screen type. INPUTS OScrn = OpalScreen structure describing source data. BitPlanes = Array of bitplane pointers to take the destination data. DestWidth = Width in bytes of destination planes (must be even). Lines = Total number of scan lines to convert. TopLine = Starting line for conversion within the OpalScreen. RESULT None CONSIDERATIONS All bitplanes must be on a word boundary and the destination width must be even. SEE ALSO BitplanetoOV() opal.library/OVtoILBM NAME OVtoILBM -- Converts OpalVision bit planes to interleaved bitmap format. SYNOPSIS void OVtoILBM (OScrn, ILBMData, DestWidth, Lines, TopLine) A0 A1 D0 D1 D2 struct OpalScreen *OScrn; UBYTE *ILBMData; long DestWidth; long Lines; long TopLine; FUNCTION Converts bitplane information from the supplied OpalScreen, starting at the scan line indicated by TopLine, into interleaved bitmap format. If the source OpalScreen is wider than the destination width, the planes will be clipped. If the OpalScreen is narrower, the extra bytes on each line will be skipped. The OpalScreen can be any size, and reside in fast or chip ram. The memory pointed to by ILBMData must be large enough to hold DestWidth * lines * (8 or 16 or 24 depending on screen type) bytes. INPUTS OScrn = OpalScreen structure describing source data. ILBMData = Pointer to buffer to hold destination ILBM data. DestWidth = Width of destination ILBM planes. (must be even) Lines = Total number of scan lines to convert. TopLine = Starting line for conversion within the OpalScreen. RESULT None CONSIDERATIONS ILBMData must start on a word boundary, and DestWidth must be even. SEE ALSO ILBMtoOV() opal.library/OVtoRGB NAME OVtoRGB -- Converts OpalVision bitplane data to three planes of RGB. SYNOPSIS void OVtoRGB (OScrn, RGBPlanes[], Top, Left, Width, Height) A0 A1 D0 D1 D2 D3 struct OpalScreen *OScrn; UBYTE **RGBPlanes[]; long Top; long Left; long Width; long Height; FUNCTION This call converts bitplane data from the OpalScreen into three planes, one containing Red, one Blue and the last Green, each of these has one byte per pixel. This is useful for making 'brush' cut-outs, or for subsequent scaling of data. This function is more flexible than the other memory conversion routines in that it can convert a rectangular region of bitplane memory positioned anywhere within the source screen. The OpalScreen can be any size, and reside in fast or chip ram. INPUTS OScrn = OpalScreen structure containing source bitplanes. RGBPlanes = Pointer to an array of 3 plane pointers. Top = x coordinate of top left hand corner to start conversion. Left = y coordinate of top left hand corner to start conversion. Width = Width in pixels of region to cut. Height = Number of lines to cut. RESULT CONSIDERATIONS The destination planes must be on a word boundary. SEE ALSO RGBtoOV() opal.library/PaletteMap24 NAME PaletteMap24 -- Enable/Disable palette mapping. SYNOPSIS PaletteMap24 (PaletteMap) D0 BOOL PaletteMap; FUNCTION If PaletteMap = TRUE, turn on palette mapping, else turn palette mapping off. This function always operates on the active display screen. INPUTS PaletteMap = True to turn palette mapping on, to turn it off. RESULT None CONSIDERATIONS This function cannot be used in 15bit mode. SEE ALSO SetPalette24() opal.library/ReadPFPixel24 NAME ReadPFPixel24 -- Returns the state of a give playfield stencil pixel. SYNOPSIS Result = ReadPFPixel24 (OScrn, x, y) D0 A0 D0 D1 long Result; struct OpalScreen *OScrn; long x; long y; FUNCTION This function returns 1 if the corresponding playfield stencil pixel is set, or 0 if it is cleared. If the coordinates are outside of the clip boundary then -1 is returned. INPUTS OScrn = OpalScreen to be read. x = x Coordinate of pixel to read. y = y Coordinate of pixel to read. RESULT Result = 0 if pixel clear , or 1 if pixel set, -1 if pixel is out of range. CONSIDERATIONS SEE ALSO WritePFPixel24() ClearPFStencil24() SetPFStencil24() opal.library/ReadPixel24 NAME ReadPixel24 -- Returns colour information for a given pixel. SYNOPSIS Error = ReadPixel24 (OScrn, x, y) D0 A0 D0 D1 long Error; struct OpalScreen *OScrn; long x; long y; FUNCTION Return the colour (bit plane) information for a given pixel. If the OpalScreen is in palette mapped mode, the actual bit plane data (and not the corresponding palette value) will be returned. The returned value is placed in Red, Green and Blue in the OpalScreen structure while in 24bit modes. In 15bit mode, the colour is returned in Red and Green, while in 8bit mode, the colour is returned in Red. The GetPen macros can be used to extract the components from the returned value. Use the macros GetCol24(), GetCol15(), GetCol8() or GetCol8P() for 8 bit palette mapped to return the pixel value. If the coordinates are outside the screen's clipping region, Error will be -1, else Error = 0. This function can operate on any sized screens in chip or fast ram. INPUTS OScrn = OpalScreen to be read. x = x Coordinate of pixel to read. y = y Coordinate of pixel to read. RESULT Error = 0 if no error occurred, or -1 if pixel was out of the clipping region. CONSIDERATIONS SEE ALSO WritePixel24() opal.library/ReadPRPixel24 NAME ReadPRPixel24 -- Returns the state of a give priority stencil pixel. SYNOPSIS Result = ReadPRPixel24 (OScrn, x, y) D0 A0 D0 D1 long Result; struct OpalScreen *OScrn; long x; long y; FUNCTION This function returns 1 if the corresponding priority stencil pixel is set, or 0 if it is cleared. If the coordinates are outside of the clip boundary then -1 is returned. INPUTS OScrn = OpalScreen to be read. x = x Coordinate of pixel to read. y = y Coordinate of pixel to read. RESULT Result = 0 if pixel clear , or 1 if pixel set, -1 if pixel is out of range. CONSIDERATIONS SEE ALSO WritePRPixel24() ClearPRStencil24() SetPRStencil24() opal.library/RectFill24 NAME RectFill24 -- Draws a solid rectangle. SYNOPSIS void RectFill24 (OScrn, Left, Top, Bottom, Right) A0 D0 D1 D2 D3 struct OpalScreen *OScrn; long Left; long Top; long Bottom; long Right; FUNCTION Draws a solid rectangle with the colour specified by Pen_R,Pen_G & Pen_B in the OpalScreen structure. The Rectangle is clipped if all or part of it lies outside the clipping region. INPUTS OScrn = OpalScreen to be rendered into. Left = x coordinate of top left-hand corner of the rectangle. Top = y coordinate of top left-hand corner of the rectangle. Bottom = x coordinate of the bottom right-hand corner of rectangle. Right = y coordinate of the bottom right-hand corner of rectangle. RESULT None CONSIDERATIONS SEE ALSO opal.library/Refresh24 NAME Refresh24 -- Refreshes the frame buffer. SYNOPSIS void Refresh24 (void) FUNCTION Initiates DMA of the currently displayed OpalScreen to the framebuffer. This function will update the framebuffer in the minimum number of frames required, stop DMA (updates) and return. This function should be called after any drawing routine, and other routines such as LoadIFF24 which modify memory, to make the frame buffer (and hence display) consistent with the image in Amiga memory. INPUTS None RESULT None CONSIDERATIONS SEE ALSO UpdateDelay24() StopUpdate24() UpdatePFStencil24() UpdateAll24() opal.library/RegWait24 NAME RegWait24 -- Wait for register update to complete. SYNOPSIS void RegWait24 (void); FUNCTION This function waits for register information to be updated to the OpalVision before returning, or returns immediately if no updates are pending. This function is important for synchronizing your program with the OpalVision's update scheme. After any direct modification of OpalVision registers or after a call to a library function which modifies registers, this function should be called to allow the update to occur, If this function is not called register data may be lost. INPUTS None RESULT None CONSIDERATIONS SEE ALSO opal.library/RGBtoOV NAME RGBtoOV -- Converts three planes of RGB to OpalVision bitplane data. SYNOPSIS void RGBtoOV (OScrn, RGBPlanes[], Top, Left, Width, Height) A0 A1 D0 D1 D2 D3 struct OpalScreen *OScrn; UBYTE **RGBPlanes[]; long Top; long Left; long Width; long Height; FUNCTION This call converts three source planes, one containing Red, one Blue and the last Green into OpalVision bitplane format. This function is useful for pasting clipped regions (using OVtoRGB) back into OpalVision memory, or for pasting back data after scaling. Unlike the other conversion routines, this function is clipped if it is outside of the clipping region, this enables it to be used as a drawing function rather than a conversion function. The OpalScreen can be any size, and reside in fast or chip ram. INPUTS OScrn = OpalScreen structure containing destination bitplanes. RGBPlanes = Pointer to an array of 3 plane pointers. Top = x coordinate of top left hand corner to start conversion. Left = y coordinate of top left hand corner to start conversion. Width = Width in pixels of region to cut. Height = Number of lines to cut. RESULT None CONSIDERATIONS SEE ALSO OVtoRGB() opal.library/SaveIFF24 NAME SaveIFF24 -- Save an OpalScreen as an IFF file. SYNOPSIS Error = SaveIFF24 (OScrn, FileName, ChunkFunction, Flags) D0 A0 A1 A2 D0 long Error; struct OpalScreen *OScrn; char *FileName; long (*ChunkFunction)(); long Flags; FUNCTION SaveIFF24 will save any sized OpalScreen in normal IFF file format. The chunks written will include CAMG - Containing the resolution (Hires/Interlace/Overscan) CMAP - Colour map if in 8bit mode. CLUT - Colour lookup tables if in true colour mode. OVTN - OpalVision 24bit thumb-nail for display in OpalPaint, OpalShow and other system software. BODY - Standard 24 bit ILBM data using byte run encoding. If ChunkFunction is not NULL, the function that it points at will be called after the file has been opened (and FORM ILBM has been written) and before any other chunks have been written. ChunkFunction is used to insert your own chunks into the IFF file before any of the above chunks. The DOS File Handle for the open file will be passed to the function on the stack (in standard C calling convention) the chunk function must return 0 or an error code. Flags: OVFASTFORMAT - Save as OpalVision fast format. NOTHUMBNAIL - Inhibit writing thumb-nail chunk. SAVEMASK24 - Saves mask plane if one exists. INPUTS OScrn = OpalScreen to be saved. FileName = Filename of file to be written (including full path). ChunkFunction = Pointer to code to be executed after file is opened. RESULT Error = 0 if no error code, >0 if error occurred. CONSIDERATIONS SEE ALSO LoadImage24() SaveJPEG24() opal.library/SaveJPEG24 NAME SaveJPEG24 -- Save an OpalScreen as a JPEG JFIF file. SYNOPSIS Error = SaveJPEG24 (OScrn, FileName, Flags, Quality) D0 A0 A1 D0 D1 long Error; struct OpalScreen *OScrn; char *FileName; long Flags; long Quality; FUNCTION SaveJPEG24 will save any sized OpalScreen in the JPEG JFIF file format. JPEG is a compression standard which enables a large amount of compression to be gained on continuous tone images with minimum loss in image quality. It should be stressed that this compression method is based on continuous tone images and compression of images with sharp edges may suffer more degradation. For more details see the JPEG draft standard ISO/IEC Dis10918-1. This generates a base line JPEG file using interleaved components, Huffman entropy compression and 8 bit quatization tables. A thumbnail will also be written into the APP0 marker of the JFIF file unless the NOTHUMBNAIL flag is set. The quality factor is a percentage value (0...100) which defines the allowable amount of loss in the compressed image. A factor of 100 corresponds to a quantization table of all 1's and hence has no quantization loss. A value of 50 corresponds to the quantization tables suggested by the draft standard as being acceptable for good image quality. A reasonable default value to use is 75, using this level for continuous tone scanned images a compression factor of between 15:1 and 20:1 is typical. Flags: NOTHUMBNAIL - Inhibit writing thumb-nail chunk. INPUTS OScrn = OpalScreen to be saved. FileName= Filename of file to be written (including full path). Flags = See above. Quality = (0...100) This determines the amount of loss allowed in the compression of the image. 100 % corresponds to minimum loss. RESULT Error = 0 if no error code, >0 if error occurred. CONSIDERATIONS SEE ALSO LoadImage24() opal.library/Scroll24 NAME Scroll24 -- Scrolls currently displayed OpalVision image. SYNOPSIS void Scroll24 (DeltaX, DeltaY) D0 D1 long DeltaX; long DeltaY; FUNCTION This function scrolls the currently displayed image by DeltaX pixels horizontally, and DeltaY lines vertically, by modifying the video load address register in the OpalVision. DeltaX and DeltaY are signed values, to enable scrolling in all directions. This function also clears the ADDLOAD bit on the first CoPro instruction if it is not already cleared. INPUTS DeltaX = Number of pixels to scroll horizontally. DeltaY = Number of lines to scroll vertically. RESULT None CONSIDERATIONS For the Scroll to function correctly, update DMA to the framebuffer must be turned off by calling StopUpdate24(). SEE ALSO SetLoadAddress24() opal.library/SetControlBit24 NAME SetControlBit24 -- Modifies a bit in the control line register. SYNOPSIS void SetControlBit24 (FrameNumber, BitNumber, State) D0 D1 D2 long FrameNumber; long BitNumber; BOOL State; FUNCTION Sets or clears a bit in the control line register. See "The Opal Control Line Register" for details. There are 14 different versions of the control line register used to update the maximum of 12 different memory segments. These differ by the state of the bank and field write enable bits. The frame number variable specifies which one of these registers should be updated, for bits such as AUTO or COL/CoPro a global change may be required (i.e. changing all 12 control lines). Frame Number Description 0 Red Bank0, Field0 Update 1 Green Bank0, Field0 Update 2 Blue Bank0, Field0 Update 3 Red Bank0, Field1 Update 4 Green Bank0, Field1 Update 5 Blue Bank0, Field1 Update 6 Red Bank1, Field0 Update 7 Green Bank1, Field0 Update 8 Blue Bank1, Field0 Update 9 Red Bank1, Field1 Update 10 Green Bank1, Field1 Update 11 Blue Bank1, Field1 Update 12 Field 0 Display only 13 Field 1 Display only INPUTS FrameNumber = The OpalVision update frame number to modify. One frame corresponds to one bank update (maximum 12 frames, 2 noupdate lists). BitNumber = Bit number within control line to modify (4...19). State = State to be written into bit (Boolean). RESULT None CONSIDERATIONS These bits should be modified with caution. SEE ALSO Control Line Register opal.library/SetCoPro24 NAME SetCoPro24 -- Modifies a single instruction in the CoPro list. SYNOPSIS void SetCoPro24 (InstructionNumber, Instruction); D0 D1 long InstructionNumber; long Instruction; FUNCTION This function modifies a single CoPro instruction and initiates an update to the OpalVision CoPro. Note that this function is much faster than calling UpdateCoPro24(). INPUTS InstructionNumber = The CoPro instruction number (0...289) Instruction = 8Bit CoPro instruction. See "The CoPro" RESULT None CONSIDERATIONS InstructionNumber should be less than LastCoProIns in the OpalScreen structure. SEE ALSO UpdateCoPro24() opal.library/SetDisplayBottom24 NAME SetDisplayBottom24 -- Sets the lower limit of the OpalVision screen. SYNOPSIS Result = SetDisplayBottom24 (BottomLine); D0 long BottomLine; BOOL Result; FUNCTION This function specifies the lower limit of the OpalVision screen. Below this point Amiga only graphics will be displayed. Once a display bottom has been set, the region below that line will always contains Amiga graphics regardless of whether the frame buffer is being updated or not. This is useful for displaying Amiga gadgets on the screen. INPUTS BottomLine -Specifies the last line of OpalVision graphics. RESULT Result = 1 if operation successful, 0 if operation failed. CONSIDERATIONS This function uses the CoPro to enable Amiga graphics on the bottom section of the screen. To ensure that the display is not corrupted, only CoPro instructions up to the line specified by LastCoProIns in the OpalScreen structure should be modified. SEE ALSO ClearDisplayBottom24 () opal.library/SetHires24 NAME SetHires24 -- Enable a hires display for a section of the screen. SYNOPSIS Result = SetHires24 (TopLine, Lines); D0 D1 long TopLine; long Lines; FUNCTION Sets the HIRESDISP bits on CoPro instructions starting at TopLine for 'Lines' number of lines. Both TopLine and Lines must be specified as a non-interlaced scan line (i.e. must be divided by 2 if an interlaced screen). INPUTS TopLine -Specifies the first line to start setting HIRESDISP bits. Lines -Number of lines to modify. RESULT None CONSIDERATIONS SEE ALSO SetLores24 () opal.library/SetLoadAddress24 NAME SetLoadAddress24 -- Updates the OpalVision load address register. SYNOPSIS void SetLoadAddress24 (void) FUNCTION This function uses the Load Address value in the displayed OpalScreen structure to update the load address register in the OpalVision. This function is useful for scrolling and distortion effects. The modulo for a scan line is given in the OpalScreen structure and is independent of the display resolution. INPUTS None RESULT None CONSIDERATIONS Load Address only has an effect when a CoPro instruction having its ADDLOAD bit cleared is executed. Therefore a combination of CoPro instructions and the address load register are required to produce the effect. SEE ALSO Scroll24() opal.library/SetLores24 NAME SetLores24 -- Enable a Lores display for a section of the screen. SYNOPSIS Result = SetLores24 (TopLine, Lines); D0 D1 long TopLine; long Lines; FUNCTION Clears the HIRESDISP bits on CoPro instructions starting at TopLine for 'Lines' number of lines. Both TopLine and Lines must be specified as a non-interlaced scan line (i.e. must be divided by 2 if an interlaced screen). INPUTS TopLine -Specifies the first line to start clearing HIRESDISP bits. Lines -Number of lines to modify. RESULT None CONSIDERATIONS SEE ALSO SetHires24 () opal.library/SetPFStencil24 NAME SetPFStencil24 -- Sets the PlayField Stencil of the specified Screen. SYNOPSIS void SetPFStencil24 (OScrn); A0 struct OpalScreen *OScrn; FUNCTION Sets the playfield stencil (least significant bit of green bank 0) of all of the pixels in the specified screen. INPUTS OScrn = OpalScreen structure. RESULT None CONSIDERATIONS This will only have an effect if Dual Playfield mode has been set up using DualPlayField24(). SEE ALSO ClearPFStencil() DualPlayField24() SinglePlayField24() opal.library/SetPRStencil24 NAME SetPRStencil24 -- Sets the Priority Stencil of the specified Screen. SYNOPSIS void SetPRStencil24 (OScrn); A0 struct OpalScreen *OScrn; FUNCTION Sets the priority stencil (least significant bit of blue bank 0) of all pixels in the specified screen. INPUTS OScrn = OpalScreen structure. RESULT None CONSIDERATIONS This will only have an effect if dual OpalVision/Amiga display mode has been set up using DualDisplay24(). SEE ALSO ClearPRStencil() DualDisplay24() SingleDisplay24() opal.library/SetRGB24 NAME SetRGB24 -- Updates a single palette entry to the OpalVision palette registers. SYNOPSIS void SetRGB24 (Entry, Red, Green, Blue); D0 D1 D2 D3 long Entry; long Red; long Green; long Blue; FUNCTION This function updates a single palette entry in the OpalVision palette registers. INPUTS Entry - The entry selected for update (0-255). Red - Red value (0-255). Green - Green value (0-255). Blue - Blue value (0-255). RESULT None CONSIDERATIONS This function will only have a visible effect when in palette mapped mode. SEE ALSO PaletteMap () SetPalette () opal.library/SetScreen24 NAME SetScreen24 -- Fills screen with a specified colour. SYNOPSIS void SetScreen24 (OScrn) A0 struct OpalScreen *OScrn; FUNCTION This function is similar to ClearScreen24, but fills the screen with the colour contained in Pen_R,Pen_G & Pen_B in the OpalScreen structure. INPUTS None RESULT None CONSIDERATIONS SEE ALSO ClearScreen24() opal.library/SetSprite24 NAME SetSprite24 -- Allows Amiga sprites to be displayed over OpalVision graphics. SYNOPSIS void SetSprite24 (SpriteData, SpriteNumber); A0 D0 USHORT *SpriteData; long SpriteNumber; FUNCTION This function allows Amiga hardware sprites to be displayed in OpalVision graphics. Sprites are displayed during both display and update cycles and due to this the sprite data is written into the frame buffer memory along with the video data. This may be undesirable in some cases, so the sprite may be removed before starting updates using Refresh24() or UpdateDelay24() by calling SetSprite24() with SpriteData = NULL SpriteData is a pointer to a data definition of a spite as passed to the SetPointer() function in the intuition library. The SpriteNumber is the hardware sprite number to be used to display the sprite, this will normally be 0 to modify the mouse pointer sprite. N.B. Passing -1 for the SpriteData will use the currently active Amiga Sprite in the system. For example SetSprite24((USHORT *) - 1,0) will allow the currently active mouse pointer to be displayed over the 24 bit image. INPUTS SpriteData - pointer to the sprite data. SpriteNumber - Amiga hardware sprite number (0...7). RESULT None CONSIDERATIONS All sprites other than the mouse pointer sprite should be allocated by the user using GetSprite () as sprite 0 is normally used for the mouse pointer and another sprite is required by the opal library for normal screen updates. Sprites will only be visible during display cycles if Amiga priority is set and dual display mode is active. SEE ALSO opal.library/SingleDisplay24 NAME SingleDisplay24 -- Sets up an Amiga/OpalVision single display. SYNOPSIS void SingleDisplay24 (void); FUNCTION This function sets the DUALDISPLAY bit of all CoPro instructions, allowing an OpalVision or Amiga only display. INPUTS None RESULT None CONSIDERATIONS If Amiga display bottom has been set, using the SetDisplayBottom24() the CoPro instructions will not be modified for that region of the display. SEE ALSO DualDisplay24() opal.library/SinglePlayField24 NAME SinglePlayField24() -- Sets up an Amiga or OpalVision single playfield. SYNOPSIS void SinglePlayField24 (void) FUNCTION This function clears the DUALPLAYFIELD bit of all coprocessor instructions, Allowing only one of OpalVision playfield to be displayed. INPUTS None RESULT None CONSIDERATIONS If an Amiga display bottom has been set, the coprocessor instructions will not be modified for that region of the display. SEE ALSO DualPlayField24() opal.library/StopUpdate24 NAME StopUpdate24 -- Stops updates to the frame buffer memory. SYNOPSIS void StopUpdate24 (void); FUNCTION This function stops updates to the OpalVision frame buffer memory initiated with a call to UpdateDelay24(). This allows changes to be made to the Amiga memory without affecting the OpalVision frame buffer memory thus offering inherent double buffering. Stopping updates will also reduce the DMA load on the Amiga. INPUTS None RESULT None CONSIDERATIONS This function may take up to 1 frame as it must wait for the current frame update to be completed. SEE ALSO UpdateDelay24() Refresh24() opal.library/UpdateAll24 NAME UpdateAll24 -- Resets the internal update structure so all required banks are updated. SYNOPSIS void UpdateAll24 (void); FUNCTION Resets the internal update structure so that all required banks are updated. This function is useful after a call to UpdatePFStencil24() to reinitialise the internal state of the library so that all the required segments are updated correctly on subsequent calls to Refresh24() or UpdateDelay24(). INPUTS None RESULT None CONSIDERATIONS SEE ALSO UpdatePFStencil24() opal.library/UpdateCoPro24 NAME UpdateCoPro24() -- Writes CoPro list for the current display screen to Video coprocessor SYNOPSIS void UpdateCoPro24 (void); FUNCTION Encodes the entire CoPro instruction list from the displayed screen structure and initiates a coprocessor update. This function also updates the Load Address Register. INPUTS None RESULT None CONSIDERATIONS Modifying the coprocessor list in the screen structure does not have any effect on the display until UpdateCoPro24 () is called. The CoPro list will not be updated in the OpalVision until the next vertical blanking period. SEE ALSO SetCoPro24() RegWait24() opal.library/UpdateDelay24 NAME UpdateDelay24 () -- Sets the delay between consecutive frame buffer updates. SYNOPSIS void UpdateDelay24 (FrameDelay); D0 long FrameDelay; FUNCTION This function allows a variable frame delay between consecutive frame buffer updates. Setting a frame delay of zero enables continuous full speed updates. This function also initiates continuous updates to the OpalVision frame buffer memory which will continue until either Refresh24() or StopUpdate24() is called. Setting a delay increases free bus DMA bandwidth to increase performance of the CPU and other DMA devices. INPUTS FrameDelay = Number of Frames to pause between frame buffer updates. RESULT None CONSIDERATIONS UpdateAll24() and UpdatePFStencil24() determine which memory segments will be updated during an update sequence. SEE ALSO StopUpdate24() UpdateAll24() UpdatePFStencil24() Refresh24() opal.library/UpdatePalette24 NAME UpdatePalette 24 -- Loads all 256 entries of Red, Green and Blue values in the OpalScreen structure onto the OpalVision palette registers. SYNOPSIS void UpdatePalette (void); FUNCTION Updates the OpalVision palette registers with the palette values in the OpalScreen structure. This also updates the Pixel Read mask and the Command Register and uses the Palette Load Address as an offset for the palette update. INPUTS None RESULT None CONSIDERATIONS Updates will have no effect in non palette mapped modes. SEE ALSO SetRGB24 () PaletteMap24 () opal.library/UpdatePFStencil24 NAME UpdatePFStencil24() -- Updates playfield stencil at highest possible rate. SYNOPSIS void UpdatePFStencil24(void); FUNCTION Enables updates to only the segments containing the playfield stencil (green segments). The speed of update is three times that of a normal 24bit update. This enables quick playfield transitions. This function does not update the playfield stencil as such, but modifies the internal state of the library so that subsequent calls to Refresh24() or UpdateDelay24() will only update the segments containing the playfield stencil. The internal state of the library can be returned to normal by calling UpdateAll24(). To use the playfield stencil in 8bit mode, the green bank contains the stencil and therefore must be updated. The most convenient way to do this is to write the frame for the first playfield in the red segment of bank 0 using WriteFrame24(0) and the second playfield into the red segment of bank 1 using WriteFrame24(3). UpdatePFStencil24() will call WriteFrame24(1) when in 8bit mode to switch to the green segment. Placing you playfields in segments other than the green segment will give you the full 256 colours rather than 128. INPUTS None RESULT None CONSIDERATIONS SEE ALSO UpdateDelay24 () DualPlayField24() SinglePlayField24() Refresh24() UpdateAll24() opal.library/UpdateRegs24() NAME UpdateRegs24 () -- Updates the hardware registers for the current display screen SYNOPSIS void UpdateRegs24 (void) FUNCTION Updates the Pixel Read mask, Command register and Palette Load Address registers in the OpalVision with the values from the current display screen structure (See "Registers"). INPUTS None RESULT None CONSIDERATIONS Changing register values in the screen structure does not take effect until an update has been initiated. Register updates are not completed until the next vertical blanking period. SEE ALSO RegWait24() opal.library/WriteFrame24 NAME WriteFrame24 -- Sets the current frame to be written to within the frame buffer memory. SYNOPSIS void WriteFrame24 (Frame); D0 long Frame; FUNCTION Depending on the resolution of the displayed OpalVision screen, a number of screens can be stored in the frame buffer memory. The number of frames available for the screens resolution are given in the MaxFrames variable in the OpalScreen structure. WriteFrame24() allows each individual frame to be written separately where Frame is in the range 0...MaxFrames. Using a combination of WriteFrame24 and DisplayFrame24, it is possible to store several images in frame buffer memory and to perform simple page flip animation. INPUTS Frame = Frame number to display (0...MaxFrames). RESULT None CONSIDERATIONS The display frame and the write frame, must reside in the same field area in the frame buffer memory. (See "Memory Segment Diagram"). Due to this WriteFrame24() has the side effect of changing the display frame if the new write frame is in a different field. SEE ALSO DisplayFrame24() opal.library/WritePFPixel24 NAME WritePFPixel24 () -- Set or clear a pixel in the playfield stencil. SYNOPSIS Result = WritePFPixel24 (OScrn, x, y); D0 A0 D0 D1 struct OpalScreen *OScrn; long x; long y; long Result; FUNCTION Sets or clears a pixel in the playfield stencil depending on the state of Pen_R in the screen structure. If Pen_R is = 0, the pixel will be cleared else it is set. The SetPFPen macro can be used to initialize Pen_R. INPUTS OScrn = A pointer to an OpalScreen structure. x = x coordinate of pixel. y = y coordinate of pixel. RESULT Result = -1 if the pixel is outside the clip boundary else 0. CONSIDERATIONS This function only has visible effect in dual playfield mode. SEE ALSO ReadPFPixel24() UpdatePFStencil() DualPlayField24() SinglePlayfield24() opal.library/WritePixel24 NAME WritePixel24 () -- Write a pixel into an OpalScreen. SYNOPSIS Result = WritePixel24 (OScrn, x, y); D0 A0 D0 D1 struct OpalScreen *OScrn; long x; long y; long Result; FUNCTION Writes a pixel in the specified OpalScreen using the current pen value in that structure. The macro SetPen can be used to initialize pen values correctly. INPUTS OScrn = A pointer to an OpalScreen structure. x = x coordinate of pixel. y = y coordinate of pixel. RESULT Result = -1 if the pixel is outside the clip boundary else 0. CONSIDERATIONS SEE ALSO ReadPixel24() opal.library/WritePRPixel24 NAME WritePRPixel24 () -- Set or clear a pixel in the priority stencil. SYNOPSIS Result = WritePRPixel24 (OScrn, x, y); D0 A0 D0 D1 struct OpalScreen *OScrn; long x; long y; long Result; FUNCTION Sets or clears a pixel in the priority stencil depending on the state of Pen_R in the screen structure. If Pen_R is = 0, the pixel will be cleared else it is set. The macro SetPRPen can be used to initialize the state of Pen_R. INPUTS OScrn = A pointer to an OpalScreen structure. x = x coordinate of pixel. y = y coordinate of pixel. RESULT Result = -1 if the pixel is outside the clip boundary else 0. CONSIDERATIONS This function only has visible effect when the priority stencil is enabled. SEE ALSO ReadPRPixel24() EnablePRStencil24() DisablePRStencil24() opal.library/WriteThumbnail24 NAME WriteThumbnail24 -- Writes an IFF thumb-nail chunk into a file. SYNOPSIS ReturnCode = WriteThumbnail24 (OScrn, File); D0 A0 A1 struct OpalScreen *OScrn; BPTR File; long ReturnCode; FUNCTION This function generates a 24 bit thumb-nail for the given OpalScreen and writes an IFF OVTN thumb- nail chunk into the given file. INPUTS OScrn = OpalScreen to generate the thumb-nail for. File = File Handle of the file to write thumb-nail to. RESULT ReturnCode = 0 if all ok, or an OpalVision Error code if en error occurred. CONSIDERATIONS SEE ALSO SaveIFF24() LoadIFF24() opalreq.library/OpalRequester NAME OpalRequester -- The OpalVision file requester. SYNOPSIS ReturnCode = OpalRequester (OReq); D0 A0 struct OpalReq *OReq; FUNCTION This is the entry point for the OpalVision requester. OReq is a pointer to a properly initialised OpalReq structure defined in the above sections. The requester will be displayed and handled completely by the library, when the user has selected a file or hit cancel, this function will return the selected file and directory name in OReq. OKHit will be cleared if the user hit the Cancel gadget and set otherwise. INPUTS OReq = A pointer to a correctly initialised OpalReq structure. RESULT ReturnCode = 0 if all ok = OR_ERR_OUTOFMEM if there is not enough memory to display requester = OR_ERR_INUSE if the requester is currently in use. CONSIDERATIONS For this release the intuition screen used to display the requester must be hires interlaced, and have atleast 2 bit planes. SEE ALSO