Retargetable graphics


Retargetable graphics is a device driver API mainly used by third-party graphics hardware to interface with AmigaOS via a set of libraries. The software libraries may include software tools to adjust resolution, screen colors, pointers, and screenmodes. It will use available hardware and will not extend the capabilities in any way.
The Amiga OS 3.x intuition.library is limited to 8-bit display depths, but RTG libraries make it possible to handle higher depths such as 24 bits; on Amiga there are two common APIs: Picasso 96 and CyberGraphX, which are almost compatible with each other. Both Picasso 96 and CyberGraphX require at least 4 MB RAM and a 68020 CPU to operate.

EGS and other early graphics card drivers

Although Commodore planned to introduce retargetable graphics in future version of AmigaOS, the company was not able to deliver such solution before its demise. Third-party graphics card manufacturers were thus forced to create their own software layers on top of AmigaOS, incompatible with each other.
Most of these early Amiga graphics card drivers shared common limitations: compatibility with current applications was maintained by opening Workbench on the graphics card—usually in 16 or 256 colours ; full graphics card features like high-colour and true-colour display could be used only by applications directly programmed for such driver software. Earliest of these solutions like Grafexa and SAGE libraries were able to display only their own applications on the graphics card without any support for "Workbench emulation". Examples of other drivers are EGS, Merlin/Domino, Omnibus, Retina, Graffity, Picasso, and ProBench. Of these, Picasso offered good compatibility with older applications, because most OS-compliant programs could be promoted to graphics card display, and relatively strong software support. ProBench was released as a new "Workbench emulator" for the old Merlin graphics card in 1994, and version 3 introduced 16 bit colour depth and compatibility with CyberGraphX.
Enhanced Graphics System was developed by Viona Development using the Cluster language for Piccolo and Spectrum graphics boards, supporting screen depths up to 24 bits. It requires a minimum of RAM and of hard disk space. EGS was first presented with the EGS 110/24 card at the World of Commodore/Amiga show in New York in April 1992. It supported a broader range of graphics cards than other drivers and was seen by some Amiga magazines as the next RTG standard for Amiga, but its compatibility with most Amiga applications was limited.
Graphic cardExpansion typeGraphic chip
EGS 110/24GVP LocalBusINMOS G364 framebuffer
EGS 28/24Zorro II / IIICirrus Logic GD5426
RetinaZorro IINCR 77C22E+
VisionaZorro IIIMS G300C
PiccoloZorro II / IIICirrus Logic GD5426
Piccolo SD64Zorro II / IIICirrus Logic GD5434
RainbowZorro II
Rainbow IIZorro IIAnalog Devices ADV7120
Rainbow IIIZorro IIIInmos G365

CyberGraphX

CyberGraphX, is a retargetable graphics API for the Amiga and compatible computer systems developed by Thomas Sontowski and Frank Mariak and later adopted by Phase5 for use with their graphics cards. Many other graphics card manufacturers that offered hardware for Amiga and compatible systems also used it.
Introduced in 1995 with the CyberVision64 graphics card, CyberGraphX was the first RTG software to allow full true-colour screens for Workbench and applications—older solutions supported only 256 colours or a four-colour Workbench with some 24-bit windows. CyberGraphX quickly eclipsed all older graphics card drivers and by 1995 was acclaimed as the best solution for displaying Workbench and other applications. Being available free of charge for users of supported cards, it became the de facto RTG standard for Amiga. CyberGraphX V4 was the last release for AmigaOS; MorphOS uses CyberGraphX V5.

Supported graphic cards

These graphic cards are supported by CyberGraphX:
Graphic cardExpansion typeGraphic chip
PCIAvenger
3DFX Voodoo3 3000Avenger
3DFX Voodoo3 3500Avenger
3DFX Voodoo4 4500Napalm
3DFX Voodoo5 5500Napalm
A2410Texas Instruments TMS32010
Amiga AGAInternal PCBLisa
ATI Radeon 7000VERV100
ATI Radeon 7200R100
ATI Radeon 7500RV200
ATI Radeon 8500 LER200
ATI Radeon 9000RV250
ATI Radeon 9000 ProRV250
ATI Radeon 9100R200
ATI Radeon 9100 LER200
ATI Radeon 9200 SERV280
ATI Radeon 9200RV280
ATI Radeon 9200 ProRV280
ATI Radeon 9250RV280
ATI Radeon 9600 ProRV350
ATI Radeon 9600 XTRV360
ATI Radeon 9700 ProR300
ATI Radeon 9800R350
ATI Rage 128 Pro
BlizzardVisionPPCPermedia 2
CyberVision64/3DZorro II/Zorro IIIS3 ViRGE
CyberVision64Zorro IIIS3 Trio64
CyberVisionPPCPermedia 2
DraCo AltaisDracoBusSymbios Logic 77C32BLT
DraCo Altais PlusDracoBusS3 Trio 64 V+
Domino
PicassoIIZorro IICirrus Logic GD5426
PicassoII+Cirrus Logic GD5428
PicassoIVZorro II/Zorro IIICirrus Logic GD5446
Piccolo
Piccolo SD64Cirrus Logic GD5434
Pixel64
Retina BLT Z3Zorro IIISymbios Logic 77C32BLT
Spectrum
XGI Volari V3XT
XGI Volari V5
XGI Volari V5XT
XGI Volari V8
SiS 300 / 305
SiS 315
SiS 6326

Picasso96

Picasso96 is the RTG device driver library set used by the Picasso IV and other graphics boards. Its development was started in 1996 by Village Tronic, and it is compatible with CyberGraphX. Although the first releases were ridden with bugs and stability problems, by version 1.17 most issues with Picasso96 were corrected. Compatibility with CyberGraphX was also improved.
Picasso96 was selected as the RTG standard for AmigaOS 4, at first released as a 68k binary in AmigaOS 4.0 pre-release, with a full PowerPC port following later in 2004 in the next OS update. AmigaOS 4.1 Final Edition integrated RTG functions directly into graphics.library.

Supported graphic cards

These graphic cards are supported by the Picasso96 system.
Graphic cardExpansion typeGraphic chip
Cybervision64/3DZorro II/Zorro IIIS3 Virge
Cybervision64Zorro IIIS3 86C764 Trio64
DominoTseng Labs ET4000
MerlinZorro II/IIITseng Labs ET4000W32
oMniBusZorro II+ISATseng Labs ET4000AX
PicassoIIZorro IICirrus Logic GD5426
PicassoII+Cirrus Logic GD5428
PicassoIVZorro II/Zorro IIICirrus Logic GD5446
Piccolo
Piccolo SD64Cirrus Logic GD5434
Pixel64
Retina BLT Z3
EGS 28/24 SpectrumCirrus Logic GD5426
UAEgfxHost OSEmulated

Picasso96 as used by AmigaOS 4 supports also Voodoo 3, Voodoo 4/5, and Radeon R100, R200, R300, R520, R700, HD 5000 series, HD 6000 series, and HD 7000 series. The RadeonHD AmigaOS 4 driver is created and maintained by Hans de Ruiter. Ongoing development of the driver for the AmigaOS platform being exclusively funded and owned by A-EON Technology Ltd.

RTG Master

The higher level API was created by Steffen Haeuser for developing 2D and 3D games requiring chunky graphics. RTG Master supports both graphics cards and the Amiga chipset. An example of game using RTG Master is Genetic Species.