Back to Open Graphics

The original feature list for the PCI graphics card called OGC1 which will run the OGA architecture. While some features OGC1 are in flux, these proposed features are a good baseline for what features we feel are important to include. OGC1 will be produced after testing and development is completed on the OGD development boards.

Physical properties and connectors

• PCB is half-height and half-length
• DVI-I output providing digital and analog signals
• Pin header for TV output
• PCI connection first then AGP version (later PCI-Express)
• PROM hot-reset header (on FPGA boards)
• User configurable headers
• Passively cooled

Accessories

• DVI -> VGA converter
• TV-Out expansion kit

Technical properties

• GPU will be either:
  • Xilinx Spartan 3 FPGA (more expensive, for development/testing)
  • A purpose-made ASIC (cheaper, for mass production)
• 128 MB of 400MHz 128-bit DDR RAM (four 256 Mb chips) -> 1.6 billion pixels / sec
• S-Video?, component YUV, NTSC, PAL, SECAM using external device(What chip?? )
• 250 MHz pixel clock (165MHz for DVI)
• Max resolution at least 2048x2048 (apple's 30" is target)
• Single-head: output selectable between DVI, VGA and TV-out

Software properties

Architecture

• DMA for rendering commands
• Interrupts for rendering and DMA state changes
• Emulation of 8-bit and 16-bit pixel formats
• Single 64x64 full colour alphablended hardware cursor

Standards

• VESA standards:
  • Display Data Channel, DDC
  • Extended Display Identification Data, EDID
  • Display Power Management Signalling DPMS
  • VESA BIOS Extensions, VBE 2.0 (possibly VBE 3.0)
• DVI reduced blanking
• progressive scan
• interlaced

3D properties

• Supports most of OpenGL 1.3, plus some later features
• Extensions for 2D (see below)

Data format

• All rendering coordinates and colour components are 25bit float.
• Framebuffer pixels are always 32bit ARGB.

Performance

• Dual pixel pipeline at 200 MHz
• 400 million pixels/second
• Triangle rate limited by host interface speed

Gouraud shading

• Linear stepping with perspective correction
• Diffuse and specular

Texture mapping

• Linear stepping over 1D/2D textures, with perspective correction
• Bilinear interpolation
• Arbitrary size nonrepeated textures
• Power-of-two sized repeated textures
• MIPmaps and Trilinear interpolation
• Two texture units

Other 3D features

• Depth buffering (25bit float Wbuffering)
• Fog
• Ownership-, Alpha-, and Scissor-tests
• Alpha blend

2D features

• Polylines (solid and patterned)
• Plane mask
• Logical rasterop (<acronym title="Graphical Device Interface">GDI</acronym> ROP4)
• Patterns (8x8 colour, 32x32 mono)
• Rectangular clipping
• Colour or key and mask

Motion video playback acceleration

• hardware scaling
• YUV <> RGB conversion colorspace conversion

Other features

• Bit swapping for bigendian/ littleendian conversion
• Some MesaGL security features (possible feature)
• Logic ops, planemasks
• PROM reading/writing interface
• Integer scaling (possible feature)
• WindowID, 8bit overlay, dual LUT
• Vertical interrupts

Supported platforms

Initially, support for the following platforms are planned:

• Linux
• Windows

Due to the open source nature of the drivers, and the planned availability of reference code and full specifications, it should be possible to support this card on many other platforms.

Pricing

A petition was made on-line regarding the pricing of OGC. Petitioners specified whether they were willing to pay either $100 or $200. For this pricing an ASIC will need to be made but this petition has shown there is demand for a reasonably priced Open Graphics Card.
http://www.petitiononline.com/3dc4rdlb/petition.html