Single logical screen in X windows with direct hardware access to the frame buffer for 3D rendering

• US 6,417,849 B2
• Filed: 07/31/1998
• Issued: 07/09/2002
• Est. Priority Date: 07/31/1998
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Walls, Jeffrey Joel, Lefebvre, Kevin T., Lukasik, Derek J., Hoffman, Don B.
• Primary Examiner(s): Vo, Cliff N.
• Assistant Examiner(s): MANCUSO, HUEDUNG XUAN CAO
• Application Number:
  US09/127,773
• Publication Number:
  US 20010012014A1
• Time in Patent Office: 1,439 Days
• Field of Search: 345/419, 345/329, 345/330, 345/331, 345/332, 345/418, 345/4, 345/733, 345/755, 345/516
• US Class Current: 345/419
• CPC Class Codes: G06F 3/1423 controlling a plurality of local displays, e.g. CRT and flat panel display
• CPC Class Codes: G06T 15/005 General purpose rendering architectures

Abstract

Single Logical Screen and Direct Hardware Access in a 3D environment are combined by passing a single stream of protocol to the X Server, which in turn passes the information to multiple 3D rendering processes for display on individual screens (monitors). Multiple instances of a single daemon implement the rendering processes. The X Server communicates with an instance of the daemon functioning as a master daemon, which in turn controls the remaining instances functioning as slave daemons. All daemons communicate through common shared memory segments. This achieves both efficiency and performance, since duplicated distribution of commands and data is avoided. Each of the daemons is driven by the contents of the shared memory segments. To facilitate this, an X Client, the X Server and the daemons are all interconnected with separate control and data paths.

Claims

1. A 3D graphics system comprising:

a computer containing a plurality of frame buffers;

a plurality of monitors respectively coupled to the plurality of frame buffers;

an X client including an unmodified 3D application program, the X client executing on the computer;

a single logical screen X server executing on the computer; and

a 3D rendering library executing on the computer and having direct hardware access connections to each of the plurality of frame buffers.

2. The system of claim 1, wherein the SLS X server communicates with multiple instances of a single daemon.

3. The system of claim 2, wherein the multiple instances of a single daemon are in communication with each of the plurality of frame buffers, respectively.

4. The system of claim 2, wherein the SLS X server communicates with multiple instances of a single daemon via a master daemon.

5. The system of claim 2, wherein each of the multiple instances of a single daemon communicate through common shared memory segments.

6. The system of claim 4, wherein the SLS X server communicates with at least one slave daemon via a master daemon.

7. The system of claim 6, wherein the SLS X server, the X client and all daemons are interconnected with separate control and data paths.

8. The system of claim 6, wherein 3D rendering commands are encapsulated for extraction by each of the at least one slave daemon and the master daemon, respectively.

9. The system of claim 6, wherein 3D rendering commands are responsive to a 3D rendering trigger that identifies a respective buffer for each of the daemons and that communicates to the master daemon whether it needs to trigger that at least one slave daemon.

10. The system of claim 1, wherein the 3D rendering library is selected from the group consisting of OpenGL, Starbase, programmer'"'"'s hierarchical interactive graphics system (PHIGS), and PHIGS extension to X Windows (PEX).

12. The system of claim 10, wherein the means for controllably distributing 3D rendering commands comprises a master daemon in communication with at least one slave daemon.

11. A 3D graphics system, comprising:

means for controllably distributing display information among a plurality of display monitors, wherein the plurality of display monitors behaves as a single logical screen; and

means for controllably distributing 3D rendering commands to a plurality of frame buffers each associated with a respective display monitor, the plurality of frame buffers configured to support the operation of a single logical screen, wherein the 3D rendering commands are distributed from a shared memory device.

13. The system of claim 11, wherein the means for controllably distributing 3D rendering commands comprises a master daemon in communication with a shared memory device.

14. The system of claim 13, wherein the master daemon is responsive to a start command that comprises information indicative that the master daemon needs to propagate the start command to at least one slave daemon and the identity of a command source buffer from which the master and the at least one slave daemon are to receive commands.

15. A method of 3D rendering in a multiple monitor 3D graphics system, comprising:

querying a single logical screen status;

determining if the single screen logical status indicates a 3D rendering is in order;

providing identifiers for each of a plurality of multiple instances of a single daemon, wherein each of the plurality of daemons is associated with a respective monitor;

storing appropriate 3D rendering commands in a shared memory;

determining the device path for the frame buffer associated with the current daemon;

determining an associated shared memory segment for the current daemon;

determining if a window state has changed, if the determination is negative, processing the commands in a 2D graphics buffer and a 3D fast rendering buffer, if the determination is positive, determine which daemons are associated with the window; and

passing the clip list for the associated daemon.

16. The method of claim 15, wherein the 3D fast rendering buffer is implemented with a shared memory.

17. The method of claim 15, wherein each of the plurality of daemons is in communication with dedicated frame buffer for the respective monitor.

18. The method of claim 17, wherein each of the plurality of daemons is in communication with a dedicated frame buffer for the respective monitor via a direct hardware access.

19. A computer-readable medium having a computer program, said computer program comprising:

analyzing logic configured to determine if a 3D rendering is necessary for at least one frame buffer in communication with a computing device, the computing device configured to support a plurality of frame buffers configured to operate as a single frame buffer for generating a single logical screen;

logic configured to provide identifiers to each of a plurality of multiple instances of a single daemon, wherein each of the plurality of daemons is associated with a respective frame buffer;

storing logic configured to store 3D rendering commands in a shared memory; and

logic configured to manage the distribution of 3D rendering commands to the plurality of frame buffers, wherein the 3D rendering commands are distributed from the shared memory device.

20. The computer readable medium of claim 19, wherein the logic configured to manage 3D rendering command distribution comprises logic configured to select between at least a 3D fast rendering buffer and a display command buffer.