Starbase Functionality

This section contains information on Starbase calls that are not supported by the HP Visualize-FX devices. This section also contains information on gescapes that are supported by the HP Visualize-FX devices.

Calls Not Supported on the HP Visualize-FX Devices

The following calls are not supported when using the HP Visualize-FX devices:

bf_texture_index
contour_enable
define_contour_table
define_texture
texture_index
texture_viewport
texture_window

Conditional Support of Starbase Calls on the HP Visualize-FX Devices

The following calls are supported with the listed exceptions:

Title not available (Conditional Support of Starbase Calls on the HP Visualize-FX Devices )

alpha_transparency

The HP Visualize-FX devices support alpha transparency. Alpha only applies to filled areas such as polygons, quadrilateral meshes, triangular strips, and spline surfaces. Vector primitives are not rendered with alpha_transparency. The alpha transparency feature is limited to CMAP_FULL in a depth 12 or 24 visual. Only the floating point version of these primitives will be rendered with alpha transparency; device coordinate primitives do NOT use alpha. The HP Visualize-FX devices do not support alpha transparency with attenuation. (See alpha_transparency(3G) in the Starbase Reference manual for the list of parameters). Note that Starbase does not utilize a hardware alpha buffer to implement alpha transparency.

block_read, block_write

The raw parameter for the block_read and block_write commands is used by this driver to do plane-major reads and writes. It is enabled by the gescape R_BIT_MODE.

The storage destination supplied by the user as the source or destination must be organized as follows.

The data from each plane is packed with eight pixels per byte.
Each row must begin on a byte boundary. Thus, the size of the rectangle as specified by the 〈length_x〉 and 〈length_y〉 parameters must correspond to an integral number of bytes.
The data for the next plane begins on the following byte boundary.
Clip to the screen limits.
The first pixel in the source rectangle is placed in the high-order bit of the first byte in each plane region.
When clipping, part of each plane region will not be read (block_read) or altered (block_write).

A bit mask selects the planes to read or write. The initial value of this mask is 1 (one) indicating that only plane 0 is to be accessed. The value of the mask may be changed using the R_BIT_MASK or GR2D_PLANE_MASK gescapes. GR2D_PLANE_MASK is discussed in the appendix of the HP-UX Starbase Device Drivers Manual. The planes selected by the mask are expected to reside in consecutive plane locations in the user storage area. This reduces the storage requirements to exactly what is needed but also presents the potential for addressing violations or undesirable results.

For example, if the plane mask is changed to specify more planes between a block_read and a following block_write from the same location, the block_write will attempt to access storage for planes that were not read (and perhaps not allocated). The application program must ensure consistency in these operations.

fill_dither

The ability to dither is disabled if the number of colors specified by fill_dither is one. However, if the number of colors specified is greater than 1, the default dither cell size of 16 is used. Dithering is only used in depth 8 visuals while in either the CMAP_FULL or CMAP_MONOTONIC color map mode, and in depth 12 visuals while in CMAP_FULL color map mode.

interior_style

The styles INT_PATTERN and INT_HATCH are not supported by the HP Visualize-FX devices.

light_source

Up to 15 directional light sources are available on HP Visualize-FX devices. The HP Visualize-FX devices' hardware accelerates up to eight directional light sources. Using nine to fifteen directional light sources will cause a noticeable performance degradation.

line_filter, perimeter_filter

Anti-aliasing is supported on the HP Visualize-FX devices. Anti-aliasing for this device applies only to floating point vectors. Device coordinate and integer (primitives that use gopen's INT_XFORM mode) primitives do not use anti-aliasing. The anti-aliasing features are also limited to the CMAP_FULL color map mode in a depth 12 or 24 visual.

The HP Visualize-FX devices have three anti-aliasing modes that may be specified with the line_filter and perimeter_filter procedures. The index values are assigned as follows:

Title not available (Conditional Support of Starbase Calls on the HP Visualize-FX Devices )

0

Anti-aliasing disabled, all vectors have one pixel wide output.

1

Anti-aliasing enabled, all vectors have two pixel wide output. Pixel values are multiplied by the alpha value and blended with the background according the the formula:

pixel_color = (new_pixel × α) +
(old_pixel × (1 - α));

2

Anti-aliasing enabled, all vectors have two pixel wide output. Pixel values are multiplied by the alpha value and blended with the background according to the formula:

pixel_color= (new_pixel × α) + old_pixel

3

Anti-aliasing enabled, but with no alpha blending.

pixel_color=new_pixel

Note that this implementation of 2 pixel wide anti-aliasing differs from the CRX-48Z (with 3-wide anti-aliasing). It is also slightly different than the anti-aliasing implementation on the HP Visualize-48 and HP Visualize-48XP.

shade_mode

The color map mode may be selected. Shading can be turned on only if using PowerShade. Shading is not supported on device coordinate primitives even with PowerShade. Note that the HP Visualize-FX devices automatically use PowerShade.

text_precision

Only STROKE_TEXT precision is supported.

vertex_format

If using PowerShade software, vertex_format is fully functional. Note that the HP Visualize-FX devices automatically use PowerShade.

*_with_data

The following routines are called with_data routines because they allow you to send extra vertex data. These with_data routines are supported by the HP Visualize-FX devices.

partial_polygon_with_data3d
polygon_with_data3d
polyhedron_with_data
polyline_with_data3d
polymarker_with_data3d
polyquad_with_data3d
polytriangle_with_data3d
quadrilateral_mesh_with_data
triangle_strip_with_data

Note that the TEXTURE_MAP flag applies only to the TurboVRX devices via the texture_* routines. This extra data per vertex is not used in the tm_* routines.

For detailed information on these routines, read the Starbase Reference and "Appendix A" of this document. In some cases, you will be able to find the routines under their own name, but in other cases, you will need to use the first part of the routine name to locate these routines (e.g., polyline_with_data3d is described on the man page for polyline(3G)).

Supported Gescapes

The hpvisx device driver supports the following gescape operations on the HP Visualize-FX configurations. Refer to Appendix A of the HP-UX Starbase Device Drivers Manual and Appendix A of this addenda for details on gescapes.

BLOCK_WRITE_SKIPCOUNT — Specify byte skip count during block write.
COLOR_RECOVERY_CONTROL — Disable HP Color Recovery.
CUBIC_POLYPOINT — Specify points to be rendered in a cubic volume specified in modeling coordinates.
DC_PIXEL_WRITE — Specify points to be rendered along a horizontal scan line.
DRAW_POINTS — Select different modes of rounding for rendered points.
GAMMA_CORRECTION — Enable/disable gamma correction.
GCRX_PIXEL_REPLICATE — Pan and zoom a raster image.
IGNORE_RELEASE — Trigger only when button pressed.
ILLUMINATION_ENABLE — Turn on/off illumination bits.
LINEAR_POLYPOINT — Specify points to be rendered along a line specified in modeling coordinates.
LS_OVERFLOW_CONTROL — Set light source overflow handling.
POLYGON_TRANSPARENCY — Segment control over front/back face screen.
READ_COLOR_MAP — Read Color Map.
R_BIT_MASK — Bit mask.
R_BIT_MODE — Bit mode.
R_GET_FRAME_BUFFER — Read frame buffer address.
R_LINE_TYPE — User defined line style and repeat length.
R_LOCK_DEVICE — Lock device.
R_READ_FB — Write an image to a window whose shade mode is set to CMAP_FULL.
R_WRITE_FB — Read the image out of a window created with the shade mode set to CMAP_FULL.
R_UNLOCK_DEVICE — Unlock device.
SET_POLYGON_OFFSET — Enable Z-buffer biasing of fill pixels.
STEREO — Activate stereo output mode.
SWITCH_SEMAPHORE — Semaphore Control.
TRANSPARENCY — Set screen door transparency mask (front face and back face).
TRIGGER_ON_RELEASE — Trigger only when button is released.
WIDELINE_CONTROL — Turn on/off and set attributes of widelines.
ZBANK_ACCESS — Enable/disable Z-buffer block operations.
ZWRITE_ENABLE — Enable/disable replacement of Z value.

Exceptions to Gescape Support




	NOTE: Because gescape operations are device-dependent, the exceptions discussed below may be removed in future drivers.

Title not available (Exceptions to Gescape Support )

GAMMA_CORRECTION: Gamma correction is implemented by modifying the color map. It is available only in 12-bit visuals and 24-bit DirectColor visuals on the HP Visualize-FX devices. For information on the gescape GAMMA_CORRECTION, refer to Appendix A in the HP-UX Starbase Device Drivers Manual. If a global gamma correction value has been set via the X server or the gamma correction tool, that global gamma correction value will be used and the color map will not be modified. See the Graphics Administration Guide for more information about the gamma correction tool.

The features involved (along with the names of the affected gescape operations) are listed below. For more details in the gescape operations, refer to Appendix A in the HP-UX Starbase Device Drivers Manual.

Title not available (Exceptions to Gescape Support )

R_BIT_MASK: The gescape operation R_BIT_MASK defines a plane mask to the driver that is used for bit/pixel access to a single plane in the frame buffer. As with other device drivers, only the plane corresponding to the highest bit set in the mask is transferred.
R_BIT_MODE: When calling block_read or block_write with the raw parameter set to TRUE, the driver supports bit/pixel frame buffer access to single planes.

Modified Gescapes

The HP Visualize-FX devices support the Z_CLIP_VOXEL flag for the CUBIC_POLYPOINT and LINEAR_POLYPOINT gescapes. This flag enables read-only Z-clipping of the point primitives against the existing contents of the Z-buffer. The Z-buffer is not modified.

For CUBIC_POLYPOINT, the Z_CLIP_VOXEL flag is one of several in the vertex format argument, arg1.i[8]. For LINEAR_POLYPOINT, the Z_CLIP_VOXEL flag is one of several in arg1.i[8]. Consult the gescape chapter for more information about LINEAR_POLYPOINT and CUBIC_POLYPOINT.

Starbase Functionality

Technical documentation

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Calls Not Supported on the HP Visualize-FX Devices

Conditional Support of Starbase Calls on the HP Visualize-FX Devices

Supported Gescapes

Exceptions to Gescape Support

Modified Gescapes