Starbase Functionality

Calls Not Supported

The hpvmx driver does not support the following Starbase calls if you are using Starbase without the PowerShade software. When executed, these calls will produce no result (that is, they are ignored).

alpha_transparency               hidden_surface
backface_control                 light_ambient
bf_alpha_transparency            light_attenuation
bf_control                       light_model
bf_fill_color                    light_switch
bf_interior_style                line_filter
bf_perimeter_color               perimeter_filter
bf_perimeter_repeat_length       set_capping_planes
bf_perimeter_type                set_model_clip_indicator
bf_surface_coefficients          set_model_clip_volume
bf_surface_model                 surface_coefficients
bf_texture_index                 surface_model
contour_enable                   texture_index
define_contour_table             texture_viewport
define_texture                   texture_window
define_trimming_curve            viewpoint
deformation_mode                 zbuffer_switch

Using PowerShade with HP VMX

By using PowerShade with HP VMX, a much wider set of functionality is supported. The following calls are not supported when using PowerShade with HP VMX:

alpha_transparency               deformation_mode
bf_alpha_transparency            line_filter
bf_texture_index                 perimeter_filter
contour_enable                   texture_index
define_contour_table             texture_viewport
define_texture                   texture_window

Conditional Support of Starbase Calls with HP VMX

The following Starbase calls are supported with the listed exceptions:

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 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 Appendix A of this 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 address 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.

double_buffer

HP VMX supports only 8/8 double-buffering. Attempts to double-buffer with less than 8 planes will default to 8/8 double-buffering.

pattern_define

For HP VMX, the maximum pattern size is 4x4. If a pattern larger than 4x4 is specified, an error message is printed and the previous pattern is retained.

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.

text_precision

Only STROKE_TEXT precision is supported.

vertex_format

If not using PowerShade software, vertex_formats use parameter must be set to zero. Any extra coordinates will be ignored. If using PowerShade software, vertex_format is fully functional.

with_data

The following routines are called with_data routines because they contain with_data in their routine names. These with_data routines are supported by HP VMX:

partial_polygon_with_ data3d
polygon_with_data3d
polyhedron_with_data
polyline_with_data3d
polymarker_with_data3d
quadrilateral_mesh_with_ data
triangle_strip_with_data

For detailed information on these routines, read the Starbase Reference. 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 hpvmx driver supports the following gescape operations. Refer to Appendix A of this manual for details on gescapes.

BAD_SAMPLE_ON_DIFF_SCREEN: Restore the locator and choice sampling of the X11 pointer device.
BLOCK_WRITE_ SKIP_COUNT: Specify byte skip count during block write.
DRAW_POINTS: Select different modes of rounding for rendered points.
IGNORE_ RELEASE: Trigger only when button is pressed.
OLD_SAMPLE_ ON_DIFF_ SCREEN: Inquire the locator and choice sampling of the X11 pointer device.
R_BIT_MASK: Define bit mask for bit mode block ops.
R_BIT_MODE: Enable/disable bit mode block ops.
R_GET_FRAME_ BUFFER: Read the address of the device frame buffer and control space.
R_LINE_TYPE: User-defined line style and repeat length.
READ_COLOR_ MAP: Copy the hardware color map into the software color map.
TRIGGER_ON RELEASE: Trigger only when button is released.

Additional Gescapes Supported with PowerShade

ILLUMINATION_ENABLE: Turn on/off illumination bits.
LS_OVERFLOW_ CONTROL: Set light source overflow handling.
POLYGON_ TRANSPARENCY: Segment control over front/back face "screen door."
TRANSPARENCY: Set screen door transparency mask (front face and back face)
ZBANK_ACCESS: Enable/disable Z-buffer block operations.
ZWRITE_ENABLE: Enable/disable replacement of Z value.

Exceptions to Gescape Support




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

R_GET_FRAME_BUFFER: This gescape is used to return the addresses of both the frame buffer and the control space. A zero is returned for the control space address since HP VMX has no control space. The frame buffer address is returned correctly.
SWITCH_SEMAPHORE, R_LOCK_ DEVICE, R_UNLOCK_ DEVICE: Because HP VMX renders to a virtual memory frame buffer, device locking is not necessary. Therefore, these gescapes have no effect on HP VMX.