NAME
vpSeti, vpSetd - set the value of an option
SYNOPSIS
#include <volpack.h>
vpResult
vpSeti(vpc, option, value)
vpContext *vpc;
int option;
int value;
vpResult
vpSetd(vpc, option, value)
vpContext *vpc;
int option;
double value;
ARGUMENTS
vpc VolPack context from vpCreateContext.
option Constant that specifies the option to be set.
value New value for the option.
DESCRIPTION
These functions are used to set the values of integer- or double-valued
options in a rendering context. The following list summarizes the
integer-valued options that can be set with vpSeti:
VP_CONCAT_MODE
Choose whether transformation matrices are premultiplied or
postmultiplied. If value is VP_CONCAT_LEFT then matrices are
premultiplied. If value is VP_CONCAT_RIGHT then matrices are
postmultiplied. Default: VP_CONCAT_RIGHT.
VP_DEPTH_CUE_SIZE_HINT
Set the suggested number of entries in the depth cueing lookup
table. See vpSetDepthCueing(3). Default: none
VP_INT_WIDTH_HINT
Set the suggested width (in pixels) of the intermediate image
work buffer. See vpRenderRawVolume(3). Default: none
VP_INT_HEIGHT_HINT
Set the suggested height (in pixels) of the intermediate image
work buffer. See vpRenderRawVolume(3). Default: none
VP_SHADOW_LIGHT
Get the current shadow light (see vpSetShadowLookupShader(3)).
Legal values are VP_LIGHT0, VP_LIGHT1, ..., VP_LIGHT5. Default:
VP_LIGHT0
VP_SHADOW_WIDTH_HINT
Set the suggested width (in pixels) of the shadow buffer (see
vpSetShadowLookupShader(3)). Default: none
VP_SHADOW_HEIGHT_HINT
Set the suggested height (in pixels) of the shadow buffer (see
vpSetShadowLookupShader(3)). Default: none
VP_SHADOW_BIAS
Set the current shadow bias value (see
vpSetShadowLookupShader(3)). The value is an integral distance
in units of voxels. Default: 4
VP_AXIS_OVERRIDE
Force the rendering routine to composite along a particular
principle viewing axis, regardless of the current viewing
direction. Legal values are VP_X_AXIS, VP_Y_AXIS or VP_Z_AXIS.
Set the value to VP_NO_AXIS to let VolPack choose the optimal
axis automatically (the default). This option is normally used
only for debugging.
VP_TRACE_SHADOW_K
When pixel tracing is enabled (see vpTracePixel(3)) and shadows
are enabled (the VP_SHADOW option to vpEnable(3)), this option
is used to choose one shadow buffer pixel to trace. The value
must be a voxel slice number. The shadow buffer pixel that gets
traced is the shadow pixel that affects the traced image pixel
at the indicated slice.
The following list summarizes the double-valued options that can be set
with vpSetd:
VP_DEPTH_CUE_QUANTIZATION
Set the difference in depth between two adjacent entries in the
depth cueing lookup table (see vpSetDepthCueing(3)). Must be
greater than 0.0 and less than 1.0. Default: 1/255
VP_MAX_RAY_OPACITY
Set the maximum opacity threshold. During rendering, when a
pixel’s opacity reaches this threshold no more voxels are
composited into the pixel. To maximize performance, the value
should be as low as possible without adversely affecting image
quality. Must be in the range 0.0-1.0 (1.0 is the default and
0.95 is the suggested value). Default: 1.0
VP_MIN_VOXEL_OPACITY
Set the minimum opacity threshold. During classification, if a
voxel’s opacity is less than or equal to this threshold then the
voxel is discarded before rendering. To maximize performance,
the value should be as high as possible without adversely
affecting image quality. Must be in the range 0.0-1.0 (0.0 is
the default and 0.05 is the suggested value). Default: 0.0
ERRORS
The normal return value is VP_OK. The following error return values
are possible:
VPERROR_BAD_OPTION
The option argument is invalid.
VPERROR_BAD_VALUE
The value argument is invalid or out of range.
SEE ALSO
VolPack(3), vpCreateContext(3), vpGeti(3)