1991-2006
Silicon Graphics, Inc.
glSampleCoverage
3G
glSampleCoverage
specify multisample coverage parameters
C Specification
void glSampleCoverage
GLclampf value
GLboolean invert
Parameters
value
Specify a single floating-point sample coverage value. The value is
clamped to the range
0
1
.
The initial value is 1.0.
invert
Specify a single boolean value representing if the coverage masks should be
inverted. GL_TRUE and GL_FALSE are accepted. The initial value
is GL_FALSE.
Description
Multisampling samples a pixel multiple times at various
implementation-dependent subpixel locations to generate antialiasing
effects. Multisampling transparently antialiases points, lines, polygons,
bitmaps, and images if it is enabled.
value is used in constructing a temporary mask used in determining which
samples will be used in resolving the final fragment color. This mask is
bitwise-anded with the coverage mask generated from the multisampling
computation. If the invert flag is set, the temporary mask is inverted
(all bits flipped) and then the bitwise-and is computed.
If an implementation does not have any multisample buffers available, or
multisampling is disabled, rasterization occurs with only a single sample
computing a pixel's final RGB color.
Provided an implementation supports multisample buffers, and multisampling
is enabled, then a pixel's final color is generated by combining several
samples per pixel. Each sample contains color, depth, and stencil
information, allowing those operations to be performed on each sample.
Notes
glSampleCoverage is available only if the GL version is 1.3 or greater.
Errors
GL_INVALID_OPERATION is generated if glSampleCoverage is executed between the
execution of glBegin and the corresponding execution of glEnd.
Associated Gets
glGet with argument GL_SAMPLE_COVERAGE_VALUE
glGet with argument GL_SAMPLE_COVERAGE_INVERT
glIsEnabled with argument GL_MULTISAMPLE
glIsEnabled with argument GL_SAMPLE_ALPHA_TO_COVERAGE
glIsEnabled with argument GL_SAMPLE_ALPHA_TO_ONE
glIsEnabled with argument GL_SAMPLE_COVERAGE
See Also
glEnable,
glPushAttrib
Copyright
Copyright 1991-2006
Silicon Graphics, Inc. This document is licensed under the SGI
Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/.