glSampleCoverage — specify multisample coverage parameters
void glSampleCoverage( | GLclampf | value, |
GLboolean | invert) ; |
value
Specify a single floating-point sample coverage value. The value is clamped to the range . 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
.
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.
GL_INVALID_OPERATION
is generated if glSampleCoverage
is executed between the execution of glBegin and the corresponding execution of glEnd.
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
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