Graphics Reference
In-Depth Information
void
glEnable
(GLenum cap)
void
glDisable
(GLenum cap)
glEnable
and
glDisable
enable and disable various capabilities. The
initial value for each capability is set to
GL_FALSE
except for
GL_DITHER
,
which is set to
GL_TRUE
. The error code
GL_INVALID_ENUM
is generated if
cap
is not a valid state enum.
cap
state to enable or disable, can be:
GL_BLEND
GL_CULL_FACE
GL_DEPTH_TEST
GL_DITHER
GL_POLYGON_OFFSET_FILL
GL_PRIMITIVE_RESTART_FIXED_INDEX
GL_RASTERIZER_DISCARD
GL_SAMPLE_ALPHA_TO_COVERAGE
GL_SAMPLE_COVERAGE
GL_SCISSOR_TEST
GL_STENCIL_TEST
Later chapters will describe the specific state enables for each pipeline
stage shown in Figure 1-1. You can also check whether a state is currently
enabled or disabled by using the
gIisEnabled
command.
GLboolean
gIisEnabled
(GLenum cap)
Returns
GL_TRUE
or
GL_FALSE
depending on whether the state being
queried is enabled or disabled. Generates the error code
GL_INVALID_
ENUM
if
cap
is not a valid state enum.
Specific state values such as blend factor, depth test values, and so on can
also be queried using appropriate
glGet***
commands. These commands
are described in detail in Chapter 15, “State Queries.”
