HP b2600 Reference Manual page 109

D
glDisable
This token enables HP's occlusion-testing extension. If any geometry is rendered while
occlusion culling is enabled, and if that geometry would be visible (i.e., rendering it
would affect the Z-buffer), the occlusion test state bit is set, indicating that the rendered
object is visible. This is typically done to increase performance: if every pixel of a
bounding box would be "behind" the current Z-buffer values for those pixels (i.e., the
bounding box is entirely occluded), anything you would draw within that bounding box
would also be behind the current Z values, and therefore you can cull it (i.e., avoid
processing that geometry through the pipeline). Note that this enable has no effect on
the current render mode, or any other OpenGL state.
GL_POINT_SMOOTH
If enabled, draw points with proper filtering. Otherwise, draw aliased points. See
glPointSize.
GL_POLYGON_OFFSET_FILL
If enabled, and if the polygon is rendered in GL_FILL mode, an offset is added to depth
values of a polygon's fragments before the depth comparison is performed. See
glPolygonOffset.
GL_POLYGON_OFFSET_LINE
If enabled, and if the polygon is rendered in GL_LINE mode, an offset is added to depth
values of a polygon's fragments before the depth comparison is performed. See
glPolygonOffset.
GL_POLYGON_OFFSET_POINT
If enabled, an offset is added to depth values of a polygon's fragments before the depth
comparison is performed, if the polygon is rendered in GL_POINT mode. See
glPolygonOffset.
GL_POLYGON_SMOOTH
If enabled, draw polygons with proper filtering. Otherwise, draw aliased polygons. For
correct anti-aliased polygons, an alpha buffer is needed and the polygons must be sorted
front to back.
GL_POLYGON_STIPPLE
If enabled, use the current polygon stipple pattern when rendering polygons. See
glPolygonStipple.
GL_RESCALE_NORMAL_EXT
When normal rescaling is enabled, a new operation is added to the transformation of the
normal vector into eye coordinates. The normal vector is rescaled after it is multiplied by
the inverse modelview matrix and before it is normalized. The rescale factor is chosen so
that in many cases normal vectors with unit length in object coordinates will not need to
be normalized as they are transformed into eye coordinates.
GL_SCISSOR_TEST
If enabled, discard fragments that are outside the scissor rectangle. See glScissor.
GL_STENCIL_TEST
If enabled, do stencil testing and update the stencil buffer. See glStencilFunc and
glStencilOp.
GL_TEXTURE_1D
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Chapter 4