mirror of
https://github.com/QB64-Phoenix-Edition/QB64pe.git
synced 2024-07-03 15:51:20 +00:00
39 lines
1.8 KiB
Plaintext
39 lines
1.8 KiB
Plaintext
'''_glPolygonOffset:''' set the scale and units used to calculate depth values
|
|
|
|
|
|
{{PageSyntax}}
|
|
|
|
SUB _glPolygonOffset (BYVAL factor AS SINGLE, BYVAL units AS SINGLE)
|
|
void '''_glPolygonOffset'''(GLfloat {{Parameter|factor}}, GLfloat {{Parameter|units}});
|
|
|
|
|
|
; factor
|
|
: Specifies a scale factor that is used to create a variable depth offset for each polygon. The initial value is 0.
|
|
; units
|
|
: Is multiplied by an implementation-specific value to create a constant depth offset. The initial value is 0.
|
|
|
|
|
|
{{PageDescription}}
|
|
|
|
When {{KW|_GL_POLYGON_OFFSET_FILL}}, {{KW|_GL_POLYGON_OFFSET_LINE}}, or {{KW|_GL_POLYGON_OFFSET_POINT}} is enabled, each fragment's ''depth'' value will be offset after it is interpolated from the ''depth'' values of the appropriate vertices. The value of the offset is ''factor'' * ''DZ'' + ''r'' * ''units'', where ''DZ'' is a measurement of the change in depth relative to the screen area of the polygon, and ''r'' is the smallest value that is guaranteed to produce a resolvable offset for a given implementation. The offset is added before the depth test is performed and before the value is written into the depth buffer.
|
|
|
|
'''_glPolygonOffset''' is useful for rendering hidden-line images, for applying decals to surfaces, and for rendering solids with highlighted edges.
|
|
|
|
|
|
{{PageUseWith}}
|
|
|
|
{{KW|_glIsEnabled}} with argument {{KW|_GL_POLYGON_OFFSET_FILL}}, {{KW|_GL_POLYGON_OFFSET_LINE}}, or {{KW|_GL_POLYGON_OFFSET_POINT}}.
|
|
|
|
{{KW|_glGet}} with argument {{KW|_GL_POLYGON_OFFSET_FACTOR}} or {{KW|_GL_POLYGON_OFFSET_UNITS}}.
|
|
|
|
|
|
{{PageSeeAlso}}
|
|
|
|
[[_GL|SUB _GL]]
|
|
{{KW|_glDepthFunc}}, {{KW|_glEnable}}
|
|
|
|
|
|
{{PageCopyright}}
|
|
|
|
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/ http://oss.sgi.com/projects/FreeB/].
|