openGL API之glPolygonOffset函数

openGL API之glPolygonOffset函数

openGL系列文章目录

文章目录

​​openGL系列文章目录​​​​glPolygonOffset官方文档​​​​一翻译​​

glPolygonOffset官方文档

​​glPolygonOffset官方文档地址​​​ Name glPolygonOffset — set the scale and units used to calculate depth values

C Specification void glPolygonOffset( GLfloat factor, GLfloat units);

Parameters 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.

Description When GL_POLYGON_OFFSET_FILL, GL_POLYGON_OFFSET_LINE, or 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.

Associated Gets glIsEnabled with argument GL_POLYGON_OFFSET_FILL, GL_POLYGON_OFFSET_LINE, or GL_POLYGON_OFFSET_POINT.

glGet with argument GL_POLYGON_OFFSET_FACTOR or GL_POLYGON_OFFSET_UNITS.

Version Support OpenGL Version Function / Feature Name 2.0 2.1 3.0 3.1 3.2 3.3 4.0 4.1 4.2 4.3 4.4 4.5 glPolygonOffset ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ See Also glDepthFunc, glEnable, glGet, glIsEnabled

Copyright Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2010-2014 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see glPolygonOffset - 设置用于计算深度值的比例和单位

C规范 void glPolygonOffset（GLfloat factor,

GLfloat units）;

1 参数 factor

指定用于为每个多边形创建变量深度偏移的比例因子。初始值为0。

units

乘以特定于实现的值以创建恒定的深度偏移。初始值为0。

描述 启用GL_POLYGON_OFFSET_FILL后，每个片段的深度值将在从相应顶点的深度值进行插值后进行偏移。偏移的值是factor×DZ + r×units，其中DZ是相对于多边形的屏幕区域的深度变化的度量，并且r是保证给定的可解析偏移的最小值实现。注意在执行深度测试并将值写入深度缓冲区之前添加偏移量。

glPolygonOffset可用于渲染隐藏线图像，将贴花应用于曲面以及渲染具有突出显示边的实体。（用于解决Z-fighting）

相关Gets glIsEnabled 参数GL_POLYGON_OFFSET_FILL。

glGet 参数GL_POLYGON_OFFSET_FACTOR或GL_POLYGON_OFFSET_UNITS。

另见 glDepthFunc，glEnable，glGet ，glIsEnabled

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