📄 polygonmode.html
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<HTML><BODY><PRE> <STRONG>NAME</STRONG> <STRONG>glPolygonMode</STRONG> - select a polygon rasterization mode <STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG> void <STRONG>glPolygonMode</STRONG>( GLenum <EM>face</EM>, GLenum <EM>mode</EM> ) <STRONG>PARAMETERS</STRONG> <EM>face</EM> Specifies the polygons that <EM>mode</EM> applies to. Must be <STRONG>GL_FRONT</STRONG> for front-facing polygons, <STRONG>GL_BACK</STRONG> for back- facing polygons, or <STRONG>GL_FRONT_AND_BACK</STRONG> for front- and back-facing polygons. <EM>mode</EM> Specifies how polygons will be rasterized. Accepted values are <STRONG>GL_POINT</STRONG>, <STRONG>GL_LINE</STRONG>, and <STRONG>GL_FILL</STRONG>. The initial value is <STRONG>GL_FILL</STRONG> for both front- and back- facing polygons. <STRONG>DESCRIPTION</STRONG> <STRONG>glPolygonMode</STRONG> controls the interpretation of polygons for rasterization. <EM>face</EM> describes which polygons <EM>mode</EM> applies to: front-facing polygons (<STRONG>GL_FRONT</STRONG>), back-facing polygons (<STRONG>GL_BACK</STRONG>), or both (<STRONG>GL_FRONT_AND_BACK</STRONG>). The polygon mode affects only the final rasterization of polygons. In particular, a polygon's vertices are lit and the polygon is clipped and possibly culled before these modes are applied. Three modes are defined and can be specified in <EM>mode</EM>: <STRONG>GL_POINT</STRONG> Polygon vertices that are marked as the start of a boundary edge are drawn as points. Point attributes such as <STRONG>GL_POINT_SIZE</STRONG> and <STRONG>GL_POINT_SMOOTH</STRONG> control the rasterization of the points. Polygon rasterization attributes other than <STRONG>GL_POLYGON_MODE</STRONG> have no effect. <STRONG>GL_LINE</STRONG> Boundary edges of the polygon are drawn as line segments. They are treated as connected line segments for line stippling; the line stipple counter and pattern are not reset between segments (see <STRONG>glLineStipple</STRONG>). Line attributes such as <STRONG>GL_LINE_WIDTH</STRONG> and <STRONG>GL_LINE_SMOOTH</STRONG> control the rasterization of the lines. Polygon rasterization attributes other than <STRONG>GL_POLYGON_MODE</STRONG> have no effect. <STRONG>GL_FILL</STRONG> The interior of the polygon is filled. Polygon attributes such as <STRONG>GL_POLYGON_STIPPLE</STRONG> and <STRONG>GL_POLYGON_SMOOTH</STRONG> control the rasterization of the polygon. <STRONG>EXAMPLES</STRONG> To draw a surface with filled back-facing polygons and outlined front-facing polygons, call glPolygonMode(<STRONG>GL_FRONT</STRONG>, <STRONG>GL_LINE</STRONG>); <STRONG>NOTES</STRONG> Vertices are marked as boundary or nonboundary with an edge flag. Edge flags are generated internally by the GL when it decomposes polygons; they can be set explicitly using <STRONG>glEdgeFlag</STRONG>. <STRONG>ERRORS</STRONG> <STRONG>GL_INVALID_ENUM</STRONG> is generated if either <EM>face</EM> or <EM>mode</EM> is not an accepted value. <STRONG>GL_INVALID_OPERATION</STRONG> is generated if <STRONG>glPolygonMode</STRONG> is executed between the execution of <STRONG>glBegin</STRONG> and the corresponding execution of <STRONG>glEnd</STRONG>. <STRONG>ASSOCIATED</STRONG> <STRONG>GETS</STRONG> <STRONG>glGet</STRONG> with argument <STRONG>GL_POLYGON_MODE</STRONG> <STRONG>SEE</STRONG> <STRONG>ALSO</STRONG> <STRONG>glBegin</STRONG>, <STRONG>glEdgeFlag</STRONG>, <STRONG>glLineStipple</STRONG>, <STRONG>glLineWidth</STRONG>, <STRONG>glPointSize</STRONG>, <STRONG>glPolygonStipple</STRONG></PRE></BODY></HTML>⌨️ 快捷键说明
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