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Aliii

Polygons: clockwise or counterclockwise

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Aliii    1456

In OpenGL the "default direction" for triangles is CCW. Makes sense. However, ...is there a standard direction like that for line-strips/polygons? .....I have polygons that are built up from many triangles. It feels more natural to have the points of the line-strip ordered clockwise but I wanted to know if theres a standard for that or it doesnt matter.

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phil_t    8084

Winding order is used for culling backfaces. So that's why there needs to be an established convention. But you need at least 3 vertices to do that (to calculate a normal that indicates whether something faces in or out of the screen), so it doesn't really make sense for lines.

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Aliii    1456

Thanks. I was not precise. ....my English. I draw a polygon with the mouse. Which is practically a closed polyline/line-strip. Sometimes I need to reorder the points so the polygon is always "drawn" the same direction. (I dont draw the polygon directly, I build it up from triangles. The triangles are drawn CCW.) Should the points of the polygon ordered CW or CCW? 

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