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*mode*-
Specifies the primitive or primitives that will be created from vertices
presented between
**glBegin**and the subsequent**glEnd**. Ten symbolic constants are accepted:**GL_POINTS**,**GL_LINES**,**GL_LINE_STRIP**,**GL_LINE_LOOP**,**GL_TRIANGLES**,**GL_TRIANGLE_STRIP**,**GL_TRIANGLE_FAN**,**GL_QUADS**,**GL_QUAD_STRIP**, and**GL_POLYGON**.

**GL_POINTS**- Treats each vertex as a single point. Vertex $n$ defines point $n$. $N$ points are drawn.
**GL_LINES**- Treats each pair of vertices as an independent line segment. Vertices $2n^-^1$ and $2n$ define line $n$. $N/2$ lines are drawn.
**GL_LINE_STRIP**- Draws a connected group of line segments from the first vertex to the last. Vertices $n$ and $n~+~1$ define line $n$. $N^-^1$ lines are drawn.
**GL_LINE_LOOP**- Draws a connected group of line segments from the first vertex to the last, then back to the first. Vertices $n$ and $n~+~1$ define line $n$. The last line, however, is defined by vertices $N$ and $1$. $N$ lines are drawn.
**GL_TRIANGLES**- Treats each triplet of vertices as an independent triangle. Vertices $3n^-^2$, $3n^-^1$, and $3n$ define triangle $n$. $N/3$ triangles are drawn.
**GL_TRIANGLE_STRIP**- Draws a connected group of triangles. One triangle is defined for each vertex presented after the first two vertices. For odd $n$, vertices $n$, $n~+~1$, and $n~+~2$ define triangle $n$. For even $n$, vertices $n~+~1$, $n$, and $n~+~2$ define triangle $n$. $N^-^2$ triangles are drawn.
**GL_TRIANGLE_FAN**- Draws a connected group of triangles. One triangle is defined for each vertex presented after the first two vertices. Vertices $1$, $n~+~1$, and $n~+~2$ define triangle $n$. $N^-^2$ triangles are drawn.
**GL_QUADS**- Treats each group of four vertices as an independent quadrilateral. Vertices $4n^-^3$, $4n^-^2$, $4n^-^1$, and $4n$ define quadrilateral $n$. $N/4$ quadrilaterals are drawn.
**GL_QUAD_STRIP**- Draws a connected group of quadrilaterals. One quadrilateral is defined for each pair of vertices presented after the first pair. Vertices $2n^-^1$, $2n$, $2n~+~2$, and $2n~+~1$ define quadrilateral $n$. $N/2^-^1$ quadrilaterals are drawn. Note that the order in which vertices are used to construct a quadrilateral from strip data is different from that used with independent data.
**GL_POLYGON**-
Draws a single,
convex polygon.
Vertices $1$ through $N$ define this polygon.
Only a subset of GL commands can be used between
**glBegin**and**glEnd**. The commands are**glVertex**,**glColor**,**glIndex**,**glNormal**,**glTexCoord**,**glEvalCoord**,**glEvalPoint**,**glArrayElement**,**glMaterial**, and**glEdgeFlag**. Also, it is acceptable to use**glCallList**or**glCallLists**to execute display lists that include only the preceding commands. If any other GL command is executed between**glBegin**and**glEnd**, the error flag is set and the command is ignored. Regardless of the value chosen for*mode*, there is no limit to the number of vertices that can be defined between**glBegin**and**glEnd**. Lines, triangles, quadrilaterals, and polygons that are incompletely specified are not drawn. Incomplete specification results when either too few vertices are provided to specify even a single primitive or when an incorrect multiple of vertices is specified. The incomplete primitive is ignored; the rest are drawn. The minimum specification of vertices for each primitive is as follows: 1 for a point, 2 for a line, 3 for a triangle, 4 for a quadrilateral, and 3 for a polygon. Modes that require a certain multiple of vertices are**GL_LINES**(2),**GL_TRIANGLES**(3),**GL_QUADS**(4), and**GL_QUAD_STRIP**(2).

- NAME
- C SPECIFICATION
- PARAMETERS
- C SPECIFICATION
- DESCRIPTION
- ERRORS
- SEE ALSO