HP b2600 Reference Manual page 21

GL_TRIANGLE_FAN
GL_QUADS
GL_QUAD_STRIP
GL_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).
Errors
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Chapter 2
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.
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.
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/21 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.
Draws a single, convex polygon. Vertices 1 through n define this
polygon.
GL_INVALID_ENUM is generated if mode is set to an unaccepted value.
GL_INVALID_OPERATION is generated if glBegin is executed between a glBegin
and the corresponding execution of glEnd.
GL_INVALID_OPERATION is generated if glEnd is executed without being
preceded by a glBegin.
GL_INVALID_OPERATION is generated if a command other than glVertex, glColor,
glIndex, glNormal, glTexCoord, glEvalCoord, glEvalPoint, glArrayElement,
glMaterial, glEdgeFlag, glCallList, or glCallLists is executed between the execution
of glBegin and the corresponding execution glEnd.
B
glBegin
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